Add a nearest-neighbor scaling option to Viewport's Scaling 3D Mode p…

…roperty

This is useful for 3D games with a pixel art appearance, or when
using a resolution scale of `0.5` to improve performance without
compromising crispness too much when not using FSR 1.0.

The property hints now allow decreasing the scale further to accomodate
for pixel art use cases, as well as increased precision in the value
(useful for a scale of `0.3333`).

doc/classes/RenderingServer.xml

@@ -4510,7 +4510,11 @@
 		<constant name="VIEWPORT_SCALING_3D_MODE_FSR2" value="2" enum="ViewportScaling3DMode">
 			Use AMD FidelityFX Super Resolution 2.2 upscaling for the viewport's 3D buffer. The amount of scaling can be set using [member Viewport.scaling_3d_scale]. Values less than [code]1.0[/code] will be result in the viewport being upscaled using FSR2. Values greater than [code]1.0[/code] are not supported and bilinear downsampling will be used instead. A value of [code]1.0[/code] will use FSR2 at native resolution as a TAA solution.
 		</constant>
-		<constant name="VIEWPORT_SCALING_3D_MODE_MAX" value="3" enum="ViewportScaling3DMode">
+		<constant name="VIEWPORT_SCALING_3D_MODE_NEAREST" value="3" enum="ViewportScaling3DMode">
+			Use nearest-neighbor filtering for the viewport's 3D buffer. This looks crisper than [constant VIEWPORT_SCALING_3D_MODE_BILINEAR] and has no additional rendering cost. The amount of scaling can be set using [member Viewport.scaling_3d_scale]. Values greater than [code]1.0[/code] are not supported and bilinear downsampling will be used instead. A value of [code]1.0[/code] disables scaling.
+			[b]Note:[/b] To avoid uneven pixel scaling, it's highly recommended to use a value equal to an integer divisor of 1, such as [code]1.0 / 2 = 0.5[/code]. For example, it's best to use a scale of [code]0.5[/code] (2×2), [code]0.3333[/code] (3×3), [code]0.25[/code] (4×4), [code]0.2[/code] (5×5) and so on.
+		</constant>
+		<constant name="VIEWPORT_SCALING_3D_MODE_MAX" value="4" enum="ViewportScaling3DMode">
 			Represents the size of the [enum ViewportScaling3DMode] enum.
 		</constant>
 		<constant name="VIEWPORT_UPDATE_DISABLED" value="0" enum="ViewportUpdateMode">

doc/classes/Viewport.xml

@@ -446,7 +446,11 @@
 		<constant name="SCALING_3D_MODE_FSR2" value="2" enum="Scaling3DMode">
 			Use AMD FidelityFX Super Resolution 2.2 upscaling for the viewport's 3D buffer. The amount of scaling can be set using [member Viewport.scaling_3d_scale]. Values less than [code]1.0[/code] will be result in the viewport being upscaled using FSR2. Values greater than [code]1.0[/code] are not supported and bilinear downsampling will be used instead. A value of [code]1.0[/code] will use FSR2 at native resolution as a TAA solution.
 		</constant>
-		<constant name="SCALING_3D_MODE_MAX" value="3" enum="Scaling3DMode">
+		<constant name="SCALING_3D_MODE_NEAREST" value="3" enum="Scaling3DMode">
+			Use nearest-neighbor filtering for the viewport's 3D buffer. This looks crisper than [constant SCALING_3D_MODE_BILINEAR] and has no additional rendering cost. The amount of scaling can be set using [member scaling_3d_scale]. Values greater than [code]1.0[/code] are not supported and bilinear downsampling will be used instead. A value of [code]1.0[/code] disables scaling.
+			[b]Note:[/b] To avoid uneven pixel scaling, it's highly recommended to use a value equal to an integer divisor of 1, such as [code]1.0 / 2 = 0.5[/code]. For example, it's best to use a scale of [code]0.5[/code] (2×2), [code]0.3333[/code] (3×3), [code]0.25[/code] (4×4), [code]0.2[/code] (5×5) and so on.
+		</constant>
+		<constant name="SCALING_3D_MODE_MAX" value="4" enum="Scaling3DMode">
 			Represents the size of the [enum Scaling3DMode] enum.
 		</constant>
 		<constant name="MSAA_DISABLED" value="0" enum="MSAA">

