tr_image.c

quakeIII源码这个不用我多说吧

	}
	if ( t < 31.0/32 ) {
		s *= (t - 1.0f/32.0f) / (30.0f/32.0f);
	}

	// we need to leave a lot of clamp range
	s *= 8;

	if ( s > 1.0 ) {
		s = 1.0;
	}

	d = tr.fogTable[ (int)(s * (FOG_TABLE_SIZE-1)) ];

	return d;
}

/*
================
R_CreateFogImage
================
*/
#define	FOG_S	256
#define	FOG_T	32
static void R_CreateFogImage( void ) {
	int		x,y;
	byte	*data;
	float	g;
	float	d;
	float	borderColor[4];

	data = ri.Hunk_AllocateTempMemory( FOG_S * FOG_T * 4 );

	g = 2.0;

	// S is distance, T is depth
	for (x=0 ; x<FOG_S ; x++) {
		for (y=0 ; y<FOG_T ; y++) {
			d = R_FogFactor( ( x + 0.5f ) / FOG_S, ( y + 0.5f ) / FOG_T );

			data[(y*FOG_S+x)*4+0] = 
			data[(y*FOG_S+x)*4+1] = 
			data[(y*FOG_S+x)*4+2] = 255;
			data[(y*FOG_S+x)*4+3] = 255*d;
		}
	}
	// standard openGL clamping doesn't really do what we want -- it includes
	// the border color at the edges.  OpenGL 1.2 has clamp-to-edge, which does
	// what we want.
	tr.fogImage = R_CreateImage("*fog", (byte *)data, FOG_S, FOG_T, qfalse, qfalse, GL_CLAMP );
	ri.Hunk_FreeTempMemory( data );

	borderColor[0] = 1.0;
	borderColor[1] = 1.0;
	borderColor[2] = 1.0;
	borderColor[3] = 1;

	qglTexParameterfv( GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, borderColor );
}

/*
==================
R_CreateDefaultImage
==================
*/
#define	DEFAULT_SIZE	16
static void R_CreateDefaultImage( void ) {
	int		x;
	byte	data[DEFAULT_SIZE][DEFAULT_SIZE][4];

	// the default image will be a box, to allow you to see the mapping coordinates
	Com_Memset( data, 32, sizeof( data ) );
	for ( x = 0 ; x < DEFAULT_SIZE ; x++ ) {
		data[0][x][0] =
		data[0][x][1] =
		data[0][x][2] =
		data[0][x][3] = 255;

		data[x][0][0] =
		data[x][0][1] =
		data[x][0][2] =
		data[x][0][3] = 255;

		data[DEFAULT_SIZE-1][x][0] =
		data[DEFAULT_SIZE-1][x][1] =
		data[DEFAULT_SIZE-1][x][2] =
		data[DEFAULT_SIZE-1][x][3] = 255;

		data[x][DEFAULT_SIZE-1][0] =
		data[x][DEFAULT_SIZE-1][1] =
		data[x][DEFAULT_SIZE-1][2] =
		data[x][DEFAULT_SIZE-1][3] = 255;
	}
	tr.defaultImage = R_CreateImage("*default", (byte *)data, DEFAULT_SIZE, DEFAULT_SIZE, qtrue, qfalse, GL_REPEAT );
}

/*
==================
R_CreateBuiltinImages
==================
*/
void R_CreateBuiltinImages( void ) {
	int		x,y;
	byte	data[DEFAULT_SIZE][DEFAULT_SIZE][4];

	R_CreateDefaultImage();

	// we use a solid white image instead of disabling texturing
	Com_Memset( data, 255, sizeof( data ) );
	tr.whiteImage = R_CreateImage("*white", (byte *)data, 8, 8, qfalse, qfalse, GL_REPEAT );

	// with overbright bits active, we need an image which is some fraction of full color,
	// for default lightmaps, etc
	for (x=0 ; x<DEFAULT_SIZE ; x++) {
		for (y=0 ; y<DEFAULT_SIZE ; y++) {
			data[y][x][0] = 
			data[y][x][1] = 
			data[y][x][2] = tr.identityLightByte;
			data[y][x][3] = 255;			
		}
	}

	tr.identityLightImage = R_CreateImage("*identityLight", (byte *)data, 8, 8, qfalse, qfalse, GL_REPEAT );


	for(x=0;x<32;x++) {
		// scratchimage is usually used for cinematic drawing
		tr.scratchImage[x] = R_CreateImage("*scratch", (byte *)data, DEFAULT_SIZE, DEFAULT_SIZE, qfalse, qtrue, GL_CLAMP );
	}

	R_CreateDlightImage();
	R_CreateFogImage();
}


/*
===============
R_SetColorMappings
===============
*/
void R_SetColorMappings( void ) {
	int		i, j;
	float	g;
	int		inf;
	int		shift;

	// setup the overbright lighting
	tr.overbrightBits = r_overBrightBits->integer;
	if ( !glConfig.deviceSupportsGamma ) {
		tr.overbrightBits = 0;		// need hardware gamma for overbright
	}

	// never overbright in windowed mode
	if ( !glConfig.isFullscreen ) 
	{
		tr.overbrightBits = 0;
	}

	// allow 2 overbright bits in 24 bit, but only 1 in 16 bit
	if ( glConfig.colorBits > 16 ) {
		if ( tr.overbrightBits > 2 ) {
			tr.overbrightBits = 2;
		}
	} else {
		if ( tr.overbrightBits > 1 ) {
			tr.overbrightBits = 1;
		}
	}
	if ( tr.overbrightBits < 0 ) {
		tr.overbrightBits = 0;
	}

	tr.identityLight = 1.0f / ( 1 << tr.overbrightBits );
	tr.identityLightByte = 255 * tr.identityLight;


	if ( r_intensity->value <= 1 ) {
		ri.Cvar_Set( "r_intensity", "1" );
	}

	if ( r_gamma->value < 0.5f ) {
		ri.Cvar_Set( "r_gamma", "0.5" );
	} else if ( r_gamma->value > 3.0f ) {
		ri.Cvar_Set( "r_gamma", "3.0" );
	}

	g = r_gamma->value;

	shift = tr.overbrightBits;

	for ( i = 0; i < 256; i++ ) {
		if ( g == 1 ) {
			inf = i;
		} else {
			inf = 255 * pow ( i/255.0f, 1.0f / g ) + 0.5f;
		}
		inf <<= shift;
		if (inf < 0) {
			inf = 0;
		}
		if (inf > 255) {
			inf = 255;
		}
		s_gammatable[i] = inf;
	}

	for (i=0 ; i<256 ; i++) {
		j = i * r_intensity->value;
		if (j > 255) {
			j = 255;
		}
		s_intensitytable[i] = j;
	}

	if ( glConfig.deviceSupportsGamma )
	{
		GLimp_SetGamma( s_gammatable, s_gammatable, s_gammatable );
	}
}

/*
===============
R_InitImages
===============
*/
void	R_InitImages( void ) {
	Com_Memset(hashTable, 0, sizeof(hashTable));
	// build brightness translation tables
	R_SetColorMappings();

	// create default texture and white texture
	R_CreateBuiltinImages();
}

/*
===============
R_DeleteTextures
===============
*/
void R_DeleteTextures( void ) {
	int		i;

	for ( i=0; i<tr.numImages ; i++ ) {
		qglDeleteTextures( 1, &tr.images[i]->texnum );
	}
	Com_Memset( tr.images, 0, sizeof( tr.images ) );

	tr.numImages = 0;

	Com_Memset( glState.currenttextures, 0, sizeof( glState.currenttextures ) );
	if ( qglBindTexture ) {
		if ( qglActiveTextureARB ) {
			GL_SelectTexture( 1 );
			qglBindTexture( GL_TEXTURE_2D, 0 );
			GL_SelectTexture( 0 );
			qglBindTexture( GL_TEXTURE_2D, 0 );
		} else {
			qglBindTexture( GL_TEXTURE_2D, 0 );
		}
	}
}

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

SKINS

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

/*
==================
CommaParse

This is unfortunate, but the skin files aren't
compatable with our normal parsing rules.
==================
*/
static char *CommaParse( char **data_p ) {
	int c = 0, len;
	char *data;
	static	char	com_token[MAX_TOKEN_CHARS];

	data = *data_p;
	len = 0;
	com_token[0] = 0;

	// make sure incoming data is valid
	if ( !data ) {
		*data_p = NULL;
		return com_token;
	}

	while ( 1 ) {
		// skip whitespace
		while( (c = *data) <= ' ') {
			if( !c ) {
				break;
			}
			data++;
		}


		c = *data;

