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// common shadow map functions shared by terrainDecails.frag / tcmask_instanced.frag shaders
float getShadowMapDepthComp(vec2 base_uv, float u, float v, vec2 shadowMapSizeInv, int cascadeIndex, float z)
{
vec2 uv = base_uv + vec2(u, v) * shadowMapSizeInv;
return texture( shadowMap, vec4(uv, cascadeIndex, z) );
}
float getShadowVisibility(vec3 fragPosModelSpace, vec3 fragPosViewSpace, float NdotL, float offset)
{
#if WZ_SHADOW_MODE == 0 || WZ_SHADOW_FILTER_SIZE == 0
// no shadow-mapping
return 1.0;
#else
// Shadow Mapping
float depthValue = abs(fragPosViewSpace.z/gl_FragCoord.w);
int cascadeIndex = 0;
// for (int i = 0; i < WZ_SHADOW_CASCADES_COUNT - 1; ++i)
// {
// if (depthValue >= ShadowMapCascadeSplits[i])
// {
// cascadeIndex = i + 1;
// }
// }
// unrolled loop, using vec4 swizzles
#if WZ_SHADOW_CASCADES_COUNT > 1
if (depthValue >= ShadowMapCascadeSplits.x)
{
cascadeIndex = 1;
}
#endif
#if WZ_SHADOW_CASCADES_COUNT > 2
if (depthValue >= ShadowMapCascadeSplits.y)
{
cascadeIndex = 2;
}
#endif
#if WZ_SHADOW_CASCADES_COUNT > 3
if (depthValue >= ShadowMapCascadeSplits.z)
{
cascadeIndex = 3;
}
#endif
vec4 shadowPos = ShadowMapMVPMatrix[cascadeIndex] * vec4(fragPosModelSpace, 1.0);
vec3 pos = shadowPos.xyz / shadowPos.w;
float bias = (sqrt(1.0 - NdotL*NdotL) / NdotL) * offset; // should be faster than tan(acos(NdotL))
#if WZ_SHADOW_MODE == 1
// Optimized PCF algorithm
// See: https://therealmjp.github.io/posts/shadow-maps/
// And: http://www.ludicon.com/castano/blog/articles/shadow-mapping-summary-part-1/
vec2 shadowMapSize = vec2(float(ShadowMapSize), float(ShadowMapSize));
float visibility = 0.f;
float lightDepth = pos.z;
lightDepth += bias;
vec2 uv = pos.xy * shadowMapSize; // 1 unit - 1 texel
vec2 shadowMapSizeInv = 1.0 / shadowMapSize;
vec2 base_uv;
base_uv.x = floor(uv.x + 0.5);
base_uv.y = floor(uv.y + 0.5);
float s = (uv.x + 0.5 - base_uv.x);
float t = (uv.y + 0.5 - base_uv.y);
base_uv -= vec2(0.5, 0.5);
base_uv *= shadowMapSizeInv;
float sum = 0.0;
#if WZ_SHADOW_FILTER_SIZE <= 3
// 3x3
float uw0 = (3.0 - 2.0 * s);
float uw1 = (1.0 + 2.0 * s);
float u0 = (2.0 - s) / uw0 - 1.0;
float u1 = s / uw1 + 1.0;
float vw0 = (3.0 - 2.0 * t);
float vw1 = (1.0 + 2.0 * t);
float v0 = (2.0 - t) / vw0 - 1.0;
float v1 = t / vw1 + 1.0;
sum += uw0 * vw0 * getShadowMapDepthComp(base_uv, u0, v0, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw1 * vw0 * getShadowMapDepthComp(base_uv, u1, v0, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw0 * vw1 * getShadowMapDepthComp(base_uv, u0, v1, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw1 * vw1 * getShadowMapDepthComp(base_uv, u1, v1, shadowMapSizeInv, cascadeIndex, lightDepth);
visibility = sum * 1.0 / 16.0;
#elif WZ_SHADOW_FILTER_SIZE > 3 && WZ_SHADOW_FILTER_SIZE <= 5
// 5x5
float uw0 = (4.0 - 3.0 * s);
float uw1 = 7.0;
float uw2 = (1.0 + 3.0 * s);
float u0 = (3.0 - 2.0 * s) / uw0 - 2.0;
float u1 = (3.0 + s) / uw1;
float u2 = s / uw2 + 2.0;
float vw0 = (4.0 - 3.0 * t);
float vw1 = 7.0;
float vw2 = (1.0 + 3.0 * t);
float v0 = (3.0 - 2.0 * t) / vw0 - 2.0;
float v1 = (3.0 + t) / vw1;
float v2 = t / vw2 + 2.0;
sum += uw0 * vw0 * getShadowMapDepthComp(base_uv, u0, v0, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw1 * vw0 * getShadowMapDepthComp(base_uv, u1, v0, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw2 * vw0 * getShadowMapDepthComp(base_uv, u2, v0, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw0 * vw1 * getShadowMapDepthComp(base_uv, u0, v1, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw1 * vw1 * getShadowMapDepthComp(base_uv, u1, v1, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw2 * vw1 * getShadowMapDepthComp(base_uv, u2, v1, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw0 * vw2 * getShadowMapDepthComp(base_uv, u0, v2, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw1 * vw2 * getShadowMapDepthComp(base_uv, u1, v2, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw2 * vw2 * getShadowMapDepthComp(base_uv, u2, v2, shadowMapSizeInv, cascadeIndex, lightDepth);
