/*
Copyright (C) 1996-2001 Id Software, Inc.
Copyright (C) 2002-2009 John Fitzgibbons and others
Copyright (C) 2007-2008 Kristian Duske
Copyright (C) 2010-2014 QuakeSpasm developers

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.
*/

//gl_texmgr.c -- fitzquake's texture manager. manages opengl texture images

#include "quakedef.h"

const int	gl_solid_format = 3;
const int	gl_alpha_format = 4;

static cvar_t	gl_texturemode = {"gl_texturemode", "", CVAR_ARCHIVE};
static cvar_t	gl_texture_anisotropy = {"gl_texture_anisotropy", "1", CVAR_ARCHIVE};
static cvar_t	gl_max_size = {"gl_max_size", "0", CVAR_NONE};
static cvar_t	gl_picmip = {"gl_picmip", "0", CVAR_NONE};
static GLint	gl_hardware_maxsize;

#define	MAX_GLTEXTURES	2048
static int numgltextures;
static gltexture_t	*active_gltextures, *free_gltextures;
gltexture_t		*notexture, *nulltexture;

unsigned int d_8to24table[256];
unsigned int d_8to24table_fbright[256];
unsigned int d_8to24table_fbright_fence[256];
unsigned int d_8to24table_nobright[256];
unsigned int d_8to24table_nobright_fence[256];
unsigned int d_8to24table_conchars[256];
unsigned int d_8to24table_shirt[256];
unsigned int d_8to24table_pants[256];

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

	COMMANDS

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

typedef struct
{
	int	magfilter;
	int	minfilter;
	const char  *name;
} glmode_t;
static glmode_t glmodes[] = {
	{GL_NEAREST, GL_NEAREST,		"GL_NEAREST"},
	{GL_NEAREST, GL_NEAREST_MIPMAP_NEAREST,	"GL_NEAREST_MIPMAP_NEAREST"},
	{GL_NEAREST, GL_NEAREST_MIPMAP_LINEAR,	"GL_NEAREST_MIPMAP_LINEAR"},
	{GL_LINEAR,  GL_LINEAR,			"GL_LINEAR"},
	{GL_LINEAR,  GL_LINEAR_MIPMAP_NEAREST,	"GL_LINEAR_MIPMAP_NEAREST"},
	{GL_LINEAR,  GL_LINEAR_MIPMAP_LINEAR,	"GL_LINEAR_MIPMAP_LINEAR"},
};
#define NUM_GLMODES (int)(sizeof(glmodes)/sizeof(glmodes[0]))
static int glmode_idx = NUM_GLMODES - 1; /* trilinear */

/*
===============
TexMgr_DescribeTextureModes_f -- report available texturemodes
===============
*/
static void TexMgr_DescribeTextureModes_f (void)
{
	int i;

	for (i = 0; i < NUM_GLMODES; i++)
		Con_SafePrintf ("   %2i: %s\n", i + 1, glmodes[i].name);

	Con_Printf ("%i modes\n", i);
}

/*
===============
TexMgr_SetFilterModes
===============
*/
static void TexMgr_SetFilterModes (gltexture_t *glt)
{
	GL_Bind (glt);

	if (glt->flags & TEXPREF_NEAREST)
	{
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	}
	else if (glt->flags & TEXPREF_LINEAR)
	{
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	}
	else if (glt->flags & TEXPREF_MIPMAP)
	{
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, glmodes[glmode_idx].magfilter);
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, glmodes[glmode_idx].minfilter);
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, gl_texture_anisotropy.value);
	}
	else
	{
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, glmodes[glmode_idx].magfilter);
		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, glmodes[glmode_idx].magfilter);
	}
}

/*
===============
TexMgr_TextureMode_f -- called when gl_texturemode changes
===============
*/
static void TexMgr_TextureMode_f (cvar_t *var)
{
	gltexture_t	*glt;
	int i;

	for (i = 0; i < NUM_GLMODES; i++)
	{
		if (!Q_strcmp (glmodes[i].name, gl_texturemode.string))
		{
			if (glmode_idx != i)
			{
				glmode_idx = i;
				for (glt = active_gltextures; glt; glt = glt->next)
					TexMgr_SetFilterModes (glt);
				Sbar_Changed (); //sbar graphics need to be redrawn with new filter mode
				//FIXME: warpimages need to be redrawn, too.
			}
			return;
		}
	}

	for (i = 0; i < NUM_GLMODES; i++)
	{
		if (!q_strcasecmp (glmodes[i].name, gl_texturemode.string))
		{
			Cvar_SetQuick (&gl_texturemode, glmodes[i].name);
			return;
		}
	}

	i = atoi(gl_texturemode.string);
	if (i >= 1 && i <= NUM_GLMODES)
	{
		Cvar_SetQuick (&gl_texturemode, glmodes[i-1].name);
		return;
	}

	Con_Printf ("\"%s\" is not a valid texturemode\n", gl_texturemode.string);
	Cvar_SetQuick (&gl_texturemode, glmodes[glmode_idx].name);
}

/*
===============
TexMgr_Anisotropy_f -- called when gl_texture_anisotropy changes
===============
*/
static void TexMgr_Anisotropy_f (cvar_t *var)
{
	if (gl_texture_anisotropy.value < 1)
	{
		Cvar_SetQuick (&gl_texture_anisotropy, "1");
	}
	else if (gl_texture_anisotropy.value > gl_max_anisotropy)
	{
		Cvar_SetValueQuick (&gl_texture_anisotropy, gl_max_anisotropy);
	}
	else
	{
		gltexture_t	*glt;
		for (glt = active_gltextures; glt; glt = glt->next)
		{
		/*  TexMgr_SetFilterModes (glt);*/
		    if (glt->flags & TEXPREF_MIPMAP) {
			GL_Bind (glt);
			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, glmodes[glmode_idx].magfilter);
			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, glmodes[glmode_idx].minfilter);
			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, gl_texture_anisotropy.value);
		    }
		}
	}
}

