Reorganize data files into a directory structure

[r2c2.git] / data / r2c2 / sky.shader

diff --git a/data/r2c2/sky.shader b/data/r2c2/sky.shader
new file mode 100644 (file)
index 0000000..66dd8ec
--- /dev/null
+++ b/data/r2c2/sky.shader
@@ -0,0 +1,54 @@
+vertex_shader "
+       varying vec3 eye_look_dir;
+       void main()
+       {
+               vec4 eye_pos = vec4(mat3(gl_ModelViewMatrix)*gl_Vertex.xyz, 1);
+               gl_Position = gl_ProjectionMatrix*eye_pos;
+               eye_look_dir = eye_pos.xyz;
+       }";
+
+fragment_shader "
+       uniform vec3 eye_sky_dir;
+       uniform vec3 wavelengths;
+       uniform float scatter_constant;
+       uniform float sun_intensity;
+       uniform float sun_size;
+       varying vec3 eye_look_dir;
+       float thickness(float c, float r)
+       {
+               float rc = r*c;
+               return sqrt(2.0*r+1.0+rc*rc)-rc;
+       }
+       float srgb(float c)
+       {
+               if(c<0.0031308)
+                       return 12.92*c;
+               else
+                       return (1.055)*pow(c, 1.0/2.4)-0.055;
+       }
+       void main()
+       {
+               vec3 n_eye_look_dir = normalize(eye_look_dir);
+               vec3 n_eye_sun_dir = normalize(gl_LightSource[0].position.xyz);
+
+               if(dot(n_eye_look_dir, eye_sky_dir)>0)
+               {
+                       float look_scale = thickness(dot(n_eye_look_dir, eye_sky_dir), 635.0);
+                       float sun_scale = thickness(dot(n_eye_sun_dir, eye_sky_dir), 635.0);
+                       float c = dot(n_eye_look_dir, n_eye_sun_dir);
+                       float scatter_strength = (1.0+c*c)/2.0;
+                       vec3 scatter_factor = scatter_constant/pow(wavelengths, vec3(4.0));
+
+                       vec3 color;
+                       float scale_ratio = look_scale/sun_scale;
+                       if(scale_ratio>0.999 && scale_ratio<1.001)
+                               color = sun_intensity*scatter_strength*scatter_factor*sun_scale*exp(-scatter_factor*sun_scale);
+                       else
+                               color = sun_intensity*scatter_strength*(exp(-scatter_factor*sun_scale)-exp(-scatter_factor*look_scale))/(1.0-sun_scale/look_scale);
+                       if(dot(n_eye_look_dir, n_eye_sun_dir)>cos(sun_size))
+                               color += exp(-scatter_factor*look_scale)*sun_intensity;
+                       gl_FragColor = vec4(srgb(color.r), srgb(color.g), srgb(color.b), 1.0);
+               }
+               else
+                       gl_FragColor = vec4(vec3(0.0), 1.0);
+       }";