/*
Copyright (C) 1997-2001 Id Software, Inc.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

// sw_main.c
#include <limits.h>

#ifdef USE_SDL3
#include <SDL3/SDL.h>
#else
#include <SDL2/SDL.h>
#include <SDL2/SDL_video.h>
#endif

#include "header/local.h"

#define NUMSTACKEDGES		2048
#define NUMSTACKSURFACES	1024
#define MAXALIASVERTS		2048
#define MAXLIGHTS		1024 // allow some very large lightmaps

viddef_t	vid;
pixel_t		*vid_buffer = NULL;
static pixel_t	*swap_buffers = NULL;
static pixel_t	*swap_frames[2] = {NULL, NULL};
static int	swap_current = 0;
espan_t		*vid_polygon_spans = NULL;
pixel_t		*vid_colormap = NULL;
pixel_t		*vid_alphamap = NULL;
light_t		vid_lightthreshold = 0;
static int	vid_minu, vid_minv, vid_maxu, vid_maxv;
static int	vid_zminu, vid_zminv, vid_zmaxu, vid_zmaxv;
static qboolean IsHighDPIaware;

// last position  on map
static vec3_t	lastvieworg;
static vec3_t	lastviewangles;
qboolean	fastmoving;
static qboolean	palette_changed;

refimport_t	ri;

byte		d_8to24table[256 * 4];

vec3_t		skyaxis;

refdef_t	r_newrefdef;

model_t		*r_worldmodel;

pixel_t		*r_warpbuffer;

typedef struct swstate_s
{
	qboolean	fullscreen;
	int		prev_mode; // last valid SW mode

	unsigned char	gammatable[256];
	unsigned char	currentpalette[1024];
} swstate_t;

static swstate_t sw_state;

void	*colormap;
float	r_time1;
int	r_numallocatededges;
int	r_numallocatedverts;
int	r_numallocatedtriangles;
int	r_numallocatedlights;
int	r_numallocatededgebasespans;
float	r_aliasuvscale = 1.0;
qboolean	r_outofsurfaces;
qboolean	r_outofedges;
qboolean	r_outofverts;
qboolean	r_outoftriangles;
qboolean	r_outoflights;
qboolean	r_outedgebasespans;

qboolean	r_dowarp;

mvertex_t	*r_pcurrentvertbase;

int		c_surf;
static int	r_cnumsurfs;
int	r_clipflags;

//
// view origin
//
vec3_t	vup, base_vup;
vec3_t	vpn, base_vpn;
vec3_t	vright, base_vright;
vec3_t	r_origin;

//
// screen size info
//
oldrefdef_t	r_refdef;
float		xscale, yscale;
float		xscaleinv, yscaleinv;
float		xscaleshrink, yscaleshrink;
float		aliasxscale, aliasyscale, aliasxcenter, aliasycenter;

cplane_t	screenedge[4];

//
// refresh flags
//
int		r_framecount = 1;	// so frame counts initialized to 0 don't match
int		r_visframecount;
int		r_polycount;
int		r_drawnpolycount;

int		*pfrustum_indexes[4];
int			r_viewcluster, r_oldviewcluster;

image_t  	*r_notexture_mip;

float	da_time1, da_time2, dp_time1, dp_time2, db_time1, db_time2, rw_time1, rw_time2;
float	se_time1, se_time2, de_time1, de_time2;

cvar_t	*r_lefthand;
cvar_t	*r_gunfov;
cvar_t	*r_farsee;
cvar_t	*r_lightmap;
cvar_t	*r_colorlight;
static cvar_t	*sw_aliasstats;
cvar_t	*sw_clearcolor;
cvar_t	*sw_drawflat;
cvar_t	*sw_draworder;
static cvar_t  *r_mode;
cvar_t  *sw_stipplealpha;
cvar_t	*sw_surfcacheoverride;
cvar_t	*sw_waterwarp;
static cvar_t	*sw_overbrightbits;
cvar_t	*sw_custom_particles;
static cvar_t	*sw_anisotropic;
cvar_t	*sw_texture_filtering;
cvar_t	*r_retexturing;
cvar_t	*r_scale8bittextures;
cvar_t	*sw_gunzposition;
cvar_t	*r_validation;
static cvar_t	*sw_partialrefresh;

cvar_t	*r_drawworld;
static cvar_t	*r_drawentities;
static cvar_t	*r_dspeeds;
cvar_t	*r_fullbright;
cvar_t  *r_lerpmodels;
static cvar_t  *r_novis;
cvar_t  *r_modulate;
static cvar_t  *r_vsync;
static cvar_t  *r_customwidth;
static cvar_t  *r_customheight;

static cvar_t	*r_speeds;
cvar_t	*r_lightlevel;	//FIXME HACK
cvar_t	*r_fixsurfsky;

static cvar_t	*vid_fullscreen;
static cvar_t	*vid_gamma;

static cvar_t	*r_lockpvs;
static cvar_t	*r_palettedtexture;
cvar_t	*r_cull;

// sw_vars.c

// all global and static refresh variables are collected in a contiguous block
// to avoid cache conflicts.

//-------------------------------------------------------
// global refresh variables
//-------------------------------------------------------

// FIXME: make into one big structure, like cl or sv
// FIXME: do separately for refresh engine and driver


// d_vars.c

// all global and static refresh variables are collected in a contiguous block
// to avoid cache conflicts.

//-------------------------------------------------------
// global refresh variables
//-------------------------------------------------------

// FIXME: make into one big structure, like cl or sv
// FIXME: do separately for refresh engine and driver

float	d_sdivzstepu, d_tdivzstepu;
float	d_sdivzstepv, d_tdivzstepv;
float	d_sdivzorigin, d_tdivzorigin;

int	sadjust, tadjust, bbextents, bbextentt;

pixel_t		*cacheblock;
int		cachewidth;
pixel_t		*d_viewbuffer;
zvalue_t	*d_pzbuffer;

static void RE_BeginFrame( float camera_separation );
static void Draw_BuildGammaTable(void);
static void RE_FlushFrame(int vmin, int vmax);
static void RE_CleanFrame(void);
static void RE_EndFrame(void);
static void R_DrawBeam(const entity_t *e);

/*
================
VID_DamageZBuffer

Mark VID Z buffer as damaged and need to be recalculated
================
*/
void
VID_DamageZBuffer(int u, int v)
{
	// update U
	if (vid_zminu > u)
	{
		vid_zminu = u;
	}
	if (vid_zmaxu < u)
	{
		vid_zmaxu = u;
	}

	// update V
	if (vid_zminv > v)
	{
		vid_zminv = v;
	}
	if (vid_zmaxv < v)
	{
		vid_zmaxv = v;
	}
}

// clean z damage state
static void
VID_NoDamageZBuffer(void)
{
	vid_zminu = vid_buffer_width;
	vid_zmaxu = 0;
	vid_zminv = vid_buffer_height;
	vid_zmaxv = 0;
}

qboolean
VID_CheckDamageZBuffer(int u, int v, int ucount, int vcount)
{
	if (vid_zminv > (v + vcount) || vid_zmaxv < v)
	{
		// can be used previous zbuffer
		return false;
	}

	if (vid_zminu > u && vid_zminu > (u + ucount))
	{
		// can be used previous zbuffer
		return false;
	}

	if (vid_zmaxu < u && vid_zmaxu < (u + ucount))
	{
		// can be used previous zbuffer
		return false;
	}
	return true;
}

// Need to recalculate whole z buffer
static void
VID_WholeDamageZBuffer(void)
{
	vid_zminu = 0;
	vid_zmaxu = vid_buffer_width;
	vid_zminv = 0;
	vid_zmaxv = vid_buffer_height;
}

/*
================
VID_DamageBuffer

Mark VID buffer as damaged and need to be rewritten
================
*/
void
VID_DamageBuffer(int u, int v)
{
	// update U
	if (vid_minu > u)
	{
		vid_minu = u;
	}
	if (vid_maxu < u)
	{
		vid_maxu = u;
	}
	// update V
	if (vid_minv > v)
	{
		vid_minv = v;
	}
	if (vid_maxv < v)
	{
		vid_maxv = v;
	}
}

// clean damage state
static void
VID_NoDamageBuffer(void)
{
	vid_minu = vid_buffer_width;
	vid_maxu = 0;
	vid_minv = vid_buffer_height;
	vid_maxv = 0;
}

// Need to rewrite whole buffer
static void
VID_WholeDamageBuffer(void)
{
	vid_minu = 0;
	vid_maxu = vid_buffer_width;
	vid_minv = 0;
	vid_maxv = vid_buffer_height;
}

