Variable volumetricFogMeshFragmentShaderConst
volumetricFogMeshFragmentShader: "\n uniform float uTime;\n uniform vec3 uFogColor;\n uniform float uFogDensity;\n uniform float uFogHeight;\n uniform vec3 uCameraPosition;\n \n varying vec3 vWorldPosition;\n varying vec3 vViewDirection;\n \n float hash(vec3 p) {\n p = fract(p * vec3(443.897, 441.423, 437.195));\n p += dot(p, p.yxz + 19.19);\n return fract((p.x + p.y) * p.z);\n }\n \n float noise(vec3 p) {\n vec3 i = floor(p);\n vec3 f = fract(p);\n f = f * f * (3.0 - 2.0 * f);\n \n return mix(\n mix(mix(hash(i), hash(i + vec3(1,0,0)), f.x),\n mix(hash(i + vec3(0,1,0)), hash(i + vec3(1,1,0)), f.x), f.y),\n mix(mix(hash(i + vec3(0,0,1)), hash(i + vec3(1,0,1)), f.x),\n mix(hash(i + vec3(0,1,1)), hash(i + vec3(1,1,1)), f.x), f.y),\n f.z\n );\n }\n \n float fbm(vec3 p) {\n float value = 0.0;\n float amplitude = 0.5;\n for (int i = 0; i < 4; i++) {\n value += amplitude * noise(p);\n p *= 2.0;\n amplitude *= 0.5;\n }\n return value;\n }\n \n void main() {\n // Height-based density\n float heightFactor = exp(-max(0.0, vWorldPosition.y) / uFogHeight);\n \n // Animated noise for volumetric appearance\n vec3 noisePos = vWorldPosition * 0.02 + vec3(uTime * 0.02, 0.0, uTime * 0.01);\n float noiseVal = fbm(noisePos);\n \n float fogAmount = uFogDensity * heightFactor * (0.5 + 0.5 * noiseVal);\n \n // Fade near edges\n float dist = length(vWorldPosition.xz - uCameraPosition.xz);\n float edgeFade = smoothstep(80.0, 40.0, dist);\n \n fogAmount *= edgeFade;\n \n gl_FragColor = vec4(uFogColor, fogAmount);\n }\n" = ...