a lot

[carveJwlIkooP6JGAAIwe30JlM.git] / shaders / blit.h

diff --git a/shaders/blit.h b/shaders/blit.h
index f05194eb3b299fc9045eb7c59ca52a633d31ef0f..49e4c802ae25ea25aec799a4e15067d143a18e32 100644 (file)
--- a/shaders/blit.h
+++ b/shaders/blit.h
@@ -27,8 +27,40 @@ static struct vg_shader _shader_blit = {
 "\n"
 "in vec2 aUv;\n"
 "\n"
+"float kPi = 3.14159265358979;\n"
+"\n"
+"vec2 fisheye_distort(vec2 xy)\n"
+"{\n"
+"   float aperture = 1350.0;\n"
+"   float apertureHalf = 0.5 * aperture * (kPi / 180.0);\n"
+"   float maxFactor = sin(apertureHalf);\n"
+"\n"
+"   vec2 uv;\n"
+"   float d = length(xy);\n"
+"   if(d < (2.0-maxFactor))\n"
+"   {\n"
+"      d = length(xy * maxFactor);\n"
+"      float z = sqrt(1.0 - d * d);\n"
+"      float r = atan(d, z) / kPi;\n"
+"      float phi = atan(xy.y, xy.x);\n"
+"\n"
+"      uv.x = r * cos(phi) + 0.5;\n"
+"      uv.y = r * sin(phi) + 0.5;\n"
+"   }\n"
+"   else\n"
+"   {\n"
+"      uv = 0.5*xy + 0.5;\n"
+"   }\n"
+"   \n"
+"   return uv;\n"
+"}\n"
+"\n"
+"\n"
 "void main()\n"
 "{\n"
+"   vec2 vwarp = 2.0*aUv - 1.0;\n"
+"   vwarp = fisheye_distort( vwarp );\n"
+"\n"
 "   FragColor = texture( uTexMain, aUv );\n"
 "}\n"
 ""},