/*
================
R_InitTurb
================
*/
static void
R_InitTurb (int width)
{
	int		i;

	memset(blanktable, 0, (width+CYCLE) * sizeof(int));
	for (i = 0; i < (width+CYCLE); i++)
	{
		sintable[i] = AMP + sin(i*3.14159*2/CYCLE)*AMP;
		intsintable[i] = AMP2 + sin(i*3.14159*2/CYCLE)*AMP2; // AMP2, not 20
	}
}

void R_ImageList_f(void);
static void R_ScreenShot_f(void);

static void
R_RegisterVariables (void)
{
	sw_aliasstats = ri.Cvar_Get ("sw_polymodelstats", "0", 0);
	sw_clearcolor = ri.Cvar_Get ("sw_clearcolor", "2", 0);
	sw_drawflat = ri.Cvar_Get ("sw_drawflat", "0", 0);
	sw_draworder = ri.Cvar_Get ("sw_draworder", "0", 0);
	sw_mipcap = ri.Cvar_Get ("sw_mipcap", "0", 0);
	sw_mipscale = ri.Cvar_Get ("sw_mipscale", "1", 0);
	sw_stipplealpha = ri.Cvar_Get( "sw_stipplealpha", "0", CVAR_ARCHIVE );
	sw_surfcacheoverride = ri.Cvar_Get ("sw_surfcacheoverride", "0", 0);
	sw_waterwarp = ri.Cvar_Get ("sw_waterwarp", "1", 0);
	sw_overbrightbits = ri.Cvar_Get("sw_overbrightbits", "1.0", CVAR_ARCHIVE);
	sw_custom_particles = ri.Cvar_Get("sw_custom_particles", "0", CVAR_ARCHIVE);
	sw_texture_filtering = ri.Cvar_Get("sw_texture_filtering", "0", CVAR_ARCHIVE);
	sw_anisotropic = ri.Cvar_Get("r_anisotropic", "0", CVAR_ARCHIVE);
	r_retexturing = ri.Cvar_Get("r_retexturing", "1", CVAR_ARCHIVE);
	r_scale8bittextures = ri.Cvar_Get("r_scale8bittextures", "0", CVAR_ARCHIVE);
	sw_gunzposition = ri.Cvar_Get("sw_gunzposition", "8", CVAR_ARCHIVE);
	r_validation = ri.Cvar_Get("r_validation", "0", CVAR_ARCHIVE);

	// On MacOS texture is cleaned up after render and code have to copy a whole
	// screen to texture, other platforms save previous texture content and can be
	// copied only changed parts
#if defined(__APPLE__)
	sw_partialrefresh = ri.Cvar_Get("sw_partialrefresh", "0", CVAR_ARCHIVE);
#else
	sw_partialrefresh = ri.Cvar_Get("sw_partialrefresh", "1", CVAR_ARCHIVE);
#endif

	r_mode = ri.Cvar_Get( "r_mode", "0", CVAR_ARCHIVE );

	r_lefthand = ri.Cvar_Get( "hand", "0", CVAR_USERINFO | CVAR_ARCHIVE );
	r_gunfov = ri.Cvar_Get( "r_gunfov", "80", CVAR_ARCHIVE );
	r_farsee = ri.Cvar_Get("r_farsee", "0", CVAR_LATCH | CVAR_ARCHIVE);
	r_lightmap = ri.Cvar_Get("r_lightmap", "0", 0);
	r_colorlight = ri.Cvar_Get("sw_colorlight", "0", CVAR_ARCHIVE);
	r_speeds = ri.Cvar_Get ("r_speeds", "0", 0);
	r_fullbright = ri.Cvar_Get ("r_fullbright", "0", 0);
	r_drawentities = ri.Cvar_Get ("r_drawentities", "1", 0);
	r_drawworld = ri.Cvar_Get ("r_drawworld", "1", 0);
	r_dspeeds = ri.Cvar_Get ("r_dspeeds", "0", 0);
	r_lightlevel = ri.Cvar_Get ("r_lightlevel", "0", 0);
	r_lerpmodels = ri.Cvar_Get( "r_lerpmodels", "1", 0 );
	r_novis = ri.Cvar_Get( "r_novis", "0", 0 );
	r_modulate = ri.Cvar_Get("r_modulate", "1", CVAR_ARCHIVE);
	r_vsync = ri.Cvar_Get("r_vsync", "1", CVAR_ARCHIVE);
	r_customwidth = ri.Cvar_Get("r_customwidth", "1024", CVAR_ARCHIVE);
	r_customheight = ri.Cvar_Get("r_customheight", "768", CVAR_ARCHIVE);
	r_fixsurfsky = ri.Cvar_Get("r_fixsurfsky", "0", CVAR_ARCHIVE);
	r_palettedtexture = ri.Cvar_Get("r_palettedtexture", "0", 0);
	r_cull = ri.Cvar_Get("r_cull", "1", 0);

	vid_fullscreen = ri.Cvar_Get( "vid_fullscreen", "0", CVAR_ARCHIVE );
	vid_gamma = ri.Cvar_Get( "vid_gamma", "1.0", CVAR_ARCHIVE );

	ri.Cmd_AddCommand("modellist", Mod_Modellist_f);
	ri.Cmd_AddCommand("screenshot", R_ScreenShot_f);
	ri.Cmd_AddCommand("imagelist", R_ImageList_f);

	r_mode->modified = true; // force us to do mode specific stuff later
	vid_gamma->modified = true; // force us to rebuild the gamma table later
	sw_overbrightbits->modified = true; // force us to rebuild palette later

	r_lockpvs = ri.Cvar_Get ("r_lockpvs", "0", 0);
}

static void
R_UnRegister (void)
{
	ri.Cmd_RemoveCommand( "screenshot" );
	ri.Cmd_RemoveCommand( "modellist" );
	ri.Cmd_RemoveCommand( "imagelist" );
}

static void RE_ShutdownContext(void);
static void SWimp_CreateRender(int width, int height);
static int RE_InitContext(void *win);
static void RE_GetDrawableSize(int* width, int* height);
static qboolean RE_SetMode(void);

/*
===============
R_Init
===============
*/
static qboolean
RE_Init(void)
{
	R_RegisterVariables ();
	R_InitImages ();
	Mod_Init ();
	Draw_InitLocal ();

	view_clipplanes[0].leftedge = true;
	view_clipplanes[1].rightedge = true;
	view_clipplanes[1].leftedge = view_clipplanes[2].leftedge =
			view_clipplanes[3].leftedge = false;
	view_clipplanes[0].rightedge = view_clipplanes[2].rightedge =
			view_clipplanes[3].rightedge = false;

	r_refdef.xOrigin = XCENTERING;
	r_refdef.yOrigin = YCENTERING;

	r_aliasuvscale = 1.0;

	GetPCXPalette (&vid_colormap, (unsigned *)d_8to24table);
	vid_alphamap = vid_colormap + 64*256;

	/* set our "safe" mode */
	sw_state.prev_mode = 4;

	/* create the window and set up the context */
	if (!RE_SetMode())
	{
		R_Printf(PRINT_ALL, "%s() could not R_SetMode()\n", __func__);
		return false;
	}

	// create the window
	ri.Vid_MenuInit();

	R_Printf(PRINT_ALL, "ref_soft version: "REF_VERSION"\n");

	return true;
}

/*
===============
RE_Shutdown
===============
*/
static void
RE_Shutdown (void)
{
	// free z buffer
	if (d_pzbuffer)
	{
		free (d_pzbuffer);
		d_pzbuffer = NULL;
	}
	// free surface cache
	if (sc_base)
	{
		D_FlushCaches ();
		free (sc_base);
		sc_base = NULL;
	}

	// free colormap
	if (vid_colormap)
	{
		free (vid_colormap);
		vid_colormap = NULL;
	}

	R_UnRegister ();
	Mod_FreeAll ();
	R_ShutdownImages ();

	RE_ShutdownContext();
}

/*
===============
R_NewMap
===============
*/
void
R_NewMap (void)
{
	r_viewcluster = -1;
}

static surf_t	*lsurfs;

/*
===============
R_ReallocateMapBuffers
===============
*/
static void
R_ReallocateMapBuffers (void)
{
	if (!r_cnumsurfs || r_outofsurfaces)
	{
		if(lsurfs)
		{
			free(lsurfs);
		}

		if (r_outofsurfaces)
		{
			r_cnumsurfs *= 2;
			r_outofsurfaces = false;
		}

		if ((r_farsee->value > 0) && (r_cnumsurfs < NUMSTACKSURFACES))
			r_cnumsurfs = NUMSTACKSURFACES * 2;
		else if (r_cnumsurfs < NUMSTACKSURFACES)
			r_cnumsurfs = NUMSTACKSURFACES;

		// edge_t->surf limited size to short
		if (r_cnumsurfs > SURFINDEX_MAX)
		{
			r_cnumsurfs = SURFINDEX_MAX;
			R_Printf(PRINT_ALL, "%s: Code has limitation to surfaces count.\n",
				 __func__);
		}

		lsurfs = malloc (r_cnumsurfs * sizeof(surf_t));
		if (!lsurfs)
		{
			R_Printf(PRINT_ALL, "%s: Couldn't malloc %d bytes\n",
				 __func__, (int)(r_cnumsurfs * sizeof(surf_t)));
			return;
		}

		surfaces = lsurfs;
		// set limits
		surf_max = &surfaces[r_cnumsurfs];
		// surface 0 doesn't really exist; it's just a dummy because index 0
		// is used to indicate no edge attached to surface
		surfaces--;

		surface_p = &surfaces[2];	// background is surface 1,
						//  surface 0 is a dummy