scene/main/viewport.cpp

@@ -4505,10 +4505,10 @@ void Viewport::_bind_methods() {
 
 #ifndef _3D_DISABLED
 	ADD_GROUP("Scaling 3D", "");
-	ADD_PROPERTY(PropertyInfo(Variant::INT, "scaling_3d_mode", PROPERTY_HINT_ENUM, "Bilinear (Fastest),FSR 1.0 (Fast),FSR 2.2 (Slow)"), "set_scaling_3d_mode", "get_scaling_3d_mode");
-	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "scaling_3d_scale", PROPERTY_HINT_RANGE, "0.25,2.0,0.01"), "set_scaling_3d_scale", "get_scaling_3d_scale");
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "scaling_3d_mode", PROPERTY_HINT_ENUM, "Bilinear (Fastest),FSR 1.0 (Fast),FSR 2.2 (Slow),Nearest (Fastest)"), "set_scaling_3d_mode", "get_scaling_3d_mode");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "scaling_3d_scale", PROPERTY_HINT_RANGE, "0.1,2.0,0.0001"), "set_scaling_3d_scale", "get_scaling_3d_scale");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "texture_mipmap_bias", PROPERTY_HINT_RANGE, "-2,2,0.001"), "set_texture_mipmap_bias", "get_texture_mipmap_bias");
-	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "fsr_sharpness", PROPERTY_HINT_RANGE, "0,2,0.1"), "set_fsr_sharpness", "get_fsr_sharpness");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "fsr_sharpness", PROPERTY_HINT_RANGE, "0,2,0.01"), "set_fsr_sharpness", "get_fsr_sharpness");
 #endif
 	ADD_GROUP("Variable Rate Shading", "vrs_");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "vrs_mode", PROPERTY_HINT_ENUM, "Disabled,Texture,Depth buffer,XR"), "set_vrs_mode", "get_vrs_mode");
@@ -4557,6 +4557,7 @@ void Viewport::_bind_methods() {
 	BIND_ENUM_CONSTANT(SCALING_3D_MODE_BILINEAR);
 	BIND_ENUM_CONSTANT(SCALING_3D_MODE_FSR);
 	BIND_ENUM_CONSTANT(SCALING_3D_MODE_FSR2);
+	BIND_ENUM_CONSTANT(SCALING_3D_MODE_NEAREST);
 	BIND_ENUM_CONSTANT(SCALING_3D_MODE_MAX);
 
 	BIND_ENUM_CONSTANT(MSAA_DISABLED);

scene/main/viewport.h

@@ -99,6 +99,7 @@ class Viewport : public Node {
 		SCALING_3D_MODE_BILINEAR,
 		SCALING_3D_MODE_FSR,
 		SCALING_3D_MODE_FSR2,
+		SCALING_3D_MODE_NEAREST,
 		SCALING_3D_MODE_MAX
 	};
 

servers/rendering/renderer_rd/effects/tone_mapper.cpp

@@ -81,7 +81,7 @@ ToneMapper::~ToneMapper() {
 	tonemap.shader.version_free(tonemap.shader_version);
 }
 
