Fixed bug 3355 - false "Invalid renderer" after creating an "opengles2" renderer.

Call SDL_GL_GetDrawableSize() directly because we may be in the initialization path and SDL_GetRendererOutputSize() will fail because the renderer magic isn't set up yet.
diff --git a/src/render/opengl/SDL_render_gl.c b/src/render/opengl/SDL_render_gl.c
index 85319ea..410de46 100644
--- a/src/render/opengl/SDL_render_gl.c
+++ b/src/render/opengl/SDL_render_gl.c
@@ -592,7 +592,6 @@
 GL_GetOutputSize(SDL_Renderer * renderer, int *w, int *h)
 {
     SDL_GL_GetDrawableSize(renderer->window, w, h);
-
     return 0;
 }
 
@@ -1020,7 +1019,7 @@
     } else {
         int w, h;
 
-        SDL_GetRendererOutputSize(renderer, &w, &h);
+        SDL_GL_GetDrawableSize(renderer, &w, &h);
         data->glViewport(renderer->viewport.x, (h - renderer->viewport.y - renderer->viewport.h),
                          renderer->viewport.w, renderer->viewport.h);
     }
@@ -1058,7 +1057,7 @@
         } else {
             int w, h;
 
-            SDL_GetRendererOutputSize(renderer, &w, &h);
+            SDL_GL_GetDrawableSize(renderer, &w, &h);
             data->glScissor(renderer->viewport.x + rect->x, h - renderer->viewport.y - rect->y - rect->h, rect->w, rect->h);
         }
     } else {
diff --git a/src/render/opengles/SDL_render_gles.c b/src/render/opengles/SDL_render_gles.c
index f0856d7..5f96b22 100644
--- a/src/render/opengles/SDL_render_gles.c
+++ b/src/render/opengles/SDL_render_gles.c
@@ -672,7 +672,7 @@
     } else {
         int w, h;
 
-        SDL_GetRendererOutputSize(renderer, &w, &h);
+        SDL_GL_GetDrawableSize(renderer, &w, &h);
         data->glViewport(renderer->viewport.x, (h - renderer->viewport.y - renderer->viewport.h),
                          renderer->viewport.w, renderer->viewport.h);
     }
@@ -715,7 +715,7 @@
         } else {
             int w, h;
 
-            SDL_GetRendererOutputSize(renderer, &w, &h);
+            SDL_GL_GetDrawableSize(renderer, &w, &h);
             data->glScissor(renderer->viewport.x + rect->x, h - renderer->viewport.y - rect->y - rect->h, rect->w, rect->h);
         }
     } else {
diff --git a/src/render/opengles2/SDL_render_gles2.c b/src/render/opengles2/SDL_render_gles2.c
index c419c0f..c846a7b 100644
--- a/src/render/opengles2/SDL_render_gles2.c
+++ b/src/render/opengles2/SDL_render_gles2.c
@@ -388,7 +388,7 @@
     } else {
         int w, h;
 
-        SDL_GetRendererOutputSize(renderer, &w, &h);
+        SDL_GL_GetDrawableSize(renderer->window, &w, &h);
         data->glViewport(renderer->viewport.x, (h - renderer->viewport.y - renderer->viewport.h),
                          renderer->viewport.w, renderer->viewport.h);
     }
@@ -417,7 +417,7 @@
         } else {
             int w, h;
 
-            SDL_GetRendererOutputSize(renderer, &w, &h);
+            SDL_GL_GetDrawableSize(renderer->window, &w, &h);
             data->glScissor(renderer->viewport.x + rect->x, h - renderer->viewport.y - rect->y - rect->h, rect->w, rect->h);
         }
     } else {