From 5abc7bf3af097682592321acbcb96db83db575c9 Mon Sep 17 00:00:00 2001
From: Faerbit <faerbit@gmail.com>
Date: Thu, 4 Dec 2014 14:53:07 +0100
Subject: [PATCH] Implemented poisson sampling.

---
 Shader/phong.fsh | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/Shader/phong.fsh b/Shader/phong.fsh
index 74564e1..5574051 100644
--- a/Shader/phong.fsh
+++ b/Shader/phong.fsh
@@ -26,6 +26,25 @@ uniform float fogEnd;
 uniform vec4 fogColor;
 uniform vec3 cameraCenter;
 
+vec2 poissonDisk[16] = vec2[](
+   vec2( -0.94201624, -0.39906216 ),
+   vec2( 0.94558609, -0.76890725 ),
+   vec2( -0.094184101, -0.92938870 ),
+   vec2( 0.34495938, 0.29387760 ),
+   vec2( -0.91588581, 0.45771432 ),
+   vec2( -0.81544232, -0.87912464 ),
+   vec2( -0.38277543, 0.27676845 ),
+   vec2( 0.97484398, 0.75648379 ),
+   vec2( 0.44323325, -0.97511554 ),
+   vec2( 0.53742981, -0.47373420 ),
+   vec2( -0.26496911, -0.41893023 ),
+   vec2( 0.79197514, 0.19090188 ),
+   vec2( -0.24188840, 0.99706507 ),
+   vec2( -0.81409955, 0.91437590 ),
+   vec2( 0.19984126, 0.78641367 ),
+   vec2( 0.14383161, -0.14100790 )
+);
+
 void main()
 {   
     vec3 ambientColor = ambientFactor * ambientColor;
@@ -61,15 +80,12 @@ void main()
     // shadows 
     float bias = 0.001*tan(acos(clamp(dot(vNormal, -directionalLightVector), 0.0, 1.0)));
     bias = clamp(bias, 0.0, 0.01);
-    vec3 biasedShadowCoord = vec3(shadowCoord);
-    biasedShadowCoord.z = shadowCoord.z - bias;
     float visibility = 1.0;
     if (shadowCoord.x > 0.0 && shadowCoord.x < 1.0) {
         if (shadowCoord.y > 0.0 && shadowCoord.y < 1.0) {
-            visibility = texture(shadowMap, biasedShadowCoord);
-            //if (texture(shadowMap, vec3(shadowCoord), bias) < shadowCoord.z) {
-                //visibility = 0.5;
-            //}
+            for (int i=0; i<16; i++) {
+                visibility -= 0.0625*(1.0-texture(shadowMap, vec3(shadowCoord.xy + poissonDisk[i]/700.0, (shadowCoord.z - bias)/shadowCoord.w)));
+            }
         }
     }