Solara-Shaders/shaders/lib/surface/parallax.glsl
2024-06-22 15:15:55 -04:00

76 lines
2.7 KiB
GLSL

vec4 ReadNormal(vec2 coord) {
coord = fract(coord) * vTexCoordAM.pq + vTexCoordAM.st;
return texture2DGradARB(normals, coord, dcdx, dcdy);
}
vec2 GetParallaxCoord(vec2 texCoord, float parallaxFade, out float surfaceDepth) {
vec2 coord = vTexCoord.st;
surfaceDepth = 1.0;
if (viewVector != viewVector) {
return texCoord;
}
float sampleStep = 1.0 / PARALLAX_QUALITY;
float currentStep = 1.0;
vec2 scaledDir = viewVector.xy * PARALLAX_DEPTH / -viewVector.z;
vec2 stepDir = scaledDir * sampleStep * (1.0 - parallaxFade);
vec3 normalMap = ReadNormal(coord).xyz * 2.0 - 1.0;
float normalCheck = normalMap.x + normalMap.y;
if (parallaxFade >= 1.0 || normalCheck < -1.999) return texCoord;
float depth = ReadNormal(coord).a;
for(int i = 0; i < PARALLAX_QUALITY; i++){
if (currentStep <= depth) break;
coord += stepDir;
depth = ReadNormal(coord).a;
currentStep -= sampleStep;
}
coord = fract(coord.st) * vTexCoordAM.pq + vTexCoordAM.st;
surfaceDepth = currentStep;
return coord;
}
float GetParallaxShadow(float surfaceDepth, float parallaxFade, vec2 coord, vec3 lightVec,
mat3 tbn) {
float parallaxshadow = 1.0;
if(parallaxFade >= 1.0) return 1.0;
float height = surfaceDepth;
if(height > 1.0 - 0.5 / PARALLAX_QUALITY) return 1.0;
vec3 parallaxdir = tbn * lightVec;
parallaxdir.xy *= PARALLAX_DEPTH * SELF_SHADOW_ANGLE;
vec2 newvTexCoord = (coord - vTexCoordAM.st) / vTexCoordAM.pq;
float sampleStep = 0.32 / SELF_SHADOW_QUALITY;
vec2 ptexCoord = fract(newvTexCoord + parallaxdir.xy * sampleStep) *
vTexCoordAM.pq + vTexCoordAM.st;
float texHeight = texture2DGradARB(normals, coord, dcdx, dcdy).a;
float texHeightOffset = texture2DGradARB(normals, ptexCoord, dcdx, dcdy).a;
float texFactor = clamp((height - texHeightOffset) / sampleStep + 1.0, 0.0, 1.0);
height = mix(height, texHeight, texFactor);
for(int i = 0; i < SELF_SHADOW_QUALITY; i++) {
float currentHeight = height + parallaxdir.z * sampleStep * i;
vec2 parallaxCoord = fract(newvTexCoord + parallaxdir.xy * i * sampleStep) *
vTexCoordAM.pq + vTexCoordAM.st;
float offsetHeight = texture2DGradARB(normals, parallaxCoord, dcdx, dcdy).a;
float sampleShadow = clamp(1.0 - (offsetHeight - currentHeight) * SELF_SHADOW_STRENGTH, 0.0, 1.0);
parallaxshadow = min(parallaxshadow, sampleShadow);
if (parallaxshadow < 0.01) break;
}
parallaxshadow *= parallaxshadow;
parallaxshadow = mix(parallaxshadow, 1.0, parallaxFade);
return parallaxshadow;
}