mirror of
https://github.com/Kelsidavis/WoWee.git
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4fc3689dcc
Skybox: replace sphere-mesh approach with a fullscreen triangle that reconstructs the world-space ray direction analytically via inverse projection/view matrices. Eliminates clip.w=0 degeneracy at the horizon and correctly maps altitude to dir.z in the Z-up coordinate system. Clouds: hemisphere mesh was storing altitude in aPos.y (Y-up convention); the Z-up view matrix projected this sideways, making clouds appear vertical. Store altitude in aPos.z and update the fragment shader to read dir.z as altitude and dir.xy as the horizontal UV plane.
63 lines
1.5 KiB
GLSL
63 lines
1.5 KiB
GLSL
#version 450
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layout(push_constant) uniform Push {
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vec4 cloudColor;
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float density;
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float windOffset;
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} push;
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layout(location = 0) in vec3 vWorldDir;
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layout(location = 0) out vec4 outColor;
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float hash(vec2 p) {
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return fract(sin(dot(p, vec2(127.1, 311.7))) * 43758.5453);
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}
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float noise(vec2 p) {
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vec2 i = floor(p);
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vec2 f = fract(p);
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f = f * f * (3.0 - 2.0 * f);
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float a = hash(i);
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float b = hash(i + vec2(1.0, 0.0));
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float c = hash(i + vec2(0.0, 1.0));
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float d = hash(i + vec2(1.0, 1.0));
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return mix(mix(a, b, f.x), mix(c, d, f.x), f.y);
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}
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float fbm(vec2 p) {
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float val = 0.0;
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float amp = 0.5;
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for (int i = 0; i < 4; i++) {
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val += amp * noise(p);
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p *= 2.0;
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amp *= 0.5;
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}
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return val;
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}
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void main() {
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vec3 dir = normalize(vWorldDir);
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float altitude = dir.z; // Z is up in the Z-up world coordinate system
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if (altitude < 0.0) discard;
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vec2 uv = dir.xy / (altitude + 0.001); // XY is the horizontal plane
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uv += push.windOffset;
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float cloud1 = fbm(uv * 0.8);
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float cloud2 = fbm(uv * 1.6 + 5.0);
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float cloud = cloud1 * 0.7 + cloud2 * 0.3;
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cloud = smoothstep(0.35, 0.65, cloud) * push.density;
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float edgeBreak = noise(uv * 4.0);
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cloud *= smoothstep(0.2, 0.5, edgeBreak);
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float horizonFade = smoothstep(0.0, 0.15, altitude);
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cloud *= horizonFade;
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float edgeSoftness = smoothstep(0.0, 0.3, cloud);
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float alpha = cloud * edgeSoftness;
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if (alpha < 0.01) discard;
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outColor = vec4(push.cloudColor.rgb, alpha);
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}
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