/*
===============
TexMgr_Imagelist_f -- report loaded textures
===============
*/
static void TexMgr_Imagelist_f (void)
{
	float mb;
	float texels = 0;
	gltexture_t	*glt;

	for (glt = active_gltextures; glt; glt = glt->next)
	{
		Con_SafePrintf ("   %4i x%4i %s\n", glt->width, glt->height, glt->name);
		if (glt->flags & TEXPREF_MIPMAP)
			texels += glt->width * glt->height * 4.0f / 3.0f;
		else
			texels += (glt->width * glt->height);
	}

	mb = texels * (Cvar_VariableValue("vid_bpp") / 8.0f) / 0x100000;
	Con_Printf ("%i textures %i pixels %1.1f megabytes\n", numgltextures, (int)texels, mb);
}

/*
===============
TexMgr_Imagedump_f -- dump all current textures to TGA files
===============
*/
static void TexMgr_Imagedump_f (void)
{
	char tganame[MAX_OSPATH], tempname[MAX_OSPATH], dirname[MAX_OSPATH];
	gltexture_t	*glt;
	byte *buffer;
	char *c;

	//create directory
	q_snprintf(dirname, sizeof(dirname), "%s/imagedump", com_gamedir);
	Sys_mkdir (dirname);

	//loop through textures
	for (glt = active_gltextures; glt; glt = glt->next)
	{
		q_strlcpy (tempname, glt->name, sizeof(tempname));
		while ( (c = strchr(tempname, ':')) ) *c = '_';
		while ( (c = strchr(tempname, '/')) ) *c = '_';
		while ( (c = strchr(tempname, '*')) ) *c = '_';
		q_snprintf(tganame, sizeof(tganame), "imagedump/%s.tga", tempname);

		GL_Bind (glt);
		if (glt->flags & TEXPREF_ALPHA)
		{
			buffer = (byte *) malloc(glt->width*glt->height*4);
			glGetTexImage(GL_TEXTURE_2D, 0, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
			Image_WriteTGA (tganame, buffer, glt->width, glt->height, 32, true);
		}
		else
		{
			buffer = (byte *) malloc(glt->width*glt->height*3);
			glGetTexImage(GL_TEXTURE_2D, 0, GL_RGB, GL_UNSIGNED_BYTE, buffer);
			Image_WriteTGA (tganame, buffer, glt->width, glt->height, 24, true);
		}
		free (buffer);
	}

	Con_Printf ("dumped %i textures to %s\n", numgltextures, dirname);
}

/*
===============
TexMgr_FrameUsage -- report texture memory usage for this frame
===============
*/
float TexMgr_FrameUsage (void)
{
	float mb;
	float texels = 0;
	gltexture_t	*glt;

	for (glt = active_gltextures; glt; glt = glt->next)
	{
		if (glt->visframe == r_framecount)
		{
			if (glt->flags & TEXPREF_MIPMAP)
				texels += glt->width * glt->height * 4.0f / 3.0f;
			else
				texels += (glt->width * glt->height);
		}
	}

	mb = texels * (Cvar_VariableValue("vid_bpp") / 8.0f) / 0x100000;
	return mb;
}

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

	TEXTURE MANAGER

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

/*
================
TexMgr_FindTexture
================
*/
gltexture_t *TexMgr_FindTexture (qmodel_t *owner, const char *name)
{
	gltexture_t	*glt;

	if (name)
	{
		for (glt = active_gltextures; glt; glt = glt->next)
		{
			if (glt->owner == owner && !strcmp (glt->name, name))
				return glt;
		}
	}

	return NULL;
}

/*
================
TexMgr_NewTexture
================
*/
gltexture_t *TexMgr_NewTexture (void)
{
	gltexture_t *glt;

	if (numgltextures == MAX_GLTEXTURES)
		Sys_Error("numgltextures == MAX_GLTEXTURES\n");

	glt = free_gltextures;
	free_gltextures = glt->next;
	glt->next = active_gltextures;
	active_gltextures = glt;

	glGenTextures(1, &glt->texnum);
	numgltextures++;
	return glt;
}

static void GL_DeleteTexture (gltexture_t *texture);

//ericw -- workaround for preventing TexMgr_FreeTexture during TexMgr_ReloadImages
static qboolean in_reload_images;

/*
================
TexMgr_FreeTexture
================
*/
void TexMgr_FreeTexture (gltexture_t *kill)
{
	gltexture_t *glt;

	if (in_reload_images)
		return;
	
	if (kill == NULL)
	{
		Con_Printf ("TexMgr_FreeTexture: NULL texture\n");
		return;
	}

	if (active_gltextures == kill)
	{
		active_gltextures = kill->next;
		kill->next = free_gltextures;
		free_gltextures = kill;

		GL_DeleteTexture(kill);
		numgltextures--;
		return;
	}

	for (glt = active_gltextures; glt; glt = glt->next)
	{
		if (glt->next == kill)
		{
			glt->next = kill->next;
			kill->next = free_gltextures;
			free_gltextures = kill;

			GL_DeleteTexture(kill);
			numgltextures--;
			return;
		}
	}

	Con_Printf ("TexMgr_FreeTexture: not found\n");
}

/*
================
TexMgr_FreeTextures

compares each bit in "flags" to the one in glt->flags only if that bit is active in "mask"
================
*/
void TexMgr_FreeTextures (unsigned int flags, unsigned int mask)
{
	gltexture_t *glt, *next;

	for (glt = active_gltextures; glt; glt = next)
	{
		next = glt->next;
		if ((glt->flags & mask) == (flags & mask))
			TexMgr_FreeTexture (glt);
	}
}

