From adce527880eace0ff6025fb0dc0e4b98b669ea78 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pa=CC=84vels=20Nadtoc=CC=8Cajevs?=
 <7645683+bruvzg@users.noreply.github.com>
Date: Tue, 26 Aug 2025 21:01:44 +0300
Subject: [PATCH] Check renderer type when setting 3D upscaling mode.

---
 servers/rendering/renderer_viewport.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/servers/rendering/renderer_viewport.cpp b/servers/rendering/renderer_viewport.cpp
index 820b4c9dd0e..1ff3b2d9295 100644
--- a/servers/rendering/renderer_viewport.cpp
+++ b/servers/rendering/renderer_viewport.cpp
@@ -145,6 +145,12 @@ void RendererViewport::_configure_3d_render_buffers(Viewport *p_viewport) {
 				scaling_3d_mode = RS::VIEWPORT_SCALING_3D_MODE_OFF;
 			}
 
+			if (scaling_3d_mode != RS::VIEWPORT_SCALING_3D_MODE_OFF && scaling_3d_mode != RS::VIEWPORT_SCALING_3D_MODE_BILINEAR && OS::get_singleton()->get_current_rendering_method() == "gl_compatibility") {
+				scaling_3d_mode = RS::VIEWPORT_SCALING_3D_MODE_BILINEAR;
+				scaling_type = RS::scaling_3d_mode_type(scaling_3d_mode);
+				WARN_PRINT_ONCE("MetalFX and FSR upscaling are not supported in the Compatibility renderer. Falling back to bilinear scaling.");
+			}
+
 			if (scaling_3d_mode == RS::VIEWPORT_SCALING_3D_MODE_METALFX_TEMPORAL && !RD::get_singleton()->has_feature(RD::SUPPORTS_METALFX_TEMPORAL)) {
 				if (RD::get_singleton()->has_feature(RD::SUPPORTS_METALFX_SPATIAL)) {
 					// Prefer MetalFX spatial if it is supported, which will be much more efficient than FSR2,
@@ -974,6 +980,9 @@ void RendererViewport::viewport_set_scaling_3d_mode(RID p_viewport, RS::Viewport
 		ERR_FAIL_COND_EDMSG(p_mode == RS::VIEWPORT_SCALING_3D_MODE_FSR2, "FSR2 is only available when using the Forward+ renderer.");
 		ERR_FAIL_COND_EDMSG(p_mode == RS::VIEWPORT_SCALING_3D_MODE_METALFX_TEMPORAL, "MetalFX Temporal is only available when using the Forward+ renderer.");
 	}
+	if (rendering_method == "gl_compatibility") {
+		ERR_FAIL_COND_EDMSG(p_mode == RS::VIEWPORT_SCALING_3D_MODE_METALFX_SPATIAL, "MetalFX Spatial is only available when using the Forward+ and Mobile renderers.");
+	}
 
 	if (viewport->scaling_3d_mode == p_mode) {
 		return;