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90 lines
1.9 KiB
90 lines
1.9 KiB
#version 330 core
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#define FOV 90
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#define EPSILON 0.01
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#define MAX_STEPS 64
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#define NEAR_D 0.
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#define FAR_D 20.
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#define GRAD_EPSILON 0.0001
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#define saturate(x) clamp(x, 0, 1)
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uniform vec2 u_Resolution;
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uniform vec4 u_Mouse;
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uniform float u_Time;
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out vec4 color;
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#include "utils.glsl"
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#include "march_prolog.glsl"
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#include "hg_sdf.glsl"
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#include "colormap_cool.glsl"
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vec3 ray_dir(float fov, vec2 uv) {
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float z = 1./tan(radians(fov)/2.);
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return normalize(vec3(uv, z));
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}
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SceneResult scene_f(vec3 p) {
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SceneResult box = SceneResult(fBox(p, vec3(1)), 1.);
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SceneResult sphere = SceneResult(fSphere(p + vec3(1), 1.0), 2.);
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return min_sr(box, sphere);
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}
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vec3 estimate_scene_normal(vec3 p) {
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vec3 dx = vec3(GRAD_EPSILON, 0, 0);
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vec3 dy = vec3(0, GRAD_EPSILON, 0);
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vec3 dz = vec3(0, 0, GRAD_EPSILON);
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return normalize(vec3(
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scene_f(p + dx).d - scene_f(p - dx).d,
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scene_f(p + dy).d - scene_f(p - dy).d,
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scene_f(p + dz).d - scene_f(p - dz).d
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));
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}
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vec3 raymarch(vec3 o, vec3 d, float start, float end) {
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float t = start;
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for (int i = 0; i < MAX_STEPS; i++) {
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float dist = scene_f(o + d*t);
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if (dist < EPSILON || t > end)
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return vec3(t, i, 0.);
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t += dist;
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}
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return vec3(end, MAX_STEPS, 0.);
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}
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vec4 shade(vec3 p) {
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vec3 normal = estimate_scene_normal(p);
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return vec4((normal + vec3(1.0))/2.0, 1.0);
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}
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void main() {
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vec2 mouse_uv = u_Mouse.xy * 2.0 / u_Resolution.xy - 1.0;
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vec2 uv = gl_FragCoord.xy * 2.0 / u_Resolution.xy - 1.0;
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uv.x *= u_Resolution.x/u_Resolution.y;
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vec3 eye = vec3(0., 0., -5.);
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mat3 lookAt = calcLookAtMatrix(eye, vec3(0., 0., 0.), u_Time);
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vec3 dir = normalize(lookAt * ray_dir(FOV, uv));
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color = vec4(0.);
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vec3 result = raymarch(eye, dir, NEAR_D, FAR_D);
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float depth = result.x;
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float iters = result.y;
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if (depth >= FAR_D) {
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color = vec4(1.0, 0.5, 1.0, 1.0);
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return;
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}
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color = colormap(iters/MAX_STEPS+0.5);
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vec3 p = eye + dir * depth;
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color = shade(p);
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}
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