Replace OIDN denoiser with a JNLM denoiser compute shader implementation.

COPYRIGHT.txt

@@ -63,6 +63,13 @@ Copyright: 2011, Ole Kniemeyer, MAXON, www.maxon.net
  2007-2014, Juan Linietsky, Ariel Manzur
 License: Expat and Zlib
 
+Files: ./modules/lightmapper_rd/lm_compute.glsl
+Comment: Joint Non-Local Means (JNLM) denoiser
+Copyright: 2020, Manuel Prandini
+ 2014-present, Godot Engine contributors
+ 2007-2014, Juan Linietsky, Ariel Manzur
+License: Expat
+
 Files: ./platform/android/java/lib/aidl/com/android/*
  ./platform/android/java/lib/res/layout/status_bar_ongoing_event_progress_bar.xml
  ./platform/android/java/lib/src/com/google/android/*

doc/classes/LightmapGI.xml

@@ -24,6 +24,9 @@
 		<member name="camera_attributes" type="CameraAttributes" setter="set_camera_attributes" getter="get_camera_attributes">
 			The [CameraAttributes] resource that specifies exposure levels to bake at. Auto-exposure and non exposure properties will be ignored. Exposure settings should be used to reduce the dynamic range present when baking. If exposure is too high, the [LightmapGI] will have banding artifacts or may have over-exposure artifacts.
 		</member>
+		<member name="denoiser_strength" type="float" setter="set_denoiser_strength" getter="get_denoiser_strength" default="0.1">
+			The strength of denoising step applied to the generated lightmaps. Only effective if [member use_denoiser] is [code]true[/code].
+		</member>
 		<member name="directional" type="bool" setter="set_directional" getter="is_directional" default="false">
 			If [code]true[/code], bakes lightmaps to contain directional information as spherical harmonics. This results in more realistic lighting appearance, especially with normal mapped materials and for lights that have their direct light baked ([member Light3D.light_bake_mode] set to [constant Light3D.BAKE_STATIC]). The directional information is also used to provide rough reflections for static and dynamic objects. This has a small run-time performance cost as the shader has to perform more work to interpret the direction information from the lightmap. Directional lightmaps also take longer to bake and result in larger file sizes.
 			[b]Note:[/b] The property's name has no relationship with [DirectionalLight3D]. [member directional] works with all light types.
@@ -59,8 +62,7 @@
 			To further speed up bake times, decrease [member bounces], disable [member use_denoiser] and increase the lightmap texel size on 3D scenes in the Import doc.
 		</member>
 		<member name="use_denoiser" type="bool" setter="set_use_denoiser" getter="is_using_denoiser" default="true">
-			If [code]true[/code], uses a CPU-based denoising algorithm on the generated lightmap. This eliminates most noise within the generated lightmap at the cost of longer bake times. File sizes are generally not impacted significantly by the use of a denoiser, although lossless compression may do a better job at compressing a denoised image.
+			If [code]true[/code], uses a GPU-based denoising algorithm on the generated lightmap. This eliminates most noise within the generated lightmap at the cost of longer bake times. File sizes are generally not impacted significantly by the use of a denoiser, although lossless compression may do a better job at compressing a denoised image.
-			[b]Note:[/b] The built-in denoiser (OpenImageDenoise) may crash when denoising lightmaps in large scenes. If you encounter a crash at the end of lightmap baking, try disabling [member use_denoiser].
 		</member>
 	</members>
 	<constants>

modules/lightmapper_rd/lightmapper_rd.cpp

@@ -614,24 +614,28 @@ void LightmapperRD::_raster_geometry(RenderingDevice *rd, Size2i atlas_size, int
 	}
 }
 