		R_Printf(PRINT_ALL, "Allocated %d surfaces.\n", r_cnumsurfs);
	}

	if (!r_numallocatedlights || r_outoflights)
	{
		free(blocklights);

		if (r_outoflights)
		{
			r_numallocatedlights *= 2;
			r_outoflights = false;
		}

		if (r_numallocatedlights < MAXLIGHTS)
			r_numallocatedlights = MAXLIGHTS;

		blocklights = malloc (r_numallocatedlights * sizeof(light_t));
		if (!blocklights)
		{
			R_Printf(PRINT_ALL, "%s: Couldn't malloc %d bytes\n",
				 __func__, (int)(r_numallocatedlights * sizeof(light_t)));
			return;
		}

		// set limits
		blocklight_max = &blocklights[r_numallocatedlights];

		R_Printf(PRINT_ALL, "Allocated %d lights.\n", r_numallocatedlights);
	}

	if (!r_numallocatededges || r_outofedges)
	{
		free(r_edges);

		if (r_outofedges)
		{
			r_numallocatededges *= 2;
			r_outofedges = false;
		}

		if ((r_farsee->value > 0) && (r_numallocatededges < NUMSTACKEDGES * 2))
			r_numallocatededges = NUMSTACKEDGES * 2;
		else if (r_numallocatededges < NUMSTACKEDGES)
			r_numallocatededges = NUMSTACKEDGES;

		r_edges = malloc (r_numallocatededges * sizeof(edge_t));
		if (!r_edges)
		{
			R_Printf(PRINT_ALL, "%s: Couldn't malloc %d bytes\n",
				 __func__, (int)(r_numallocatededges * sizeof(edge_t)));
			return;
		}

		// set limits
		edge_max = &r_edges[r_numallocatededges];
		edge_p = r_edges;

		R_Printf(PRINT_ALL, "Allocated %d edges.\n", r_numallocatededges);
	}

	if (!r_numallocatedverts || r_outofverts)
	{
		if (finalverts)
		{
			free(finalverts);
		}

		if (r_outofverts)
		{
			r_numallocatedverts *= 2;
			r_outofverts = false;
		}

		if (r_numallocatedverts < MAXALIASVERTS)
			r_numallocatedverts = MAXALIASVERTS;

		finalverts = malloc(r_numallocatedverts * sizeof(finalvert_t));
		if (!finalverts)
		{
			R_Printf(PRINT_ALL, "%s: Couldn't malloc %d bytes\n",
				 __func__, (int)(r_numallocatedverts * sizeof(finalvert_t)));
			return;
		}
		finalverts_max = &finalverts[r_numallocatedverts];

		R_Printf(PRINT_ALL, "Allocated %d verts.\n", r_numallocatedverts);
	}

	if (!r_numallocatedtriangles || r_outoftriangles)
	{
		if (triangle_spans)
		{
			free(triangle_spans);
		}

		if (r_outoftriangles)
		{
			r_numallocatedtriangles *= 2;
			r_outoftriangles = false;
		}

		// one more for the terminator
		if (r_numallocatedtriangles < vid.height+1)
			r_numallocatedtriangles = vid.height+1;

		triangle_spans  = malloc(r_numallocatedtriangles * sizeof(spanpackage_t));
		if (!triangle_spans)
		{
			R_Printf(PRINT_ALL, "%s: Couldn't malloc %d bytes\n",
				 __func__, (int)(r_numallocatedtriangles * sizeof(spanpackage_t)));
			return;
		}
		triangles_max = &triangle_spans[r_numallocatedtriangles];

		R_Printf(PRINT_ALL, "Allocated %d triangle spans.\n", r_numallocatedtriangles);
	}

	if (!r_numallocatededgebasespans || r_outedgebasespans)
	{
		if (edge_basespans)
		{
			free(edge_basespans);
		}

		if (r_outedgebasespans)
		{
			r_numallocatededgebasespans *= 2;
			r_outedgebasespans = false;
		}

		// used up to 8 * width spans for render, allocate once  before use
		if (r_numallocatededgebasespans < vid_buffer_width * 8)
			r_numallocatededgebasespans = vid_buffer_width * 8;

		edge_basespans  = malloc(r_numallocatededgebasespans * sizeof(espan_t));
		if (!edge_basespans)
		{
			R_Printf(PRINT_ALL, "%s: Couldn't malloc %d bytes\n",
				 __func__, (int)(r_numallocatededgebasespans * sizeof(espan_t)));
			return;
		}
		max_span_p = &edge_basespans[r_numallocatededgebasespans];

		R_Printf(PRINT_ALL, "Allocated %d edgespans.\n", r_numallocatededgebasespans);
	}
}


/*
===============
R_MarkLeaves

Mark the leaves and nodes that are in the PVS for the current
cluster
===============
*/
static void
R_MarkLeaves (void)
{
	const byte	*vis;
	mnode_t	*node;
	int		i;
	mleaf_t	*leaf;

	if (r_oldviewcluster == r_viewcluster && !r_novis->value && r_viewcluster != -1)
		return;

	// development aid to let you run around and see exactly where
	// the pvs ends
	if (r_lockpvs->value)
		return;

	r_visframecount++;
	r_oldviewcluster = r_viewcluster;

	if (r_novis->value || r_viewcluster == -1 || !r_worldmodel->vis)
	{
		// mark everything
		for (i=0 ; i<r_worldmodel->numleafs ; i++)
			r_worldmodel->leafs[i].visframe = r_visframecount;
		for (i=0 ; i<r_worldmodel->numnodes ; i++)
			r_worldmodel->nodes[i].visframe = r_visframecount;
		return;
	}

	vis = Mod_ClusterPVS (r_viewcluster, r_worldmodel);

	for (i=0,leaf=r_worldmodel->leafs ; i<r_worldmodel->numleafs ; i++, leaf++)
	{
		int cluster;

		cluster = leaf->cluster;
		if (cluster == -1)
			continue;
		if (vis[cluster>>3] & (1<<(cluster&7)))
		{
			node = (mnode_t *)leaf;
			do
			{
				if (node->visframe == r_visframecount)
					break;
				node->visframe = r_visframecount;
				node = node->parent;
			} while (node);
		}
	}
}

/*
** R_DrawNullModel
**
** IMPLEMENT THIS!
*/
static void
R_DrawNullModel(void)
{
}

/*
=============
R_DrawEntitiesOnList
=============
*/
static void
R_DrawEntitiesOnList (void)
{
	int			i;
	qboolean	translucent_entities = false;

	if (!r_drawentities->value)
		return;

	// all bmodels have already been drawn by the edge list
	for (i=0 ; i<r_newrefdef.num_entities ; i++)
	{
		entity_t *currententity = &r_newrefdef.entities[i];

		if ( currententity->flags & RF_TRANSLUCENT )
		{
			translucent_entities = true;
			continue;
		}

		if ( currententity->flags & RF_BEAM )
		{
			modelorg[0] = -r_origin[0];
			modelorg[1] = -r_origin[1];
			modelorg[2] = -r_origin[2];
			VectorCopy(vec3_origin, r_entorigin);
			R_DrawBeam(currententity);
		}
		else
		{
			const model_t *currentmodel = currententity->model;
			if (!currentmodel)
			{
				R_DrawNullModel();
				continue;
			}
			VectorCopy (currententity->origin, r_entorigin);
			VectorSubtract (r_origin, r_entorigin, modelorg);

			switch (currentmodel->type)
			{
			case mod_sprite:
				R_DrawSprite(currententity, currentmodel);
				break;

			case mod_alias:
				R_AliasDrawModel(currententity, currentmodel);
				break;

			case mod_brush:
				break;

			default:
				R_Printf(PRINT_ALL, "%s: Bad modeltype %d\n",
					__func__, currentmodel->type);
				return;
			}
		}
	}

	if ( !translucent_entities )
		return;

	for (i=0 ; i<r_newrefdef.num_entities ; i++)
	{
		entity_t *currententity = &r_newrefdef.entities[i];

		if ( !( currententity->flags & RF_TRANSLUCENT ) )
			continue;

		if ( currententity->flags & RF_BEAM )
		{
			modelorg[0] = -r_origin[0];
			modelorg[1] = -r_origin[1];
			modelorg[2] = -r_origin[2];
			VectorCopy(vec3_origin, r_entorigin);
			R_DrawBeam(currententity);
		}
		else
		{
			const model_t *currentmodel = currententity->model;
			if (!currentmodel)
			{
				R_DrawNullModel();
				continue;
			}
			VectorCopy (currententity->origin, r_entorigin);
			VectorSubtract (r_origin, r_entorigin, modelorg);

			switch (currentmodel->type)
			{
			case mod_sprite:
				R_DrawSprite(currententity, currentmodel);
				break;

			case mod_alias:
				R_AliasDrawModel(currententity, currentmodel);
				break;

			case mod_brush:
				break;

			default:
				R_Printf(PRINT_ALL, "%s: Bad modeltype %d\n",
					__func__, currentmodel->type);
				return;
			}
		}
	}
}


