raze/wadsrc/static/shaders_gles/glsl/func_paletted.fp
2021-10-16 18:42:02 +02:00

70 lines
2.4 KiB
GLSL

const int RF_ShadeInterpolate = 64;
vec4 ProcessTexel()
{
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 (DEF_NPOT_EMULATION == 1)
{
float period = floor(coordY / uNpotEmulation.y);
coordX += uNpotEmulation.x * floor(mod(coordY, uNpotEmulation.y));
coordY = period + mod(coordY, uNpotEmulation.y);
}
#endif
#endif
newCoord = vec2(coordX, coordY);
color = texture(tex, newCoord);
#if ((DEF_BLEND_FLAGS & 16384) != 0)
float visibility = max(uGlobVis * uLightFactor * z - 0.5, 0.0);
#else
float visibility = max(uGlobVis * uLightFactor * z, 0.0);
#endif
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 ((DEF_BLEND_FLAGS & 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);
}
#endif
//palettedColor.a = color.r == 0.0? 0.0 : 1.0;// 1.0-floor(color.r);
// Replaces above line without branch
palettedColor.a = floor(color.r + 0.999);
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.
// This replaces the above line to avoid the branch and the discard.. Seems to look the same but could be unforeseen issues.
float alpha = step(uAlphaThreshold, color.a);
return vec4(color.rgb, alpha);
}