Added GLFW_ACCELERATION window hint for hardware acceleration

CONTRIBUTORS.md

@@ -291,6 +291,7 @@ video tutorials.
  - Jonas Ådahl
  - Lasse Öörni
  - Leonard König
+ - Tianlan Zhou
  - All the unmentioned and anonymous contributors in the GLFW community, for bug
    reports, patches, feedback, testing and encouragement
 

README.md

@@ -205,6 +205,7 @@ information on what to include when reporting a bug.
    (#442)
  - [EGL] Added ANGLE backend selection via `EGL_ANGLE_platform_angle` extension
    (#1380)
+ - Added `GLFW_ACCELERATION` window hint for hardware acceleration (#TODO)
 
 
 ## Changelog since 3.3

docs/news.md

@@ -141,6 +141,16 @@ contexts.
 [ANGLE]: https://chromium.googlesource.com/angle/angle/
 
 
+#### Window hint for hardware acceleration {#acceleration_34}
+
+You can use window hint [GLFW_ACCELERATION](@ref GLFW_ACCELERATION_hint) to
+specify whether hardware acceleration is preferred or not.  The default value
+is to prefer hardware acceleration.  You can get whether hardware acceleration
+is enabled with the window attribute
+[GLFW_ACCELERATION](@ref GLFW_ACCELERATION_attrib).  This feature is only
+available on WGL currently.
+
+
 ### Caveats for version 3.4 {#caveats}
 
 #### Multiple sets of native access functions {#native_34}
@@ -227,6 +237,13 @@ Events posted with @ref glfwPostEmptyEvent now use a separate unnamed pipe
 instead of sending an X11 client event to the helper window.
 
 
+#### Microsoft GDI software OpenGL ICD support {#gdi_opengl_icd_34}
+
+GLFW now supports creating window when the Microsoft GDI software OpenGL ICD is
+the only available implementation.
+See [GLFW_ACCELERATION](@ref GLFW_ACCELERATION_hint) for more details.
+
+
 ### Deprecations in version 3.4 {#deprecations_34}
 
 ### Removals in 3.4 {#removals_34}
@@ -322,6 +339,7 @@ then GLFW will fail to initialize.
  - @ref GLFW_WAYLAND_PREFER_LIBDECOR
  - @ref GLFW_WAYLAND_DISABLE_LIBDECOR
  - @ref GLFW_SCALE_FRAMEBUFFER
+ - @ref GLFW_ACCELERATION
 
 
 ## Release notes for earlier versions {#news_archive}

docs/window.md

@@ -336,6 +336,15 @@ __GLFW_DOUBLEBUFFER__ specifies whether the framebuffer should be double
 buffered.  You nearly always want to use double buffering.  This is a hard
 constraint.  Possible values are `GLFW_TRUE` and `GLFW_FALSE`.
 
+@anchor GLFW_ACCELERATION
+@anchor GLFW_ACCELERATION_hint
+__GLFW_ACCELERATION__ specifies whether the hardware acceleration should be
+preferred.  By default, hardware acceleration is preferred, and will fallback
+to no acceleration if hardware acceleration is unavailable.  Possible values
+are `GLFW_TRUE` and `GLFW_FALSE`.
+
+This hint only has an effect on WGL.
+
 
 #### Monitor related hints {#window_hints_mtr}
 
@@ -1487,6 +1496,11 @@ __GLFW_DOUBLEBUFFER__ indicates whether the specified window is double-buffered
 when rendering with OpenGL or OpenGL ES.  This can be set before creation with
 the [GLFW_DOUBLEBUFFER](@ref GLFW_DOUBLEBUFFER_hint) window hint.
 
+@anchor GLFW_ACCELERATION_attrib
+__GLFW_ACCELERATION__ indicates whether the specified window is hardware
+accelerated when rendering with OpenGL or OpenGL ES.  This can be set before
+creation with the [GLFW_ACCELERATION](@ref GLFW_ACCELERATION_hint) window hint.
+
 
 ## Buffer swapping {#buffer_swap}
 

include/GLFW/glfw3.h

@@ -1022,6 +1022,14 @@ extern "C" {
  *  [attribute](@ref GLFW_DOUBLEBUFFER_attrib).
  */
 #define GLFW_DOUBLEBUFFER           0x00021010
+/*! @brief Hardware acceleration hint.
+ *
+ *  Hardware acceleration [hint](@ref GLFW_ACCELERATION_hint) and
+ *  [attribute](@ref GLFW_ACCELERATION_attrib).
+ *
+ *  @since Added in version 3.4.
+ */
+#define GLFW_ACCELERATION           0x00021011
 
 /*! @brief Context client API hint and attribute.
  *
@@ -3158,9 +3166,6 @@ GLFWAPI void glfwWindowHintString(int hint, const char* value);
  *  GLFW_VERSION_UNAVAILABLE, @ref GLFW_FORMAT_UNAVAILABLE, @ref
  *  GLFW_NO_WINDOW_CONTEXT and @ref GLFW_PLATFORM_ERROR.
  *
- *  @remark @win32 Window creation will fail if the Microsoft GDI software
- *  OpenGL implementation is the only one available.
- *
  *  @remark @win32 If the executable has an icon resource named `GLFW_ICON,` it
  *  will be set as the initial icon for the window.  If no such icon is present,
  *  the `IDI_APPLICATION` icon will be used instead.  To set a different icon,

src/context.c

@@ -312,6 +312,9 @@ const _GLFWfbconfig* _glfwChooseFBConfig(const _GLFWfbconfig* desired,
 
             if (desired->sRGB && !current->sRGB)
                 extraDiff++;
+
+            if (desired->acceleration && !current->acceleration)
+                extraDiff++;
         }
 
