Fix excessive re-creation of VR viewport textures

Due to the freeing and re-creation of textures performed when binding
offscreen viewports, VR viewport textures would be needlessly
re-created every drawing iteration, leading to a negative impact on VR
frame rate.

This was brought to light by 6738ecb64e8b, which introduced an
additional texture clear operation on initialization and was
prohibitively costly on some systems when performed every frame.

Now, the textures for VR viewports will not be always re-created
during offscreen binding, but only when necessary using a pre-drawing
step (`wm_xr_session_surface_offscreen_ensure()`).

Reviewed By: jbakker, fclem

Differential Revision: https://developer.blender.org/D14059

1 files changed, 3 insertions, 1 deletions

diff --git a/source/blender/gpu/GPU_viewport.h b/source/blender/gpu/GPU_viewport.h
index 917b87efeaa..263d1d7c90f 100644
--- a/source/blender/gpu/GPU_viewport.h
+++ b/source/blender/gpu/GPU_viewport.h
@@ -79,7 +79,9 @@ void GPU_viewport_colorspace_set(GPUViewport *viewport,
 /**
  * Should be called from DRW after DRW_opengl_context_enable.
  */
-void GPU_viewport_bind_from_offscreen(GPUViewport *viewport, struct GPUOffScreen *ofs);
+void GPU_viewport_bind_from_offscreen(GPUViewport *viewport,
+                                      struct GPUOffScreen *ofs,
+                                      bool is_xr_surface);
 /**
  * Clear vars assigned from offscreen, so we don't free data owned by `GPUOffScreen`.
  */