-void ToneMapper::tonemapper(RID p_source_color, RID p_dst_framebuffer, const TonemapSettings &p_settings) {
+void ToneMapper::tonemapper(RID p_source_color, RID p_dst_framebuffer, const TonemapSettings &p_settings, RS::CanvasItemTextureFilter p_filter_mode) {
 	UniformSetCacheRD *uniform_set_cache = UniformSetCacheRD::get_singleton();
 	ERR_FAIL_NULL(uniform_set_cache);
 	MaterialStorage *material_storage = MaterialStorage::get_singleton();
@@ -137,7 +137,8 @@ void ToneMapper::tonemapper(RID p_source_color, RID p_dst_framebuffer, const Ton
 	RID default_sampler = material_storage->sampler_rd_get_default(RS::CANVAS_ITEM_TEXTURE_FILTER_LINEAR, RS::CANVAS_ITEM_TEXTURE_REPEAT_DISABLED);
 	RID default_mipmap_sampler = material_storage->sampler_rd_get_default(RS::CANVAS_ITEM_TEXTURE_FILTER_LINEAR_WITH_MIPMAPS, RS::CANVAS_ITEM_TEXTURE_REPEAT_DISABLED);
 
-	RD::Uniform u_source_color(RD::UNIFORM_TYPE_SAMPLER_WITH_TEXTURE, 0, Vector<RID>({ default_sampler, p_source_color }));
+	RID viewport_scale_sampler = material_storage->sampler_rd_get_default(p_filter_mode, RS::CANVAS_ITEM_TEXTURE_REPEAT_DISABLED);
+	RD::Uniform u_source_color(RD::UNIFORM_TYPE_SAMPLER_WITH_TEXTURE, 0, Vector<RID>({ viewport_scale_sampler, p_source_color }));
 
 	RD::Uniform u_exposure_texture;
 	u_exposure_texture.uniform_type = RD::UNIFORM_TYPE_SAMPLER_WITH_TEXTURE;
@@ -178,7 +179,7 @@ void ToneMapper::tonemapper(RID p_source_color, RID p_dst_framebuffer, const Ton
 	RD::get_singleton()->draw_list_end();
 }
 
-void ToneMapper::tonemapper(RD::DrawListID p_subpass_draw_list, RID p_source_color, RD::FramebufferFormatID p_dst_format_id, const TonemapSettings &p_settings) {
+void ToneMapper::tonemapper(RD::DrawListID p_subpass_draw_list, RID p_source_color, RD::FramebufferFormatID p_dst_format_id, const TonemapSettings &p_settings, RS::CanvasItemTextureFilter p_filter_mode) {
 	UniformSetCacheRD *uniform_set_cache = UniformSetCacheRD::get_singleton();
 	ERR_FAIL_NULL(uniform_set_cache);
 	MaterialStorage *material_storage = MaterialStorage::get_singleton();
@@ -216,9 +217,11 @@ void ToneMapper::tonemapper(RD::DrawListID p_subpass_draw_list, RID p_source_col
 	RID default_sampler = material_storage->sampler_rd_get_default(RS::CANVAS_ITEM_TEXTURE_FILTER_LINEAR, RS::CANVAS_ITEM_TEXTURE_REPEAT_DISABLED);
 	RID default_mipmap_sampler = material_storage->sampler_rd_get_default(RS::CANVAS_ITEM_TEXTURE_FILTER_LINEAR_WITH_MIPMAPS, RS::CANVAS_ITEM_TEXTURE_REPEAT_DISABLED);
 
+	RID viewport_scale_sampler = material_storage->sampler_rd_get_default(p_filter_mode, RS::CANVAS_ITEM_TEXTURE_REPEAT_DISABLED);
 	RD::Uniform u_source_color;
 	u_source_color.uniform_type = RD::UNIFORM_TYPE_INPUT_ATTACHMENT;
 	u_source_color.binding = 0;
+	u_source_color.append_id(viewport_scale_sampler);
 	u_source_color.append_id(p_source_color);
 
 	RD::Uniform u_exposure_texture;

servers/rendering/renderer_rd/effects/tone_mapper.h

@@ -150,8 +150,8 @@ class ToneMapper {
 		bool convert_to_srgb = false;
 	};
 
