Initial implementation of experimental gamma ramp API.

src/win32/CMakeLists.txt

@@ -23,6 +23,7 @@ set(libglfw_SOURCES
     ${common_SOURCES}
     win32_enable.c 
     win32_fullscreen.c
+    win32_gamma.c
     win32_glext.c
     win32_init.c 
     win32_joystick.c

src/win32/platform.h

@@ -156,6 +156,8 @@ typedef int  (WINAPI * DESCRIBEPIXELFORMAT_T) (HDC,int,UINT,LPPIXELFORMATDESCRIP
 typedef int  (WINAPI * GETPIXELFORMAT_T) (HDC);
 typedef BOOL (WINAPI * SETPIXELFORMAT_T) (HDC,int,const PIXELFORMATDESCRIPTOR*);
 typedef BOOL (WINAPI * SWAPBUFFERS_T) (HDC);
+typedef BOOL (WINAPI * GETDEVICEGAMMARAMP_T) (HDC,PVOID);
+typedef BOOL (WINAPI * SETDEVICEGAMMARAMP_T) (HDC,PVOID);
 #endif // _GLFW_NO_DLOAD_GDI32
 
 // winmm.dll function pointer typedefs
@@ -174,12 +176,16 @@ typedef DWORD (WINAPI * TIMEGETTIME_T) (void);
 #define _glfw_GetPixelFormat      _glfwLibrary.Win32.gdi.GetPixelFormat
 #define _glfw_SetPixelFormat      _glfwLibrary.Win32.gdi.SetPixelFormat
 #define _glfw_SwapBuffers         _glfwLibrary.Win32.gdi.SwapBuffers
+#define _glfw_GetDeviceGammaRamp  _glfwLibrary.Win32.gdi.GetDeviceGammaRamp
+#define _glfw_SetDeviceGammaRamp  _glfwLibrary.Win32.gdi.SetDeviceGammaRamp
 #else
 #define _glfw_ChoosePixelFormat   ChoosePixelFormat
 #define _glfw_DescribePixelFormat DescribePixelFormat
 #define _glfw_GetPixelFormat      GetPixelFormat
 #define _glfw_SetPixelFormat      SetPixelFormat
 #define _glfw_SwapBuffers         SwapBuffers
+#define _glfw_GetDeviceGammaRamp  GetDeviceGammaRamp
+#define _glfw_SetDeviceGammaRamp  SetDeviceGammaRamp
 #endif // _GLFW_NO_DLOAD_GDI32
 
 // winmm.dll shortcuts
@@ -264,6 +270,7 @@ typedef struct _GLFWlibraryWin32
     ATOM      classAtom;       // Window class atom
     HHOOK     keyboardHook;    // Keyboard hook handle
     DWORD     foregroundLockTimeout;
+    HDC       desktopDC;
 
     // Default monitor
     struct {
@@ -291,6 +298,8 @@ typedef struct _GLFWlibraryWin32
         GETPIXELFORMAT_T      GetPixelFormat;
         SETPIXELFORMAT_T      SetPixelFormat;
         SWAPBUFFERS_T         SwapBuffers;
+        GETDEVICEGAMMARAMP_T  GetDeviceGammaRamp;
+        SETDEVICEGAMMARAMP_T  SetDeviceGammaRamp;
     } gdi;
 #endif // _GLFW_NO_DLOAD_GDI32
 

src/win32/win32_gamma.c

@@ -0,0 +1,67 @@
+//========================================================================
+// GLFW - An OpenGL framework
+// Platform:    Win32/WGL
+// API version: 2.7
+// WWW:         http://www.glfw.org/
+//------------------------------------------------------------------------
+// Copyright (c) 2002-2006 Marcus Geelnard
+// Copyright (c) 2006-2010 Camilla Berglund <elmindreda@elmindreda.org>
+//
+// This software is provided 'as-is', without any express or implied
+// warranty. In no event will the authors be held liable for any damages
+// arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it
+// freely, subject to the following restrictions:
+//
+// 1. The origin of this software must not be misrepresented; you must not
+//    claim that you wrote the original software. If you use this software
+//    in a product, an acknowledgment in the product documentation would
+//    be appreciated but is not required.
+//
+// 2. Altered source versions must be plainly marked as such, and must not
+//    be misrepresented as being the original software.
+//
+// 3. This notice may not be removed or altered from any source
+//    distribution.
+//
+//========================================================================
+
+#include "internal.h"
+
+#include <limits.h>
+
+
+//************************************************************************
+//****                  GLFW internal functions                       ****
+//************************************************************************
+
+//========================================================================
+// Save the gamma ramp to our internal copy
+//========================================================================
+
+void _glfwPlatformSaveGammaRamp(int ramp)
+{
+    if (!_glfwLibrary.gammaSize)
+    {
+        return;
+    }
+    _glfw_GetDeviceGammaRamp(_glfwLibrary.Win32.desktopDC,
+                             _glfwLibrary.gammaRamp[ramp]);
+}
+
+
+//========================================================================
+// Restore the gamma ramp to our internal copy of the gamma ramp
+//========================================================================
+
+void _glfwPlatformRestoreGammaRamp(int ramp)
+{
+    if (!_glfwLibrary.gammaSize)
+    {
+        return;
+    }
+    _glfw_SetDeviceGammaRamp(_glfwLibrary.Win32.desktopDC,
+                             _glfwLibrary.gammaRamp[ramp]);
+}