-LightmapperRD::BakeError LightmapperRD::_dilate(RenderingDevice *rd, Ref<RDShaderFile> &compute_shader, RID &compute_base_uniform_set, PushConstant &push_constant, RID &source_light_tex, RID &dest_light_tex, const Size2i &atlas_size, int atlas_slices) {
+static Vector<RD::Uniform> dilate_or_denoise_common_uniforms(RID &p_source_light_tex, RID &p_dest_light_tex) {
 	Vector<RD::Uniform> uniforms;
-	{
 	{
 		RD::Uniform u;
 		u.uniform_type = RD::UNIFORM_TYPE_IMAGE;
 		u.binding = 0;
-			u.append_id(dest_light_tex);
+		u.append_id(p_dest_light_tex);
 		uniforms.push_back(u);
 	}
 	{
 		RD::Uniform u;
 		u.uniform_type = RD::UNIFORM_TYPE_TEXTURE;
 		u.binding = 1;
-			u.append_id(source_light_tex);
+		u.append_id(p_source_light_tex);
 		uniforms.push_back(u);
 	}
-	}
+
+	return uniforms;
+}
+
+LightmapperRD::BakeError LightmapperRD::_dilate(RenderingDevice *rd, Ref<RDShaderFile> &compute_shader, RID &compute_base_uniform_set, PushConstant &push_constant, RID &source_light_tex, RID &dest_light_tex, const Size2i &atlas_size, int atlas_slices) {
+	Vector<RD::Uniform> uniforms = dilate_or_denoise_common_uniforms(source_light_tex, dest_light_tex);
 
 	RID compute_shader_dilate = rd->shader_create_from_spirv(compute_shader->get_spirv_stages("dilate"));
 	ERR_FAIL_COND_V(compute_shader_dilate.is_null(), BAKE_ERROR_LIGHTMAP_CANT_PRE_BAKE_MESHES); //internal check, should not happen
@@ -667,7 +671,77 @@ LightmapperRD::BakeError LightmapperRD::_dilate(RenderingDevice *rd, Ref<RDShade
 	return BAKE_OK;
 }
 