-	void tonemapper(RID p_source_color, RID p_dst_framebuffer, const TonemapSettings &p_settings);
-	void tonemapper(RD::DrawListID p_subpass_draw_list, RID p_source_color, RD::FramebufferFormatID p_dst_format_id, const TonemapSettings &p_settings);
+	void tonemapper(RID p_source_color, RID p_dst_framebuffer, const TonemapSettings &p_settings, RS::CanvasItemTextureFilter p_filter = RS::CANVAS_ITEM_TEXTURE_FILTER_LINEAR);
+	void tonemapper(RD::DrawListID p_subpass_draw_list, RID p_source_color, RD::FramebufferFormatID p_dst_format_id, const TonemapSettings &p_settings, RS::CanvasItemTextureFilter p_filter = RS::CANVAS_ITEM_TEXTURE_FILTER_LINEAR);
 };
 
 } // namespace RendererRD

servers/rendering/renderer_rd/renderer_scene_render_rd.cpp

@@ -557,6 +557,7 @@ void RendererSceneRenderRD::_render_buffers_post_process_and_tonemap(const Rende
 		tonemap.convert_to_srgb = !texture_storage->render_target_is_using_hdr(render_target);
 
 		RID dest_fb;
+		RS::CanvasItemTextureFilter filter_mode = RS::CANVAS_ITEM_TEXTURE_FILTER_LINEAR;
 		bool use_intermediate_fb = use_fsr;
 		if (use_intermediate_fb) {
 			// If we use FSR to upscale we need to write our result into an intermediate buffer.
@@ -568,9 +569,14 @@ void RendererSceneRenderRD::_render_buffers_post_process_and_tonemap(const Rende
 			// Target size in this case is lying as we never get our real target size communicated.
 			// Bit nasty but...
 			dest_fb = texture_storage->render_target_get_rd_framebuffer(render_target);
+
+			if (rb->get_scaling_3d_mode() == RS::VIEWPORT_SCALING_3D_MODE_NEAREST) {
+				// Make the hardware perform nearest-neighbor filtering when scaling the viewport 3D buffer.
+				filter_mode = RS::CANVAS_ITEM_TEXTURE_FILTER_NEAREST;
+			}
 		}
 
-		tone_mapper->tonemapper(color_texture, dest_fb, tonemap);
+		tone_mapper->tonemapper(color_texture, dest_fb, tonemap, filter_mode);
 
 		RD::get_singleton()->draw_command_end_label();
 	}

servers/rendering/renderer_viewport.cpp

@@ -121,8 +121,8 @@ void RendererViewport::_configure_3d_render_buffers(Viewport *p_viewport) {
 			bool scaling_3d_is_fsr = (scaling_3d_mode == RS::VIEWPORT_SCALING_3D_MODE_FSR) || (scaling_3d_mode == RS::VIEWPORT_SCALING_3D_MODE_FSR2);
 			bool use_taa = p_viewport->use_taa;
 
-			if (scaling_3d_is_fsr && (scaling_3d_scale > 1.0)) {
-				// FSR is not designed for downsampling.
+			if ((scaling_3d_is_fsr || scaling_3d_mode == RS::VIEWPORT_SCALING_3D_MODE_NEAREST) && (scaling_3d_scale > 1.0)) {
+				// FSR and nearest-neighbor scaling are not designed for downsampling.
 				// Fall back to bilinear scaling.
 				WARN_PRINT_ONCE("FSR 3D resolution scaling is not designed for downsampling. Falling back to bilinear 3D resolution scaling.");
 				scaling_3d_mode = RS::VIEWPORT_SCALING_3D_MODE_BILINEAR;
@@ -150,6 +150,7 @@ void RendererViewport::_configure_3d_render_buffers(Viewport *p_viewport) {
 
 			switch (scaling_3d_mode) {
 				case RS::VIEWPORT_SCALING_3D_MODE_BILINEAR:
+				case RS::VIEWPORT_SCALING_3D_MODE_NEAREST:
 					// Clamp 3D rendering resolution to reasonable values supported on most hardware.
 					// This prevents freezing the engine or outright crashing on lower-end GPUs.
 					width = CLAMP(p_viewport->size.width * scaling_3d_scale, 1, 16384);