/*
================
TexMgr_FreeTexturesForOwner
================
*/
void TexMgr_FreeTexturesForOwner (qmodel_t *owner)
{
	gltexture_t *glt, *next;

	for (glt = active_gltextures; glt; glt = next)
	{
		next = glt->next;
		if (glt && glt->owner == owner)
			TexMgr_FreeTexture (glt);
	}
}

/*
================
TexMgr_DeleteTextureObjects
================
*/
void TexMgr_DeleteTextureObjects (void)
{
	gltexture_t *glt;

	for (glt = active_gltextures; glt; glt = glt->next)
	{
		GL_DeleteTexture (glt);
	}
}

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

	INIT

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

/*
=================
TexMgr_LoadPalette -- johnfitz -- was VID_SetPalette, moved here, renamed, rewritten
=================
*/
void TexMgr_LoadPalette (void)
{
	byte *pal, *src, *dst;
	int i, mark;
	FILE *f;

	COM_FOpenFile ("gfx/palette.lmp", &f, NULL);
	if (!f)
		Sys_Error ("Couldn't load gfx/palette.lmp");

	mark = Hunk_LowMark ();
	pal = (byte *) Hunk_Alloc (768);
	fread (pal, 1, 768, f);
	fclose(f);

	//standard palette, 255 is transparent
	dst = (byte *)d_8to24table;
	src = pal;
	for (i = 0; i < 256; i++)
	{
		*dst++ = *src++;
		*dst++ = *src++;
		*dst++ = *src++;
		*dst++ = 255;
	}
	((byte *) &d_8to24table[255]) [3] = 0;

	//fullbright palette, 0-223 are black (for additive blending)
	src = pal + 224*3;
	dst = (byte *) &d_8to24table_fbright[224];
	for (i = 224; i < 256; i++)
	{
		*dst++ = *src++;
		*dst++ = *src++;
		*dst++ = *src++;
		*dst++ = 255;
	}
	for (i = 0; i < 224; i++)
	{
		dst = (byte *) &d_8to24table_fbright[i];
		dst[3] = 255;
		dst[2] = dst[1] = dst[0] = 0;
	}

	//nobright palette, 224-255 are black (for additive blending)
	dst = (byte *)d_8to24table_nobright;
	src = pal;
	for (i = 0; i < 256; i++)
	{
		*dst++ = *src++;
		*dst++ = *src++;
		*dst++ = *src++;
		*dst++ = 255;
	}
	for (i = 224; i < 256; i++)
	{
		dst = (byte *) &d_8to24table_nobright[i];
		dst[3] = 255;
		dst[2] = dst[1] = dst[0] = 0;
	}

	//fullbright palette, for fence textures
	memcpy(d_8to24table_fbright_fence, d_8to24table_fbright, 256*4);
	d_8to24table_fbright_fence[255] = 0; // Alpha of zero.

	//nobright palette, for fence textures
	memcpy(d_8to24table_nobright_fence, d_8to24table_nobright, 256*4);
	d_8to24table_nobright_fence[255] = 0; // Alpha of zero.

	//conchars palette, 0 and 255 are transparent
	memcpy(d_8to24table_conchars, d_8to24table, 256*4);
	((byte *) &d_8to24table_conchars[0]) [3] = 0;

	Hunk_FreeToLowMark (mark);
}

/*
================
TexMgr_NewGame
================
*/
void TexMgr_NewGame (void)
{
	TexMgr_FreeTextures (0, TEXPREF_PERSIST); //deletes all textures where TEXPREF_PERSIST is unset
	TexMgr_LoadPalette ();
}

/*
=============
TexMgr_RecalcWarpImageSize -- called during init, and after a vid_restart

choose safe warpimage size and resize existing warpimage textures
=============
*/
void TexMgr_RecalcWarpImageSize (void)
{
	int	mark;
	gltexture_t *glt;
	byte *dummy;

	//
	// find the new correct size
	//
	//oldsize = gl_warpimagesize;

	gl_warpimagesize = TexMgr_SafeTextureSize (512);

	while (gl_warpimagesize > vid.width)
		gl_warpimagesize >>= 1;
	while (gl_warpimagesize > vid.height)
		gl_warpimagesize >>= 1;

	// ericw -- removed early exit if (gl_warpimagesize == oldsize).
	// after vid_restart TexMgr_ReloadImage reloads textures
	// to tx->source_width/source_height, which might not match oldsize.
	// fixes: https://sourceforge.net/p/quakespasm/bugs/13/
	
	//
	// resize the textures in opengl
	//
	mark = Hunk_LowMark();
	dummy = (byte *) Hunk_Alloc (gl_warpimagesize*gl_warpimagesize*4);

	for (glt = active_gltextures; glt; glt = glt->next)
	{
		if (glt->flags & TEXPREF_WARPIMAGE)
		{
			GL_Bind (glt);
			glTexImage2D (GL_TEXTURE_2D, 0, gl_solid_format, gl_warpimagesize, gl_warpimagesize, 0, GL_RGBA, GL_UNSIGNED_BYTE, dummy);
			glt->width = glt->height = gl_warpimagesize;
		}
	}

	Hunk_FreeToLowMark (mark);
}

/*
================
TexMgr_Init

must be called before any texture loading
================
*/
void TexMgr_Init (void)
{
	int i;
	static byte notexture_data[16] = {159,91,83,255,0,0,0,255,0,0,0,255,159,91,83,255}; //black and pink checker
	static byte nulltexture_data[16] = {127,191,255,255,0,0,0,255,0,0,0,255,127,191,255,255}; //black and blue checker
	extern texture_t *r_notexture_mip, *r_notexture_mip2;

	// init texture list
	free_gltextures = (gltexture_t *) Hunk_AllocName (MAX_GLTEXTURES * sizeof(gltexture_t), "gltextures");
	active_gltextures = NULL;
	for (i = 0; i < MAX_GLTEXTURES - 1; i++)
		free_gltextures[i].next = &free_gltextures[i+1];
	free_gltextures[i].next = NULL;
	numgltextures = 0;

