From 5367bef3ef81eb0c6f345ff3813985e62773e374 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Thu, 3 Jan 2013 00:35:03 +0100
Subject: [PATCH] Ability to specify buffer range in BufferTexture.

Extension ARB_texture_buffer_range in OpenGL 4.3.
---
 src/BufferTexture.cpp | 16 ++++++++++++++--
 src/BufferTexture.h   | 25 ++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/src/BufferTexture.cpp b/src/BufferTexture.cpp
index 7fd4f6d50..621d4feee 100644
--- a/src/BufferTexture.cpp
+++ b/src/BufferTexture.cpp
@@ -23,23 +23,35 @@
 namespace Magnum {
 
 BufferTexture::SetBufferImplementation BufferTexture::setBufferImplementation = &BufferTexture::setBufferImplementationDefault;
+BufferTexture::SetBufferRangeImplementation BufferTexture::setBufferRangeImplementation = &BufferTexture::setBufferRangeImplementationDefault;
 
 void BufferTexture::initializeContextBasedFunctionality(Context* context) {
     if(context->isExtensionSupported<Extensions::GL::EXT::direct_state_access>()) {
         Debug() << "BufferTexture: using" << Extensions::GL::EXT::direct_state_access::string() << "features";
 
         setBufferImplementation = &BufferTexture::setBufferImplementationDSA;
+        setBufferRangeImplementation = &BufferTexture::setBufferRangeImplementationDSA;
     }
 }
 
-void BufferTexture::setBufferImplementationDefault(BufferTexture::InternalFormat internalFormat, Buffer* buffer) {
+void BufferTexture::setBufferImplementationDefault(InternalFormat internalFormat, Buffer* buffer) {
     bindInternal();
     glTexBuffer(GL_TEXTURE_BUFFER, GLenum(internalFormat), buffer->id());
 }
 
-void BufferTexture::setBufferImplementationDSA(BufferTexture::InternalFormat internalFormat, Buffer* buffer) {
+void BufferTexture::setBufferImplementationDSA(InternalFormat internalFormat, Buffer* buffer) {
     glTextureBufferEXT(id(), GL_TEXTURE_BUFFER, GLenum(internalFormat), buffer->id());
 }
 
+void BufferTexture::setBufferRangeImplementationDefault(InternalFormat internalFormat, Buffer* buffer, GLintptr offset, GLsizeiptr size) {
+    bindInternal();
+    glTexBufferRange(GL_TEXTURE_BUFFER, GLenum(internalFormat), buffer->id(), offset, size);
+}
+
+void BufferTexture::setBufferRangeImplementationDSA(InternalFormat internalFormat, Buffer* buffer, GLintptr offset, GLsizeiptr size) {
+    glTextureBufferRangeEXT(id(), GL_TEXTURE_BUFFER, GLenum(internalFormat), buffer->id(), offset, size);
+}
+
+
 }
 #endif
diff --git a/src/BufferTexture.h b/src/BufferTexture.h
index 37cc3c9a1..4a6130fb1 100644
--- a/src/BufferTexture.h
+++ b/src/BufferTexture.h
@@ -62,7 +62,7 @@ AbstractShaderProgram documentation for more information.
 
 @section BufferTexture-performance-optimization Performance optimizations
 If extension @extension{EXT,direct_state_access} is available, setBuffer()
-uses DSA function to avoid unnecessary calls to @fn_gl{ActiveTexture} and
+functions use DSA to avoid unnecessary calls to @fn_gl{ActiveTexture} and
 @fn_gl{BindTexture}. See @ref AbstractTexture-performance-optimization
 "relevant section in AbstractTexture documentation" and respective function
 documentation for more information.
@@ -214,6 +214,24 @@ class MAGNUM_EXPORT BufferTexture: private AbstractTexture {
             (this->*setBufferImplementation)(internalFormat, buffer);
         }
 
+        /**
+         * @brief Set texture buffer
+         * @param internalFormat    Internal format
+         * @param buffer            %Buffer
+         * @param offset            Offset
+         * @param size              Data size
+         *
+         * Binds range of given buffer to this texture. The buffer itself can
+         * be then filled with data of proper format at any time using Buffer
+         * own data setting functions.
+         * @requires_gl43 %Extension @extension{ARB,texture_buffer_range}
+         * @see @fn_gl{ActiveTexture}, @fn_gl{BindTexture} and @fn_gl{TexBuffer}
+         *      or @fn_gl_extension{TextureBufferRange,EXT,direct_state_access}
+         */
+        inline void setBuffer(InternalFormat internalFormat, Buffer* buffer, GLintptr offset, GLsizeiptr size) {
+            (this->*setBufferRangeImplementation)(internalFormat, buffer, offset, size);
+        }
+
     private:
         static void MAGNUM_LOCAL initializeContextBasedFunctionality(Context* context);
 
@@ -221,6 +239,11 @@ class MAGNUM_EXPORT BufferTexture: private AbstractTexture {
         void MAGNUM_LOCAL setBufferImplementationDefault(InternalFormat internalFormat, Buffer* buffer);
         void MAGNUM_LOCAL setBufferImplementationDSA(InternalFormat internalFormat, Buffer* buffer);
         static SetBufferImplementation setBufferImplementation;
+
+        typedef void(BufferTexture::*SetBufferRangeImplementation)(InternalFormat, Buffer*, GLintptr, GLsizeiptr);
+        void MAGNUM_LOCAL setBufferRangeImplementationDefault(InternalFormat internalFormat, Buffer* buffer, GLintptr offset, GLsizeiptr size);
+        void MAGNUM_LOCAL setBufferRangeImplementationDSA(InternalFormat internalFormat, Buffer* buffer, GLintptr offset, GLsizeiptr size);
+        static SetBufferRangeImplementation setBufferRangeImplementation;
 };
 
 }