playcanvas/build/playcanvas/src/scene/shader-lib/chunks/lit/frag/shadowPCSS.js

PlayCanvas WebGL game engine

var shadowPCSSPS = "\n#define PCSS_SAMPLE_COUNT 16\nuniform float pcssDiskSamples[PCSS_SAMPLE_COUNT];\nuniform float pcssSphereSamples[PCSS_SAMPLE_COUNT];\nvec2 vogelDisk(int sampleIndex, float count, float phi, float r) {\n	const float GoldenAngle = 2.4;\n	float theta = float(sampleIndex) * GoldenAngle + phi;\n	float sine = sin(theta);\n	float cosine = cos(theta);\n	return vec2(r * cosine, r * sine);\n}\nvec3 vogelSphere(int sampleIndex, float count, float phi, float r) {\n	const float GoldenAngle = 2.4;\n	float theta = float(sampleIndex) * GoldenAngle + phi;\n	float weight = float(sampleIndex) / count;\n	return vec3(cos(theta) * r, weight, sin(theta) * r);\n}\nfloat noise(vec2 screenPos) {\n	const float PHI = 1.61803398874989484820459;\n	return fract(sin(dot(screenPos * PHI, screenPos)) * screenPos.x);\n}\nfloat viewSpaceDepth(float depth, mat4 invProjection) {\n	float z = depth * 2.0 - 1.0;\n	vec4 clipSpace = vec4(0.0, 0.0, z, 1.0);\n	vec4 viewSpace = invProjection * clipSpace;\n	return viewSpace.z;\n}\nfloat PCSSBlockerDistance(TEXTURE_ACCEPT(shadowMap), vec2 sampleCoords[PCSS_SAMPLE_COUNT], vec2 shadowCoords, vec2 searchSize, float z, vec4 cameraParams) {\n	float blockers = 0.0;\n	float averageBlocker = 0.0;\n	for (int i = 0; i < PCSS_SAMPLE_COUNT; i++) {\n		vec2 offset = sampleCoords[i] * searchSize;\n		vec2 sampleUV = shadowCoords + offset;\n		float blocker = texture2DLod(shadowMap, sampleUV, 0.0).r;\n		float isBlocking = step(blocker, z);\n		blockers += isBlocking;\n		averageBlocker += blocker * isBlocking;\n	}\n	if (blockers > 0.0)\n		return averageBlocker / blockers;\n	return -1.0;\n}\nfloat PCSS(TEXTURE_ACCEPT(shadowMap), vec3 shadowCoords, vec4 cameraParams, vec2 shadowSearchArea) {\n	float receiverDepth = linearizeDepth(shadowCoords.z, cameraParams);\n	vec2 samplePoints[PCSS_SAMPLE_COUNT];\n	float noise = noise( gl_FragCoord.xy ) * 2.0 * PI;\n	for (int i = 0; i < PCSS_SAMPLE_COUNT; i++) {\n		float pcssPresample = pcssDiskSamples[i];\n		samplePoints[i] = vogelDisk(i, float(PCSS_SAMPLE_COUNT), noise, pcssPresample);\n	}\n	float averageBlocker = PCSSBlockerDistance(TEXTURE_PASS(shadowMap), samplePoints, shadowCoords.xy, shadowSearchArea, receiverDepth, cameraParams);\n	if (averageBlocker == -1.0) {\n		return 1.0;\n	} else {\n		float depthDifference = (receiverDepth - averageBlocker) / 3.0;\n		vec2 filterRadius = depthDifference * shadowSearchArea;\n		float shadow = 0.0;\n		for (int i = 0; i < PCSS_SAMPLE_COUNT; i ++)\n		{\n			vec2 sampleUV = samplePoints[i] * filterRadius;\n			sampleUV = shadowCoords.xy + sampleUV;\n			float depth = texture2DLod(shadowMap, sampleUV, 0.0).r;\n			shadow += step(receiverDepth, depth);\n		}\n		return shadow / float(PCSS_SAMPLE_COUNT);\n	} \n}\n#ifndef WEBGPU\nfloat PCSSCubeBlockerDistance(samplerCube shadowMap, vec3 lightDirNorm, vec3 samplePoints[PCSS_SAMPLE_COUNT], float z, float shadowSearchArea) {\n	float blockers = 0.0;\n	float averageBlocker = 0.0;\n	for (int i = 0; i < PCSS_SAMPLE_COUNT; i++) {\n		vec3 sampleDir = lightDirNorm + samplePoints[i] * shadowSearchArea;\n		sampleDir = normalize(sampleDir);\n		float blocker = textureCubeLod(shadowMap, sampleDir, 0.0).r;\n		float isBlocking = step(blocker, z);\n		blockers += isBlocking;\n		averageBlocker += blocker * isBlocking;\n	}\n	if (blockers > 0.0)\n		return averageBlocker / blockers;\n	return -1.0;\n}\nfloat PCSSCube(samplerCube shadowMap, vec4 shadowParams, vec3 shadowCoords, vec4 cameraParams, float shadowSearchArea, vec3 lightDir) {\n	\n	vec3 samplePoints[PCSS_SAMPLE_COUNT];\n	float noise = noise( gl_FragCoord.xy ) * 2.0 * PI;\n	for (int i = 0; i < PCSS_SAMPLE_COUNT; i++) {\n		float r = pcssSphereSamples[i];\n		samplePoints[i] = vogelSphere(i, float(PCSS_SAMPLE_COUNT), noise, r);\n	}\n	float receiverDepth = length(lightDir) * shadowParams.w + shadowParams.z;\n	vec3 lightDirNorm = normalize(lightDir);\n	\n	float averageBlocker = PCSSCubeBlockerDistance(shadowMap, lightDirNorm, samplePoints, receiverDepth, shadowSearchArea);\n	if (averageBlocker == -1.0) {\n		return 1.0;\n	} else {\n		float filterRadius = ((receiverDepth - averageBlocker) / averageBlocker) * shadowSearchArea;\n		float shadow = 0.0;\n		for (int i = 0; i < PCSS_SAMPLE_COUNT; i++)\n		{\n			vec3 offset = samplePoints[i] * filterRadius;\n			vec3 sampleDir = lightDirNorm + offset;\n			sampleDir = normalize(sampleDir);\n			float depth = textureCubeLod(shadowMap, sampleDir, 0.0).r;\n			shadow += step(receiverDepth, depth);\n		}\n		return shadow / float(PCSS_SAMPLE_COUNT);\n	}\n}\nfloat getShadowPointPCSS(samplerCube shadowMap, vec3 shadowCoord, vec4 shadowParams, vec4 cameraParams, vec2 shadowSearchArea, vec3 lightDir) {\n	return PCSSCube(shadowMap, shadowParams, shadowCoord, cameraParams, shadowSearchArea.x, lightDir);\n}\n#endif\nfloat getShadowSpotPCSS(TEXTURE_ACCEPT(shadowMap), vec3 shadowCoord, vec4 shadowParams, vec4 cameraParams, vec2 shadowSearchArea, vec3 lightDir) {\n	return PCSS(TEXTURE_PASS(shadowMap), shadowCoord, cameraParams, shadowSearchArea);\n}\n";

export { shadowPCSSPS as default };