279 lines
7.5 KiB
GLSL
279 lines
7.5 KiB
GLSL
#[compute]
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#version 450
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// Workgroup size
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layout(local_size_x = 4, local_size_y = 4, local_size_z = 4) in;
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// Storage buffer
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layout(set = 0, binding = 0, std430) buffer DataBuffer {
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float sample_points[];
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} voxels;
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layout(set = 0, binding = 1) uniform Params {
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int world_size;
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float threshold;
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float u_time;
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} params;
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layout(set = 0, binding = 2, std430) buffer SurfaceBuffer {
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float surface_points[];
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} surface;
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layout(set = 0, binding = 3, std430) buffer IndexBuffer {
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uint indices[];
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} mesh_indices;
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layout(set = 0, binding = 4, std430) buffer Counter {
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uint count;
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} index_count;
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layout(set = 0, binding = 5, std430) buffer NormalsBuffer {
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float normals[];
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} normal;
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layout(set = 0, binding = 6, std430) buffer ChunkPos {
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float position_array[];
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} chunk;
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layout(set = 0, binding = 7, std430) buffer PlayerEdits {
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float position_size_array[];
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} edits;
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uint index3(uint x, uint y, uint z) {
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return x + y * params.world_size + z * params.world_size * params.world_size;
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}
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void store_surface_point(uint idx, vec3 pos) {
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uint base = idx * 3u;
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surface.surface_points[base + 0u] = pos.x;
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surface.surface_points[base + 1u] = pos.y;
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surface.surface_points[base + 2u] = pos.z;
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}
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//
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// Description : Array and textureless GLSL 2D/3D/4D simplex
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// noise functions.
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// Author : Ian McEwan, Ashima Arts.
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// Maintainer : stegu
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// Lastmod : 20201014 (stegu)
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// License : Copyright (C) 2011 Ashima Arts. All rights reserved.
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// Distributed under the MIT License. See LICENSE file.
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// https://github.com/ashima/webgl-noise
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// https://github.com/stegu/webgl-noise
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//
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vec3 mod289(vec3 x) {
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return x - floor(x * (1.0 / 289.0)) * 289.0;
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}
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vec4 mod289(vec4 x) {
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return x - floor(x * (1.0 / 289.0)) * 289.0;
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}
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vec4 permute(vec4 x) {
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return mod289(((x*34.0)+10.0)*x);
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}
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vec4 taylorInvSqrt(vec4 r)
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{
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return 1.79284291400159 - 0.85373472095314 * r;
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}
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float sdsphere(vec3 p, float radius) {
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return length(p) - radius;
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}
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float snoise(vec3 v)
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{
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const vec2 C = vec2(1.0/6.0, 1.0/3.0) ;
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const vec4 D = vec4(0.0, 0.5, 1.0, 2.0);
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// First corner
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vec3 i = floor(v + dot(v, C.yyy) );
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vec3 x0 = v - i + dot(i, C.xxx) ;
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// Other corners
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vec3 g = step(x0.yzx, x0.xyz);
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vec3 l = 1.0 - g;
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vec3 i1 = min( g.xyz, l.zxy );
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vec3 i2 = max( g.xyz, l.zxy );
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// x0 = x0 - 0.0 + 0.0 * C.xxx;
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// x1 = x0 - i1 + 1.0 * C.xxx;
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// x2 = x0 - i2 + 2.0 * C.xxx;
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// x3 = x0 - 1.0 + 3.0 * C.xxx;
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vec3 x1 = x0 - i1 + C.xxx;
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vec3 x2 = x0 - i2 + C.yyy; // 2.0*C.x = 1/3 = C.y
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vec3 x3 = x0 - D.yyy; // -1.0+3.0*C.x = -0.5 = -D.y
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// Permutations
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i = mod289(i);
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vec4 p = permute( permute( permute(
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i.z + vec4(0.0, i1.z, i2.z, 1.0 ))
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+ i.y + vec4(0.0, i1.y, i2.y, 1.0 ))
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+ i.x + vec4(0.0, i1.x, i2.x, 1.0 ));
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// Gradients: 7x7 points over a square, mapped onto an octahedron.
