src/video/windows/SDL_windowsopengles.c
author Sam Lantinga <slouken@libsdl.org>
Mon, 09 Jan 2017 10:10:33 -0800
changeset 10800 f3439b0eb486
parent 10737 3406a0f8b041
child 11175 cbc6a8a5b701
permissions -rw-r--r--
Fixed bug 3100 - SetSwapInterval should now be enabled for ANGLE/EGL

Mark Logan 2015-08-24 15:57:50 UTC
In SDL_windowsopengles.c, WIN_GLES_SetSwapInterval is as follows:

WIN_GLES_SetSwapInterval(_THIS, int interval)
{
/* FIXME: This should call SDL_EGL_SetSwapInterval, but ANGLE has a bug that prevents this
* from working if we do (the window contents freeze and don't swap properly). So, we ignore
* the request for now.
*/
SDL_Log("WARNING: Ignoring SDL_GL_SetSwapInterval call due to ANGLE bug");
return 0;
}

With a recent version of ANGLE (early July) calling SDL_EGL_SetSwapInterval with a D3D11 backend appears to work just fine. I am working on testing this with D3D9.

--

Alex Szpakowski

I found the bug, it was fixed in 2013. https://bugs.chromium.org/p/angleproject/issues/detail?id=481

In my opinion it should be safe to unconditionally use SetSwapInterval now. Anyone who encounters the bug should update their ANGLE to a version less than 3 years old, especially since they'd be using a SDL version that's 3+ years newer than their ANGLE version.
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2017 Sam Lantinga <slouken@libsdl.org>
     4 
     5   This software is provided 'as-is', without any express or implied
     6   warranty.  In no event will the authors be held liable for any damages
     7   arising from the use of this software.
     8 
     9   Permission is granted to anyone to use this software for any purpose,
    10   including commercial applications, and to alter it and redistribute it
    11   freely, subject to the following restrictions:
    12 
    13   1. The origin of this software must not be misrepresented; you must not
    14      claim that you wrote the original software. If you use this software
    15      in a product, an acknowledgment in the product documentation would be
    16      appreciated but is not required.
    17   2. Altered source versions must be plainly marked as such, and must not be
    18      misrepresented as being the original software.
    19   3. This notice may not be removed or altered from any source distribution.
    20 */
    21 #include "../../SDL_internal.h"
    22 
    23 #if SDL_VIDEO_DRIVER_WINDOWS && SDL_VIDEO_OPENGL_EGL
    24 
    25 #include "SDL_windowsvideo.h"
    26 #include "SDL_windowsopengles.h"
    27 #include "SDL_windowsopengl.h"
    28 #include "SDL_log.h"
    29 
    30 /* EGL implementation of SDL OpenGL support */
    31 
    32 int
    33 WIN_GLES_LoadLibrary(_THIS, const char *path) {
    34 
    35     /* If the profile requested is not GL ES, switch over to WIN_GL functions  */
    36     if (_this->gl_config.profile_mask != SDL_GL_CONTEXT_PROFILE_ES) {
    37 #if SDL_VIDEO_OPENGL_WGL
    38         WIN_GLES_UnloadLibrary(_this);
    39         _this->GL_LoadLibrary = WIN_GL_LoadLibrary;
    40         _this->GL_GetProcAddress = WIN_GL_GetProcAddress;
    41         _this->GL_UnloadLibrary = WIN_GL_UnloadLibrary;
    42         _this->GL_CreateContext = WIN_GL_CreateContext;
    43         _this->GL_MakeCurrent = WIN_GL_MakeCurrent;
    44         _this->GL_SetSwapInterval = WIN_GL_SetSwapInterval;
    45         _this->GL_GetSwapInterval = WIN_GL_GetSwapInterval;
    46         _this->GL_SwapWindow = WIN_GL_SwapWindow;
    47         _this->GL_DeleteContext = WIN_GL_DeleteContext;
    48         return WIN_GL_LoadLibrary(_this, path);
    49 #else
    50         return SDL_SetError("SDL not configured with OpenGL/WGL support");
    51 #endif
    52     }
    53     
    54     if (_this->egl_data == NULL) {
    55         return SDL_EGL_LoadLibrary(_this, NULL, EGL_DEFAULT_DISPLAY);
    56     }
    57 
    58     return 0;
    59 }
    60 
    61 SDL_GLContext
    62 WIN_GLES_CreateContext(_THIS, SDL_Window * window)
    63 {
    64     SDL_GLContext context;
    65     SDL_WindowData *data = (SDL_WindowData *)window->driverdata;
    66 
    67 #if SDL_VIDEO_OPENGL_WGL
    68     if (_this->gl_config.profile_mask != SDL_GL_CONTEXT_PROFILE_ES) {
    69         /* Switch to WGL based functions */
    70         WIN_GLES_UnloadLibrary(_this);
    71         _this->GL_LoadLibrary = WIN_GL_LoadLibrary;
    72         _this->GL_GetProcAddress = WIN_GL_GetProcAddress;
    73         _this->GL_UnloadLibrary = WIN_GL_UnloadLibrary;
    74         _this->GL_CreateContext = WIN_GL_CreateContext;
    75         _this->GL_MakeCurrent = WIN_GL_MakeCurrent;
    76         _this->GL_SetSwapInterval = WIN_GL_SetSwapInterval;
    77         _this->GL_GetSwapInterval = WIN_GL_GetSwapInterval;
    78         _this->GL_SwapWindow = WIN_GL_SwapWindow;
    79         _this->GL_DeleteContext = WIN_GL_DeleteContext;
    80 
    81         if (WIN_GL_LoadLibrary(_this, NULL) != 0) {
    82             return NULL;
    83         }
    84 
    85         return WIN_GL_CreateContext(_this, window);
    86     }
    87 #endif
    88 
    89     context = SDL_EGL_CreateContext(_this, data->egl_surface);
    90     return context;
    91 }
    92 
    93 void
    94 WIN_GLES_DeleteContext(_THIS, SDL_GLContext context)
    95 {
    96     SDL_EGL_DeleteContext(_this, context);
    97     WIN_GLES_UnloadLibrary(_this);
    98 }
    99 
   100 SDL_EGL_SwapWindow_impl(WIN)
   101 SDL_EGL_MakeCurrent_impl(WIN)
   102 
   103 int
   104 WIN_GLES_SetupWindow(_THIS, SDL_Window * window)
   105 {
   106     /* The current context is lost in here; save it and reset it. */
   107     SDL_WindowData *windowdata = (SDL_WindowData *) window->driverdata;
   108     SDL_Window *current_win = SDL_GL_GetCurrentWindow();
   109     SDL_GLContext current_ctx = SDL_GL_GetCurrentContext();
   110 
   111 
   112     if (_this->egl_data == NULL) {
   113         if (SDL_EGL_LoadLibrary(_this, NULL, EGL_DEFAULT_DISPLAY) < 0) {
   114             SDL_EGL_UnloadLibrary(_this);
   115             return -1;
   116         }
   117     }
   118   
   119     /* Create the GLES window surface */
   120     windowdata->egl_surface = SDL_EGL_CreateSurface(_this, (NativeWindowType)windowdata->hwnd);
   121 
   122     if (windowdata->egl_surface == EGL_NO_SURFACE) {
   123         return SDL_SetError("Could not create GLES window surface");
   124     }
   125 
   126     return WIN_GLES_MakeCurrent(_this, current_win, current_ctx);    
   127 }
   128 
   129 #endif /* SDL_VIDEO_DRIVER_WINDOWS && SDL_VIDEO_OPENGL_EGL */
   130 
   131 /* vi: set ts=4 sw=4 expandtab: */