raze/wadsrc/static/shaders/glsl/func_paletted.fp
2021-02-12 14:55:42 +01:00

61 lines
2.2 KiB
GLSL

const int RF_ShadeInterpolate = 64;
//===========================================================================
//
//
//
//===========================================================================
vec4 ProcessTexel()
{
int blendflags = int(uTextureAddColor.a);
float fullbright = 0.0;
vec4 color;
float coordX = vTexCoord.x;
float coordY = vTexCoord.y;
vec2 newCoord;
// z is the depth in view space, positive going into the screen
float z = abs(pixelpos.w);
#ifdef NPOT_EMULATION
// Coordinate adjustment for NPOT textures. It is somehow fitting that Build games exploited this texture wrapping quirk of the software rendering engine...
if (uNpotEmulation.y != 0.0)
{
float period = floor(coordY / uNpotEmulation.y);
coordX += uNpotEmulation.x * floor(mod(coordY, uNpotEmulation.y));
coordY = period + mod(coordY, uNpotEmulation.y);
}
#endif
newCoord = vec2(coordX, coordY);
color = texture(tex, newCoord);
float visibility = max(uGlobVis * uLightFactor * z - ((blendflags & 16384) != 0? 0.5 : 0.0), 0.0);
float numShades = float(uPalLightLevels & 255);
float shade = (1.0 - uLightLevel) * (numShades);
shade = clamp((shade + visibility), 0.0, numShades - 1.0);
int palindex = int(color.r * 255.0 + 0.1); // The 0.1 is for roundoff error compensation.
int shadeindex = int(floor(shade));
float colorIndexF = texelFetch(texture3, ivec2(palindex, shadeindex), 0).r;
int colorIndex = int(colorIndexF * 255.0 + 0.1); // The 0.1 is for roundoff error compensation.
vec4 palettedColor = texelFetch(texture2, ivec2(colorIndex, 0), 0);
if ((blendflags & 16384) != 0)
{
// Get the next shaded palette index for interpolation
colorIndexF = texelFetch(texture3, ivec2(palindex, shadeindex+1), 0).r;
colorIndex = int(colorIndexF * 255.0 + 0.1); // The 0.1 is for roundoff error compensation.
vec4 palettedColorNext = texelFetch(texture2, ivec2(colorIndex, 0), 0);
float shadeFrac = mod(shade, 1.0);
palettedColor.rgb = mix(palettedColor.rgb, palettedColorNext.rgb, shadeFrac);
}
palettedColor.a = color.r == 0.0? 0.0 : 1.0;// 1.0-floor(color.r);
color = palettedColor;
if (color.a < uAlphaThreshold) discard; // it's only here that we have the alpha value available to be able to perform the alpha test.
return vec4(color.rgb, 1.0);
}