Variable simpleTerrainFragmentShaderConst
simpleTerrainFragmentShader: "\n uniform vec3 uGroundColor;\n uniform vec3 uRockColor;\n uniform float uRoughness;\n \n varying vec2 vUv;\n varying vec3 vPosition;\n varying vec3 vNormal;\n \n float hash(vec2 p) {\n return fract(sin(dot(p, vec2(127.1, 311.7))) * 43758.5453);\n }\n \n float noise(vec2 p) {\n vec2 i = floor(p);\n vec2 f = fract(p);\n f = f * f * (3.0 - 2.0 * f);\n \n float a = hash(i);\n float b = hash(i + vec2(1.0, 0.0));\n float c = hash(i + vec2(0.0, 1.0));\n float d = hash(i + vec2(1.0, 1.0));\n \n return mix(mix(a, b, f.x), mix(c, d, f.x), f.y);\n }\n \n void main() {\n // Base color with noise variation\n float n = noise(vPosition.xz * 0.5);\n vec3 color = mix(uGroundColor * 0.8, uGroundColor * 1.2, n);\n \n // Add rock color based on slope\n float slope = 1.0 - vNormal.y;\n color = mix(color, uRockColor, smoothstep(0.3, 0.7, slope));\n \n // Simple lighting\n vec3 lightDir = normalize(vec3(1.0, 1.0, 0.5));\n float lighting = max(dot(vNormal, lightDir), 0.3);\n color *= lighting;\n \n // Add roughness variation\n float roughnessNoise = noise(vPosition.xz * 2.0);\n color *= 1.0 - uRoughness * roughnessNoise * 0.3;\n \n gl_FragColor = vec4(color, 1.0);\n }\n" = ...