-LightmapperRD::BakeError LightmapperRD::bake(BakeQuality p_quality, bool p_use_denoiser, int p_bounces, float p_bias, int p_max_texture_size, bool p_bake_sh, GenerateProbes p_generate_probes, const Ref<Image> &p_environment_panorama, const Basis &p_environment_transform, BakeStepFunc p_step_function, void *p_bake_userdata, float p_exposure_normalization) {
+LightmapperRD::BakeError LightmapperRD::_denoise(RenderingDevice *p_rd, Ref<RDShaderFile> &p_compute_shader, const RID &p_compute_base_uniform_set, PushConstant &p_push_constant, RID p_source_light_tex, RID p_source_normal_tex, RID p_dest_light_tex, float p_denoiser_strength, const Size2i &p_atlas_size, int p_atlas_slices, bool p_bake_sh, BakeStepFunc p_step_function) {
+	RID denoise_params_buffer = p_rd->uniform_buffer_create(sizeof(DenoiseParams));
+	DenoiseParams denoise_params;
+	denoise_params.spatial_bandwidth = 5.0f;
+	denoise_params.light_bandwidth = p_denoiser_strength;
+	denoise_params.albedo_bandwidth = 1.0f;
+	denoise_params.normal_bandwidth = 0.1f;
+	denoise_params.filter_strength = 10.0f;
+	p_rd->buffer_update(denoise_params_buffer, 0, sizeof(DenoiseParams), &denoise_params);
+
+	Vector<RD::Uniform> uniforms = dilate_or_denoise_common_uniforms(p_source_light_tex, p_dest_light_tex);
+	{
+		RD::Uniform u;
+		u.uniform_type = RD::UNIFORM_TYPE_TEXTURE;
+		u.binding = 2;
+		u.append_id(p_source_normal_tex);
+		uniforms.push_back(u);
+	}
+	{
+		RD::Uniform u;
+		u.uniform_type = RD::UNIFORM_TYPE_UNIFORM_BUFFER;
+		u.binding = 3;
+		u.append_id(denoise_params_buffer);
+		uniforms.push_back(u);
+	}
+
+	RID compute_shader_denoise = p_rd->shader_create_from_spirv(p_compute_shader->get_spirv_stages("denoise"));
+	ERR_FAIL_COND_V(compute_shader_denoise.is_null(), BAKE_ERROR_LIGHTMAP_CANT_PRE_BAKE_MESHES);
+
+	RID compute_shader_denoise_pipeline = p_rd->compute_pipeline_create(compute_shader_denoise);
+	RID denoise_uniform_set = p_rd->uniform_set_create(uniforms, compute_shader_denoise, 1);
+
+	// We denoise in fixed size regions and synchronize execution to avoid GPU timeouts.
+	// We use a region with 1/4 the amount of pixels if we're denoising SH lightmaps, as
+	// all four of them are denoised in the shader in one dispatch.
+	const int max_region_size = p_bake_sh ? 512 : 1024;
+	int x_regions = (p_atlas_size.width - 1) / max_region_size + 1;
+	int y_regions = (p_atlas_size.height - 1) / max_region_size + 1;
+	for (int s = 0; s < p_atlas_slices; s++) {
+		p_push_constant.atlas_slice = s;
+
+		for (int i = 0; i < x_regions; i++) {
+			for (int j = 0; j < y_regions; j++) {
+				int x = i * max_region_size;
+				int y = j * max_region_size;
+				int w = MIN((i + 1) * max_region_size, p_atlas_size.width) - x;
+				int h = MIN((j + 1) * max_region_size, p_atlas_size.height) - y;
+				p_push_constant.region_ofs[0] = x;
+				p_push_constant.region_ofs[1] = y;
+
+				RD::ComputeListID compute_list = p_rd->compute_list_begin();
+				p_rd->compute_list_bind_compute_pipeline(compute_list, compute_shader_denoise_pipeline);
+				p_rd->compute_list_bind_uniform_set(compute_list, p_compute_base_uniform_set, 0);
+				p_rd->compute_list_bind_uniform_set(compute_list, denoise_uniform_set, 1);
+				p_rd->compute_list_set_push_constant(compute_list, &p_push_constant, sizeof(PushConstant));
+				p_rd->compute_list_dispatch(compute_list, (w - 1) / 8 + 1, (h - 1) / 8 + 1, 1);
+				p_rd->compute_list_end();
+
+				p_rd->submit();
+				p_rd->sync();
+			}
+		}
+	}
+
+	p_rd->free(compute_shader_denoise);
+	p_rd->free(denoise_params_buffer);
+
+	return BAKE_OK;
+}
+
+LightmapperRD::BakeError LightmapperRD::bake(BakeQuality p_quality, bool p_use_denoiser, float p_denoiser_strength, int p_bounces, float p_bias, int p_max_texture_size, bool p_bake_sh, GenerateProbes p_generate_probes, const Ref<Image> &p_environment_panorama, const Basis &p_environment_transform, BakeStepFunc p_step_function, void *p_bake_userdata, float p_exposure_normalization) {
 	if (p_step_function) {
 		p_step_function(0.0, RTR("Begin Bake"), p_bake_userdata, true);
 	}
@@ -1434,27 +1508,11 @@ LightmapperRD::BakeError LightmapperRD::bake(BakeQuality p_quality, bool p_use_d
 			p_step_function(0.8, RTR("Denoising"), p_bake_userdata, true);
 		}
 
-		Ref<LightmapDenoiser> denoiser = LightmapDenoiser::create();
+		{
-		if (denoiser.is_valid()) {
+			SWAP(light_accum_tex, light_accum_tex2);
-			for (int i = 0; i < atlas_slices * (p_bake_sh ? 4 : 1); i++) {
+			BakeError error = _denoise(rd, compute_shader, compute_base_uniform_set, push_constant, light_accum_tex2, normal_tex, light_accum_tex, p_denoiser_strength, atlas_size, atlas_slices, p_bake_sh, p_step_function);
-				Vector<uint8_t> s = rd->texture_get_data(light_accum_tex, i);
+			if (unlikely(error != BAKE_OK)) {
-				Ref<Image> img = Image::create_from_data(atlas_size.width, atlas_size.height, false, Image::FORMAT_RGBAH, s);
+				return error;
-
-				Ref<Image> denoised = denoiser->denoise_image(img);
-				if (denoised != img) {
-					denoised->convert(Image::FORMAT_RGBAH);
-					Vector<uint8_t> ds = denoised->get_data();
-					denoised.unref(); //avoid copy on write
-					{ //restore alpha
-						uint32_t count = s.size() / 2; //uint16s
-						const uint16_t *src = (const uint16_t *)s.ptr();
-						uint16_t *dst = (uint16_t *)ds.ptrw();
-						for (uint32_t j = 0; j < count; j += 4) {
-							dst[j + 3] = src[j + 3];
-						}
-					}
-					rd->texture_update(light_accum_tex, i, ds);
-				}
 			}
 		}
 

modules/lightmapper_rd/lightmapper_rd.h

@@ -229,11 +229,22 @@ class LightmapperRD : public Lightmapper {
 	Vector<Ref<Image>> bake_textures;
 	Vector<Color> probe_values;
 
