88 lines
2.7 KiB
GLSL
88 lines
2.7 KiB
GLSL
#version 330 core
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in vec2 vUV;
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in vec3 vWorldPos;
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out vec4 FragColor;
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uniform sampler2D uHeightTex;
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uniform float uMinV;
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uniform float uMaxV;
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uniform float uHeightScale;
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uniform vec2 uTexelSize;
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uniform vec2 uPlaneSize;
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uniform vec3 uCameraPos;
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uniform vec3 uLightDir;
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uniform vec3 uColorZero;
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uniform vec3 uColorLow;
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uniform vec3 uColorMid;
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uniform vec3 uColorHigh;
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float saturate(float x) { return clamp(x, 0.0, 1.0); }
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float value01(float v) {
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return saturate((v - uMinV) / max(uMaxV - uMinV, 1e-6));
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}
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float maxNeighborValue(vec2 uv) {
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vec2 texSizeF = 1.0 / uTexelSize;
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ivec2 texSizeI = ivec2(max(vec2(1.0), floor(texSizeF + 0.5)));
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ivec2 maxCoord = texSizeI - ivec2(1);
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vec2 texelF = clamp(uv * texSizeF, vec2(0.0), vec2(maxCoord));
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ivec2 base = ivec2(floor(texelF));
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ivec2 base10 = min(base + ivec2(1, 0), maxCoord);
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ivec2 base01 = min(base + ivec2(0, 1), maxCoord);
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ivec2 base11 = min(base + ivec2(1, 1), maxCoord);
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float v00 = texelFetch(uHeightTex, base, 0).r;
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float v10 = texelFetch(uHeightTex, base10, 0).r;
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float v01 = texelFetch(uHeightTex, base01, 0).r;
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float v11 = texelFetch(uHeightTex, base11, 0).r;
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return max(max(v00, v10), max(v01, v11));
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}
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vec3 colorRamp(float t) {
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if (t < 0.5) {
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return mix(uColorLow, uColorMid, t / 0.5);
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}
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return mix(uColorMid, uColorHigh, (t - 0.5) / 0.5);
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}
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void main() {
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float vC = texture(uHeightTex, vUV).r;
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bool isZero = abs(vC) <= 1e-6;
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float t = value01(vC);
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float m = maxNeighborValue(vUV);
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float eps = max(1e-4, 0.001 * (uMaxV - uMinV));
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float force = smoothstep(uMaxV - eps, uMaxV, m);
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t = max(t, force);
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vec3 base = isZero ? uColorZero : colorRamp(t);
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float vL = texture(uHeightTex, vUV - vec2(uTexelSize.x, 0.0)).r;
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float vR = texture(uHeightTex, vUV + vec2(uTexelSize.x, 0.0)).r;
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float vD = texture(uHeightTex, vUV - vec2(0.0, uTexelSize.y)).r;
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float vU = texture(uHeightTex, vUV + vec2(0.0, uTexelSize.y)).r;
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float hL = value01(vL) * uHeightScale;
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float hR = value01(vR) * uHeightScale;
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float hD = value01(vD) * uHeightScale;
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float hU = value01(vU) * uHeightScale;
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float dx = max(1e-6, uPlaneSize.x * uTexelSize.x);
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float dy = max(1e-6, uPlaneSize.y * uTexelSize.y);
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float dHx = (hR - hL) / (2.0 * dx);
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float dHy = (hU - hD) / (2.0 * dy);
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vec3 N = normalize(vec3(-dHx, -dHy, -1.0));
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vec3 L = normalize(uLightDir);
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vec3 V = normalize(uCameraPos - vWorldPos);
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vec3 H = normalize(L + V);
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float diff = saturate(dot(N, L));
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float spec = pow(saturate(dot(N, H)), 24.0);
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vec3 col = base * (0.50 + 0.50 * diff);
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col += vec3(1.0) * spec * 0.18;
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FragColor = vec4(clamp(col, 0.0, 1.0), 1.0);
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}
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