Added support for using the generate mip map extension within osgText.

include/osg/Texture

@@ -70,6 +70,8 @@
 #define GL_TEXTURE_3D                     0x806F
 #endif
 
+
+
 namespace osg {
 
 /** Texture base class which encapsulates OpenGl texture functionality which common betweent the various types of OpenGL textures.*/
@@ -248,6 +250,7 @@ class SG_EXPORT Texture : public osg::StateAttribute
                 bool isTextureMirroredRepeatSupported() const { return _isTextureMirroredRepeatSupported; }
                 bool isTextureEdgeClampSupported() const { return _isTextureEdgeClampSupported; }
                 bool isTextureBorderClampSupported() const { return _isTextureBorderClampSupported; }
+                bool isGenerateMipMapSupported() const { return _isGenerateMipMapSupported; }
 
                 GLint maxTextureSize() const { return _maxTextureSize; }
 
@@ -265,6 +268,7 @@ class SG_EXPORT Texture : public osg::StateAttribute
                 bool    _isTextureMirroredRepeatSupported;
                 bool    _isTextureEdgeClampSupported;
                 bool    _isTextureBorderClampSupported;
+                bool    _isGenerateMipMapSupported;
                 
                 GLint   _maxTextureSize;
 

src/osg/Texture.cpp

@@ -518,12 +518,12 @@ Texture::Extensions::Extensions(const Extensions& rhs):
     Referenced()
 {
     _isTextureFilterAnisotropicSupported = rhs._isTextureFilterAnisotropicSupported;
+    _isTextureCompressionARBSupported = rhs._isTextureCompressionARBSupported;
+    _isTextureCompressionS3TCSupported = rhs._isTextureCompressionS3TCSupported;
     _isTextureMirroredRepeatSupported = rhs._isTextureMirroredRepeatSupported;
     _isTextureEdgeClampSupported = rhs._isTextureEdgeClampSupported;
     _isTextureBorderClampSupported = rhs._isTextureBorderClampSupported;
-
+    _isGenerateMipMapSupported = rhs._isGenerateMipMapSupported;
-    _isTextureCompressionARBSupported = rhs._isTextureCompressionARBSupported;
-    _isTextureCompressionS3TCSupported = rhs._isTextureCompressionS3TCSupported;
 
     _maxTextureSize = rhs._maxTextureSize;
 
@@ -540,6 +540,8 @@ void Texture::Extensions::lowestCommonDenominator(const Extensions& rhs)
     if (!rhs._isTextureCompressionARBSupported) _isTextureCompressionARBSupported = false;
     if (!rhs._isTextureCompressionS3TCSupported) _isTextureCompressionS3TCSupported = false;
     
+    if (!rhs._isGenerateMipMapSupported) _isGenerateMipMapSupported = false;
+
     if (rhs._maxTextureSize<_maxTextureSize) _maxTextureSize = rhs._maxTextureSize;
 
     if (!rhs._glCompressedTexImage2D) _glCompressedTexImage2D = 0;
@@ -549,12 +551,14 @@ void Texture::Extensions::setupGLExtenions()
 {
  
     _isTextureFilterAnisotropicSupported = isGLExtensionSupported("GL_EXT_texture_filter_anisotropic");
+    _isTextureCompressionARBSupported = isGLExtensionSupported("GL_ARB_texture_compression");
+    _isTextureCompressionS3TCSupported = isGLExtensionSupported("GL_EXT_texture_compression_s3tc");
     _isTextureMirroredRepeatSupported = isGLExtensionSupported("GL_IBM_texture_mirrored_repeat");
     _isTextureEdgeClampSupported = isGLExtensionSupported("GL_EXT_texture_edge_clamp");
     _isTextureBorderClampSupported = isGLExtensionSupported("GL_ARB_texture_border_clamp");
+    _isGenerateMipMapSupported = (strncmp((const char*)glGetString(GL_VERSION),"1.4",3)>=0) ||
+                                  isGLExtensionSupported("GL_SGIS_generate_mipmap");
 
-    _isTextureCompressionARBSupported = isGLExtensionSupported("GL_ARB_texture_compression");
-    _isTextureCompressionS3TCSupported = isGLExtensionSupported("GL_EXT_texture_compression_s3tc");
 
     glGetIntegerv(GL_MAX_TEXTURE_SIZE,&_maxTextureSize);
 

src/osgText/Font.cpp

@@ -119,7 +119,7 @@ void Font::addGlyph(unsigned int width, unsigned int height, unsigned int charco
         // reserve enough space for the glyphs.
         glyphTexture->setTextureSize(256,256);
         glyphTexture->setFilter(osg::Texture::MIN_FILTER,osg::Texture::LINEAR);
-        //glyphTexture->setFilter(osg::Texture::MIN_FILTER,osg::Texture::LINEAR_MIPMAP_LINEAR);
+        glyphTexture->setFilter(osg::Texture::MIN_FILTER,osg::Texture::LINEAR_MIPMAP_LINEAR);
         //glyphTexture->setFilter(osg::Texture::MAG_FILTER,osg::Texture::NEAREST);
         glyphTexture->setFilter(osg::Texture::MAG_FILTER,osg::Texture::LINEAR);
         glyphTexture->setMaxAnisotropy(8);
@@ -245,6 +245,9 @@ void Font::GlyphTexture::apply(osg::State& state) const
     }
 
 
+    const Extensions* extensions = getExtensions(contextID,true);
+    bool generateMipMapSupported = extensions->isGenerateMipMapSupported();
+
     // get the globj for the current contextID.
     GLuint& handle = getTextureObject(contextID);
 
@@ -256,7 +259,22 @@ void Font::GlyphTexture::apply(osg::State& state) const
 
         applyTexParameters(GL_TEXTURE_2D,state);
         
-        //glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS,GL_TRUE);
+        // need to look at generate mip map extension if mip mapping required.
+        switch(_min_filter)
+        {
+        case NEAREST_MIPMAP_NEAREST:
+        case NEAREST_MIPMAP_LINEAR:
+        case LINEAR_MIPMAP_NEAREST:
+        case LINEAR_MIPMAP_LINEAR:
+            if (generateMipMapSupported) {
+                glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS,GL_TRUE);
+            }
+            else glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, LINEAR);
+            break;
+        default:
+            // not mip mapping so no problems.
+            break;
+        }
                
         // allocate the texture memory.
         glTexImage2D( GL_TEXTURE_2D, 0, GL_LUMINANCE_ALPHA,
@@ -271,11 +289,27 @@ void Font::GlyphTexture::apply(osg::State& state) const
         // reuse texture by binding.
         glBindTexture( GL_TEXTURE_2D, handle );
         if (getTextureParameterDirty(contextID))
+        {
             applyTexParameters(GL_TEXTURE_2D,state);
 
+            // need to look at generate mip map extension if mip mapping required.
+            switch(_min_filter)
+            {
+            case NEAREST_MIPMAP_NEAREST:
+            case NEAREST_MIPMAP_LINEAR:
+            case LINEAR_MIPMAP_NEAREST:
+            case LINEAR_MIPMAP_LINEAR:
+                if (generateMipMapSupported) glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS,GL_TRUE);
+                else glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, LINEAR);
+                break;
+            default:
+                // not mip mapping so no problems.
+                break;
+            }
+        }
+
     }
     
-    //glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS,GL_TRUE);
 
     // now subload the glyphs that are outstanding for this graphics context.
     GlyphPtrList& glyphsWereSubloading = _glyphsToSubload[contextID];