/*
=============
R_BmodelCheckBBox
=============
*/
static int
R_BmodelCheckBBox (const float *minmaxs)
{
	int i, clipflags;

	clipflags = 0;

	for (i=0 ; i<4 ; i++)
	{
		vec3_t acceptpt, rejectpt;
		int *pindex;
		float d;

		// generate accept and reject points
		// FIXME: do with fast look-ups or integer tests based on the sign bit
		// of the floating point values
		pindex = pfrustum_indexes[i];

		rejectpt[0] = minmaxs[pindex[0]];
		rejectpt[1] = minmaxs[pindex[1]];
		rejectpt[2] = minmaxs[pindex[2]];

		d = DotProduct (rejectpt, view_clipplanes[i].normal);
		d -= view_clipplanes[i].dist;

		if (d <= 0)
			return BMODEL_FULLY_CLIPPED;

		acceptpt[0] = minmaxs[pindex[3+0]];
		acceptpt[1] = minmaxs[pindex[3+1]];
		acceptpt[2] = minmaxs[pindex[3+2]];

		d = DotProduct (acceptpt, view_clipplanes[i].normal);
		d -= view_clipplanes[i].dist;

		if (d <= 0)
			clipflags |= (1<<i);
	}

	return clipflags;
}


/*
===================
R_FindTopnode

Find the first node that splits the given box
===================
*/
static mnode_t *
R_FindTopnode (vec3_t mins, vec3_t maxs)
{
	mnode_t *node;

	node = r_worldmodel->nodes;

	while (1)
	{
		cplane_t *splitplane;
		int sides;

		if (node->visframe != r_visframecount)
			return NULL;		// not visible at all

		if (node->contents != CONTENTS_NODE)
		{
			if (node->contents != CONTENTS_SOLID)
				return	node;	// we've reached a non-solid leaf, so it's
						//  visible and not BSP clipped
			return NULL;	// in solid, so not visible
		}

		splitplane = node->plane;
		sides = BOX_ON_PLANE_SIDE(mins, maxs, splitplane);

		if (sides == 3)
			return node;	// this is the splitter

		// not split yet; recurse down the contacted side
		if (sides & 1)
			node = node->children[0];
		else
			node = node->children[1];
	}
}


/*
=============
RotatedBBox

Returns an axially aligned box that contains the input box at the given rotation
=============
*/
static void
RotatedBBox (const vec3_t mins, const vec3_t maxs, vec3_t angles, vec3_t tmins, vec3_t tmaxs)
{
	vec3_t	tmp, v;
	int		i, j;
	vec3_t	forward, right, up;

	if (!angles[0] && !angles[1] && !angles[2])
	{
		VectorCopy (mins, tmins);
		VectorCopy (maxs, tmaxs);
		return;
	}

	for (i=0 ; i<3 ; i++)
	{
		tmins[i] = (vec_t)INT_MAX; // Set maximum values for world range
		tmaxs[i] = (vec_t)INT_MIN;  // Set minimal values for world range
	}

	AngleVectors (angles, forward, right, up);

	for ( i = 0; i < 8; i++ )
	{
		if ( i & 1 )
			tmp[0] = mins[0];
		else
			tmp[0] = maxs[0];

		if ( i & 2 )
			tmp[1] = mins[1];
		else
			tmp[1] = maxs[1];

		if ( i & 4 )
			tmp[2] = mins[2];
		else
			tmp[2] = maxs[2];


		VectorScale (forward, tmp[0], v);
		VectorMA (v, -tmp[1], right, v);
		VectorMA (v, tmp[2], up, v);

		for (j=0 ; j<3 ; j++)
		{
			if (v[j] < tmins[j])
				tmins[j] = v[j];
			if (v[j] > tmaxs[j])
				tmaxs[j] = v[j];
		}
	}
}

/*
=============
R_DrawBEntitiesOnList
=============
*/
static void
R_DrawBEntitiesOnList (void)
{
	int		i, clipflags;
	vec3_t		oldorigin;
	vec3_t		mins, maxs;
	float		minmaxs[6];
	mnode_t		*topnode;

	if (!r_drawentities->value)
		return;

	VectorCopy (modelorg, oldorigin);

	for (i=0 ; i<r_newrefdef.num_entities ; i++)
	{
		entity_t *currententity = &r_newrefdef.entities[i];
		const model_t *currentmodel = currententity->model;
		if ( currententity->flags & RF_BEAM )
			continue;
		if (!currentmodel)
			continue;
		if (currentmodel->nummodelsurfaces == 0)
			continue;	// clip brush only
		if (currentmodel->type != mod_brush)
			continue;
		// see if the bounding box lets us trivially reject, also sets
		// trivial accept status
		RotatedBBox (currentmodel->mins, currentmodel->maxs,
			currententity->angles, mins, maxs);
		VectorAdd (mins, currententity->origin, minmaxs);
		VectorAdd (maxs, currententity->origin, (minmaxs+3));

		clipflags = R_BmodelCheckBBox (minmaxs);
		if (clipflags == BMODEL_FULLY_CLIPPED)
			continue;	// off the edge of the screen

		topnode = R_FindTopnode (minmaxs, minmaxs+3);
		if (!topnode)
			continue;	// no part in a visible leaf

		VectorCopy (currententity->origin, r_entorigin);
		VectorSubtract (r_origin, r_entorigin, modelorg);

		r_pcurrentvertbase = currentmodel->vertexes;

		// FIXME: stop transforming twice
		R_RotateBmodel(currententity);

		// calculate dynamic lighting for bmodel
		R_PushDlights (currentmodel);

		if (topnode->contents == CONTENTS_NODE)
		{
			// not a leaf; has to be clipped to the world BSP
			r_clipflags = clipflags;
			R_DrawSolidClippedSubmodelPolygons(currententity, currentmodel, topnode);
		}
		else
		{
			// falls entirely in one leaf, so we just put all the
			// edges in the edge list and let 1/z sorting handle
			// drawing order
			R_DrawSubmodelPolygons(currententity, currentmodel, clipflags, topnode);
		}

		// put back world rotation and frustum clipping
		// FIXME: R_RotateBmodel should just work off base_vxx
		VectorCopy (base_vpn, vpn);
		VectorCopy (base_vup, vup);
		VectorCopy (base_vright, vright);
		VectorCopy (oldorigin, modelorg);
		R_TransformFrustum ();
	}
}

/*
================
R_EdgeDrawing

Render the map
================
*/
static void
R_EdgeDrawing (entity_t *currententity)
{
	if ( r_newrefdef.rdflags & RDF_NOWORLDMODEL )
		return;

	// Set function pointer pdrawfunc used later in this function
	R_BeginEdgeFrame ();
	edge_p = r_edges;
	surface_p = &surfaces[2];	// background is surface 1,
					//  surface 0 is a dummy

	if (r_dspeeds->value)
	{
		rw_time1 = SDL_GetTicks();
	}

	// Build the Global Edget Table
	// Also populate the surface stack and count # surfaces to render (surf_max is the max)
	R_RenderWorld (currententity);

	if (r_dspeeds->value)
	{
		rw_time2 = SDL_GetTicks();
		db_time1 = rw_time2;
	}

	R_DrawBEntitiesOnList ();

	if (r_dspeeds->value)
	{
		db_time2 = SDL_GetTicks();
		se_time1 = db_time2;
	}

	// Use the Global Edge Table to maintin the Active Edge Table: Draw the world as scanlines
	// Write the Z-Buffer (but no read)
	R_ScanEdges (currententity, surface_p);
}

//=======================================================================

static void	R_GammaCorrectAndSetPalette(const unsigned char *palette);

/*
=============
R_CalcPalette

=============
*/
static void
R_CalcPalette (void)
{
	static qboolean modified;
	byte	palette[256][4], *in, *out;
	int		i, j;
	float	alpha, one_minus_alpha;
	vec3_t	premult;
	int		v;

	alpha = r_newrefdef.blend[3];
	if (alpha <= 0)
	{
		if (modified)
		{	// set back to default
			modified = false;
			R_GammaCorrectAndSetPalette( d_8to24table );
			return;
		}
		return;
	}

	modified = true;
	if (alpha > 1)
		alpha = 1;

	premult[0] = r_newrefdef.blend[0]*alpha*255;
	premult[1] = r_newrefdef.blend[1]*alpha*255;
	premult[2] = r_newrefdef.blend[2]*alpha*255;

	one_minus_alpha = (1.0 - alpha);

	in = d_8to24table;
	out = palette[0];
	for (i=0 ; i<256 ; i++, in+=4, out+=4)
	{
		for (j=0 ; j<3 ; j++)
		{
			v = premult[j] + one_minus_alpha * in[j];
			if (v > 255)
				v = 255;
			out[j] = v;
		}
		out[3] = 255;
	}

