[egl] add support for vendor-specific GL extensions

on implementations which have a single EGL backend, it is straight-
forward to query the EGL implementation for the supported GL extensions

the mechanism added in this commit will only work on implementations
which have a single EGL backend; on implementations which have
multiple backends, this feature should be disabled at compile-time

for EGLImage extensions, call into a wrapper layer implementation to
translate the meta-EGL object into the vendor object before calling into
the vendor's EGLImage implementation

Change-Id: I4c930a506a743b6ea88c4b2e769a9ea5ebf8e0d0

1 files changed, 62 insertions, 0 deletions

diff --git a/opengl/libs/EGL/egl.cpp b/opengl/libs/EGL/egl.cpp
index de740a3..eeb587a 100644
--- a/opengl/libs/EGL/egl.cpp
+++ b/opengl/libs/EGL/egl.cpp
@@ -42,6 +42,14 @@
 #include "egl_impl.h"
 #include "Loader.h"
 
+// Enable this define to allow querying vendor-specific GL extensions. This
+// currently will only work correctly for implementations which have a single
+// EGL backend; multiple EGL backends are not supported.
+// There's also an extra subtlety with the EGLimage entry points in GL, which
+// can't work properly if they're called directly (they have to go through
+// a wrapper).
+#define ENABLE_VENDOR_EXTENSIONS
+
 #define MAKE_CONFIG(_impl, _index)  ((EGLConfig)(((_impl)<<24) | (_index)))
 #define setError(_e, _r) setErrorEtc(__FUNCTION__, __LINE__, _e, _r)
 
@@ -58,6 +66,11 @@ static char const * const gExtensionString  =
         "EGL_KHR_image "
         "EGL_KHR_image_base "
         "EGL_KHR_image_pixmap "
+#ifdef ENABLE_VENDOR_EXTENSIONS
+        "EGL_KHR_gl_texture_2D_image "
+        "EGL_KHR_gl_texture_cubemap_image "
+        "EGL_KHR_gl_renderbuffer_image "
+#endif
         "EGL_ANDROID_image_native_buffer "
         "EGL_ANDROID_swap_rectangle "
         "EGL_ANDROID_get_render_buffer "
@@ -1315,6 +1328,31 @@ EGLint eglGetError(void)
     return result;
 }
 
+#ifdef ENABLE_VENDOR_EXTENSIONS
+// Note: Similar implementations of this function also exist in gl2.cpp and
+// gl.cpp, and are used by applications that call the exported entry points
+// directly.
+typedef void (GL_APIENTRYP PFNGLEGLIMAGETARGETTEXTURE2DOESPROC) (GLenum target, GLeglImageOES image);
+typedef void (GL_APIENTRYP PFNGLEGLIMAGETARGETRENDERBUFFERSTORAGEOESPROC) (GLenum target, GLeglImageOES image);
+
+static PFNGLEGLIMAGETARGETTEXTURE2DOESPROC glEGLImageTargetTexture2DOES_impl = NULL;
+static PFNGLEGLIMAGETARGETRENDERBUFFERSTORAGEOESPROC glEGLImageTargetRenderbufferStorageOES_impl = NULL;
+
+static void glEGLImageTargetTexture2DOES_wrapper(GLenum target, GLeglImageOES image)
+{
+    GLeglImageOES implImage =
+        (GLeglImageOES)egl_get_image_for_current_context((EGLImageKHR)image);
+    glEGLImageTargetTexture2DOES_impl(target, implImage);
+}
+
+static void glEGLImageTargetRenderbufferStorageOES_wrapper(GLenum target, GLeglImageOES image)
+{
+    GLeglImageOES implImage =
+        (GLeglImageOES)egl_get_image_for_current_context((EGLImageKHR)image);
+    glEGLImageTargetRenderbufferStorageOES_impl(target, implImage);
+}
+#endif
+
 __eglMustCastToProperFunctionPointerType eglGetProcAddress(const char *procname)
 {
     // eglGetProcAddress() could be the very first function called
@@ -1330,6 +1368,30 @@ __eglMustCastToProperFunctionPointerType eglGetProcAddress(const char *procname)
     addr = findProcAddress(procname, gExtentionMap, NELEM(gExtentionMap));
     if (addr) return addr;
 
+#ifdef ENABLE_VENDOR_EXTENSIONS
+    addr = 0;
+    for (int i=0 ; i<IMPL_NUM_IMPLEMENTATIONS ; i++) {
+        egl_connection_t* const cnx = &gEGLImpl[i];
+        if (cnx->dso) {
+            if (cnx->egl.eglGetProcAddress) {
+                addr = cnx->egl.eglGetProcAddress(procname);
+                if (addr) {
+                    if (!strcmp(procname, "glEGLImageTargetTexture2DOES")) {
+                        glEGLImageTargetTexture2DOES_impl = (PFNGLEGLIMAGETARGETTEXTURE2DOESPROC)addr;
+                        return (__eglMustCastToProperFunctionPointerType)glEGLImageTargetTexture2DOES_wrapper;
+                    }
+                    if (!strcmp(procname, "glEGLImageTargetRenderbufferStorageOES")) {
+                        glEGLImageTargetRenderbufferStorageOES_impl = (PFNGLEGLIMAGETARGETRENDERBUFFERSTORAGEOESPROC)addr;
+                        return (__eglMustCastToProperFunctionPointerType)glEGLImageTargetRenderbufferStorageOES_wrapper;
+                    }
+
+                    return addr;
+                }
+            }
+        }
+    }
+#endif
+
     return NULL; // TODO: finish implementation below
 
     addr = findProcAddress(procname, gGLExtentionMap, NELEM(gGLExtentionMap));