Remove 16× MSAA support due to driver bugs and low performance

In the `master` branch, 16× MSAA caused the entire system to freeze on NVIDIA GPUs. This is likely caused by graphics drivers not actually implementing 16× MSAA, but combining 8× MSAA with 2× SSAA instead. On top of that, modern shader complexity makes 16× MSAA very difficult to use while keeping a good framerate. 8× MSAA is hard enough to use as it is.
godotengine · Aug 25, 2021 · 7192852 · 7192852
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commit 7192852
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Showing 9 changed files with 10 additions and 21 deletions.
diff --git a/doc/classes/RenderingServer.xml b/doc/classes/RenderingServer.xml
@@ -3788,21 +3788,18 @@
 		<constant name="VIEWPORT_SDF_SCALE_MAX" value="3" enum="ViewportSDFScale">
 		</constant>
 		<constant name="VIEWPORT_MSAA_DISABLED" value="0" enum="ViewportMSAA">
-			Multisample antialiasing is disabled.
+			Multisample antialiasing for 3D is disabled. This is the default value, and also the fastest setting.
 		</constant>
 		<constant name="VIEWPORT_MSAA_2X" value="1" enum="ViewportMSAA">
-			Multisample antialiasing uses 2 samples per pixel.
+			Multisample antialiasing uses 2 samples per pixel for 3D. This has a moderate impact on performance.
 		</constant>
 		<constant name="VIEWPORT_MSAA_4X" value="2" enum="ViewportMSAA">
-			Multisample antialiasing uses 4 samples per pixel.
+			Multisample antialiasing uses 4 samples per pixel for 3D. This has a high impact on performance.
 		</constant>
 		<constant name="VIEWPORT_MSAA_8X" value="3" enum="ViewportMSAA">
-			Multisample antialiasing uses 8 samples per pixel.
+			Multisample antialiasing uses 8 samples per pixel for 3D. This has a very high impact on performance. Likely unsupported on low-end and older hardware.
 		</constant>
-		<constant name="VIEWPORT_MSAA_16X" value="4" enum="ViewportMSAA">
-			Multisample antialiasing uses 16 samples per pixel.
-		</constant>
-		<constant name="VIEWPORT_MSAA_MAX" value="5" enum="ViewportMSAA">
+		<constant name="VIEWPORT_MSAA_MAX" value="4" enum="ViewportMSAA">
 		</constant>
 		<constant name="VIEWPORT_SCREEN_SPACE_AA_DISABLED" value="0" enum="ViewportScreenSpaceAA">
 		</constant>

diff --git a/doc/classes/Viewport.xml b/doc/classes/Viewport.xml
@@ -307,10 +307,7 @@
 		<constant name="MSAA_8X" value="3" enum="MSAA">
 			Use 8× Multisample Antialiasing. This has a very high performance cost. The difference between 4× and 8× MSAA may not always be visible in real gameplay conditions. Likely unsupported on low-end and older hardware.
 		</constant>
-		<constant name="MSAA_16X" value="4" enum="MSAA">
-			Use 16× Multisample Antialiasing. This has a very high performance cost. The difference between 8× and 16× MSAA may not always be visible in real gameplay conditions. Likely unsupported on medium and low-end hardware.
-		</constant>
-		<constant name="MSAA_MAX" value="5" enum="MSAA">
+		<constant name="MSAA_MAX" value="4" enum="MSAA">
 			Represents the size of the [enum MSAA] enum.
 		</constant>
 		<constant name="SCREEN_SPACE_AA_DISABLED" value="0" enum="ScreenSpaceAA">

diff --git a/scene/main/scene_tree.cpp b/scene/main/scene_tree.cpp
@@ -1346,7 +1346,7 @@ SceneTree::SceneTree() {
 	current_scene = nullptr;
 
 	const int msaa_mode = GLOBAL_DEF("rendering/anti_aliasing/quality/msaa", 0);
-	ProjectSettings::get_singleton()->set_custom_property_info("rendering/anti_aliasing/quality/msaa", PropertyInfo(Variant::INT, "rendering/anti_aliasing/quality/msaa", PROPERTY_HINT_ENUM, String::utf8("Disabled (Fastest),2× (Fast),4× (Average),8× (Slow),16× (Slower)")));
+	ProjectSettings::get_singleton()->set_custom_property_info("rendering/anti_aliasing/quality/msaa", PropertyInfo(Variant::INT, "rendering/anti_aliasing/quality/msaa", PROPERTY_HINT_ENUM, String::utf8("Disabled (Fastest),2× (Average),4× (Slow),8× (Slowest)")));
 	root->set_msaa(Viewport::MSAA(msaa_mode));
 
 	const int ssaa_mode = GLOBAL_DEF("rendering/anti_aliasing/quality/screen_space_aa", 0);

