Implement water simulation and surface shader for forest pond

[libs/gl.git] / demos / forestpond / data / water_variance_x.glsl

diff --git a/demos/forestpond/data/water_variance_x.glsl b/demos/forestpond/data/water_variance_x.glsl
new file mode 100644 (file)
index 0000000..9f4c554
--- /dev/null
+++ b/demos/forestpond/data/water_variance_x.glsl
@@ -0,0 +1,23 @@
+#pragma MSP stage(compute)
+layout(local_size_x=8, local_size_y=8) in;
+
+uniform sampler2D surface_in;
+uniform sampler2D bottom_in;
+uniform sampler2D normals_in;
+layout(r16f) uniform image2D variance_out;
+
+void main()
+{
+       ivec2 coord = ivec2(gl_GlobalInvocationID.xy)+ivec2(4, 1);
+       float variance = 0.0;
+       for(int i=-3; i<=3; ++i)
+       {
+               ivec2 c = coord+ivec2(i, 0);
+               float depth = texelFetch(surface_in, c, 0).x-texelFetch(bottom_in, c, 0).x;
+               vec2 normal_xy = texelFetch(normals_in, c, 0).xy*2.0-1.0;
+               float xy_sq = dot(normal_xy, normal_xy);
+               float slope_sq = xy_sq/max(1-xy_sq, 0.001);
+               variance += slope_sq*clamp(depth, 0.0, 1.0);
+       }
+       imageStore(variance_out, coord, vec4(variance/7.0, 0.0, 0.0, 0.0));
+}