From 8573194aa03cc38c7e7034986aac9b317a1585ec Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 28 May 2008 13:01:44 +0000
Subject: [PATCH] From Michael Platings, "Yes it's definitely a driver problem
 - I submitted a bug report to nvidia 6 months ago and the issue is still "in
 progress". I've given up waiting for them!

Platform - various Intel Windows XP SP2 PCs with various nvidia cards
including GeForce 8800 GTS and Quadro FX 4500, and various driver
versions including the latest WHQL 175.16.

I investigated your concerns about glGenerateMipmapEXT being slower than
GL_GENERATE_MIPMAP_SGIS, and for power-of-two textures, to my surprise
it is. For a 512*512 texture, glGenerateMipmapEXT takes on average 10ms,
while GL_GENERATE_MIPMAP_SGIS takes on average 6ms. Therefore I have
modified the code to only use glGenerateMipmapEXT if the texture has a
non-power-of-two width or height. I am resubmitting all the files
previously submitted (only "Texture.cpp" has significant changes since
my previous submission, I've also replaced tabs with spaces in
"Texture").
"
---
 src/osg/Texture.cpp | 47 ++++++++++++++++++++++++++-------------------
 1 file changed, 27 insertions(+), 20 deletions(-)

diff --git a/src/osg/Texture.cpp b/src/osg/Texture.cpp
index f7c33c6ce..d4e2a922d 100644
--- a/src/osg/Texture.cpp
+++ b/src/osg/Texture.cpp
@@ -1425,19 +1425,26 @@ Texture::GenerateMipmapMode Texture::mipmapBeforeTexImage(const State& state, bo
 {
     if (hardwareMipmapOn)
     {
-        //GL_GENERATE_MIPMAP_SGIS with non-power-of-two textures on NVIDIA hardware
-        //is extremely slow. Use glGenerateMipmapEXT() instead if supported.
-        if (_internalFormatType != SIGNED_INTEGER &&
-            _internalFormatType != UNSIGNED_INTEGER &&
-            FBOExtensions::instance(state.getContextID(), true)->glGenerateMipmapEXT)
+        int width = getTextureWidth();
+        int height = getTextureHeight();
+
+        //quick bithack to determine whether width or height are non-power-of-two
+        if ((width & (width - 1)) || (height & (height - 1)))
         {
-            return GENERATE_MIPMAP;
-        }
-        else
-        {
-            glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS, GL_TRUE);
-            return GENERATE_MIPMAP_TEX_PARAMETER;
+            //GL_GENERATE_MIPMAP_SGIS with non-power-of-two textures on NVIDIA hardware
+            //is extremely slow. Use glGenerateMipmapEXT() instead if supported.
+            if (_internalFormatType != SIGNED_INTEGER &&
+                _internalFormatType != UNSIGNED_INTEGER)
+            {
+                if (FBOExtensions::instance(state.getContextID(), true)->glGenerateMipmapEXT)
+                {
+                    return GENERATE_MIPMAP;
+                }
+            }
         }
+
+        glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS, GL_TRUE);
+        return GENERATE_MIPMAP_TEX_PARAMETER;
     }
     return GENERATE_MIPMAP_NONE;
 }
@@ -1447,7 +1454,15 @@ void Texture::mipmapAfterTexImage(State& state, GenerateMipmapMode beforeResult)
     switch (beforeResult)
     {
     case GENERATE_MIPMAP:
-        generateMipmap(state);
+        {
+            unsigned int contextID = state.getContextID();
+            TextureObject* textureObject = getTextureObject(contextID);
+            if (textureObject)
+            {
+                osg::FBOExtensions* fbo_ext = osg::FBOExtensions::instance(contextID, true);
+                fbo_ext->glGenerateMipmapEXT(textureObject->_target);
+            }
+        }
         break;
     case GENERATE_MIPMAP_TEX_PARAMETER:
         glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS, GL_FALSE);
@@ -1481,9 +1496,6 @@ void Texture::generateMipmap(State& state) const
     if (fbo_ext->glGenerateMipmapEXT)
     {
         textureObject->bind();
-        
-        // osg::notify(osg::NOTICE)<<"Using generate glGenerateMipmap"<<std::endl;
-        
         fbo_ext->glGenerateMipmapEXT(textureObject->_target);
         
         // inform state that this texture is the current one bound.
@@ -1507,12 +1519,7 @@ void Texture::generateMipmap(State& state) const
 
 void Texture::compileGLObjects(State& state) const
 {
-    // osg::Timer_t startTick = osg::Timer::instance()->tick();
-
     apply(state);
-
-    // osg::Timer_t endTick = osg::Timer::instance()->tick();
-    // osg::notify(osg::NOTICE)<<"compile time = "<<osg::Timer::instance()->delta_m(startTick, endTick)<<std::endl;;
 }
 
 void Texture::resizeGLObjectBuffers(unsigned int maxSize)