diff --git a/scene/main/viewport.cpp b/scene/main/viewport.cpp
@@ -3587,7 +3587,7 @@ void Viewport::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "snap_2d_transforms_to_pixel"), "set_snap_2d_transforms_to_pixel", "is_snap_2d_transforms_to_pixel_enabled");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "snap_2d_vertices_to_pixel"), "set_snap_2d_vertices_to_pixel", "is_snap_2d_vertices_to_pixel_enabled");
 	ADD_GROUP("Rendering", "");
-	ADD_PROPERTY(PropertyInfo(Variant::INT, "msaa", PROPERTY_HINT_ENUM, String::utf8("Disabled (Fastest),2× (Fast),4× (Average),8× (Slow),16× (Slower)")), "set_msaa", "get_msaa");
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "msaa", PROPERTY_HINT_ENUM, String::utf8("Disabled (Fastest),2× (Average),4× (Slow),8× (Slowest)")), "set_msaa", "get_msaa");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "screen_space_aa", PROPERTY_HINT_ENUM, "Disabled (Fastest),FXAA (Fast)"), "set_screen_space_aa", "get_screen_space_aa");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "use_debanding"), "set_use_debanding", "is_using_debanding");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "use_occlusion_culling"), "set_use_occlusion_culling", "is_using_occlusion_culling");
@@ -3633,7 +3633,6 @@ void Viewport::_bind_methods() {
 	BIND_ENUM_CONSTANT(MSAA_2X);
 	BIND_ENUM_CONSTANT(MSAA_4X);
 	BIND_ENUM_CONSTANT(MSAA_8X);
-	BIND_ENUM_CONSTANT(MSAA_16X);
 	BIND_ENUM_CONSTANT(MSAA_MAX);
 
 	BIND_ENUM_CONSTANT(SCREEN_SPACE_AA_DISABLED);

diff --git a/scene/main/viewport.h b/scene/main/viewport.h
@@ -104,7 +104,7 @@ class Viewport : public Node {
 		MSAA_2X,
 		MSAA_4X,
 		MSAA_8X,
-		MSAA_16X,
+		// 16x MSAA is not supported due to its high cost and driver bugs.
 		MSAA_MAX
 	};
 

diff --git a/servers/rendering/renderer_rd/forward_clustered/render_forward_clustered.cpp b/servers/rendering/renderer_rd/forward_clustered/render_forward_clustered.cpp
@@ -223,7 +223,6 @@ void RenderForwardClustered::RenderBufferDataForwardClustered::configure(RID p_c
 			RD::TEXTURE_SAMPLES_2,
 			RD::TEXTURE_SAMPLES_4,
 			RD::TEXTURE_SAMPLES_8,
-			RD::TEXTURE_SAMPLES_16
 		};
 
 		texture_samples = ts[p_msaa];
@@ -1163,7 +1162,7 @@ void RenderForwardClustered::_render_scene(RenderDataRD *p_render_data, const Co
 		render_buffer = (RenderBufferDataForwardClustered *)render_buffers_get_data(p_render_data->render_buffers);
 	}
 	RendererSceneEnvironmentRD *env = get_environment(p_render_data->environment);
-	static const int texture_multisamples[RS::VIEWPORT_MSAA_MAX] = { 1, 2, 4, 8, 16 };
+	static const int texture_multisamples[RS::VIEWPORT_MSAA_MAX] = { 1, 2, 4, 8 };
 
 	//first of all, make a new render pass
 	//fill up ubo

diff --git a/servers/rendering/renderer_rd/forward_mobile/render_forward_mobile.cpp b/servers/rendering/renderer_rd/forward_mobile/render_forward_mobile.cpp
@@ -158,7 +158,6 @@ void RenderForwardMobile::RenderBufferDataForwardMobile::configure(RID p_color_b
 			RD::TEXTURE_SAMPLES_2,
 			RD::TEXTURE_SAMPLES_4,
 			RD::TEXTURE_SAMPLES_8,
-			RD::TEXTURE_SAMPLES_16
 		};
 
 		texture_samples = ts[p_msaa];

diff --git a/servers/rendering_server.cpp b/servers/rendering_server.cpp
@@ -2210,7 +2210,6 @@ void RenderingServer::_bind_methods() {
 	BIND_ENUM_CONSTANT(VIEWPORT_MSAA_2X);
 	BIND_ENUM_CONSTANT(VIEWPORT_MSAA_4X);
 	BIND_ENUM_CONSTANT(VIEWPORT_MSAA_8X);
-	BIND_ENUM_CONSTANT(VIEWPORT_MSAA_16X);
 	BIND_ENUM_CONSTANT(VIEWPORT_MSAA_MAX);
 
 	BIND_ENUM_CONSTANT(VIEWPORT_SCREEN_SPACE_AA_DISABLED);

diff --git a/servers/rendering_server.h b/servers/rendering_server.h
@@ -826,7 +826,6 @@ class RenderingServer : public Object {
 		VIEWPORT_MSAA_2X,
 		VIEWPORT_MSAA_4X,
 		VIEWPORT_MSAA_8X,
-		VIEWPORT_MSAA_16X,
 		VIEWPORT_MSAA_MAX,
 	};