From 6361d93af20f4ae39044101baa8a5b71d1e1975b Mon Sep 17 00:00:00 2001
From: Brad Larson <larson@sunsetlakesoftware.com>
Date: Fri, 25 May 2012 14:13:57 -0500
Subject: [PATCH] Fixed a precision issue and some divide-by-zero problems with
 the color dodge blend.

---
 framework/Source/GPUImageColorDodgeBlendFilter.m | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/framework/Source/GPUImageColorDodgeBlendFilter.m b/framework/Source/GPUImageColorDodgeBlendFilter.m
index baf7b351e..5898c23af 100755
--- a/framework/Source/GPUImageColorDodgeBlendFilter.m
+++ b/framework/Source/GPUImageColorDodgeBlendFilter.m
@@ -3,7 +3,7 @@
 NSString *const kGPUImageColorDodgeBlendFragmentShaderString = SHADER_STRING
 ( 
  
- precision lowp float;
+ precision mediump float;
  
  varying highp vec2 textureCoordinate;
  varying highp vec2 textureCoordinate2;
@@ -20,7 +20,7 @@ void main()
      vec3 rightHandProduct = overlay.rgb * (1.0 - base.a) + base.rgb * (1.0 - overlay.a);
      
      vec3 firstBlendColor = baseOverlayAlphaProduct + rightHandProduct;
-     vec3 overlayRGB = (overlay.rgb / overlay.a) * step(0.0, overlay.a);
+     vec3 overlayRGB = clamp((overlay.rgb / clamp(overlay.a, 0.01, 1.0)) * step(0.0, overlay.a), 0.0, 0.99);
      
      vec3 secondBlendColor = (base.rgb * overlay.a) / (1.0 - overlayRGB) + rightHandProduct;