71 lines
1.7 KiB
Plaintext
71 lines
1.7 KiB
Plaintext
uniform sampler2D Texture;
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uniform sampler2D uShadowMap;
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uniform vec3 uLightDir;
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varying vec2 texCoord;
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varying vec4 fragPosLightSpace;
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varying vec3 fragNormal;
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float computeShadow(vec4 lightSpacePos, vec3 normal)
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{
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vec3 projCoords = lightSpacePos.xyz / lightSpacePos.w;
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projCoords = projCoords * 0.5 + 0.5;
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if (projCoords.x < 0.0 || projCoords.x > 1.0 ||
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projCoords.y < 0.0 || projCoords.y > 1.0 ||
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projCoords.z > 1.0)
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{
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return 0.0;
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}
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float currentDepth = projCoords.z;
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// Slope-dependent bias: large for grazing angles, tiny for surfaces facing the light
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float bias = 0.0004;
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if (dot(normal, normal) > 0.001)
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{
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float cosTheta = dot(normalize(normal), -normalize(uLightDir));
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bias = max(0.002 * (1.0 - cosTheta), 0.0002);
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}
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// 3x3 PCF (percentage-closer filtering) for softer shadows
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float shadow = 0.0;
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float texelSize = 1.0 / 2048.0;
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for (int x = -1; x <= 1; x++)
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{
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for (int y = -1; y <= 1; y++)
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{
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float pcfDepth = texture2D(uShadowMap, projCoords.xy + vec2(float(x), float(y)) * texelSize).r;
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shadow += currentDepth - bias > pcfDepth ? 1.0 : 0.0;
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}
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}
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shadow /= 9.0;
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return shadow;
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}
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void main()
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{
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vec4 color = texture2D(Texture, texCoord);
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float ambient = 0.4;
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float diffuseStrength = 0.6;
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// Compute diffuse term; if normals are missing (zero-length) treat as fully lit
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float diffuse = 1.0;
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vec3 n = fragNormal;
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if (dot(n, n) > 0.001)
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{
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n = normalize(n);
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diffuse = max(dot(n, -normalize(uLightDir)), 0.0);
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}
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float shadow = computeShadow(fragPosLightSpace, fragNormal);
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// Shadow dims only the diffuse contribution; ambient is always present
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float lighting = ambient + diffuseStrength * diffuse * (1.0 - shadow);
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color.rgb *= lighting;
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gl_FragColor = color;
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}
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