SL-19835 Fix for inaccurate water fog on transparent objects when camera is above water.

1 files changed, 4 insertions, 2 deletions

diff --git a/indra/newview/lldrawpoolalpha.cpp b/indra/newview/lldrawpoolalpha.cpp
index 6aa2316589..060129d275 100644
--- a/indra/newview/lldrawpoolalpha.cpp
+++ b/indra/newview/lldrawpoolalpha.cpp
@@ -243,11 +243,13 @@ void LLDrawPoolAlpha::forwardRender(bool rigged)
     //enable writing to alpha for emissive effects
     gGL.setColorMask(true, true);
 
-    bool write_depth = rigged || 
+    bool write_depth = rigged ||
         LLDrawPoolWater::sSkipScreenCopy
         // we want depth written so that rendered alpha will
         // contribute to the alpha mask used for impostors
-        || LLPipeline::sImpostorRenderAlphaDepthPass;
+        || LLPipeline::sImpostorRenderAlphaDepthPass
+        || getType() == LLDrawPoolAlpha::POOL_ALPHA_PRE_WATER; // needed for accurate water fog
+
 
     LLGLDepthTest depth(GL_TRUE, write_depth ? GL_TRUE : GL_FALSE);