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// The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
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float n_ = 0.142857142857; // 1.0/7.0
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vec3 ns = n_ * D.wyz - D.xzx;
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vec4 j = p - 49.0 * floor(p * ns.z * ns.z); // mod(p,7*7)
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vec4 x_ = floor(j * ns.z);
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vec4 y_ = floor(j - 7.0 * x_ ); // mod(j,N)
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vec4 x = x_ *ns.x + ns.yyyy;
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vec4 y = y_ *ns.x + ns.yyyy;
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vec4 h = 1.0 - abs(x) - abs(y);
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vec4 b0 = vec4( x.xy, y.xy );
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vec4 b1 = vec4( x.zw, y.zw );
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//vec4 s0 = vec4(lessThan(b0,0.0))*2.0 - 1.0;
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//vec4 s1 = vec4(lessThan(b1,0.0))*2.0 - 1.0;
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vec4 s0 = floor(b0)*2.0 + 1.0;
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vec4 s1 = floor(b1)*2.0 + 1.0;
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vec4 sh = -step(h, vec4(0.0));
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vec4 a0 = b0.xzyw + s0.xzyw*sh.xxyy ;
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vec4 a1 = b1.xzyw + s1.xzyw*sh.zzww ;
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vec3 p0 = vec3(a0.xy,h.x);
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vec3 p1 = vec3(a0.zw,h.y);
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vec3 p2 = vec3(a1.xy,h.z);
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vec3 p3 = vec3(a1.zw,h.w);
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//Normalise gradients
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vec4 norm = taylorInvSqrt(vec4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3)));
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p0 *= norm.x;
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p1 *= norm.y;
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p2 *= norm.z;
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p3 *= norm.w;
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// Mix final noise value
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vec4 m = max(0.5 - vec4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0);
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m = m * m;
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return 105.0 * dot( m*m, vec4( dot(p0,x0), dot(p1,x1),
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dot(p2,x2), dot(p3,x3) ) ) + params.threshold;
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}
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const ivec3 AXIS[3] = ivec3[](
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ivec3(1,0,0),
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ivec3(0,1,0),
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ivec3(0,0,1)
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);
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const ivec3 SURFACE_AXIS[8] = ivec3[](
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ivec3(1,0,0),
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ivec3(0,1,0),
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ivec3(0,0,1),
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ivec3(1,0,1),
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ivec3(0,1,1),
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ivec3(1,1,0),
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ivec3(1,1,1),
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ivec3(0,0,0)
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);
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// The 12 edges of a cube (pairs of corner indices 0-7)
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const ivec2 EDGE_CORNERS[12] = ivec2[](
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ivec2(0,1), ivec2(1,2), ivec2(2,3), ivec2(3,0), // Bottom face edges
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ivec2(4,5), ivec2(5,6), ivec2(6,7), ivec2(7,4), // Top face edges
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ivec2(0,4), ivec2(1,5), ivec2(2,6), ivec2(3,7) // Vertical edges
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);
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// The 8 corners of a cube
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const ivec3 CORNERS[8] = ivec3[](
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ivec3(0,0,0), ivec3(1,0,0), ivec3(1,1,0), ivec3(0,1,0),
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ivec3(0,0,1), ivec3(1,0,1), ivec3(1,1,1), ivec3(0,1,1)
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);
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float get_noise_at(vec3 p) {
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float chunk_x = chunk.position_array[0] * -.5;
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float chunk_y = chunk.position_array[1] * -.5;
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float chunk_z = chunk.position_array[2] * -.5;
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p = p - vec3(chunk_x, chunk_y, chunk_z);
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p = p / 20.0;
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float return_value = 10000.0;
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for (int i = 0; i < edits.position_size_array.length(); i += 4){
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return_value = min(return_value, sdsphere(p + vec3(edits.position_size_array[i] * -0.025, edits.position_size_array[i + 1] * -0.025, edits.position_size_array[i + 2] * -0.025), edits.position_size_array[i + 3]));
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}
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return_value = min(return_value, snoise(p));
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return return_value;
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}
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// Calculate normal using central difference
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vec3 calculate_normal(vec3 p) {
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float e = 0.01; // Small epsilon
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float dx = get_noise_at(p + vec3(e, 0, 0)) - get_noise_at(p - vec3(e, 0, 0));
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float dy = get_noise_at(p + vec3(0, e, 0)) - get_noise_at(p - vec3(0, e, 0));
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float dz = get_noise_at(p + vec3(0, 0, e)) - get_noise_at(p - vec3(0, 0, e));
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return normalize(vec3(dx, dy, dz));
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}
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vec3 grid_to_world(uvec3 grid_id) {
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return (vec3(grid_id) - params.world_size / 2.0) * 0.5;
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}
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void main() {
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ivec3 id = ivec3(gl_GlobalInvocationID);
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if (any(greaterThanEqual(id, uvec3(params.world_size)))) return;
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vec3 p = grid_to_world(id);
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uint idx = index3(id.x, id.y, id.z);
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voxels.sample_points[idx] = get_noise_at(p);
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memoryBarrierBuffer();
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barrier();
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vec3 intersection_sum = vec3(0.0);
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uint count = 0;
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// Dual Contouring requires checking all 12 edges of the voxel.
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// If ANY of these 12 edges has a sign change, this voxel MUST have a vertex.
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for (int i = 0; i < 12; i++) {
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ivec3 c1_off = CORNERS[EDGE_CORNERS[i].x];
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ivec3 c2_off = CORNERS[EDGE_CORNERS[i].y];
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uvec3 c1 = id + uvec3(c1_off);
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uvec3 c2 = id + uvec3(c2_off);
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// Bounds check to prevent sampling noise outside the allocated buffer
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if (any(greaterThanEqual(c1, uvec3(params.world_size))) ||
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any(greaterThanEqual(c2, uvec3(params.world_size)))) continue;
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float d1 = get_noise_at(grid_to_world(c1));
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float d2 = get_noise_at(grid_to_world(c2));
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// Standard sign-change test
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if ((d1 < 0.0) != (d2 < 0.0) && d1 != -d2) {
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// Linear interpolation to find the exact crossing point on the edge
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float t = d1 / (d1 - d2);
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intersection_sum += mix(vec3(c1), vec3(c2), t);
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count++;
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}
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}
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if (count > 0) {
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vec3 avg_pos = intersection_sum / float(count);
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store_surface_point(idx, avg_pos);
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// Normals should be calculated at the exact averaged surface point
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vec3 world_p = (avg_pos - params.world_size / 2.0) * vec3(0.5);
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vec3 n = calculate_normal(world_p);
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uint base = idx * 3u;
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normal.normals[base + 0] = n.x;
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normal.normals[base + 1] = n.y;
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normal.normals[base + 2] = n.z;
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} else {
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// Explicitly mark empty voxels to prevent them from being used in Pass 2
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store_surface_point(idx, vec3(-1.0));
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}
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}
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