1 files changed, 21 insertions, 0 deletions
diff --git a/progs/glsl/shadowtex.frag b/progs/glsl/shadowtex.frag
new file mode 100644
index 00000000000..a6a80da47f2
--- /dev/null
+++ b/progs/glsl/shadowtex.frag
@@ -0,0 +1,21 @@
+// Fragment shader for 2D texture with shadow attenuation
+// Brian Paul
+
+
+uniform sampler2D tex2d;
+uniform vec3 lightPos;
+
+void main()
+{
+   // XXX should compute this from lightPos
+   vec2 shadowCenter = vec2(-0.25, -0.25);
+
+   // d = distance from center
+   float d = distance(gl_TexCoord[0].xy, shadowCenter);
+
+   // attenuate and clamp
+   d = clamp(d * d * d, 0.0, 2.0);
+
+   // modulate texture by d for shadow effect
+   gl_FragColor = d * texture2D(tex2d, gl_TexCoord[0].xy, 0.0);
+}