+	struct DenoiseParams {
+		float spatial_bandwidth;
+		float light_bandwidth;
+		float albedo_bandwidth;
+		float normal_bandwidth;
+
+		float filter_strength;
+		float pad[3];
+	};
+
 	BakeError _blit_meshes_into_atlas(int p_max_texture_size, Vector<Ref<Image>> &albedo_images, Vector<Ref<Image>> &emission_images, AABB &bounds, Size2i &atlas_size, int &atlas_slices, BakeStepFunc p_step_function, void *p_bake_userdata);
 	void _create_acceleration_structures(RenderingDevice *rd, Size2i atlas_size, int atlas_slices, AABB &bounds, int grid_size, Vector<Probe> &probe_positions, GenerateProbes p_generate_probes, Vector<int> &slice_triangle_count, Vector<int> &slice_seam_count, RID &vertex_buffer, RID &triangle_buffer, RID &lights_buffer, RID &triangle_cell_indices_buffer, RID &probe_positions_buffer, RID &grid_texture, RID &seams_buffer, BakeStepFunc p_step_function, void *p_bake_userdata);
 	void _raster_geometry(RenderingDevice *rd, Size2i atlas_size, int atlas_slices, int grid_size, AABB bounds, float p_bias, Vector<int> slice_triangle_count, RID position_tex, RID unocclude_tex, RID normal_tex, RID raster_depth_buffer, RID rasterize_shader, RID raster_base_uniform);
 
 	BakeError _dilate(RenderingDevice *rd, Ref<RDShaderFile> &compute_shader, RID &compute_base_uniform_set, PushConstant &push_constant, RID &source_light_tex, RID &dest_light_tex, const Size2i &atlas_size, int atlas_slices);
+	BakeError _denoise(RenderingDevice *p_rd, Ref<RDShaderFile> &p_compute_shader, const RID &p_compute_base_uniform_set, PushConstant &p_push_constant, RID p_source_light_tex, RID p_source_normal_tex, RID p_dest_light_tex, float p_denoiser_strength, const Size2i &p_atlas_size, int p_atlas_slices, bool p_bake_sh, BakeStepFunc p_step_function);
 
 public:
 	virtual void add_mesh(const MeshData &p_mesh) override;
@@ -241,7 +252,7 @@ public:
 	virtual void add_omni_light(bool p_static, const Vector3 &p_position, const Color &p_color, float p_energy, float p_range, float p_attenuation, float p_size, float p_shadow_blur) override;
 	virtual void add_spot_light(bool p_static, const Vector3 &p_position, const Vector3 p_direction, const Color &p_color, float p_energy, float p_range, float p_attenuation, float p_spot_angle, float p_spot_attenuation, float p_size, float p_shadow_blur) override;
 	virtual void add_probe(const Vector3 &p_position) override;
-	virtual BakeError bake(BakeQuality p_quality, bool p_use_denoiser, int p_bounces, float p_bias, int p_max_texture_size, bool p_bake_sh, GenerateProbes p_generate_probes, const Ref<Image> &p_environment_panorama, const Basis &p_environment_transform, BakeStepFunc p_step_function = nullptr, void *p_bake_userdata = nullptr, float p_exposure_normalization = 1.0) override;
+	virtual BakeError bake(BakeQuality p_quality, bool p_use_denoiser, float p_denoiser_strength, int p_bounces, float p_bias, int p_max_texture_size, bool p_bake_sh, GenerateProbes p_generate_probes, const Ref<Image> &p_environment_panorama, const Basis &p_environment_transform, BakeStepFunc p_step_function = nullptr, void *p_bake_userdata = nullptr, float p_exposure_normalization = 1.0) override;
 
 	int get_bake_texture_count() const override;
 	Ref<Image> get_bake_texture(int p_index) const override;

modules/lightmapper_rd/lm_compute.glsl

@@ -5,6 +5,7 @@ secondary = "#define MODE_BOUNCE_LIGHT";
 dilate = "#define MODE_DILATE";
 unocclude = "#define MODE_UNOCCLUDE";
 light_probes = "#define MODE_LIGHT_PROBES";
+denoise = "#define MODE_DENOISE";
 