	// palette
	TexMgr_LoadPalette ();

	Cvar_RegisterVariable (&gl_max_size);
	Cvar_RegisterVariable (&gl_picmip);
	Cvar_RegisterVariable (&gl_texture_anisotropy);
	Cvar_SetCallback (&gl_texture_anisotropy, &TexMgr_Anisotropy_f);
	gl_texturemode.string = glmodes[glmode_idx].name;
	Cvar_RegisterVariable (&gl_texturemode);
	Cvar_SetCallback (&gl_texturemode, &TexMgr_TextureMode_f);
	Cmd_AddCommand ("gl_describetexturemodes", &TexMgr_DescribeTextureModes_f);
	Cmd_AddCommand ("imagelist", &TexMgr_Imagelist_f);
	Cmd_AddCommand ("imagedump", &TexMgr_Imagedump_f);

	// poll max size from hardware
	glGetIntegerv (GL_MAX_TEXTURE_SIZE, &gl_hardware_maxsize);

	// load notexture images
	notexture = TexMgr_LoadImage (NULL, "notexture", 2, 2, SRC_RGBA, notexture_data, "", (src_offset_t)notexture_data, TEXPREF_NEAREST | TEXPREF_PERSIST | TEXPREF_NOPICMIP);
	nulltexture = TexMgr_LoadImage (NULL, "nulltexture", 2, 2, SRC_RGBA, nulltexture_data, "", (src_offset_t)nulltexture_data, TEXPREF_NEAREST | TEXPREF_PERSIST | TEXPREF_NOPICMIP);

	//have to assign these here becuase Mod_Init is called before TexMgr_Init
	r_notexture_mip->gltexture = r_notexture_mip2->gltexture = notexture;

	//set safe size for warpimages
	gl_warpimagesize = 0;
	TexMgr_RecalcWarpImageSize ();
}

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

	IMAGE LOADING

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

/*
================
TexMgr_Pad -- return smallest power of two greater than or equal to s
================
*/
int TexMgr_Pad (int s)
{
	int i;
	for (i = 1; i < s; i<<=1)
		;
	return i;
}

/*
===============
TexMgr_SafeTextureSize -- return a size with hardware and user prefs in mind
===============
*/
int TexMgr_SafeTextureSize (int s)
{
	if (!gl_texture_NPOT)
		s = TexMgr_Pad(s);
	if ((int)gl_max_size.value > 0)
		s = q_min(TexMgr_Pad((int)gl_max_size.value), s);
	s = q_min(gl_hardware_maxsize, s);
	return s;
}

/*
================
TexMgr_PadConditional -- only pad if a texture of that size would be padded. (used for tex coords)
================
*/
int TexMgr_PadConditional (int s)
{
	if (s < TexMgr_SafeTextureSize(s))
		return TexMgr_Pad(s);
	else
		return s;
}

/*
================
TexMgr_MipMapW
================
*/
static unsigned *TexMgr_MipMapW (unsigned *data, int width, int height)
{
	int	i, size;
	byte	*out, *in;

	out = in = (byte *)data;
	size = (width*height)>>1;

	for (i = 0; i < size; i++, out += 4, in += 8)
	{
		out[0] = (in[0] + in[4])>>1;
		out[1] = (in[1] + in[5])>>1;
		out[2] = (in[2] + in[6])>>1;
		out[3] = (in[3] + in[7])>>1;
	}

	return data;
}

/*
================
TexMgr_MipMapH
================
*/
static unsigned *TexMgr_MipMapH (unsigned *data, int width, int height)
{
	int	i, j;
	byte	*out, *in;

	out = in = (byte *)data;
	height>>=1;
	width<<=2;

	for (i = 0; i < height; i++, in += width)
	{
		for (j = 0; j < width; j += 4, out += 4, in += 4)
		{
			out[0] = (in[0] + in[width+0])>>1;
			out[1] = (in[1] + in[width+1])>>1;
			out[2] = (in[2] + in[width+2])>>1;
			out[3] = (in[3] + in[width+3])>>1;
		}
	}

	return data;
}

/*
================
TexMgr_ResampleTexture -- bilinear resample
================
*/
static unsigned *TexMgr_ResampleTexture (unsigned *in, int inwidth, int inheight, qboolean alpha)
{
	byte *nwpx, *nepx, *swpx, *sepx, *dest;
	unsigned xfrac, yfrac, x, y, modx, mody, imodx, imody, injump, outjump;
	unsigned *out;
	int i, j, outwidth, outheight;

	if (inwidth == TexMgr_Pad(inwidth) && inheight == TexMgr_Pad(inheight))
		return in;

	outwidth = TexMgr_Pad(inwidth);
	outheight = TexMgr_Pad(inheight);
	out = (unsigned *) Hunk_Alloc(outwidth*outheight*4);

	xfrac = ((inwidth-1) << 16) / (outwidth-1);
	yfrac = ((inheight-1) << 16) / (outheight-1);
	y = outjump = 0;

	for (i = 0; i < outheight; i++)
	{
		mody = (y>>8) & 0xFF;
		imody = 256 - mody;
		injump = (y>>16) * inwidth;
		x = 0;

		for (j = 0; j < outwidth; j++)
		{
			modx = (x>>8) & 0xFF;
			imodx = 256 - modx;

			nwpx = (byte *)(in + (x>>16) + injump);
			nepx = nwpx + 4;
			swpx = nwpx + inwidth*4;
			sepx = swpx + 4;

			dest = (byte *)(out + outjump + j);

			dest[0] = (nwpx[0]*imodx*imody + nepx[0]*modx*imody + swpx[0]*imodx*mody + sepx[0]*modx*mody)>>16;
			dest[1] = (nwpx[1]*imodx*imody + nepx[1]*modx*imody + swpx[1]*imodx*mody + sepx[1]*modx*mody)>>16;
			dest[2] = (nwpx[2]*imodx*imody + nepx[2]*modx*imody + swpx[2]*imodx*mody + sepx[2]*modx*mody)>>16;
			if (alpha)
				dest[3] = (nwpx[3]*imodx*imody + nepx[3]*modx*imody + swpx[3]*imodx*mody + sepx[3]*modx*mody)>>16;
			else
				dest[3] = 255;

