add support for OpenGL extensions

openrct2.vcxproj

@@ -42,6 +42,7 @@
     <ClCompile Include="src\diagnostic.c" />
     <ClCompile Include="src\drawing\drawing.c" />
     <ClCompile Include="src\drawing\drawing_fast.cpp" />
+    <ClCompile Include="src\drawing\engines\OpenGLAPI.cpp" />
     <ClCompile Include="src\drawing\engines\OpenGLDrawingEngine.cpp" />
     <ClCompile Include="src\drawing\engines\SoftwareDrawingEngine.cpp" />
     <ClCompile Include="src\drawing\font.c" />
@@ -336,6 +337,7 @@
     <ClInclude Include="src\cursors.h" />
     <ClInclude Include="src\diagnostic.h" />
     <ClInclude Include="src\drawing\drawing.h" />
+    <ClInclude Include="src\drawing\engines\OpenGLAPI.h" />
     <ClInclude Include="src\drawing\font.h" />
     <ClInclude Include="src\drawing\IDrawingContext.h" />
     <ClInclude Include="src\drawing\IDrawingEngine.h" />

src/drawing/engines/OpenGLAPI.cpp

@@ -0,0 +1,73 @@
+#pragma region Copyright (c) 2014-2016 OpenRCT2 Developers
+/*****************************************************************************
+ * OpenRCT2, an open source clone of Roller Coaster Tycoon 2.
+ *
+ * OpenRCT2 is the work of many authors, a full list can be found in contributors.md
+ * For more information, visit https://github.com/OpenRCT2/OpenRCT2
+ *
+ * OpenRCT2 is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * A full copy of the GNU General Public License can be found in licence.txt
+ *****************************************************************************/
+#pragma endregion
+
+#include <SDL_platform.h>
+
+#define NO_EXTERN_GLAPI
+#include "OpenGLAPI.h"
+
+#if __WINDOWS__
+
+#include <SDL_video.h>
+
+#include "../../core/Console.hpp"
+
+#pragma comment(lib, "opengl32.lib")
+
+template <typename T>
+static inline bool SetProc(T * func, const char * name)
+{
+    T address = (T)SDL_GL_GetProcAddress(name);
+    if (address == nullptr)
+    {
+        return false;
+    }
+
+    *func = address;
+    return true;
+}
+
+#define SetupOpenGLFunction(func)           \
+    {                                       \
+        if (!SetProc(&func, "" #func ""))   \
+        {                                   \
+            return "" #func "";             \
+        }                                   \
+    }
+
+static const char * TryLoadAllProcAddresses()
+{
+    SetupOpenGLFunction(glCreateShader);
+    SetupOpenGLFunction(glDeleteShader);
+
+    return nullptr;
+}
+
+#endif /* __WINDOWS__ */
+
+bool OpenGLAPI::Initialise()
+{
+#if __WINDOWS__
+    const char * failedProcName = TryLoadAllProcAddresses();
+    if (failedProcName != nullptr)
+    {
+        Console::Error::WriteFormat("Failed to load %s.\n", failedProcName);
+        return false;
+    }
+#endif
+    return true;
+}
+

src/drawing/engines/OpenGLAPI.h

@@ -0,0 +1,39 @@
+#pragma region Copyright (c) 2014-2016 OpenRCT2 Developers
+/*****************************************************************************
+ * OpenRCT2, an open source clone of Roller Coaster Tycoon 2.
+ *
+ * OpenRCT2 is the work of many authors, a full list can be found in contributors.md
+ * For more information, visit https://github.com/OpenRCT2/OpenRCT2
+ *
+ * OpenRCT2 is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * A full copy of the GNU General Public License can be found in licence.txt
+ *****************************************************************************/
+#pragma endregion
+
+#pragma once
+
+#include <SDL_opengl.h>
+
+#if __WINDOWS__
+
+#ifdef NO_EXTERN_GLAPI
+    #define GLAPI_DECL
+    #define GLAPI_SET   = nullptr
+#else
+    #define GLAPI_DECL  extern
+    #define GLAPI_SET
+#endif
+
+GLAPI_DECL PFNGLCREATESHADERPROC glCreateShader GLAPI_SET;
+GLAPI_DECL PFNGLDELETESHADERPROC glDeleteShader GLAPI_SET;
+
+#endif /* __WINDOWS__ */
+
+namespace OpenGLAPI
+{
+    bool Initialise();
+}

src/drawing/engines/OpenGLDrawingEngine.cpp

@@ -18,13 +18,9 @@
 #include <vector>
 #include <SDL_platform.h>
 
-#ifdef __WINDOWS__
-    #include <windows.h>
-    #pragma comment(lib, "opengl32.lib")
-#endif
-
-#include <sdl_opengl.h>
+#include "OpenGLAPI.h"
 
+#include "../../core/Exception.hpp"
 #include "../../core/Math.hpp"
 #include "../../core/Memory.hpp"
 #include "../IDrawingContext.h"
@@ -131,6 +127,11 @@ public:
         _context = SDL_GL_CreateContext(_window);
         SDL_GL_MakeCurrent(_window, _context);
 
+        if (!OpenGLAPI::Initialise())
+        {
+            throw Exception("Unable to initialise OpenGL.");
+        }
+
         glEnable(GL_BLEND);
         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
     }