	R_GammaCorrectAndSetPalette( ( const unsigned char * ) palette[0] );
}

//=======================================================================

static void
R_SetLightLevel (const entity_t *currententity)
{
	vec3_t		light;

	if ((r_newrefdef.rdflags & RDF_NOWORLDMODEL) || (!r_drawentities->value) || (!currententity))
	{
		r_lightlevel->value = 150.0;
		return;
	}

	// save off light value for server to look at (BIG HACK!)
	R_LightPoint (currententity, r_newrefdef.vieworg, light);
	r_lightlevel->value = 150.0 * light[0];
}

static int
VectorCompareRound(const vec3_t v1, const vec3_t v2)
{
	if ((int)(v1[0] - v2[0]) || (int)(v1[1] - v2[1]) || (int)(v1[2] - v2[2]))
	{
		return 0;
	}

	return 1;
}

cplane_t frustum[4];


/*
================
RE_RenderFrame

================
*/
static void
RE_RenderFrame (refdef_t *fd)
{
	r_newrefdef = *fd;
	entity_t	ent;

	if (!r_worldmodel && !( r_newrefdef.rdflags & RDF_NOWORLDMODEL ) )
	{
		ri.Sys_Error(ERR_FATAL, "%s: NULL worldmodel", __func__);
	}

	// Need to rerender whole frame
	VID_WholeDamageBuffer();

	VectorCopy (fd->vieworg, r_refdef.vieworg);
	VectorCopy (fd->viewangles, r_refdef.viewangles);

	// compare current position with old
	if (vid_buffer_width <= 640 ||
	    !VectorCompareRound(fd->vieworg, lastvieworg) ||
	    !VectorCompareRound(fd->viewangles, lastviewangles))
	{
		fastmoving = true;
	}
	else
	{
		fastmoving = false;
	}

	// save position for next check
	VectorCopy (fd->vieworg, lastvieworg);
	VectorCopy (fd->viewangles, lastviewangles);

	if (r_speeds->value || r_dspeeds->value)
		r_time1 = SDL_GetTicks();

	R_SetupFrame ();

	R_SetFrustum(vup, vpn, vright, r_origin, r_newrefdef.fov_x, r_newrefdef.fov_y,
		frustum);

	// Using the current view cluster (r_viewcluster), retrieve and decompress
	// the PVS (Potentially Visible Set)
	R_MarkLeaves ();	// done here so we know if we're in water

	// For each dlight_t* passed via r_newrefdef.dlights, mark polygons affected by a light.
	R_PushDlights (r_worldmodel);

	// TODO: rearrange code same as in GL*_DrawWorld?
	/* auto cycle the world frame for texture animation */
	memset(&ent, 0, sizeof(ent));
	ent.frame = (int)(r_newrefdef.time * 2);

	// Build the Global Edge Table and render it via the Active Edge Table
	// Render the map
	R_EdgeDrawing (&ent);

	if (r_dspeeds->value)
	{
		se_time2 = SDL_GetTicks();
		de_time1 = se_time2;
	}

	if (fastmoving)
	{
		// redraw all
		VID_WholeDamageZBuffer();
	}
	else
	{
		// No Z rewrite required
		VID_NoDamageZBuffer();
	}
	// Draw enemies, barrel etc...
	// Use Z-Buffer mostly in read mode only.
	R_DrawEntitiesOnList ();

	if (r_dspeeds->value)
	{
		de_time2 = SDL_GetTicks();
		dp_time1 = SDL_GetTicks();
	}

	// Duh !
	R_DrawParticles ();

	if (r_dspeeds->value)
		dp_time2 = SDL_GetTicks();

	// Perform pixel palette blending ia the pics/colormap.pcx lower part lookup table.
	R_DrawAlphaSurfaces(&ent);

	// Save off light value for server to look at (BIG HACK!)
	R_SetLightLevel (&ent);

	if (r_dowarp)
		D_WarpScreen ();

	if (r_dspeeds->value)
	{
		da_time1 = SDL_GetTicks();
		da_time2 = SDL_GetTicks();
	}

	// Modify the palette (when taking hit or pickup item) so all colors are modified
	R_CalcPalette ();

	if (sw_aliasstats->value)
		R_PrintAliasStats ();

	if (r_speeds->value)
		R_PrintTimes ();

	if (r_dspeeds->value)
		R_PrintDSpeeds ();

	R_ReallocateMapBuffers();
}

/*
** R_InitGraphics
*/
static void
R_InitGraphics( int width, int height )
{
	// free z buffer
	if ( d_pzbuffer )
	{
		free(d_pzbuffer);
		d_pzbuffer = NULL;
	}

	// free surface cache
	if ( sc_base )
	{
		D_FlushCaches();
		free(sc_base);
		sc_base = NULL;
	}

	d_pzbuffer = malloc(width * height * sizeof(zvalue_t));

	R_InitCaches();

	R_GammaCorrectAndSetPalette(d_8to24table);
}

static rserr_t	SWimp_SetMode(int *pwidth, int *pheight, int mode, int fullscreen);

/*
** RE_BeginFrame
*/
static void
RE_BeginFrame( float camera_separation )
{
	// pallete without changes
	palette_changed = false;
	// run without speed optimization
	fastmoving = false;

	while (r_vsync->modified)
	{
		RE_SetMode();
	}

	/*
	** rebuild the gamma correction palette if necessary
	*/
	if ( vid_gamma->modified || sw_overbrightbits->modified )
	{
		Draw_BuildGammaTable();
		R_GammaCorrectAndSetPalette(d_8to24table);
		// we need redraw everything
		VID_WholeDamageBuffer();
		// and backbuffer should be zeroed
		memset(swap_buffers + ((swap_current + 1)&1), 0,
			vid_buffer_height * vid_buffer_width * sizeof(pixel_t));

		vid_gamma->modified = false;
		sw_overbrightbits->modified = false;
	}
}

/*
==================
R_SetMode
==================
*/
static qboolean
RE_SetMode(void)
{
	int err;
	int fullscreen;

	fullscreen = (int)vid_fullscreen->value;

	r_vsync->modified = false;

	/* a bit hackish approach to enable custom resolutions:
	   Glimp_SetMode needs these values set for mode -1 */
	vid.width = r_customwidth->value;
	vid.height = r_customheight->value;

	/*
	** if this returns rserr_invalid_mode then it set previous resolution
	*/
	if ((err = SWimp_SetMode(&vid.width, &vid.height, r_mode->value, fullscreen)) == rserr_ok)
	{
		if (r_mode->value == -1)
		{
			sw_state.prev_mode = 4; /* safe default for custom mode */
		}
		else
		{
			sw_state.prev_mode = r_mode->value;
		}
	}
	else
	{
		if (err == rserr_invalid_mode)
		{
			R_Printf(PRINT_ALL, "%s() - invalid mode\n", __func__);

			if(r_mode->value == sw_state.prev_mode)
			{
				// trying again would result in a crash anyway, give up already
				// (this would happen if your initing fails at all and your resolution already was 640x480)
				return false;
			}

			ri.Cvar_SetValue("r_mode", sw_state.prev_mode);
			r_mode->modified = false;
		}

		/* try setting it back to something safe */
		if (SWimp_SetMode(&vid.width, &vid.height, sw_state.prev_mode, 0) != rserr_ok)
		{
			R_Printf(PRINT_ALL, "%s() - could not revert to safe mode\n", __func__);
			return false;
		}
	}

	return true;
}

/*
** R_GammaCorrectAndSetPalette
*/
static void
R_GammaCorrectAndSetPalette( const unsigned char *palette )
{
	int i;

	// Replace palette
	for ( i = 0; i < 256; i++ )
	{
		if (sw_state.currentpalette[i*4+0] != sw_state.gammatable[palette[i*4+2]] ||
			sw_state.currentpalette[i*4+1] != sw_state.gammatable[palette[i*4+1]] ||
			sw_state.currentpalette[i*4+2] != sw_state.gammatable[palette[i*4+0]])
		{
			sw_state.currentpalette[i*4+0] = sw_state.gammatable[palette[i*4+2]]; // blue
			sw_state.currentpalette[i*4+1] = sw_state.gammatable[palette[i*4+1]]; // green
			sw_state.currentpalette[i*4+2] = sw_state.gammatable[palette[i*4+0]]; // red

			sw_state.currentpalette[i*4+3] = 0xFF; // alpha
			palette_changed = true;
		}
	}
}

