143 lines
2.6 KiB
GLSL
143 lines
2.6 KiB
GLSL
#version 450 core
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#define MAX_STEPS 64
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const vec2 eps = vec2(0.001, 0.0);
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layout (set = 0, binding = 1) uniform sampler2D tex;
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layout (set = 0, binding = 0) uniform Matrices {
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vec3 cam_pos;
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float time;
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vec4 viewport;
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vec3 cam_dir;
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uint n_objects;
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};
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/*
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enum Shape {
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SPHERE,
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BOX,
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PLANE,
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};
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*/
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#define SPHERE 0
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#define BOX 1
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#define PLANE 2
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struct Object {
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vec4 center;
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vec4 dimensions;
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uint id;
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uint shape;
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};
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layout (set = 0, binding = 2) readonly buffer Objects {
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Object objects[];
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};
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layout (location = 0) in vec2 pos;
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layout (location = 0) out vec4 fragColor;
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/* joins two parts of a scene */
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float op_union(float v1, float v2) {
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return min(v1, v2);
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}
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/* subtracts sdf from scene */
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float op_subtract(float v1, float v2) {
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return max(v1, -v2);
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}
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float sphere(vec3 p, vec3 c, float r) {
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return length(p-c) - r;
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}
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float box(vec3 p, vec3 c, vec3 r) {
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p -= c;
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vec3 q = abs(p) - r;
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return length(max(q,0.0)) + min(max(q.x, max(q.y,q.z)), 0.0);
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}
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float plane(vec3 p, vec3 norm, float d) {
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return dot(p, norm) + d;
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}
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float obj_to_sdf(vec3 p, uint n) {
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switch(objects[n].shape) {
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case SPHERE:
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return sphere(p, objects[n].center.xyz, objects[n].dimensions.x);
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break;
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case BOX:
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return box(p, objects[n].center.xyz, objects[n].dimensions.xyz);
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break;
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}
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}
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float map(vec2 p) {
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return sin(p.x)*sin(p.y);
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}
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float terrain(vec3 p) {
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/* render terrain with bumps */
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return box(p, vec3(0.0), vec3(100.0, 0.1, 100.0)) - abs(map(p.xz));
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}
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float sdf(vec3 pos) {
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/*float d = 100000000.0;
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for(uint i = 0; i < n_objects; i++) {
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d = op_union(d, obj_to_sdf(pos, i));
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}*/
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/*float dsphere = sphere(pos, vec3(0.0, 3.0*sin(time)-10.0, 0.0), 1.0);
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float dbox = box(pos, vec3(0.0, -10.0, 0.0), vec3(10.0, 1.0, 10.0));
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float dpellet = sphere(pos, vec3(0.0, 10.0*sin(time) - 10.0, 0.0), 0.1);
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float d = op_union(op_subtract(dbox, dsphere), dpellet);*/
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return terrain(pos);
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}
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float raycast(vec3 dir) {
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float t = 0.0;
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for(int i = 0; i < MAX_STEPS; i++) {
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float dt = sdf(cam_pos + dir * t);
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if(dt < 0.0001*t)
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return float(i)/MAX_STEPS;
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else if(dt > 200.0)
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return -1.0;
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t += dt;
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}
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return -1.0;
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}
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vec3 norm(vec3 pos) {
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return normalize(
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vec3(
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sdf(pos+eps.xyy),
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sdf(pos+eps.yxy),
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sdf(pos+eps.yyx)
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) - sdf(pos)
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);
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}
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vec3 raygen() {
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vec3 forward = cam_dir;
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vec3 right = normalize(cross(forward, vec3(0.0, 1.0, 0.0)));
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vec3 up = normalize(cross(right, forward));
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return normalize(pos.x * right + pos.y * up + forward * 2.0);
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}
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void main() {
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vec3 dir = raygen();
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float d = raycast(dir);
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if(d < 0.0)
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fragColor = vec4(0.0);
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else
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fragColor = vec4(abs(norm(d*dir+cam_pos)).r);
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} |