31 lines
1.1 KiB
GLSL

#version 430
layout (binding = 0) uniform sampler3D densities;
out vec3 varTexture;
out int varIndex;
const float step = 1.0 / 63.0;
void main(void) {
int id = gl_VertexID;
int x = id & 0x3F;
int y = (id >> 6) & 0x3F;
int z = (id >> 12) & 0x3F;
vec3 xyz = vec3(x, y, z);
gl_Position = vec4(xyz, 1.0);
varTexture = xyz * step;
int b1 = int(texture(densities, varTexture).r < 0.5f);
int b2 = int(texture(densities, varTexture + vec3(step, 0.0, 0.0)).r < 0.5f);
int b3 = int(texture(densities, varTexture + vec3(step, 0.0, step)).r < 0.5f);
int b4 = int(texture(densities, varTexture + vec3(0.0, 0.0, step)).r < 0.5f);
int b5 = int(texture(densities, varTexture + vec3(0.0, step, 0.0)).r < 0.5f);
int b6 = int(texture(densities, varTexture + vec3(step, step, 0.0)).r < 0.5f);
int b7 = int(texture(densities, varTexture + vec3(step, step, step)).r < 0.5f);
int b8 = int(texture(densities, varTexture + vec3(0.0, step, step)).r < 0.5f);
varIndex = (b1 << 7) | (b2 << 6) | (b3 << 5) | (b4 << 4) |
(b5 << 3) | (b6 << 2) | (b7 << 1) | b8;
}