/*
** RE_SetPalette
*/
static void
RE_SetPalette(const unsigned char *palette)
{
	// clear screen to black to avoid any palette flash
	RE_CleanFrame();

	if (palette)
	{
		byte palette32[1024];
		int i;

		for ( i = 0; i < 256; i++ )
		{
			palette32[i*4+0] = palette[i*3+0];
			palette32[i*4+1] = palette[i*3+1];
			palette32[i*4+2] = palette[i*3+2];
			palette32[i*4+3] = 0xFF;
		}

		R_GammaCorrectAndSetPalette( palette32 );
	}
	else
	{
		R_GammaCorrectAndSetPalette(d_8to24table);
	}
}

/*
================
Draw_BuildGammaTable
================
*/
static void
Draw_BuildGammaTable (void)
{
	int i;
	float	g;
	float	overbright;

	overbright = sw_overbrightbits->value;

	if(overbright < 0.5)
		overbright = 0.5;

	if(overbright > 4.0)
		overbright = 4.0;

	g = (2.1 - vid_gamma->value);

	if (g == 1.0)
	{
		for (i=0 ; i<256 ; i++) {
			int inf;

			inf = i * overbright;

			if (inf < 0)
				inf = 0;
			if (inf > 255)
				inf = 255;

			sw_state.gammatable[i] = inf;
		}
	}
	else
		for (i=0 ; i<256 ; i++)
		{
			int inf;

			inf = (255 * pow ( (i+0.5)/255.5 , g ) + 0.5) * overbright;
			if (inf < 0)
				inf = 0;
			if (inf > 255)
				inf = 255;
			sw_state.gammatable[i] = inf;
		}
}

/*
** R_DrawBeam
*/
static void
R_DrawBeam(const entity_t *e)
{
#define NUM_BEAM_SEGS 6

	int	i;

	vec3_t perpvec;
	vec3_t direction, normalized_direction;
	vec3_t start_points[NUM_BEAM_SEGS], end_points[NUM_BEAM_SEGS];
	vec3_t oldorigin, origin;

	oldorigin[0] = e->oldorigin[0];
	oldorigin[1] = e->oldorigin[1];
	oldorigin[2] = e->oldorigin[2];

	origin[0] = e->origin[0];
	origin[1] = e->origin[1];
	origin[2] = e->origin[2];

	normalized_direction[0] = direction[0] = oldorigin[0] - origin[0];
	normalized_direction[1] = direction[1] = oldorigin[1] - origin[1];
	normalized_direction[2] = direction[2] = oldorigin[2] - origin[2];

	if ( VectorNormalize( normalized_direction ) == 0 )
		return;

	PerpendicularVector( perpvec, normalized_direction );
	VectorScale( perpvec, e->frame / 2, perpvec );

	for ( i = 0; i < NUM_BEAM_SEGS; i++ )
	{
		RotatePointAroundVector( start_points[i], normalized_direction, perpvec, (360.0/NUM_BEAM_SEGS)*i );
		VectorAdd( start_points[i], origin, start_points[i] );
		VectorAdd( start_points[i], direction, end_points[i] );
	}

	for ( i = 0; i < NUM_BEAM_SEGS; i++ )
	{
		R_IMFlatShadedQuad( start_points[i],
				    end_points[i],
				    end_points[(i+1)%NUM_BEAM_SEGS],
				    start_points[(i+1)%NUM_BEAM_SEGS],
				    e->skinnum & 0xFF,
				    e->alpha );
	}
}


//===================================================================

/*
============
RE_SetSky
============
*/
// 3dstudio environment map names
static const char	*suf[6] = {"rt", "bk", "lf", "ft", "up", "dn"};
static const int	r_skysideimage[6] = {5, 2, 4, 1, 0, 3};
extern mtexinfo_t		r_skytexinfo[6];

static void
RE_SetSky (const char *name, float rotate, vec3_t axis)
{
	char	skyname[MAX_QPATH];
	int		i;

	Q_strlcpy (skyname, name, sizeof(skyname));
	VectorCopy (axis, skyaxis);

	for (i=0 ; i<6 ; i++)
	{
		image_t	*image;

		image = (image_t *)GetSkyImage(skyname, suf[r_skysideimage[i]],
			r_palettedtexture->value, (findimage_t)R_FindImage);

		if (!image)
		{
			R_Printf(PRINT_ALL, "%s: can't load %s:%s sky\n",
				__func__, skyname, suf[r_skysideimage[i]]);
			image = r_notexture_mip;
		}

		r_skytexinfo[i].image = image;
	}
}

/*
===============
RE_RegisterSkin
===============
*/
static struct image_s *
RE_RegisterSkin (const char *name)
{
	return R_FindImage (name, it_skin);
}

void R_Printf(int level, const char* msg, ...)
{
	va_list argptr;
	va_start(argptr, msg);
	ri.Com_VPrintf(level, msg, argptr);
	va_end(argptr);
}

static qboolean
RE_IsVsyncActive(void)
{
	if (r_vsync->value)
	{
		return true;
	}
	else
	{
		return false;
	}
}

static int RE_PrepareForWindow(void)
{
	return 0;
}

/*
=====================
RE_EndWorldRenderpass
=====================
*/
static qboolean
RE_EndWorldRenderpass( void )
{
	return true;
}

/*
===============
GetRefAPI
===============
*/
Q2_DLL_EXPORTED refexport_t
GetRefAPI(refimport_t imp)
{
	// struct for save refexport callbacks, copy of re struct from main file
	// used different variable name for prevent confusion and cppcheck warnings
	refexport_t	refexport;

	// Need to communicate the SDL major version to the client.
#ifdef USE_SDL3
	int version = SDL_VERSIONNUM_MAJOR(SDL_GetVersion());
#else
	SDL_version ver;
	SDL_VERSION(&ver);
	int version = ver.major;
#endif

	memset(&refexport, 0, sizeof(refexport_t));
	ri = imp;

	refexport.api_version = API_VERSION;
	refexport.framework_version = version;

	refexport.BeginRegistration = RE_BeginRegistration;
	refexport.RegisterModel = RE_RegisterModel;
	refexport.RegisterSkin = RE_RegisterSkin;
	refexport.DrawFindPic = RE_Draw_FindPic;
	refexport.SetSky = RE_SetSky;
	refexport.EndRegistration = RE_EndRegistration;

	refexport.RenderFrame = RE_RenderFrame;

	refexport.DrawGetPicSize = RE_Draw_GetPicSize;

	refexport.DrawPicScaled = RE_Draw_PicScaled;
	refexport.DrawStretchPic = RE_Draw_StretchPic;
	refexport.DrawCharScaled = RE_Draw_CharScaled;
	refexport.DrawTileClear = RE_Draw_TileClear;
	refexport.DrawFill = RE_Draw_Fill;
	refexport.DrawFadeScreen = RE_Draw_FadeScreen;

	refexport.DrawStretchRaw = RE_Draw_StretchRaw;

	refexport.Init = RE_Init;
	refexport.IsVSyncActive = RE_IsVsyncActive;
	refexport.Shutdown = RE_Shutdown;
	refexport.InitContext = RE_InitContext;
	refexport.GetDrawableSize = RE_GetDrawableSize;
	refexport.ShutdownContext = RE_ShutdownContext;
	refexport.PrepareForWindow = RE_PrepareForWindow;

	refexport.SetPalette = RE_SetPalette;
	refexport.BeginFrame = RE_BeginFrame;
	refexport.EndWorldRenderpass = RE_EndWorldRenderpass;
	refexport.EndFrame = RE_EndFrame;

    // Tell the client that we're unsing the
	// new renderer restart API.
    ri.Vid_RequestRestart(RESTART_NO);

	Swap_Init ();

	return refexport;
}

/*
 * FIXME: The following functions implement the render backend
 * through SDL renderer. Only small parts belong here, refresh.c
 * (at client side) needs to grow support funtions for software
 * renderers and the renderer must use them. What's left here
 * should be moved to a new file sw_sdl.c.
 *
 * Very, very problematic is at least the SDL initalization and
 * window creation in this code. That is guaranteed to clash with
 * the GL renderers (when switching GL -> Soft or the other way
 * round) and works only by pure luck. And only as long as there
 * is only one software renderer.
 */

static SDL_Window	*window = NULL;
static SDL_Texture	*texture = NULL;
static SDL_Renderer	*renderer = NULL;

int vid_buffer_height = 0;
int vid_buffer_width = 0;

static int
RE_InitContext(void *win)
{
	char title[40] = {0};

	if(win == NULL)
	{
		ri.Sys_Error(ERR_FATAL, "%s() must not be called with NULL argument!", __func__);
		return false;
	}

	window = (SDL_Window *)win;

	/* Window title - set here so we can display renderer name in it */
	snprintf(title, sizeof(title), "Yamagi Quake II %s - Soft Render", YQ2VERSION);
	SDL_SetWindowTitle(window, title);

	if (r_vsync->value)
	{
#ifdef USE_SDL3
		renderer = SDL_CreateRenderer(window, NULL);
		SDL_SetRenderVSync(renderer, 1);
#else
		renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
                if(!renderer)
                {
                	renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_SOFTWARE | SDL_RENDERER_PRESENTVSYNC);
                }
#endif
	}
	else
	{
#ifdef USE_SDL3
		renderer = SDL_CreateRenderer(window, NULL);
#else
		renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
                if(!renderer)
                {
                	renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_SOFTWARE);
                }
#endif
	}
	if(!renderer) {
		Com_Printf("Can't create renderer: %s\n", SDL_GetError());
		return false;
	}

	/* Select the color for drawing. It is set to black here. */
	SDL_SetRenderDrawColor(renderer, 0, 0, 0, 0);

	/* Clear the entire screen to our selected color. */
	SDL_RenderClear(renderer);

	/* Up until now everything was drawn behind the scenes.
	   This will show the new, black contents of the window. */
	SDL_RenderPresent(renderer);

#if SDL_VERSION_ATLEAST(2, 26, 0)
	// Figure out if we are high dpi aware.
	int flags = SDL_GetWindowFlags(win);
#ifdef USE_SDL3
	IsHighDPIaware = (flags & SDL_WINDOW_HIGH_PIXEL_DENSITY) ? true : false;
#else
	IsHighDPIaware = (flags & SDL_WINDOW_ALLOW_HIGHDPI) ? true : false;
#endif
#endif

	/* We can't rely on vid, because the context is created
	   before we had a chance to overwrite it with the drawable
	   size. */
	if (IsHighDPIaware)
	{
		RE_GetDrawableSize(&vid_buffer_width, &vid_buffer_height);
	}
	else
	{
		vid_buffer_height = vid.height;
		vid_buffer_width = vid.width;
	}

	texture = SDL_CreateTexture(renderer,
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
				    SDL_PIXELFORMAT_BGRA8888,
#else
				    SDL_PIXELFORMAT_ARGB8888,
#endif
				    SDL_TEXTUREACCESS_STREAMING,
				    vid_buffer_width, vid_buffer_height);
	if(!texture) {
		Com_Printf("Can't create texture: %s\n", SDL_GetError());
		return false;
	}
	R_InitGraphics(vid_buffer_width, vid_buffer_height);
	SWimp_CreateRender(vid_buffer_width, vid_buffer_height);

	return true;
}

/*
 * Fills the actual size of the drawable into width and height.
 */
void RE_GetDrawableSize(int* width, int* height)
{
#ifdef USE_SDL3
	SDL_GetCurrentRenderOutputSize(renderer, width, height);
#else
	SDL_GetRendererOutputSize(renderer, width, height);
#endif
}


static void
RE_ShutdownContext(void)
{
	if (swap_buffers)
	{
		free(swap_buffers);
	}
	swap_buffers = NULL;
	vid_buffer = NULL;
	swap_frames[0] = NULL;
	swap_frames[1] = NULL;

	if (sintable)
	{
		free(sintable);
	}
	sintable = NULL;

	if (intsintable)
	{
		free(intsintable);
	}
	intsintable = NULL;

	if (blanktable)
	{
		free(blanktable);
	}
	blanktable = NULL;

	if (vid_polygon_spans)
	{
		free(vid_polygon_spans);
	}
	vid_polygon_spans = NULL;

	if (newedges)
	{
		free(newedges);
	}
	newedges = NULL;

	if (removeedges)
	{
		free(removeedges);
	}
	removeedges = NULL;

	if (triangle_spans)
	{
		free(triangle_spans);
	}
	triangle_spans = NULL;

	if (warp_rowptr)
	{
		free(warp_rowptr);
	}
	warp_rowptr = NULL;

	if (warp_column)
	{
		free(warp_column);
	}
	warp_column = NULL;

	if (edge_basespans)
	{
		free(edge_basespans);
	}
	edge_basespans = NULL;

	if (finalverts)
	{
		free(finalverts);
	}
	finalverts = NULL;

	if(blocklights)
	{
		free(blocklights);
	}
	blocklights = NULL;

	if(r_edges)
	{
		free(r_edges);
	}
	r_edges = NULL;

	if(lsurfs)
	{
		free(lsurfs);
	}
	lsurfs = NULL;

	if(r_warpbuffer)
	{
		free(r_warpbuffer);
	}
	r_warpbuffer = NULL;

	if (texture)
	{
		SDL_DestroyTexture(texture);
	}
	texture = NULL;

	if (renderer)
	{
		SDL_DestroyRenderer(renderer);
	}
	renderer = NULL;
}

/*
be careful if you ever want to change width: 12.20 fixed
point math used in R_ScanEdges() overflows at width 2048 !!
*/
char shift_size;

static void
RE_CopyFrame (Uint32 * pixels, int pitch, int vmin, int vmax)
{
	Uint32 *sdl_palette = (Uint32 *)sw_state.currentpalette;

	// no gaps between images rows
	if (pitch == vid_buffer_width)
	{
		const Uint32	*max_pixels;
		Uint32	*pixels_pos;
		pixel_t	*buffer_pos;

		max_pixels = pixels + vmax;
		buffer_pos = vid_buffer + vmin;

		pixels_pos = pixels + vmin;

		while ( pixels_pos < max_pixels)
		{
			*pixels_pos = sdl_palette[*buffer_pos];
			buffer_pos++;
			pixels_pos++;
		}
	}
	else
	{
		int y,x, buffer_pos, ymin, ymax;

		ymin = vmin / vid_buffer_width;
		ymax = vmax / vid_buffer_width;

		buffer_pos = ymin * vid_buffer_width;
		pixels += ymin * pitch;
		for (y=ymin; y < ymax;  y++)
		{
			for (x=0; x < vid_buffer_width; x ++)
			{
				pixels[x] = sdl_palette[vid_buffer[buffer_pos + x]];
			}
			pixels += pitch;
			buffer_pos += vid_buffer_width;
		}
	}
}

static int
RE_BufferDifferenceStart(int vmin, int vmax)
{
	int *front_buffer, *back_buffer, *back_max;

	back_buffer = (int*)(swap_frames[0] + vmin);
	front_buffer = (int*)(swap_frames[1] + vmin);
	back_max = (int*)(swap_frames[0] + vmax);

	while (back_buffer < back_max && *back_buffer == *front_buffer) {
		back_buffer ++;
		front_buffer ++;
	}
	return (pixel_t*)back_buffer - swap_frames[0];
}

static size_t
RE_BufferDifferenceEnd(int vmin, int vmax)
{
	int *front_buffer, *back_buffer, *back_min;

	back_buffer = (int*)(swap_frames[0] + vmax);
	front_buffer = (int*)(swap_frames[1] + vmax);
	back_min = (int*)(swap_frames[0] + vmin);

	do {
		back_buffer --;
		front_buffer --;
	} while (back_buffer > back_min && *back_buffer == *front_buffer);
	// +1 for fully cover changes
	return (pixel_t*)back_buffer - swap_frames[0] + sizeof(int);
}

static void
RE_CleanFrame(void)
{
	int pitch;
	Uint32 *pixels;

	memset(swap_buffers, 0,
		vid_buffer_height * vid_buffer_width * sizeof(pixel_t) * 2);

#ifdef USE_SDL3
	if (!SDL_LockTexture(texture, NULL, (void**)&pixels, &pitch))
#else
	if (SDL_LockTexture(texture, NULL, (void**)&pixels, &pitch))
#endif
	{
		Com_Printf("Can't lock texture: %s\n", SDL_GetError());
		return;
	}

	// only cleanup texture without flush texture to screen
	memset(pixels, 0, pitch * vid_buffer_height);
	SDL_UnlockTexture(texture);

	// All changes flushed
	VID_NoDamageBuffer();
}

static void
RE_FlushFrame(int vmin, int vmax)
{
	int pitch;
	Uint32 *pixels;

#ifdef USE_SDL3
	if (!SDL_LockTexture(texture, NULL, (void**)&pixels, &pitch))
#else
	if (SDL_LockTexture(texture, NULL, (void**)&pixels, &pitch))
#endif
	{
		Com_Printf("Can't lock texture: %s\n", SDL_GetError());
		return;
	}
	if (sw_partialrefresh->value)
	{
		RE_CopyFrame (pixels, pitch / sizeof(Uint32), vmin, vmax);
	}
	else
	{
		// On MacOS texture is cleaned up after render,
		// code have to copy a whole screen to the texture
		RE_CopyFrame (pixels, pitch / sizeof(Uint32), 0, vid_buffer_height * vid_buffer_width);
	}

	if ((sw_anisotropic->value > 0) && !fastmoving)
	{
		SmoothColorImage(pixels + vmin, vmax - vmin, sw_anisotropic->value);
	}

	SDL_UnlockTexture(texture);

#ifdef USE_SDL3
	SDL_RenderTexture(renderer, texture, NULL, NULL);
#else
	SDL_RenderCopy(renderer, texture, NULL, NULL);
#endif

