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authorHunter Kvalevog <hunter@kvog.sh>2026-02-21 21:34:50 -0600
committerHunter Kvalevog <hunter@kvog.sh>2026-02-21 21:34:50 -0600
commit11379c6617602dbb8220fa83fcd544aaf94ab57d (patch)
tree9239184101406878478ccfd11ecc68d94b56fe79 /shaders/vfog.glsl
parentf7495d74d13d2fdf616bed25cb1d39d69243559d (diff)
shaders: Moved demos to https://fragcoord.xyz/u/kvog
Diffstat (limited to 'shaders/vfog.glsl')
-rw-r--r--shaders/vfog.glsl126
1 files changed, 0 insertions, 126 deletions
diff --git a/shaders/vfog.glsl b/shaders/vfog.glsl
deleted file mode 100644
index e92e957..0000000
--- a/shaders/vfog.glsl
+++ /dev/null
@@ -1,126 +0,0 @@
-#version 330 core
-
-// --------------------------------------------------------------------------------
-// Volumetric fog
-//
-// SPDX-License-Identifier: 0BSD
-// --------------------------------------------------------------------------------
-
-// --------------------------------------------------------------------------------
-// Uniforms
-// --------------------------------------------------------------------------------
-uniform float u_time;
-uniform vec3 u_cam;
-uniform int u_mode;
-uniform int u_steps;
-uniform float u_sigma;
-
-// --------------------------------------------------------------------------------
-// Vertex outputs
-// --------------------------------------------------------------------------------
-in vec3 v_p;
-in vec2 v_t;
-in vec3 v_n;
-
-// --------------------------------------------------------------------------------
-// Fragment outputs
-// --------------------------------------------------------------------------------
-out vec4 f_c;
-
-// -----------------------------------------------------------------------------
-// Ray-AABB intersection
-// ref: https://tavianator.com/2022/ray_box_boundary.html
-// -----------------------------------------------------------------------------
-bool intersect(vec3 ro, vec3 rd, vec3 bbmin, vec3 bbmax, out float t0, out float t1)
-{
- vec3 inv = 1.0f / rd;
- vec3 ta = (bbmin - ro) * inv;
- vec3 tb = (bbmax - ro) * inv;
- vec3 tmin = min(ta, tb);
- vec3 tmax = max(ta, tb);
- t0 = max(max(tmin.x, tmin.y), tmin.z);
- t1 = min(min(tmax.x, tmax.y), tmax.z);
- return t1 >= max(t0, 0.0f);
-}
-
-// -----------------------------------------------------------------------------
-// Mode 0: Basic volumetric fog
-// -----------------------------------------------------------------------------
-float sample_basic(vec3 pos)
-{
- return 1.0;
-}
-
-// -----------------------------------------------------------------------------
-// Mode 1: Fade along y axis
-// -----------------------------------------------------------------------------
-float sample_vfade(vec3 pos)
-{
- return 1.0f - pos.y;
-}
-
-// -----------------------------------------------------------------------------
-// Mode 2: Some waves
-// -----------------------------------------------------------------------------
-float sample_waves(vec3 pos)
-{
- // Fractal sum
- // ref: https://thebookofshaders.com/13/
- float h = 0.75f; // baseline
-
- // Big waves
- h += 0.08f * sin(pos.x * 2.0f + u_time);
- h += 0.08f * cos(pos.z * 2.0f + u_time * -1.1f);
-
- // Medium waves
- h += 0.05f * sin(pos.x * 5.0f + u_time * 1.7f);
- h += 0.05f * cos(pos.z * 4.0f + u_time * -2.0f);
-
- // Small but choppy waves
- h += 0.03f * sin(pos.x * 12.0f + u_time * 3.3f);
- h += 0.03f * cos(pos.z * 11.0f + u_time * -2.5f);
-
- return float(pos.y < h);
-}
-
-// --------------------------------------------------------------------------------
-// Entry point
-// --------------------------------------------------------------------------------
-void main()
-{
- vec3 bbmin = vec3(-1.0f);
- vec3 bbmax = vec3( 1.0f);
-
- vec3 ro = u_cam;
- vec3 rd = normalize(v_p - ro);
-
- float t0 = 0.0f;
- float t1 = 0.0f;
- if (!intersect(ro, rd, bbmin, bbmax, t0, t1)) {
- f_c = vec4(0.0f, 0.0f, 0.0f, 0.0f);
- return;
- }
-
- // Clamp entry point in front of camera
- float t_enter = max(t0, 0.0f);
- float t_exit = t1;
- float t_len = max(0.0f, t_exit - t_enter);
-
- float density = 0;
- for (int i = 0; i < u_steps; ++i) {
- float t = mix(t_enter, t_exit, (float(i) + 0.5f) / float(u_steps));
- vec3 p = ro + rd * t;
- switch (u_mode) {
- case 0: { density += sample_basic(p); } break;
- case 1: { density += sample_vfade(p); } break;
- case 2: { density += sample_waves(p); } break;
- }
- }
- density /= float(u_steps);
-
- // Beer-Lambert attenuation
- // ref: https://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law
- float a = 1.0f - exp(-u_sigma * t_len * density);
-
- f_c = vec4(vec3(1.0f), a);
-} \ No newline at end of file