visibility = sum * 1.0 / 144.0;
#else
// WZ_SHADOW_FILTER_SIZE > 5
// 7x7
float uw0 = (5.0 * s - 6.0);
float uw1 = (11.0 * s - 28.0);
float uw2 = -(11.0 * s + 17.0);
float uw3 = -(5.0 * s + 1.0);
float u0 = (4.0 * s - 5.0) / uw0 - 3.0;
float u1 = (4.0 * s - 16.0) / uw1 - 1.0;
float u2 = -(7.0 * s + 5.0) / uw2 + 1.0;
float u3 = -s / uw3 + 3.0;
float vw0 = (5.0 * t - 6.0);
float vw1 = (11.0 * t - 28.0);
float vw2 = -(11.0 * t + 17.0);
float vw3 = -(5.0 * t + 1.0);
float v0 = (4.0 * t - 5.0) / vw0 - 3.0;
float v1 = (4.0 * t - 16.0) / vw1 - 1.0;
float v2 = -(7.0 * t + 5.0) / vw2 + 1.0;
float v3 = -t / vw3 + 3.0;
sum += uw0 * vw0 * getShadowMapDepthComp(base_uv, u0, v0, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw1 * vw0 * getShadowMapDepthComp(base_uv, u1, v0, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw2 * vw0 * getShadowMapDepthComp(base_uv, u2, v0, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw3 * vw0 * getShadowMapDepthComp(base_uv, u3, v0, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw0 * vw1 * getShadowMapDepthComp(base_uv, u0, v1, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw1 * vw1 * getShadowMapDepthComp(base_uv, u1, v1, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw2 * vw1 * getShadowMapDepthComp(base_uv, u2, v1, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw3 * vw1 * getShadowMapDepthComp(base_uv, u3, v1, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw0 * vw2 * getShadowMapDepthComp(base_uv, u0, v2, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw1 * vw2 * getShadowMapDepthComp(base_uv, u1, v2, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw2 * vw2 * getShadowMapDepthComp(base_uv, u2, v2, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw3 * vw2 * getShadowMapDepthComp(base_uv, u3, v2, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw0 * vw3 * getShadowMapDepthComp(base_uv, u0, v3, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw1 * vw3 * getShadowMapDepthComp(base_uv, u1, v3, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw2 * vw3 * getShadowMapDepthComp(base_uv, u2, v3, shadowMapSizeInv, cascadeIndex, lightDepth);
sum += uw3 * vw3 * getShadowMapDepthComp(base_uv, u3, v3, shadowMapSizeInv, cascadeIndex, lightDepth);
visibility = sum * 1.0 / 2704.0;
#endif
// end WZ_SHADOW_FILTER_SIZE checks
#endif
// end WZ_SHADOW_MODE == 1
#if WZ_SHADOW_MODE == 2
// PCF
float visibility = texture( shadowMap, vec4(pos.xy, cascadeIndex, (pos.z+bias)) );
#if WZ_SHADOW_FILTER_SIZE >= 2
const float edgeVal = 0.5+float((WZ_SHADOW_FILTER_SIZE-2)/2);
const float startVal = -edgeVal;
const float endVal = edgeVal + 0.5;
float texelIncrement = 1.0/float(ShadowMapSize);
const float visibilityIncrement = 0.5 / WZ_SHADOW_FILTER_SIZE;
for (float y=startVal; y<endVal; y+=1.0)
{
for (float x=startVal; x<endVal; x+=1.0)
{
visibility -= visibilityIncrement*(1.0-texture( shadowMap, vec4(pos.xy + vec2(x*texelIncrement, y*texelIncrement), cascadeIndex, (pos.z+bias)) ));
}
}
#endif
// end WZ_SHADOW_FILTER_SIZE >= 2
#endif
// end WZ_SHADOW_MODE == 2
visibility = clamp(visibility, 0.5, 1.0); //to-do: min value must be the value of final ambient component
return visibility;
#endif
}
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