	SDL_RenderPresent(renderer);

	// replace use next buffer
	swap_current ++;
	vid_buffer = swap_frames[swap_current&1];

	// All changes flushed
	VID_NoDamageBuffer();
}

/*
** RE_EndFrame
**
** This does an implementation specific copy from the backbuffer to the
** front buffer.
*/
static void
RE_EndFrame (void)
{
	int vmin, vmax;

	// fix possible issue with min/max
	if (vid_minu < 0)
	{
		vid_minu = 0;
	}
	if (vid_minv < 0)
	{
		vid_minv = 0;
	}
	if (vid_maxu > vid_buffer_width)
	{
		vid_maxu = vid_buffer_width;
	}
	if (vid_maxv > vid_buffer_height)
	{
		vid_maxv = vid_buffer_height;
	}

	vmin = vid_minu + vid_minv  * vid_buffer_width;
	vmax = vid_maxu + vid_maxv  * vid_buffer_width;

	// fix to correct limit
	if (vmax > (vid_buffer_height * vid_buffer_width))
	{
		vmax = vid_buffer_height * vid_buffer_width;
	}

	// if palette changed need to flush whole buffer
	if (!palette_changed)
	{
		// search real begin/end of difference
		vmin = RE_BufferDifferenceStart(vmin, vmax);

		// no differences found
		if (vmin >= vmax)
		{
			return;
		}

		// search difference end
		vmax = RE_BufferDifferenceEnd(vmin, vmax);
		if (vmax > (vid_buffer_height * vid_buffer_width))
		{
			vmax = vid_buffer_height * vid_buffer_width;
		}
	}

	RE_FlushFrame(vmin, vmax);
}

/*
** SWimp_SetMode
*/
static rserr_t
SWimp_SetMode(int *pwidth, int *pheight, int mode, int fullscreen )
{
	rserr_t retval = rserr_ok;

	R_Printf (PRINT_ALL, "Setting mode %d:", mode );

	if ((mode >= 0) && !ri.Vid_GetModeInfo( pwidth, pheight, mode ) )
	{
		R_Printf(PRINT_ALL, " invalid mode\n");
		return rserr_invalid_mode;
	}

	/* We trying to get resolution from desktop */
	if (mode == -2)
	{
		if(!ri.GLimp_GetDesktopMode(pwidth, pheight))
		{
			R_Printf(PRINT_ALL, " can't detect mode\n");
			return rserr_invalid_mode;
		}
	}

	R_Printf(PRINT_ALL, " %dx%d (vid_fullscreen %i)\n", *pwidth, *pheight, fullscreen);

	if (fullscreen == 2)
	{
		int real_height, real_width;

		if(ri.GLimp_GetDesktopMode(&real_width, &real_height))
		{
			if (real_height)
			{
				if (real_height != *pheight)
				{
					*pwidth = ((*pheight) * real_width) / real_height;
				}
				else
				{
					*pwidth = real_width;
				}
			}
		}

		R_Printf(PRINT_ALL, "Used corrected %dx%d mode\n", *pwidth, *pheight);
	}

	if (!ri.GLimp_InitGraphics(fullscreen, pwidth, pheight))
	{
		// failed to set a valid mode in windowed mode
		return rserr_invalid_mode;
	}

	/* This is totaly obscure: For some strange reasons the renderer
	   maintains three(!) repesentations of the resolution. One comes
	   from the client and is saved in r_newrefdef. The other one
	   is determined here and saved in vid. The third one is used by
	   the backbuffer. Some calculations take all three representations
	   into account.

	   The values will always be the same. The GLimp_InitGraphics()
	   call above communicates the requested resolution to the client
	   where it ends up in the vid subsystem and the vid system writes
	   it into r_newrefdef. The backbuffer is derived from vid.

	   We can't avoid the client roundtrip, because we can get the
	   real size of the drawable (which can differ from the resolution
	   due to high dpi awareness) only after the render context was
	   created by GLimp_InitGraphics() and need to communicate it
	   somehow to the client. So we just overwrite the values saved
	   in vid with a call to RE_GetDrawableSize(), just like the
	   client does. This makes sure that both values are the same
	   and everything is okay.

	   We also need to take the special case fullscreen window into
	   account. With the fullscreen windows we cannot use the
	   drawable size, it would scale all cases to the size of the
	   window. Instead use the drawable size when the user wants
	   native resolution (the fullscreen window fills the screen)
	   and use the requested resolution in all other cases. */
	if (IsHighDPIaware)
	{
		if (vid_fullscreen->value != 2)
		{
			RE_GetDrawableSize(pwidth, pheight);
		}
		else
		{
			if (r_mode->value == -2)
			{
				/* User requested native resolution. */
				RE_GetDrawableSize(pwidth, pheight);
			}
		}
	}
	return retval;
}

static void
SWimp_CreateRender(int width, int height)
{
	swap_current = 0;
	swap_buffers = malloc(height * width * sizeof(pixel_t) * 2);
	if (!swap_buffers)
	{
		ri.Sys_Error(ERR_FATAL, "%s: Can't allocate swapbuffer.", __func__);
		// code never returns after ERR_FATAL
		return;
	}
	swap_frames[0] = swap_buffers;
	swap_frames[1] = swap_buffers + height * width * sizeof(pixel_t);
	vid_buffer = swap_frames[swap_current&1];
	// Need to rewrite whole frame
	VID_WholeDamageBuffer();

	sintable = malloc((width+CYCLE) * sizeof(int));
	intsintable = malloc((width+CYCLE) * sizeof(int));
	blanktable = malloc((width+CYCLE) * sizeof(int));

	newedges = malloc(width * sizeof(edge_t *));
	removeedges = malloc(width * sizeof(edge_t *));

	warp_rowptr = malloc((width+AMP2*2) * sizeof(byte*));
	warp_column = malloc((width+AMP2*2) * sizeof(int));

	// count of "out of items"
	r_outofsurfaces = false;
	r_outofedges = false;
	r_outofverts = false;
	r_outoftriangles = false;
	r_outoflights = false;
	r_outedgebasespans = false;
	// pointers to allocated buffers
	finalverts = NULL;
	r_edges = NULL;
	lsurfs = NULL;
	triangle_spans = NULL;
	blocklights = NULL;
	edge_basespans = NULL;
	// curently allocated items
	r_cnumsurfs = 0;
	r_numallocatededges = 0;
	r_numallocatedverts = 0;
	r_numallocatedtriangles = 0;
	r_numallocatedlights = 0;
	r_numallocatededgebasespans = 0;

	R_ReallocateMapBuffers();

	r_warpbuffer = malloc(height * width * sizeof(pixel_t));

	// 2k+ resolution and 32 == shift20_t
	if ((width >= 2048) && (sizeof(shift20_t) == 4))
	{
		shift_size = 18;
	}
	else
	{
		shift_size = 20;
	}

	R_InitTurb (width);

	vid_polygon_spans = malloc(sizeof(espan_t) * (height + 1));

	memset(sw_state.currentpalette, 0, sizeof(sw_state.currentpalette));

	R_GammaCorrectAndSetPalette( d_8to24table );
}

// this is only here so the functions in q_shared.c and q_shwin.c can link
void
Sys_Error (const char *error, ...)
{
	va_list		argptr;
	char		text[4096]; // MAXPRINTMSG == 4096

	va_start(argptr, error);
	vsnprintf(text, sizeof(text), error, argptr);
	va_end(argptr);

	ri.Sys_Error (ERR_FATAL, "%s", text);
}

void
Com_Printf(const char *msg, ...)
{
	va_list	argptr;
	va_start(argptr, msg);
	ri.Com_VPrintf(PRINT_ALL, msg, argptr);
	va_end(argptr);
}

/*
==============================================================================

SCREEN SHOTS

==============================================================================
*/

/*
==================
R_ScreenShot_f
==================
*/
static void
R_ScreenShot_f(void)
{
	int x, y;
	byte *buffer = malloc(vid_buffer_width * vid_buffer_height * 3);
	const unsigned char *palette = sw_state.currentpalette;

	if (!buffer)
	{
		R_Printf(PRINT_ALL, "R_ScreenShot: Couldn't malloc %d bytes\n", vid_buffer_width * vid_buffer_height * 3);
		return;
	}

	for (x=0; x < vid_buffer_width; x ++)
	{
		for (y=0; y < vid_buffer_height; y ++) {
			int buffer_pos = y * vid_buffer_width + x;
			buffer[buffer_pos * 3 + 0] = palette[vid_buffer[buffer_pos] * 4 + 2]; // red
			buffer[buffer_pos * 3 + 1] = palette[vid_buffer[buffer_pos] * 4 + 1]; // green
			buffer[buffer_pos * 3 + 2] = palette[vid_buffer[buffer_pos] * 4 + 0]; // blue
		}
	}

	ri.Vid_WriteScreenshot(vid_buffer_width, vid_buffer_height, 3, buffer);

	free(buffer);
}
