playcanvas
Version:
PlayCanvas WebGL game engine
62 lines (60 loc) • 3 kB
JavaScript
var shadowEVSMPS = `
float linstep(float a, float b, float v) {
return saturate((v - a) / (b - a));
}
float reduceLightBleeding(float pMax, float amount) {
return linstep(amount, 1.0, pMax);
}
float chebyshevUpperBound(vec2 moments, float mean, float minVariance, float lightBleedingReduction) {
float variance = moments.y - (moments.x * moments.x);
variance = max(variance, minVariance);
float d = mean - moments.x;
float pMax = variance / (variance + (d * d));
pMax = reduceLightBleeding(pMax, lightBleedingReduction);
return (mean <= moments.x ? 1.0 : pMax);
}
float calculateEVSM(vec3 moments, float Z, float vsmBias, float exponent) {
Z = 2.0 * Z - 1.0;
float warpedDepth = exp(exponent * Z);
moments.xy += vec2(warpedDepth, warpedDepth*warpedDepth) * (1.0 - moments.z);
float VSMBias = vsmBias;
float depthScale = VSMBias * exponent * warpedDepth;
float minVariance1 = depthScale * depthScale;
return chebyshevUpperBound(moments.xy, warpedDepth, minVariance1, 0.1);
}
float VSM16(TEXTURE_ACCEPT(tex), vec2 texCoords, float resolution, float Z, float vsmBias, float exponent) {
vec3 moments = texture2DLod(tex, texCoords, 0.0).xyz;
return calculateEVSM(moments, Z, vsmBias, exponent);
}
float getShadowVSM16(TEXTURE_ACCEPT(shadowMap), vec3 shadowCoord, vec4 shadowParams, float exponent) {
return VSM16(TEXTURE_PASS(shadowMap), shadowCoord.xy, shadowParams.x, shadowCoord.z, shadowParams.y, exponent);
}
float getShadowSpotVSM16(TEXTURE_ACCEPT(shadowMap), vec3 shadowCoord, vec4 shadowParams, float exponent, vec3 lightDir) {
return VSM16(TEXTURE_PASS(shadowMap), shadowCoord.xy, shadowParams.x, length(lightDir) * shadowParams.w + shadowParams.z, shadowParams.y, exponent);
}
float VSM32(TEXTURE_ACCEPT(tex), vec2 texCoords, float resolution, float Z, float vsmBias, float exponent) {
vec3 moments = texture2DLod(tex, texCoords, 0.0).xyz;
float pixelSize = 1.0 / resolution;
texCoords -= vec2(pixelSize);
vec3 s00 = texture2DLod(tex, texCoords, 0.0).xyz;
vec3 s10 = texture2DLod(tex, texCoords + vec2(pixelSize, 0), 0.0).xyz;
vec3 s01 = texture2DLod(tex, texCoords + vec2(0, pixelSize), 0.0).xyz;
vec3 s11 = texture2DLod(tex, texCoords + vec2(pixelSize), 0.0).xyz;
vec2 fr = fract(texCoords * resolution);
vec3 h0 = mix(s00, s10, fr.x);
vec3 h1 = mix(s01, s11, fr.x);
vec3 moments = mix(h0, h1, fr.y);
return calculateEVSM(moments, Z, vsmBias, exponent);
}
float getShadowVSM32(TEXTURE_ACCEPT(shadowMap), vec3 shadowCoord, vec4 shadowParams, float exponent) {
return VSM32(TEXTURE_PASS(shadowMap), shadowCoord.xy, shadowParams.x, shadowCoord.z, shadowParams.y, exponent);
}
float getShadowSpotVSM32(TEXTURE_ACCEPT(shadowMap), vec3 shadowCoord, vec4 shadowParams, float exponent, vec3 lightDir) {
float Z = length(lightDir) * shadowParams.w + shadowParams.z;
return VSM32(TEXTURE_PASS(shadowMap), shadowCoord.xy, shadowParams.x, Z, shadowParams.y, exponent);
}
`;
export { shadowEVSMPS as default };