From 72c0188ec37c3783133baf6960d72cb3c9d12a6c Mon Sep 17 00:00:00 2001
From: Piotr Dziwinski <piotrdz@gmail.com>
Date: Sat, 28 Jul 2012 23:36:12 +0200
Subject: GLEW

Added GLEW for loading OpenGL extensions
---
 src/CMakeLists.txt               | 24 ++++++++++++++++++++++++
 src/common/config.h.cmake        |  2 ++
 src/graphics/opengl/gldevice.cpp | 36 +++++++++++++++++++++++++++++++-----
 3 files changed, 57 insertions(+), 5 deletions(-)

(limited to 'src')

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index da8463b..3896e40 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -11,18 +11,40 @@ if (${CMAKE_SYSTEM_NAME} MATCHES "Windows")
   set(PLATFORM_WINDOWS 1)
   set(PLATFORM_LINUX   0)
   set(PLATFORM_OTHER   0)
+  # On Windows, GLEW is required
+  if (${USE_GLEW} MATCHES "auto")
+    set(USE_GLEW 1)
+  endif()
 elseif(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
   set(PLATFORM_WINDOWS 0)
   set(PLATFORM_LINUX   1)
   set(PLATFORM_OTHER   0)
+  # On Linux, we should be fine without GLEW
+  if (${USE_GLEW} MATCHES "auto")
+    set(USE_GLEW 0)
+  endif()
   # for clock_gettime
   set(PLATFORM_LIBS "-lrt")
 else()
   set(PLATFORM_WINDOWS 0)
   set(PLATFORM_LINUX   0)
   set(PLATFORM_OTHER   1)
+  # Use GLEW to be safe
+  if (${USE_GLEW} MATCHES "auto")
+    set(USE_GLEW 1)
+  endif()
 endif()
 
+set(OPTIONAL_LIBS "")
+set(OPTIONAL_INCLUDE_DIRS "")
+
+if(${USE_GLEW} EQUAL 1)
+  find_package(GLEW REQUIRED)
+  set(OPTIONAL_LIBS ${OPTIONAL_LIBS} ${GLEW_LIBRARY})
+  set(OPTIONAL_INCLUDE_DIRS ${OPTIONAL_INCLUDE_DIRS} ${GLEW_INCLUDE_PATH})
+endif()
+
+
 # Configure file
 configure_file(common/config.h.cmake ${CMAKE_CURRENT_BINARY_DIR}/common/config.h)
 
@@ -156,6 +178,7 @@ ${SDL_LIBRARY}
 ${SDLIMAGE_LIBRARY}
 ${OPENGL_LIBRARY}
 ${PNG_LIBRARIES}
+${OPTIONAL_LIBS}
 ${PLATFORM_LIBS}
 CBot
 )
@@ -165,6 +188,7 @@ ${SDL_INCLUDE_DIR}
 ${SDL_IMAGE_INCLUDE_DIR}
 ${SDLTTF_INCLUDE_DIR}
 ${PNG_INCLUDE_DIRS}
+${OPTIONAL_INCLUDE_DIRS}
 )
 
 link_directories(${CMAKE_CURRENT_SOURCE_DIR}/CBot)
diff --git a/src/common/config.h.cmake b/src/common/config.h.cmake
index d8bff91..f496db0 100644
--- a/src/common/config.h.cmake
+++ b/src/common/config.h.cmake
@@ -2,7 +2,9 @@
 
 // Macros set by CMake
 #cmakedefine DEBUG
+
 #cmakedefine PLATFORM_WINDOWS @PLATFORM_WINDOWS@
 #cmakedefine PLATFORM_LINUX @PLATFORM_LINUX@
 #cmakedefine PLATFORM_OTHER @PLATFORM_OTHER@
 
+#cmakedefine USE_GLEW @USE_GLEW@
diff --git a/src/graphics/opengl/gldevice.cpp b/src/graphics/opengl/gldevice.cpp
index d31d007..bfe7fd7 100644
--- a/src/graphics/opengl/gldevice.cpp
+++ b/src/graphics/opengl/gldevice.cpp
@@ -16,10 +16,20 @@
 
 // gldevice.cpp
 
-#include "common/image.h"
 #include "graphics/opengl/gldevice.h"
+
+#include "common/config.h"
+#include "common/image.h"
 #include "math/geometry.h"
 
+
+#if defined(USE_GLEW)
+
+// When using GLEW, only glew.h is needed
+#include <GL/glew.h>
+
+#else
+
 // Should define prototypes of used extensions as OpenGL functions
 #define GL_GLEXT_PROTOTYPES
 
@@ -27,9 +37,11 @@
 #include <GL/glu.h>
 #include <GL/glext.h>
 
+#endif // if defined(GLEW)
+
 #include <SDL/SDL.h>
 
-#include <assert.h>
+#include <cassert>
 
 
 
@@ -73,9 +85,23 @@ std::string Gfx::CGLDevice::GetError()
 
 bool Gfx::CGLDevice::Create()
 {
-    /* NOTE: extension testing is not done here as the assumed version of OpenGL to be used (1.4+)
-      must already have the required extensions. The used extensions are listed here for reference:
-        GL_ARB_multitexture, GL_EXT_texture_env_combine, GL_EXT_secondary_color */
+#if defined(USE_GLEW)
+    if (glewInit() != GLEW_OK)
+    {
+        m_error = "GLEW initialization failed";
+        return false;
+    }
+
+    if ( (! GLEW_ARB_multitexture) || (! GLEW_EXT_texture_env_combine) || (! GLEW_EXT_secondary_color) )
+    {
+        m_error = "GLEW reports required extensions not supported";
+        return false;
+    }
+
+#endif
+
+    /* NOTE: when not using GLEW, extension testing is not performed, as it is assumed that
+             glext.h is up-to-date and the OpenGL shared library has the required functions present. */
 
     m_wasInit = true;
 
-- 
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