servers/rendering_server.cpp

@@ -2253,6 +2253,7 @@ void RenderingServer::_bind_methods() {
 	BIND_ENUM_CONSTANT(VIEWPORT_SCALING_3D_MODE_BILINEAR);
 	BIND_ENUM_CONSTANT(VIEWPORT_SCALING_3D_MODE_FSR);
 	BIND_ENUM_CONSTANT(VIEWPORT_SCALING_3D_MODE_FSR2);
+	BIND_ENUM_CONSTANT(VIEWPORT_SCALING_3D_MODE_NEAREST);
 	BIND_ENUM_CONSTANT(VIEWPORT_SCALING_3D_MODE_MAX);
 
 	BIND_ENUM_CONSTANT(VIEWPORT_UPDATE_DISABLED);
@@ -2961,9 +2962,9 @@ void RenderingServer::init() {
 	GLOBAL_DEF(PropertyInfo(Variant::FLOAT, "rendering/anti_aliasing/screen_space_roughness_limiter/amount", PROPERTY_HINT_RANGE, "0.01,4.0,0.01"), 0.25);
 	GLOBAL_DEF(PropertyInfo(Variant::FLOAT, "rendering/anti_aliasing/screen_space_roughness_limiter/limit", PROPERTY_HINT_RANGE, "0.01,1.0,0.01"), 0.18);
 
-	GLOBAL_DEF(PropertyInfo(Variant::INT, "rendering/scaling_3d/mode", PROPERTY_HINT_ENUM, "Bilinear (Fastest),FSR 1.0 (Fast),FSR 2.2 (Slow)"), 0);
-	GLOBAL_DEF(PropertyInfo(Variant::FLOAT, "rendering/scaling_3d/scale", PROPERTY_HINT_RANGE, "0.25,2.0,0.01"), 1.0);
-	GLOBAL_DEF(PropertyInfo(Variant::FLOAT, "rendering/scaling_3d/fsr_sharpness", PROPERTY_HINT_RANGE, "0,2,0.1"), 0.2f);
+	GLOBAL_DEF(PropertyInfo(Variant::INT, "rendering/scaling_3d/mode", PROPERTY_HINT_ENUM, "Bilinear (Fastest),FSR 1.0 (Fast),FSR 2.2 (Slow),Nearest (Fastest)"), 0);
+	GLOBAL_DEF(PropertyInfo(Variant::FLOAT, "rendering/scaling_3d/scale", PROPERTY_HINT_RANGE, "0.1,2.0,0.0001"), 1.0);
+	GLOBAL_DEF(PropertyInfo(Variant::FLOAT, "rendering/scaling_3d/fsr_sharpness", PROPERTY_HINT_RANGE, "0,2,0.01"), 0.2f);
 	GLOBAL_DEF(PropertyInfo(Variant::FLOAT, "rendering/textures/default_filters/texture_mipmap_bias", PROPERTY_HINT_RANGE, "-2,2,0.001"), 0.0f);
 
 	GLOBAL_DEF(PropertyInfo(Variant::INT, "rendering/textures/decals/filter", PROPERTY_HINT_ENUM, "Nearest (Fast),Linear (Fast),Nearest Mipmap (Fast),Linear Mipmap (Fast),Nearest Mipmap Anisotropic (Average),Linear Mipmap Anisotropic (Average)"), DECAL_FILTER_LINEAR_MIPMAPS);

servers/rendering_server.h

@@ -808,6 +808,7 @@ class RenderingServer : public Object {
 		VIEWPORT_SCALING_3D_MODE_BILINEAR,
 		VIEWPORT_SCALING_3D_MODE_FSR,
 		VIEWPORT_SCALING_3D_MODE_FSR2,
+		VIEWPORT_SCALING_3D_MODE_NEAREST,
 		VIEWPORT_SCALING_3D_MODE_MAX,
 		VIEWPORT_SCALING_3D_MODE_OFF = 255, // for internal use only
 	};