 #[compute]
 
@@ -65,11 +66,24 @@ layout(set = 1, binding = 6) uniform texture2D environment;
 layout(rgba32f, set = 1, binding = 5) uniform restrict writeonly image2DArray primary_dynamic;
 #endif
 
-#ifdef MODE_DILATE
+#if defined(MODE_DILATE) || defined(MODE_DENOISE)
 layout(rgba16f, set = 1, binding = 0) uniform restrict writeonly image2DArray dest_light;
 layout(set = 1, binding = 1) uniform texture2DArray source_light;
 #endif
 
+#ifdef MODE_DENOISE
+layout(set = 1, binding = 2) uniform texture2DArray source_normal;
+layout(set = 1, binding = 3) uniform DenoiseParams {
+	float spatial_bandwidth;
+	float light_bandwidth;
+	float albedo_bandwidth;
+	float normal_bandwidth;
+
+	float filter_strength;
+}
+denoise_params;
+#endif
+
 layout(push_constant, std430) uniform Params {
 	ivec2 atlas_size; // x used for light probe mode total probes
 	uint ray_count;
@@ -735,4 +749,153 @@ void main() {
 	imageStore(dest_light, ivec3(atlas_pos, params.atlas_slice), c);
 
 #endif
+
+#ifdef MODE_DENOISE
+	// Joint Non-local means (JNLM) denoiser.
+	//
+	// Based on YoctoImageDenoiser's JNLM implementation with corrections from "Nonlinearly Weighted First-order Regression for Denoising Monte Carlo Renderings".
+	//
+	// <https://github.com/ManuelPrandini/YoctoImageDenoiser/blob/06e19489dd64e47792acffde536393802ba48607/libs/yocto_extension/yocto_extension.cpp#L207>
+	// <https://benedikt-bitterli.me/nfor/nfor.pdf>
+	//
+	// MIT License
+	//
+	// Copyright (c) 2020 ManuelPrandini
+	//
+	// Permission is hereby granted, free of charge, to any person obtaining a copy
+	// of this software and associated documentation files (the "Software"), to deal
+	// in the Software without restriction, including without limitation the rights
+	// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+	// copies of the Software, and to permit persons to whom the Software is
+	// furnished to do so, subject to the following conditions:
+	//
+	// The above copyright notice and this permission notice shall be included in all
+	// copies or substantial portions of the Software.
+	//
+	// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+	// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+	// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+	// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+	// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+	// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+	// SOFTWARE.
+	//
+	// Most of the constants below have been hand-picked to fit the common scenarios lightmaps
+	// are generated with, but they can be altered freely to experiment and achieve better results.
+
+	// Half the size of the patch window around each pixel that is weighted to compute the denoised pixel.
+	// A value of 1 represents a 3x3 window, a value of 2 a 5x5 window, etc.
+	const int HALF_PATCH_WINDOW = 4;
+
+	// Half the size of the search window around each pixel that is denoised and weighted to compute the denoised pixel.
+	const int HALF_SEARCH_WINDOW = 10;
+
+	// For all of the following sigma values, smaller values will give less weight to pixels that have a bigger distance
+	// in the feature being evaluated. Therefore, smaller values are likely to cause more noise to appear, but will also
+	// cause less features to be erased in the process.
+
+	// Controls how much the spatial distance of the pixels influences the denoising weight.
+	const float SIGMA_SPATIAL = denoise_params.spatial_bandwidth;
+
+	// Controls how much the light color distance of the pixels influences the denoising weight.
+	const float SIGMA_LIGHT = denoise_params.light_bandwidth;
+
+	// Controls how much the albedo color distance of the pixels influences the denoising weight.
+	const float SIGMA_ALBEDO = denoise_params.albedo_bandwidth;
+
+	// Controls how much the normal vector distance of the pixels influences the denoising weight.
+	const float SIGMA_NORMAL = denoise_params.normal_bandwidth;
+
+	// Strength of the filter. The original paper recommends values around 10 to 15 times the Sigma parameter.
+	const float FILTER_VALUE = denoise_params.filter_strength * SIGMA_LIGHT;
+
+	// Formula constants.
+	const int PATCH_WINDOW_DIMENSION = (HALF_PATCH_WINDOW * 2 + 1);
+	const int PATCH_WINDOW_DIMENSION_SQUARE = (PATCH_WINDOW_DIMENSION * PATCH_WINDOW_DIMENSION);
