Route RTT texture updates through GL backend

src/renderer_gl/opengl_capabilities.cpp

@@ -832,6 +832,8 @@ pp::foundation::Status update_opengl_texture_2d(
     }
 
     if (update.texture_id == 0U
+        || update.x < 0
+        || update.y < 0
         || update.width <= 0
         || update.height <= 0
         || update.pixel_format == 0U
@@ -844,8 +846,8 @@ pp::foundation::Status update_opengl_texture_2d(
     dispatch.tex_sub_image_2d(
         texture_2d_target(),
         0,
-        0,
-        0,
+        update.x,
+        update.y,
         update.width,
         update.height,
         update.pixel_format,

src/renderer_gl/opengl_capabilities.h

@@ -142,6 +142,8 @@ struct OpenGlTextureCubeAllocation {
 
 struct OpenGlTexture2DUpdate {
     std::uint32_t texture_id = 0;
+    std::int32_t x = 0;
+    std::int32_t y = 0;
     std::int32_t width = 0;
     std::int32_t height = 0;
     std::uint32_t pixel_format = 0;