From e821477102291f1c2e314b95800bfa82c6a1761a Mon Sep 17 00:00:00 2001
From: clayjohn <claynjohn@gmail.com>
Date: Sun, 15 Sep 2019 21:07:07 -0700
Subject: [PATCH] throw error when user tries to use Canvas background without
 sample buffer

(cherry picked from commit e65d2184b95ce22553dd6df729e79db3f75c30aa)
---
 drivers/gles3/rasterizer_scene_gles3.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gles3/rasterizer_scene_gles3.cpp b/drivers/gles3/rasterizer_scene_gles3.cpp
index 2d105e258a1..a290fc02174 100644
--- a/drivers/gles3/rasterizer_scene_gles3.cpp
+++ b/drivers/gles3/rasterizer_scene_gles3.cpp
@@ -4310,6 +4310,10 @@ void RasterizerSceneGLES3::render_scene(const Transform &p_cam_transform, const
 			if (storage->frame.current_rt->buffers.active) {
 				current_fbo = storage->frame.current_rt->buffers.fbo;
 			} else {
+				if (storage->frame.current_rt->effects.mip_maps[0].sizes.size() == 0) {
+					ERR_PRINT_ONCE("Can't use canvas background mode in a render target configured without sampling");
+					return;
+				}
 				current_fbo = storage->frame.current_rt->effects.mip_maps[0].sizes[0].fbo;
 			}