+	const float TWO_SIGMA_SPATIAL_SQUARE = 2.0f * SIGMA_SPATIAL * SIGMA_SPATIAL;
+	const float TWO_SIGMA_LIGHT_SQUARE = 2.0f * SIGMA_LIGHT * SIGMA_LIGHT;
+	const float TWO_SIGMA_ALBEDO_SQUARE = 2.0f * SIGMA_ALBEDO * SIGMA_ALBEDO;
+	const float TWO_SIGMA_NORMAL_SQUARE = 2.0f * SIGMA_NORMAL * SIGMA_NORMAL;
+	const float FILTER_SQUARE_TWO_SIGMA_LIGHT_SQUARE = FILTER_VALUE * FILTER_VALUE * TWO_SIGMA_LIGHT_SQUARE;
+	const float EPSILON = 1e-6f;
+
+#ifdef USE_SH_LIGHTMAPS
+	const uint slice_count = 4;
+	const uint slice_base = params.atlas_slice * slice_count;
+#else
+	const uint slice_count = 1;
+	const uint slice_base = params.atlas_slice;
+#endif
+
+	for (uint i = 0; i < slice_count; i++) {
+		uint lightmap_slice = slice_base + i;
+		vec3 denoised_rgb = vec3(0.0f);
+		vec4 input_light = texelFetch(sampler2DArray(source_light, linear_sampler), ivec3(atlas_pos, lightmap_slice), 0);
+		vec3 input_albedo = texelFetch(sampler2DArray(albedo_tex, linear_sampler), ivec3(atlas_pos, params.atlas_slice), 0).rgb;
+		vec3 input_normal = texelFetch(sampler2DArray(source_normal, linear_sampler), ivec3(atlas_pos, params.atlas_slice), 0).xyz;
+		if (length(input_normal) > EPSILON) {
+			// Compute the denoised pixel if the normal is valid.
+			float sum_weights = 0.0f;
+			vec3 input_rgb = input_light.rgb;
+			for (int search_y = -HALF_SEARCH_WINDOW; search_y <= HALF_SEARCH_WINDOW; search_y++) {
+				for (int search_x = -HALF_SEARCH_WINDOW; search_x <= HALF_SEARCH_WINDOW; search_x++) {
+					ivec2 search_pos = atlas_pos + ivec2(search_x, search_y);
+					vec3 search_rgb = texelFetch(sampler2DArray(source_light, linear_sampler), ivec3(search_pos, lightmap_slice), 0).rgb;
+					vec3 search_albedo = texelFetch(sampler2DArray(albedo_tex, linear_sampler), ivec3(search_pos, params.atlas_slice), 0).rgb;
+					vec3 search_normal = texelFetch(sampler2DArray(source_normal, linear_sampler), ivec3(search_pos, params.atlas_slice), 0).xyz;
+					float patch_square_dist = 0.0f;
+					for (int offset_y = -HALF_PATCH_WINDOW; offset_y <= HALF_PATCH_WINDOW; offset_y++) {
+						for (int offset_x = -HALF_PATCH_WINDOW; offset_x <= HALF_PATCH_WINDOW; offset_x++) {
+							ivec2 offset_input_pos = atlas_pos + ivec2(offset_x, offset_y);
+							ivec2 offset_search_pos = search_pos + ivec2(offset_x, offset_y);
+							vec3 offset_input_rgb = texelFetch(sampler2DArray(source_light, linear_sampler), ivec3(offset_input_pos, lightmap_slice), 0).rgb;
+							vec3 offset_search_rgb = texelFetch(sampler2DArray(source_light, linear_sampler), ivec3(offset_search_pos, lightmap_slice), 0).rgb;
+							vec3 offset_delta_rgb = offset_input_rgb - offset_search_rgb;
+							patch_square_dist += dot(offset_delta_rgb, offset_delta_rgb) - TWO_SIGMA_LIGHT_SQUARE;
+						}
+					}
+
+					patch_square_dist = max(0.0f, patch_square_dist / (3.0f * PATCH_WINDOW_DIMENSION_SQUARE));
+
+					float weight = 1.0f;
+
+					// Ignore weight if search position is out of bounds.
+					weight *= step(0, search_pos.x) * step(search_pos.x, params.atlas_size.x - 1);
+					weight *= step(0, search_pos.y) * step(search_pos.y, params.atlas_size.y - 1);
+
+					// Ignore weight if normal is zero length.
+					weight *= step(EPSILON, length(search_normal));
+
+					// Weight with pixel distance.
+					vec2 pixel_delta = vec2(search_x, search_y);
+					float pixel_square_dist = dot(pixel_delta, pixel_delta);
+					weight *= exp(-pixel_square_dist / TWO_SIGMA_SPATIAL_SQUARE);
+
+					// Weight with patch.
+					weight *= exp(-patch_square_dist / FILTER_SQUARE_TWO_SIGMA_LIGHT_SQUARE);
+
+					// Weight with albedo.
+					vec3 albedo_delta = input_albedo - search_albedo;
+					float albedo_square_dist = dot(albedo_delta, albedo_delta);
+					weight *= exp(-albedo_square_dist / TWO_SIGMA_ALBEDO_SQUARE);
+
+					// Weight with normal.
+					vec3 normal_delta = input_normal - search_normal;
+					float normal_square_dist = dot(normal_delta, normal_delta);
+					weight *= exp(-normal_square_dist / TWO_SIGMA_NORMAL_SQUARE);
+
+					denoised_rgb += weight * search_rgb;
+					sum_weights += weight;
+				}
+			}
+
+			denoised_rgb /= sum_weights;
+		} else {
+			// Ignore pixels where the normal is empty, just copy the light color.
+			denoised_rgb = input_light.rgb;
+		}
+
+		imageStore(dest_light, ivec3(atlas_pos, lightmap_slice), vec4(denoised_rgb, input_light.a));
+	}
+#endif
 }

