Variable terrainVertexShaderConst
terrainVertexShader: "\n uniform vec2 biomeCenters[7];\n uniform float biomeRadii[7];\n uniform int biomeTypes[7]; // 0=marsh, 1=forest, 2=desert, 3=tundra, 4=savanna, 5=mountain, 6=scrubland\n \n varying vec2 vUv;\n varying vec3 vPos;\n varying vec3 vWorldPos;\n varying float vElevation;\n varying float vSlope;\n varying vec3 vNormal;\n varying vec3 vTriplanarPos;\n \n // Simple hash noise\n float hash(vec2 p) { \n return fract(1e4 * sin(17.0 * p.x + p.y * 0.1) * (0.1 + abs(sin(p.y * 13.0 + p.x)))); \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 return mix(mix(hash(i), hash(i + vec2(1.0, 0.0)), f.x),\n mix(hash(i + vec2(0.0, 1.0)), hash(i + vec2(1.0, 1.0)), f.x), f.y);\n }\n \n int getBiomeType(vec2 pos) {\n int closestIdx = 0;\n float closestDist = distance(pos, biomeCenters[0]);\n \n for (int i = 1; i < 7; i++) {\n float dist = distance(pos, biomeCenters[i]);\n if (dist < closestDist) {\n closestDist = dist;\n closestIdx = i;\n }\n }\n \n return biomeTypes[closestIdx];\n }\n \n void main() {\n vUv = uv;\n vPos = position;\n \n vec4 worldPos = modelMatrix * vec4(position, 1.0);\n vec2 worldXZ = worldPos.xz;\n \n // Calculate elevation based on biome\n int biomeType = getBiomeType(worldXZ);\n float elevation = 0.0;\n \n // Mountain biome: elevated terrain with slopes up to 45 degrees\n if (biomeType == 5) {\n float n1 = noise(worldXZ * 0.05);\n float n2 = noise(worldXZ * 0.1);\n float n3 = noise(worldXZ * 0.2);\n elevation = n1 * 15.0 + n2 * 8.0 + n3 * 3.0;\n }\n // Tundra: gentle rolling hills\n else if (biomeType == 3) {\n elevation = noise(worldXZ * 0.03) * 2.0;\n }\n // Other biomes: mostly flat with subtle variation\n else {\n elevation = noise(worldXZ * 0.1) * 0.5;\n }\n \n vec3 newPosition = position;\n newPosition.y += elevation;\n \n vElevation = elevation;\n vWorldPos = (modelMatrix * vec4(newPosition, 1.0)).xyz;\n \n // Calculate approximate normal for triplanar mapping\n float dx = noise(worldXZ + vec2(0.1, 0.0)) - noise(worldXZ - vec2(0.1, 0.0));\n float dz = noise(worldXZ + vec2(0.0, 0.1)) - noise(worldXZ - vec2(0.0, 0.1));\n vec3 tangentX = normalize(vec3(1.0, dx * 10.0, 0.0));\n vec3 tangentZ = normalize(vec3(0.0, dz * 10.0, 1.0));\n vNormal = normalize(cross(tangentZ, tangentX));\n \n // Calculate slope for walkability\n vSlope = length(vec2(dx, dz)) * 10.0;\n \n // Store world position for triplanar mapping\n vTriplanarPos = vWorldPos;\n \n gl_Position = projectionMatrix * modelViewMatrix * vec4(newPosition, 1.0);\n }\n" = ...
Terrain shader - PBR textured ground with triplanar mapping and biome-specific elevation
Lifted from Otterfall procedural rendering system.