Béziers on the GPU.

[ipdf/code.git] / src / shaders / bezier_texbuf_geom.glsl

diff --git a/src/shaders/bezier_texbuf_geom.glsl b/src/shaders/bezier_texbuf_geom.glsl
new file mode 100644 (file)
index 0000000..2ee2836
--- /dev/null
+++ b/src/shaders/bezier_texbuf_geom.glsl
@@ -0,0 +1,31 @@
+#version 150
+
+uniform samplerBuffer bezier_buffer_texture; 
+uniform isamplerBuffer bezier_id_buffer_texture; 
+
+layout(lines) in;
+layout(line_strip, max_vertices = 100) out;
+
+in int objectid[];
+
+void main()
+{
+       int bezierid = texelFetch(bezier_id_buffer_texture, objectid[0]).r;
+       vec2 boundssize = gl_in[1].gl_Position.xy - gl_in[0].gl_Position.xy;
+       vec2 coeff0 = texelFetch(bezier_buffer_texture, bezierid*3).rg + gl_in[0].gl_Position.xy ;
+       vec2 coeff1 = texelFetch(bezier_buffer_texture, bezierid*3+1).rg * boundssize + gl_in[0].gl_Position.xy;
+       vec2 coeff2 = texelFetch(bezier_buffer_texture, bezierid*3+2).rg * boundssize + gl_in[0].gl_Position.xy;
+       for (int i = 0; i <= 100; ++i)
+       {
+               float t = i * 0.01f;
+               float oneminust = 1.0f - t;
+               float bernstein0 = t*t;
+               float bernstein1 = 2*t*oneminust;
+               float bernstein2 = oneminust*oneminust;
+               gl_Position = vec4(coeff0*bernstein0 + coeff1*bernstein1 + coeff2*bernstein2, 0.0, 1.0);
+               EmitVertex();
+               
+       }
+       EndPrimitive();
+}
+