scene/3d/lightmap_gi.cpp

@@ -1080,7 +1080,7 @@ LightmapGI::BakeError LightmapGI::bake(Node *p_from_node, String p_image_data_pa
 		}
 	}
 
-	Lightmapper::BakeError bake_err = lightmapper->bake(Lightmapper::BakeQuality(bake_quality), use_denoiser, bounces, bias, max_texture_size, directional, Lightmapper::GenerateProbes(gen_probes), environment_image, environment_transform, _lightmap_bake_step_function, &bsud, exposure_normalization);
+	Lightmapper::BakeError bake_err = lightmapper->bake(Lightmapper::BakeQuality(bake_quality), use_denoiser, denoiser_strength, bounces, bias, max_texture_size, directional, Lightmapper::GenerateProbes(gen_probes), environment_image, environment_transform, _lightmap_bake_step_function, &bsud, exposure_normalization);
 
 	if (bake_err == Lightmapper::BAKE_ERROR_LIGHTMAP_TOO_SMALL) {
 		return BAKE_ERROR_TEXTURE_SIZE_TOO_SMALL;
@@ -1362,12 +1362,21 @@ AABB LightmapGI::get_aabb() const {
 
 void LightmapGI::set_use_denoiser(bool p_enable) {
 	use_denoiser = p_enable;
+	notify_property_list_changed();
 }
 
 bool LightmapGI::is_using_denoiser() const {
 	return use_denoiser;
 }
 
+void LightmapGI::set_denoiser_strength(float p_denoiser_strength) {
+	denoiser_strength = p_denoiser_strength;
+}
+
+float LightmapGI::get_denoiser_strength() const {
+	return denoiser_strength;
+}
+
 void LightmapGI::set_directional(bool p_enable) {
 	directional = p_enable;
 }
@@ -1482,6 +1491,9 @@ void LightmapGI::_validate_property(PropertyInfo &p_property) const {
 	if (p_property.name == "environment_custom_energy" && environment_mode != ENVIRONMENT_MODE_CUSTOM_COLOR && environment_mode != ENVIRONMENT_MODE_CUSTOM_SKY) {
 		p_property.usage = PROPERTY_USAGE_NONE;
 	}
+	if (p_property.name == "denoiser_strength" && !use_denoiser) {
+		p_property.usage = PROPERTY_USAGE_NONE;
+	}
 }
 
