Fixed bug 3975 - Add GLES2 support for macOS via ANGLE library

Andrey

Seems latest google angle library successfully built & tested under macOS'es.

https://github.com/google/angle

We need to use GLES2 to implement true cross-platform code.

src/video/SDL_egl.c

@@ -65,6 +65,13 @@
 #define DEFAULT_OGL_ES_PVR "libGLES_CM.dll"
 #define DEFAULT_OGL_ES "libGLESv1_CM.dll"
 
+#elif SDL_VIDEO_DRIVER_COCOA
+/* EGL AND OpenGL ES support via ANGLE */
+#define DEFAULT_EGL "libEGL.dylib"
+#define DEFAULT_OGL_ES2 "libGLESv2.dylib"
+#define DEFAULT_OGL_ES_PVR "libGLES_CM.dylib"   //???
+#define DEFAULT_OGL_ES "libGLESv1_CM.dylib"     //???
+
 #else
 /* Desktop Linux */
 #define DEFAULT_OGL "libGL.so.1"

src/video/cocoa/SDL_cocoaopengl.m

@@ -25,6 +25,7 @@
 #if SDL_VIDEO_OPENGL_CGL
 #include "SDL_cocoavideo.h"
 #include "SDL_cocoaopengl.h"
+#include "SDL_cocoaopengles.h"
 
 #include <OpenGL/CGLTypes.h>
 #include <OpenGL/OpenGL.h>
@@ -165,8 +166,27 @@ Cocoa_GL_CreateContext(_THIS, SDL_Window * window)
     int glversion_minor;
 
     if (_this->gl_config.profile_mask == SDL_GL_CONTEXT_PROFILE_ES) {
-        SDL_SetError ("OpenGL ES is not supported on this platform");
+#if SDL_VIDEO_OPENGL_EGL
+        /* Switch to EGL based functions */
+        Cocoa_GL_UnloadLibrary(_this);
+        _this->GL_LoadLibrary = Cocoa_GLES_LoadLibrary;
+        _this->GL_GetProcAddress = Cocoa_GLES_GetProcAddress;
+        _this->GL_UnloadLibrary = Cocoa_GLES_UnloadLibrary;
+        _this->GL_CreateContext = Cocoa_GLES_CreateContext;
+        _this->GL_MakeCurrent = Cocoa_GLES_MakeCurrent;
+        _this->GL_SetSwapInterval = Cocoa_GLES_SetSwapInterval;
+        _this->GL_GetSwapInterval = Cocoa_GLES_GetSwapInterval;
+        _this->GL_SwapWindow = Cocoa_GLES_SwapWindow;
+        _this->GL_DeleteContext = Cocoa_GLES_DeleteContext;
+        
+        if (Cocoa_GLES_LoadLibrary(_this, NULL) != 0) {
+            return NULL;
+        }
+        return Cocoa_GLES_CreateContext(_this, window);
+#else
+        SDL_SetError("SDL not configured with EGL support");
         return NULL;
+#endif
     }
     if ((_this->gl_config.profile_mask == SDL_GL_CONTEXT_PROFILE_CORE) && !lion_or_later) {
         SDL_SetError ("OpenGL Core Profile is not supported on this platform version");

src/video/cocoa/SDL_cocoavideo.m

@@ -121,6 +121,16 @@ Cocoa_CreateDevice(int devindex)
     device->GL_GetSwapInterval = Cocoa_GL_GetSwapInterval;
     device->GL_SwapWindow = Cocoa_GL_SwapWindow;
     device->GL_DeleteContext = Cocoa_GL_DeleteContext;
+#elif SDL_VIDEO_OPENGL_EGL
+    device->GL_LoadLibrary = Cocoa_GLES_LoadLibrary;
+    device->GL_GetProcAddress = Cocoa_GLES_GetProcAddress;
+    device->GL_UnloadLibrary = Cocoa_GLES_UnloadLibrary;
+    device->GL_CreateContext = Cocoa_GLES_CreateContext;
+    device->GL_MakeCurrent = Cocoa_GLES_MakeCurrent;
+    device->GL_SetSwapInterval = Cocoa_GLES_SetSwapInterval;
+    device->GL_GetSwapInterval = Cocoa_GLES_GetSwapInterval;
+    device->GL_SwapWindow = Cocoa_GLES_SwapWindow;
+    device->GL_DeleteContext = Cocoa_GLES_DeleteContext;
 #endif
 
 #if SDL_VIDEO_VULKAN

src/video/cocoa/SDL_cocoawindow.h

@@ -25,6 +25,10 @@
 
 #import <Cocoa/Cocoa.h>
 
+#if SDL_VIDEO_OPENGL_EGL
+#include "../SDL_egl_c.h"
+#endif
+
 typedef struct SDL_WindowData SDL_WindowData;
 
 typedef enum
@@ -114,6 +118,9 @@ struct SDL_WindowData
     SDL_bool inWindowMove;
     Cocoa_WindowListener *listener;
     struct SDL_VideoData *videodata;
+#if SDL_VIDEO_OPENGL_EGL
+    EGLSurface egl_surface;
+#endif
 };
 
 extern int Cocoa_CreateWindow(_THIS, SDL_Window * window);

src/video/cocoa/SDL_cocoawindow.m

@@ -40,6 +40,7 @@
 #include "SDL_cocoamouse.h"
 #include "SDL_cocoamousetap.h"
 #include "SDL_cocoaopengl.h"
+#include "SDL_cocoaopengles.h"
 #include "SDL_assert.h"
 
 /* #define DEBUG_COCOAWINDOW */
@@ -1342,7 +1343,14 @@ Cocoa_CreateWindow(_THIS, SDL_Window * window)
             [contentView setWantsBestResolutionOpenGLSurface:YES];
         }
     }
-
+#if SDL_VIDEO_OPENGL_ES2
+#if SDL_VIDEO_OPENGL_EGL
+    if ((window->flags & SDL_WINDOW_OPENGL) &&
+        _this->gl_config.profile_mask == SDL_GL_CONTEXT_PROFILE_ES) {
+        [contentView setWantsLayer:TRUE];
+    }
+#endif /* SDL_VIDEO_OPENGL_EGL */
+#endif /* SDL_VIDEO_OPENGL_ES2 */
     [nswindow setContentView:contentView];
     [contentView release];
 
@@ -1353,6 +1361,25 @@ Cocoa_CreateWindow(_THIS, SDL_Window * window)
         [nswindow release];
         return -1;
     }
+
+    if (!(window->flags & SDL_WINDOW_OPENGL)) {
+        return 0;
+    }
+    
+    /* The rest of this macro mess is for OpenGL or OpenGL ES windows */
+#if SDL_VIDEO_OPENGL_ES2
+    if (_this->gl_config.profile_mask == SDL_GL_CONTEXT_PROFILE_ES) {
+#if SDL_VIDEO_OPENGL_EGL
+        if (Cocoa_GLES_SetupWindow(_this, window) < 0) {
+            Cocoa_DestroyWindow(_this, window);
+            return -1;
+        }
+        return 0;
+#else
+        return SDL_SetError("Could not create GLES window surface (EGL support not configured)");
+#endif /* SDL_VIDEO_OPENGL_EGL */
+    }
+#endif /* SDL_VIDEO_OPENGL_ES2 */
     return 0;
 }}