			x += xfrac;
		}
		outjump += outwidth;
		y += yfrac;
	}

	return out;
}

/*
===============
TexMgr_AlphaEdgeFix

eliminate pink edges on sprites, etc.
operates in place on 32bit data

spike -- small note that would be better to use premultiplied alpha to completely eliminate these skirts without the possibility of misbehaving.
===============
*/
static void TexMgr_AlphaEdgeFix (byte *data, int width, int height)
{
	int	i, j, n = 0, b, c[3] = {0,0,0},
		lastrow, thisrow, nextrow,
		lastpix, thispix, nextpix;
	byte	*dest = data;

	for (i = 0; i < height; i++)
	{
		lastrow = width * 4 * ((i == 0) ? height-1 : i-1);
		thisrow = width * 4 * i;
		nextrow = width * 4 * ((i == height-1) ? 0 : i+1);

		for (j = 0; j < width; j++, dest += 4)
		{
			if (dest[3]) //not transparent
				continue;

			lastpix = 4 * ((j == 0) ? width-1 : j-1);
			thispix = 4 * j;
			nextpix = 4 * ((j == width-1) ? 0 : j+1);

			b = lastrow + lastpix; if (data[b+3]) {c[0] += data[b]; c[1] += data[b+1]; c[2] += data[b+2]; n++;}
			b = thisrow + lastpix; if (data[b+3]) {c[0] += data[b]; c[1] += data[b+1]; c[2] += data[b+2]; n++;}
			b = nextrow + lastpix; if (data[b+3]) {c[0] += data[b]; c[1] += data[b+1]; c[2] += data[b+2]; n++;}
			b = lastrow + thispix; if (data[b+3]) {c[0] += data[b]; c[1] += data[b+1]; c[2] += data[b+2]; n++;}
			b = nextrow + thispix; if (data[b+3]) {c[0] += data[b]; c[1] += data[b+1]; c[2] += data[b+2]; n++;}
			b = lastrow + nextpix; if (data[b+3]) {c[0] += data[b]; c[1] += data[b+1]; c[2] += data[b+2]; n++;}
			b = thisrow + nextpix; if (data[b+3]) {c[0] += data[b]; c[1] += data[b+1]; c[2] += data[b+2]; n++;}
			b = nextrow + nextpix; if (data[b+3]) {c[0] += data[b]; c[1] += data[b+1]; c[2] += data[b+2]; n++;}

			//average all non-transparent neighbors
			if (n)
			{
				dest[0] = (byte)(c[0]/n);
				dest[1] = (byte)(c[1]/n);
				dest[2] = (byte)(c[2]/n);

				n = c[0] = c[1] = c[2] = 0;
			}
		}
	}
}

/*
===============
TexMgr_PadEdgeFixW -- special case of AlphaEdgeFix for textures that only need it because they were padded

operates in place on 32bit data, and expects unpadded height and width values
===============
*/
static void TexMgr_PadEdgeFixW (byte *data, int width, int height)
{
	byte *src, *dst;
	int i, padw, padh;

	padw = TexMgr_PadConditional(width);
	padh = TexMgr_PadConditional(height);

	//copy last full column to first empty column, leaving alpha byte at zero
	src = data + (width - 1) * 4;
	for (i = 0; i < padh; i++)
	{
		src[4] = src[0];
		src[5] = src[1];
		src[6] = src[2];
		src += padw * 4;
	}

	//copy first full column to last empty column, leaving alpha byte at zero
	src = data;
	dst = data + (padw - 1) * 4;
	for (i = 0; i < padh; i++)
	{
		dst[0] = src[0];
		dst[1] = src[1];
		dst[2] = src[2];
		src += padw * 4;
		dst += padw * 4;
	}
}

/*
===============
TexMgr_PadEdgeFixH -- special case of AlphaEdgeFix for textures that only need it because they were padded

operates in place on 32bit data, and expects unpadded height and width values
===============
*/
static void TexMgr_PadEdgeFixH (byte *data, int width, int height)
{
	byte *src, *dst;
	int i, padw, padh;

	padw = TexMgr_PadConditional(width);
	padh = TexMgr_PadConditional(height);

	//copy last full row to first empty row, leaving alpha byte at zero
	dst = data + height * padw * 4;
	src = dst - padw * 4;
	for (i = 0; i < padw; i++)
	{
		dst[0] = src[0];
		dst[1] = src[1];
		dst[2] = src[2];
		src += 4;
		dst += 4;
	}

	//copy first full row to last empty row, leaving alpha byte at zero
	dst = data + (padh - 1) * padw * 4;
	src = data;
	for (i = 0; i < padw; i++)
	{
		dst[0] = src[0];
		dst[1] = src[1];
		dst[2] = src[2];
		src += 4;
		dst += 4;
	}
}

/*
================
TexMgr_8to32
================
*/
static unsigned *TexMgr_8to32 (byte *in, int pixels, unsigned int *usepal)
{
	int i;
	unsigned *out, *data;

	out = data = (unsigned *) Hunk_Alloc(pixels*4);

	for (i = 0; i < pixels; i++)
		*out++ = usepal[*in++];

	return data;
}

/*
================
TexMgr_PadImageW -- return image with width padded up to power-of-two dimentions
================
*/
static byte *TexMgr_PadImageW (byte *in, int width, int height, byte padbyte)
{
	int i, j, outwidth;
	byte *out, *data;

	if (width == TexMgr_Pad(width))
		return in;

	outwidth = TexMgr_Pad(width);

	out = data = (byte *) Hunk_Alloc(outwidth*height);

	for (i = 0; i < height; i++)
	{
		for (j = 0; j < width; j++)
			*out++ = *in++;
		for (  ; j < outwidth; j++)
			*out++ = padbyte;
	}

	return data;
}

/*
================
TexMgr_PadImageH -- return image with height padded up to power-of-two dimentions
================
*/
static byte *TexMgr_PadImageH (byte *in, int width, int height, byte padbyte)
{
	int i, srcpix, dstpix;
	byte *data, *out;

	if (height == TexMgr_Pad(height))
		return in;

	srcpix = width * height;
	dstpix = width * TexMgr_Pad(height);

	out = data = (byte *) Hunk_Alloc(dstpix);

	for (i = 0; i < srcpix; i++)
		*out++ = *in++;
	for (     ; i < dstpix; i++)
		*out++ = padbyte;

	return data;
}

static byte *TexMgr_PreMultiply32(byte *in, size_t width, size_t height)
{
	size_t pixels = width * height;
	byte *out = (byte *) Hunk_Alloc(pixels*4);
	byte *result = out;
	while (pixels --> 0)
	{
		out[0] = (in[0]*in[3])>>8;
		out[1] = (in[1]*in[3])>>8;
		out[2] = (in[2]*in[3])>>8;
		out[3] = in[3];
		in += 4;
		out += 4;
	}
	return result;
}

/*
================
TexMgr_LoadImage32 -- handles 32bit source data
================
*/
static void TexMgr_LoadImage32 (gltexture_t *glt, unsigned *data)
{
	int	internalformat,	miplevel, mipwidth, mipheight, picmip;

	//do this before any rescaling
	if (glt->flags & TEXPREF_PREMULTIPLY)
		data = (unsigned*)TexMgr_PreMultiply32((byte*)data, glt->width, glt->height);

	if (!gl_texture_NPOT)
	{
		// resample up
		data = TexMgr_ResampleTexture (data, glt->width, glt->height, glt->flags & TEXPREF_ALPHA);
		glt->width = TexMgr_Pad(glt->width);
		glt->height = TexMgr_Pad(glt->height);
	}

	// mipmap down
	picmip = (glt->flags & TEXPREF_NOPICMIP) ? 0 : q_max((int)gl_picmip.value, 0);
	mipwidth = TexMgr_SafeTextureSize (glt->width >> picmip);
	mipheight = TexMgr_SafeTextureSize (glt->height >> picmip);
	while ((int) glt->width > mipwidth)
	{
		TexMgr_MipMapW (data, glt->width, glt->height);
		glt->width >>= 1;
		if (glt->flags & TEXPREF_ALPHA)
			TexMgr_AlphaEdgeFix ((byte *)data, glt->width, glt->height);
	}
	while ((int) glt->height > mipheight)
	{
		TexMgr_MipMapH (data, glt->width, glt->height);
		glt->height >>= 1;
		if (glt->flags & TEXPREF_ALPHA)
			TexMgr_AlphaEdgeFix ((byte *)data, glt->width, glt->height);
	}

	// upload
	GL_Bind (glt);
	internalformat = (glt->flags & TEXPREF_ALPHA) ? gl_alpha_format : gl_solid_format;
	glTexImage2D (GL_TEXTURE_2D, 0, internalformat, glt->width, glt->height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);

	// upload mipmaps
	if (glt->flags & TEXPREF_MIPMAP)
	{
		mipwidth = glt->width;
		mipheight = glt->height;

		for (miplevel=1; mipwidth > 1 || mipheight > 1; miplevel++)
		{
			if (mipwidth > 1)
			{
				TexMgr_MipMapW (data, mipwidth, mipheight);
				mipwidth >>= 1;
			}
			if (mipheight > 1)
			{
				TexMgr_MipMapH (data, mipwidth, mipheight);
				mipheight >>= 1;
			}
			glTexImage2D (GL_TEXTURE_2D, miplevel, internalformat, mipwidth, mipheight, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
		}
	}

	// set filter modes
	TexMgr_SetFilterModes (glt);
}

/*
================
TexMgr_LoadImage8 -- handles 8bit source data, then passes it to LoadImage32
================
*/
static void TexMgr_LoadImage8 (gltexture_t *glt, byte *data)
{
	extern cvar_t gl_fullbrights;
	qboolean padw = false, padh = false;
	byte padbyte;
	unsigned int *usepal;
	int i;

	// HACK HACK HACK -- taken from tomazquake
	if (strstr(glt->name, "shot1sid") &&
	    glt->width == 32 && glt->height == 32 &&
	    CRC_Block(data, 1024) == 65393)
	{
		// This texture in b_shell1.bsp has some of the first 32 pixels painted white.
		// They are invisible in software, but look really ugly in GL. So we just copy
		// 32 pixels from the bottom to make it look nice.
		memcpy (data, data + 32*31, 32);
	}

	// detect false alpha cases
	if (glt->flags & TEXPREF_ALPHA && !(glt->flags & TEXPREF_CONCHARS))
	{
		for (i = 0; i < (int) (glt->width * glt->height); i++)
			if (data[i] == 255) //transparent index
				break;
		if (i == (int) (glt->width * glt->height))
			glt->flags -= TEXPREF_ALPHA;
	}

	// choose palette and padbyte
	if (glt->flags & TEXPREF_FULLBRIGHT)
	{
		if (glt->flags & TEXPREF_ALPHA)
			usepal = d_8to24table_fbright_fence;
		else
			usepal = d_8to24table_fbright;
		padbyte = 0;
	}
	else if (glt->flags & TEXPREF_NOBRIGHT && gl_fullbrights.value)
	{
		if (glt->flags & TEXPREF_ALPHA)
			usepal = d_8to24table_nobright_fence;
		else
			usepal = d_8to24table_nobright;
		padbyte = 0;
	}
	else if (glt->flags & TEXPREF_CONCHARS)
	{
		usepal = d_8to24table_conchars;
		padbyte = 0;
	}
	else
	{
		usepal = d_8to24table;
		padbyte = 255;
	}

	// pad each dimention, but only if it's not going to be downsampled later
	if (glt->flags & TEXPREF_PAD)
	{
		if ((int) glt->width < TexMgr_SafeTextureSize(glt->width))
		{
			data = TexMgr_PadImageW (data, glt->width, glt->height, padbyte);
			glt->width = TexMgr_Pad(glt->width);
			padw = true;
		}
		if ((int) glt->height < TexMgr_SafeTextureSize(glt->height))
		{
			data = TexMgr_PadImageH (data, glt->width, glt->height, padbyte);
			glt->height = TexMgr_Pad(glt->height);
			padh = true;
		}
	}

	// convert to 32bit
	data = (byte *)TexMgr_8to32(data, glt->width * glt->height, usepal);

	// fix edges
	if ((glt->flags & TEXPREF_ALPHA) && !(glt->flags & TEXPREF_PREMULTIPLY))
		TexMgr_AlphaEdgeFix (data, glt->width, glt->height);
	else
	{
		if (padw)
			TexMgr_PadEdgeFixW (data, glt->source_width, glt->source_height);
		if (padh)
			TexMgr_PadEdgeFixH (data, glt->source_width, glt->source_height);
	}

	// upload it
	TexMgr_LoadImage32 (glt, (unsigned *)data);
}

/*
================
TexMgr_LoadLightmap -- handles lightmap data
================
*/
static void TexMgr_LoadLightmap (gltexture_t *glt, byte *data)
{
	// upload it
	GL_Bind (glt);
	glTexImage2D (GL_TEXTURE_2D, 0, lightmap_bytes, glt->width, glt->height, 0, gl_lightmap_format, GL_UNSIGNED_BYTE, data);

	// set filter modes
	TexMgr_SetFilterModes (glt);
}

/*
================
TexMgr_LoadImage -- the one entry point for loading all textures
================
*/
gltexture_t *TexMgr_LoadImage (qmodel_t *owner, const char *name, int width, int height, enum srcformat format,
			       byte *data, const char *source_file, src_offset_t source_offset, unsigned flags)
{
	unsigned short crc;
	gltexture_t *glt;
	int mark;

	if (isDedicated)
		return NULL;

	// cache check
	switch (format)
	{
	case SRC_INDEXED:
		crc = CRC_Block(data, width * height);
		break;
	case SRC_LIGHTMAP:
		crc = CRC_Block(data, width * height * lightmap_bytes);
		break;
	case SRC_RGBA:
		crc = CRC_Block(data, width * height * 4);
		break;
	default: /* not reachable but avoids compiler warnings */
		crc = 0;
	}
	if ((flags & TEXPREF_OVERWRITE) && (glt = TexMgr_FindTexture (owner, name)))
	{
		if (glt->source_crc == crc)
			return glt;
	}
	else
		glt = TexMgr_NewTexture ();

	// copy data
	glt->owner = owner;
	q_strlcpy (glt->name, name, sizeof(glt->name));
	glt->width = width;
	glt->height = height;
	glt->flags = flags;
	glt->shirt = -1;
	glt->pants = -1;
	q_strlcpy (glt->source_file, source_file, sizeof(glt->source_file));
	glt->source_offset = source_offset;
	glt->source_format = format;
	glt->source_width = width;
	glt->source_height = height;
	glt->source_crc = crc;

	//upload it
	mark = Hunk_LowMark();

	switch (glt->source_format)
	{
	case SRC_INDEXED:
		TexMgr_LoadImage8 (glt, data);
		break;
	case SRC_LIGHTMAP:
		TexMgr_LoadLightmap (glt, data);
		break;
	case SRC_RGBA:
		TexMgr_LoadImage32 (glt, (unsigned *)data);
		break;
	}

	Hunk_FreeToLowMark(mark);

	return glt;
}

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

	COLORMAPPING AND TEXTURE RELOADING

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

/*
================
TexMgr_ReloadImage -- reloads a texture, and colormaps it if needed
================
*/
void TexMgr_ReloadImage (gltexture_t *glt, int shirt, int pants)
{
	byte	translation[256];
	byte	*src, *dst, *data = NULL, *translated;
	int	mark, size, i;
//
// get source data
//
	mark = Hunk_LowMark ();

	if (glt->source_file[0] && glt->source_offset)
	{
		//lump inside file
		long size;
		FILE *f;
		COM_FOpenFile(glt->source_file, &f, NULL);
		if (!f)
			goto invalid;
		fseek (f, glt->source_offset, SEEK_CUR);
		size = (long) (glt->source_width * glt->source_height);
		/* should be SRC_INDEXED, but no harm being paranoid:  */
		if (glt->source_format == SRC_RGBA)
			size *= 4;
		else if (glt->source_format == SRC_LIGHTMAP)
			size *= lightmap_bytes;
		data = (byte *) Hunk_Alloc (size);
		fread (data, 1, size, f);
		fclose (f);
	}
	else if (glt->source_file[0] && !glt->source_offset)
		data = Image_LoadImage (glt->source_file, (int *)&glt->source_width, (int *)&glt->source_height); //simple file
	else if (!glt->source_file[0] && glt->source_offset)
		data = (byte *) glt->source_offset; //image in memory

	if (!data)
	{
invalid:
		Con_Printf ("TexMgr_ReloadImage: invalid source for %s\n", glt->name);
		Hunk_FreeToLowMark(mark);
		return;
	}