 void LightmapGI::_bind_methods() {
@@ -1518,6 +1530,9 @@ void LightmapGI::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_use_denoiser", "use_denoiser"), &LightmapGI::set_use_denoiser);
 	ClassDB::bind_method(D_METHOD("is_using_denoiser"), &LightmapGI::is_using_denoiser);
 
+	ClassDB::bind_method(D_METHOD("set_denoiser_strength", "denoiser_strength"), &LightmapGI::set_denoiser_strength);
+	ClassDB::bind_method(D_METHOD("get_denoiser_strength"), &LightmapGI::get_denoiser_strength);
+
 	ClassDB::bind_method(D_METHOD("set_interior", "enable"), &LightmapGI::set_interior);
 	ClassDB::bind_method(D_METHOD("is_interior"), &LightmapGI::is_interior);
 
@@ -1535,6 +1550,7 @@ void LightmapGI::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "directional"), "set_directional", "is_directional");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "interior"), "set_interior", "is_interior");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "use_denoiser"), "set_use_denoiser", "is_using_denoiser");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "denoiser_strength", PROPERTY_HINT_RANGE, "0.001,0.2,0.001,or_greater"), "set_denoiser_strength", "get_denoiser_strength");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "bias", PROPERTY_HINT_RANGE, "0.00001,0.1,0.00001,or_greater"), "set_bias", "get_bias");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "max_texture_size", PROPERTY_HINT_RANGE, "2048,16384,1"), "set_max_texture_size", "get_max_texture_size");
 	ADD_GROUP("Environment", "environment_");

scene/3d/lightmap_gi.h

@@ -145,6 +145,7 @@ public:
 private:
 	BakeQuality bake_quality = BAKE_QUALITY_MEDIUM;
 	bool use_denoiser = true;
+	float denoiser_strength = 0.1f;
 	int bounces = 3;
 	float bias = 0.0005;
 	int max_texture_size = 16384;
@@ -239,6 +240,9 @@ public:
 	void set_use_denoiser(bool p_enable);
 	bool is_using_denoiser() const;
 
+	void set_denoiser_strength(float p_denoiser_strength);
+	float get_denoiser_strength() const;
+
 	void set_directional(bool p_enable);
 	bool is_directional() const;
 

scene/3d/lightmapper.h

@@ -180,7 +180,7 @@ public:
 	virtual void add_omni_light(bool p_static, const Vector3 &p_position, const Color &p_color, float p_energy, float p_range, float p_attenuation, float p_size, float p_shadow_blur) = 0;
 	virtual void add_spot_light(bool p_static, const Vector3 &p_position, const Vector3 p_direction, const Color &p_color, float p_energy, float p_range, float p_attenuation, float p_spot_angle, float p_spot_attenuation, float p_size, float p_shadow_blur) = 0;
 	virtual void add_probe(const Vector3 &p_position) = 0;
-	virtual BakeError bake(BakeQuality p_quality, bool p_use_denoiser, int p_bounces, float p_bias, int p_max_texture_size, bool p_bake_sh, GenerateProbes p_generate_probes, const Ref<Image> &p_environment_panorama, const Basis &p_environment_transform, BakeStepFunc p_step_function = nullptr, void *p_step_userdata = nullptr, float p_exposure_normalization = 1.0) = 0;
+	virtual BakeError bake(BakeQuality p_quality, bool p_use_denoiser, float p_denoiser_strength, int p_bounces, float p_bias, int p_max_texture_size, bool p_bake_sh, GenerateProbes p_generate_probes, const Ref<Image> &p_environment_panorama, const Basis &p_environment_transform, BakeStepFunc p_step_function = nullptr, void *p_step_userdata = nullptr, float p_exposure_normalization = 1.0) = 0;
 
 	virtual int get_bake_texture_count() const = 0;
 	virtual Ref<Image> get_bake_texture(int p_index) const = 0;