200 lines
6.1 KiB
GLSL
200 lines
6.1 KiB
GLSL
#[compute]
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#version 450
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// Workgroup size
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layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) 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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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 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) ) );
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}
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void main() {
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uvec3 id = gl_GlobalInvocationID;
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if (id.x >= uint(params.world_size) ||
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id.y >= uint(params.world_size) ||
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id.z >= uint(params.world_size))
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return;
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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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vec3 p = vec3(id) - params.world_size / 2;
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uint idx = index3(id.x, id.y, id.z);
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voxels.sample_points[idx] = snoise((p / 10.0) + vec3(params.u_time * .5, params.u_time * .5, params.u_time * .5)) *5.0;
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int previous_sign = 0;
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vec3 previous_sample_point_coords = vec3(id.x, id.y, id.z);
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float previous_sample_point_distance = 0.0;
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vec3 intersection_points_sum = vec3(0.0, 0.0, 0.0);
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uint intersection_points_count = 0u;
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for (int sample_point_to_check_index = 0; sample_point_to_check_index < 8; sample_point_to_check_index++){
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ivec3 sample_point_to_check = ivec3(id) + SURFACE_AXIS[sample_point_to_check_index];
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// bounds check
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//if (sample_point_to_check.x < 0 || sample_point_to_check.y < 0 || sample_point_to_check.z < 0) continue;
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if (uint(sample_point_to_check.x) >= params.world_size || uint(sample_point_to_check.y) >= params.world_size || uint(sample_point_to_check.z) >= params.world_size) continue;
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uint buffer_index = index3(uint(sample_point_to_check.x), uint(sample_point_to_check.y), uint(sample_point_to_check.z));
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float sample_point_distance_from_sdf = voxels.sample_points[buffer_index];
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int current_sign = (sample_point_distance_from_sdf >= 0.0 ? 1 : -1);
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if (previous_sign != 0 && current_sign != previous_sign) {
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float t = previous_sample_point_distance / (previous_sample_point_distance - sample_point_distance_from_sdf);
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vec3 intersect = mix(vec3(previous_sample_point_coords), vec3(sample_point_to_check), t);
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intersection_points_sum += intersect;
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intersection_points_count++;
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}
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previous_sign = current_sign;
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previous_sample_point_distance = sample_point_distance_from_sdf;
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previous_sample_point_coords = sample_point_to_check;
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}
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if (intersection_points_count > 0u) {
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vec3 avg = intersection_points_sum / float(intersection_points_count);
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store_surface_point(idx, avg);
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} else {
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store_surface_point(idx, vec3(0.0)); // no surface
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}
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}
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