src/win32/win32_init.c

@@ -30,6 +30,8 @@
 
 #include "internal.h"
 
+#include <stdlib.h>
+
 #ifdef __BORLANDC__
 // With the Borland C++ compiler, we want to disable FPU exceptions
 #include <float.h>
@@ -59,12 +61,18 @@ static GLboolean initLibraries(void)
         GetProcAddress(_glfwLibrary.Win32.gdi.instance, "SetPixelFormat");
     _glfwLibrary.Win32.gdi.SwapBuffers = (SWAPBUFFERS_T)
         GetProcAddress(_glfwLibrary.Win32.gdi.instance, "SwapBuffers");
+    _glfwLibrary.Win32.gdi.GetDeviceGammaRamp  = (GETDEVICEGAMMARAMP_T)
+        GetProcAddress(_glfwLibrary.Win32.gdi.instance, "GetDeviceGammaRamp");
+    _glfwLibrary.Win32.gdi.SetDeviceGammaRamp  = (SETDEVICEGAMMARAMP_T)
+        GetProcAddress(_glfwLibrary.Win32.gdi.instance, "SetDeviceGammaRamp");
 
     if (!_glfwLibrary.Win32.gdi.ChoosePixelFormat ||
         !_glfwLibrary.Win32.gdi.DescribePixelFormat ||
         !_glfwLibrary.Win32.gdi.GetPixelFormat ||
         !_glfwLibrary.Win32.gdi.SetPixelFormat ||
-        !_glfwLibrary.Win32.gdi.SwapBuffers)
+        !_glfwLibrary.Win32.gdi.SwapBuffers ||
+        !_glfwLibrary.Win32.gdi.GetDeviceGammaRamp ||
+        !_glfwLibrary.Win32.gdi.SetDeviceGammaRamp)
     {
         return GL_FALSE;
     }
@@ -152,6 +160,19 @@ int _glfwPlatformInit(void)
 
     _glfwLibrary.Win32.instance = GetModuleHandle(NULL);
 
+    // Initialise the internal gamma ramp
+    _glfwLibrary.gammaSize = 256;
+    _glfwLibrary.gammaRamp[GLFW_GAMMA_ORIG] =
+        malloc(256 * sizeof(unsigned short) * 3);
+    _glfwLibrary.gammaRamp[GLFW_GAMMA_CURR] =
+        malloc(256 * sizeof(unsigned short) * 3);
+
+    // Get the desktop DC
+    _glfwLibrary.Win32.desktopDC = GetDC(GetDesktopWindow());
+
+    // Save the original gamma ramp
+    _glfwPlatformSaveGammaRamp(GLFW_GAMMA_ORIG);
+
     _glfwInitTimer();
 
     return GL_TRUE;
@@ -164,6 +185,13 @@ int _glfwPlatformInit(void)
 
 int _glfwPlatformTerminate(void)
 {
+    // Restore the original gamma ramp
+    _glfwPlatformRestoreGammaRamp(GLFW_GAMMA_ORIG);
+
+    // Free the gamma ramps
+    free(_glfwLibrary.gammaRamp[GLFW_GAMMA_ORIG]);
+    free(_glfwLibrary.gammaRamp[GLFW_GAMMA_CURR]);
+
     if (_glfwLibrary.Win32.classAtom)
     {
         UnregisterClass(_GLFW_WNDCLASSNAME, _glfwLibrary.Win32.instance);