		// skip double slash comments
		if ( c == '/' && data[1] == '/' )
		{
			while (*data && *data != '\n')
				data++;
		}
		// skip /* */ comments
		else if ( c=='/' && data[1] == '*' ) 
		{
			while ( *data && ( *data != '*' || data[1] != '/' ) ) 
			{
				data++;
			}
			if ( *data ) 
			{
				data += 2;
			}
		}
		else
		{
			break;
		}
	}

	if ( c == 0 ) {
		return "";
	}

	// handle quoted strings
	if (c == '\"')
	{
		data++;
		while (1)
		{
			c = *data++;
			if (c=='\"' || !c)
			{
				com_token[len] = 0;
				*data_p = ( char * ) data;
				return com_token;
			}
			if (len < MAX_TOKEN_CHARS)
			{
				com_token[len] = c;
				len++;
			}
		}
	}

	// parse a regular word
	do
	{
		if (len < MAX_TOKEN_CHARS)
		{
			com_token[len] = c;
			len++;
		}
		data++;
		c = *data;
	} while (c>32 && c != ',' );

	if (len == MAX_TOKEN_CHARS)
	{
//		Com_Printf ("Token exceeded %i chars, discarded.\n", MAX_TOKEN_CHARS);
		len = 0;
	}
	com_token[len] = 0;

	*data_p = ( char * ) data;
	return com_token;
}


/*
===============
RE_RegisterSkin

===============
*/
qhandle_t RE_RegisterSkin( const char *name ) {
	qhandle_t	hSkin;
	skin_t		*skin;
	skinSurface_t	*surf;
	char		*text, *text_p;
	char		*token;
	char		surfName[MAX_QPATH];

	if ( !name || !name[0] ) {
		Com_Printf( "Empty name passed to RE_RegisterSkin\n" );
		return 0;
	}

	if ( strlen( name ) >= MAX_QPATH ) {
		Com_Printf( "Skin name exceeds MAX_QPATH\n" );
		return 0;
	}


	// see if the skin is already loaded
	for ( hSkin = 1; hSkin < tr.numSkins ; hSkin++ ) {
		skin = tr.skins[hSkin];
		if ( !Q_stricmp( skin->name, name ) ) {
			if( skin->numSurfaces == 0 ) {
				return 0;		// default skin
			}
			return hSkin;
		}
	}

	// allocate a new skin
	if ( tr.numSkins == MAX_SKINS ) {
		ri.Printf( PRINT_WARNING, "WARNING: RE_RegisterSkin( '%s' ) MAX_SKINS hit\n", name );
		return 0;
	}
	tr.numSkins++;
	skin = ri.Hunk_Alloc( sizeof( skin_t ), h_low );
	tr.skins[hSkin] = skin;
	Q_strncpyz( skin->name, name, sizeof( skin->name ) );
	skin->numSurfaces = 0;

	// make sure the render thread is stopped
	R_SyncRenderThread();

	// If not a .skin file, load as a single shader
	if ( strcmp( name + strlen( name ) - 5, ".skin" ) ) {
		skin->numSurfaces = 1;
		skin->surfaces[0] = ri.Hunk_Alloc( sizeof(skin->surfaces[0]), h_low );
		skin->surfaces[0]->shader = R_FindShader( name, LIGHTMAP_NONE, qtrue );
		return hSkin;
	}

	// load and parse the skin file
    ri.FS_ReadFile( name, (void **)&text );
	if ( !text ) {
		return 0;
	}

	text_p = text;
	while ( text_p && *text_p ) {
		// get surface name
		token = CommaParse( &text_p );
		Q_strncpyz( surfName, token, sizeof( surfName ) );

		if ( !token[0] ) {
			break;
		}
		// lowercase the surface name so skin compares are faster
		Q_strlwr( surfName );

		if ( *text_p == ',' ) {
			text_p++;
		}

		if ( strstr( token, "tag_" ) ) {
			continue;
		}
		
		// parse the shader name
		token = CommaParse( &text_p );

		surf = skin->surfaces[ skin->numSurfaces ] = ri.Hunk_Alloc( sizeof( *skin->surfaces[0] ), h_low );
		Q_strncpyz( surf->name, surfName, sizeof( surf->name ) );
		surf->shader = R_FindShader( token, LIGHTMAP_NONE, qtrue );
		skin->numSurfaces++;
	}

	ri.FS_FreeFile( text );


	// never let a skin have 0 shaders
	if ( skin->numSurfaces == 0 ) {
		return 0;		// use default skin
	}

	return hSkin;
}


/*
===============
R_InitSkins
===============
*/
void	R_InitSkins( void ) {
	skin_t		*skin;

	tr.numSkins = 1;

	// make the default skin have all default shaders
	skin = tr.skins[0] = ri.Hunk_Alloc( sizeof( skin_t ), h_low );
	Q_strncpyz( skin->na