X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=data%2Fr2c2%2Fsky.shader;fp=data%2Fr2c2%2Fsky.shader;h=66dd8ec0e9e308a2d4ec805443e4936e961175f5;hb=78d36019ec11d62d6fd016fcbe19f566d11771ff;hp=0000000000000000000000000000000000000000;hpb=759fee443361cdcafe6fb259df3ba1b05bea0b21;p=r2c2.git

diff --git a/data/r2c2/sky.shader b/data/r2c2/sky.shader
new file mode 100644
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);
+	}";