	glt->width = glt->source_width;
	glt->height = glt->source_height;
//
// apply shirt and pants colors
//
// if shirt and pants are -1,-1, use existing shirt and pants colors
// if existing shirt and pants colors are -1,-1, don't bother colormapping
	if (shirt > -1 && pants > -1)
	{
		if (glt->source_format == SRC_INDEXED)
		{
			glt->shirt = shirt;
			glt->pants = pants;
		}
		else
			Con_Printf ("TexMgr_ReloadImage: can't colormap a non SRC_INDEXED texture: %s\n", glt->name);
	}
	if (glt->shirt > -1 && glt->pants > -1)
	{
		//create new translation table
		for (i = 0; i < 256; i++)
			translation[i] = i;

		shirt = glt->shirt * 16;
		if (shirt < 128)
		{
			for (i = 0; i < 16; i++)
				translation[TOP_RANGE+i] = shirt + i;
		}
		else
		{
			for (i = 0; i < 16; i++)
				translation[TOP_RANGE+i] = shirt+15-i;
		}

		pants = glt->pants * 16;
		if (pants < 128)
		{
			for (i = 0; i < 16; i++)
				translation[BOTTOM_RANGE+i] = pants + i;
		}
		else
		{
			for (i = 0; i < 16; i++)
				translation[BOTTOM_RANGE+i] = pants+15-i;
		}

		//translate texture
		size = glt->width * glt->height;
		dst = translated = (byte *) Hunk_Alloc (size);
		src = data;

		for (i = 0; i < size; i++)
			*dst++ = translation[*src++];

		data = translated;
	}
//
// upload it
//
	switch (glt->source_format)
	{
	case SRC_INDEXED:
		TexMgr_LoadImage8 (glt, data);
		break;
	case SRC_LIGHTMAP:
		TexMgr_LoadLightmap (glt, data);
		break;
	case SRC_RGBA:
		TexMgr_LoadImage32 (glt, (unsigned *)data);
		break;
	}

	Hunk_FreeToLowMark(mark);
}

/*
================
TexMgr_ReloadImages -- reloads all texture images. called only by vid_restart
================
*/
void TexMgr_ReloadImages (void)
{
	gltexture_t *glt;

// ericw -- tricky bug: if the hunk is almost full, an allocation in TexMgr_ReloadImage
// triggers cache items to be freed, which calls back into TexMgr to free the
// texture. If this frees 'glt' in the loop below, the active_gltextures
// list gets corrupted.
// A test case is jam3_tronyn.bsp with -heapsize 65536, and do several mode
// switches/fullscreen toggles
// 2015-09-04 -- Cache_Flush workaround was causing issues (http://sourceforge.net/p/quakespasm/bugs/10/)
// switching to a boolean flag.
	in_reload_images = true;

	for (glt = active_gltextures; glt; glt = glt->next)
	{
		glGenTextures(1, &glt->texnum);
		TexMgr_ReloadImage (glt, -1, -1);
	}
	
	in_reload_images = false;
}

/*
================
TexMgr_ReloadNobrightImages -- reloads all texture that were loaded with the nobright palette.  called when gl_fullbrights changes
================
*/
void TexMgr_ReloadNobrightImages (void)
{
	gltexture_t *glt;

	for (glt = active_gltextures; glt; glt = glt->next)
		if (glt->flags & TEXPREF_NOBRIGHT)
			TexMgr_ReloadImage(glt, -1, -1);
}

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

	TEXTURE BINDING / TEXTURE UNIT SWITCHING

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

static GLuint	currenttexture[3] = {GL_UNUSED_TEXTURE, GL_UNUSED_TEXTURE, GL_UNUSED_TEXTURE}; // to avoid unnecessary texture sets
static GLenum	currenttarget = GL_TEXTURE0_ARB;
qboolean	mtexenabled = false;

/*
================
GL_SelectTexture -- johnfitz -- rewritten
================
*/
void GL_SelectTexture (GLenum target)
{
	if (target == currenttarget)
		return;
		
	GL_SelectTextureFunc(target);
	currenttarget = target;
}

/*
================
GL_DisableMultitexture -- selects texture unit 0
================
*/
void GL_DisableMultitexture(void)
{
	if (mtexenabled)
	{
		glDisable(GL_TEXTURE_2D);
		GL_SelectTexture(GL_TEXTURE0_ARB);
		mtexenabled = false;
	}
}

/*
================
GL_EnableMultitexture -- selects texture unit 1
================
*/
void GL_EnableMultitexture(void)
{
	if (gl_mtexable)
	{
		GL_SelectTexture(GL_TEXTURE1_ARB);
		glEnable(GL_TEXTURE_2D);
		mtexenabled = true;
	}
}

/*
================
GL_Bind -- johnfitz -- heavy revision
================
*/
void GL_Bind (gltexture_t *texture)
{
	if (!texture)
		texture = nulltexture;

	if (texture->texnum != currenttexture[currenttarget - GL_TEXTURE0_ARB])
	{
		currenttexture[currenttarget - GL_TEXTURE0_ARB] = texture->texnum;
		glBindTexture (GL_TEXTURE_2D, texture->texnum);
		texture->visframe = r_framecount;
	}
}

/*
================
GL_DeleteTexture -- ericw

Wrapper around glDeleteTextures that also clears the given texture number
from our per-TMU cached texture binding table.
================
*/
static void GL_DeleteTexture (gltexture_t *texture)
{
	glDeleteTextures (1, &texture->texnum);

	if (texture->texnum == currenttexture[0]) currenttexture[0] = GL_UNUSED_TEXTURE;
	if (texture->texnum == currenttexture[1]) currenttexture[1] = GL_UNUSED_TEXTURE;
	if (texture->texnum == currenttexture[2]) currenttexture[2] = GL_UNUSED_TEXTURE;

	texture->texnum = 0;
}

/*
================
GL_ClearBindings -- ericw
 
Invalidates cached bindings, so the next GL_Bind calls for each TMU will
make real glBindTexture calls.
Call this after changing the binding outside of GL_Bind.
================
*/
void GL_ClearBindings(void)
{
	int i;
	for (i = 0; i < 3; i++)
	{
		currenttexture[i] = GL_UNUSED_TEXTURE;
	}
}
