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87 lines
2.7 KiB
GLSL
87 lines
2.7 KiB
GLSL
#ifndef LIB_MATERIAL_ALPHA
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#define LIB_MATERIAL_ALPHA
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#define FUNC_NEVER 512 // 0x0200
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#define FUNC_LESS 513 // 0x0201
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#define FUNC_EQUAL 514 // 0x0202
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#define FUNC_LEQUAL 515 // 0x0203
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#define FUNC_GREATER 516 // 0x0204
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#define FUNC_NOTEQUAL 517 // 0x0205
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#define FUNC_GEQUAL 518 // 0x0206
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#define FUNC_ALWAYS 519 // 0x0207
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float mipmapLevel(vec2 scaleduv)
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{
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vec2 dUVdx = dFdx(scaleduv);
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vec2 dUVdy = dFdy(scaleduv);
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float maxDUVSquared = max(dot(dUVdx, dUVdx), dot(dUVdy, dUVdy));
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return max(0.0, 0.5 * log2(maxDUVSquared));
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}
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float coveragePreservingAlphaScale(sampler2D diffuseMap, vec2 uv)
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{
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#if @adjustCoverage
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vec2 textureSize;
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#if @useGPUShader4
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textureSize = textureSize2D(diffuseMap, 0);
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#else
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textureSize = vec2(256.0);
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#endif
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return 1.0 + mipmapLevel(uv * textureSize) * 0.25;
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#else
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return 1.0;
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#endif
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}
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float alphaTest(float alpha, float ref)
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{
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#if @alphaToCoverage
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float coverageAlpha = (alpha - clamp(ref, 0.0001, 0.9999)) / max(fwidth(alpha), 0.0001) + 0.5;
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// Some functions don't make sense with A2C or are a pain to think about and no meshes use them anyway
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// Use regular alpha testing in such cases until someone complains.
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#if @alphaFunc == FUNC_NEVER
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discard;
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#elif @alphaFunc == FUNC_LESS
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return 1.0 - coverageAlpha;
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#elif @alphaFunc == FUNC_EQUAL
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if (alpha != ref)
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discard;
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#elif @alphaFunc == FUNC_LEQUAL
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return 1.0 - coverageAlpha;
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#elif @alphaFunc == FUNC_GREATER
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return coverageAlpha;
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#elif @alphaFunc == FUNC_NOTEQUAL
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if (alpha == ref)
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discard;
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#elif @alphaFunc == FUNC_GEQUAL
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return coverageAlpha;
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#endif
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#else
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#if @alphaFunc == FUNC_NEVER
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discard;
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#elif @alphaFunc == FUNC_LESS
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if (alpha >= ref)
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discard;
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#elif @alphaFunc == FUNC_EQUAL
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if (alpha != ref)
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discard;
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#elif @alphaFunc == FUNC_LEQUAL
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if (alpha > ref)
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discard;
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#elif @alphaFunc == FUNC_GREATER
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if (alpha <= ref)
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discard;
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#elif @alphaFunc == FUNC_NOTEQUAL
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if (alpha == ref)
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discard;
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#elif @alphaFunc == FUNC_GEQUAL
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if (alpha < ref)
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discard;
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#endif
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#endif
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return alpha;
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}
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#endif
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