         // Figure out if the current one is better than the best one found so far

src/internal.h

@@ -469,6 +469,7 @@ struct _GLFWfbconfig
     GLFWbool    sRGB;
     GLFWbool    doublebuffer;
     GLFWbool    transparent;
+    GLFWbool    acceleration;
     uintptr_t   handle;
 };
 
@@ -529,6 +530,7 @@ struct _GLFWwindow
     GLFWbool            shouldClose;
     void*               userPointer;
     GLFWbool            doublebuffer;
+    GLFWbool            acceleration;
     GLFWvidmode         videoMode;
     _GLFWmonitor*       monitor;
     _GLFWcursor*        cursor;

src/wgl_context.c

@@ -145,6 +145,8 @@ static int choosePixelFormatWGL(_GLFWwindow* window,
         {
             // Get pixel format attributes through "modern" extension
 
+            int acceleration;
+
             if (!wglGetPixelFormatAttribivARB(window->context.wgl.dc,
                                               pixelFormat, 0,
                                               attribCount,
@@ -166,8 +168,7 @@ static int choosePixelFormatWGL(_GLFWwindow* window,
             if (FIND_ATTRIB_VALUE(WGL_PIXEL_TYPE_ARB) != WGL_TYPE_RGBA_ARB)
                 continue;
 
-            if (FIND_ATTRIB_VALUE(WGL_ACCELERATION_ARB) == WGL_NO_ACCELERATION_ARB)
+            acceleration = FIND_ATTRIB_VALUE(WGL_ACCELERATION_ARB);
-                continue;
 
             if (FIND_ATTRIB_VALUE(WGL_DOUBLE_BUFFER_ARB) != fbconfig->doublebuffer)
                 continue;
@@ -210,6 +211,10 @@ static int choosePixelFormatWGL(_GLFWwindow* window,
                         u->sRGB = GLFW_TRUE;
                 }
             }
+
+            u->acceleration =
+                acceleration == WGL_GENERIC_ACCELERATION_ARB ||
+                acceleration == WGL_FULL_ACCELERATION_ARB;
         }
         else
         {
@@ -235,12 +240,6 @@ static int choosePixelFormatWGL(_GLFWwindow* window,
                 continue;
             }
 
-            if (!(pfd.dwFlags & PFD_GENERIC_ACCELERATED) &&
-                (pfd.dwFlags & PFD_GENERIC_FORMAT))
-            {
-                continue;
-            }
-
             if (pfd.iPixelType != PFD_TYPE_RGBA)
                 continue;
 
@@ -264,6 +263,10 @@ static int choosePixelFormatWGL(_GLFWwindow* window,
 
             if (pfd.dwFlags & PFD_STEREO)
                 u->stereo = GLFW_TRUE;
+
+            u->acceleration =
+                (pfd.dwFlags & PFD_GENERIC_ACCELERATED) ||
+                !(pfd.dwFlags & PFD_GENERIC_FORMAT);
         }
 
         u->handle = pixelFormat;
@@ -437,8 +440,6 @@ GLFWbool _glfwInitWGL(void)
 
     // NOTE: A dummy context has to be created for opengl32.dll to load the
     //       OpenGL ICD, from which we can then query WGL extensions
-    // NOTE: This code will accept the Microsoft GDI ICD; accelerated context
-    //       creation failure occurs during manual pixel format enumeration
 
     dc = GetDC(_glfw.win32.helperWindowHandle);
 

src/window.c

@@ -235,6 +235,7 @@ GLFWAPI GLFWwindow* glfwCreateWindow(int width, int height,
     window->cursorMode       = GLFW_CURSOR_NORMAL;
 
     window->doublebuffer = fbconfig.doublebuffer;
+    window->acceleration = fbconfig.acceleration;
 
     window->minwidth    = GLFW_DONT_CARE;
     window->minheight   = GLFW_DONT_CARE;
@@ -287,6 +288,7 @@ void glfwDefaultWindowHints(void)
     _glfw.hints.framebuffer.depthBits    = 24;
     _glfw.hints.framebuffer.stencilBits  = 8;
     _glfw.hints.framebuffer.doublebuffer = GLFW_TRUE;
+    _glfw.hints.framebuffer.acceleration = GLFW_TRUE;
 
     // The default is to select the highest available refresh rate
     _glfw.hints.refreshRate = GLFW_DONT_CARE;
@@ -346,6 +348,9 @@ GLFWAPI void glfwWindowHint(int hint, int value)
         case GLFW_SRGB_CAPABLE:
             _glfw.hints.framebuffer.sRGB = value ? GLFW_TRUE : GLFW_FALSE;
             return;
+        case GLFW_ACCELERATION:
+            _glfw.hints.framebuffer.acceleration = value ? GLFW_TRUE : GLFW_FALSE;
+            return;
         case GLFW_RESIZABLE:
             _glfw.hints.window.resizable = value ? GLFW_TRUE : GLFW_FALSE;
             return;
@@ -897,6 +902,8 @@ GLFWAPI int glfwGetWindowAttrib(GLFWwindow* handle, int attrib)
             return window->autoIconify;
         case GLFW_DOUBLEBUFFER:
             return window->doublebuffer;
+        case GLFW_ACCELERATION:
+            return window->acceleration;
         case GLFW_CLIENT_API:
             return window->context.client;
         case GLFW_CONTEXT_CREATION_API: