TAA adjustment to reduce ghosting

servers/rendering/renderer_rd/effects/taa.cpp

@@ -58,12 +58,17 @@ void TAA::resolve(RID p_frame, RID p_temp, RID p_depth, RID p_velocity, RID p_pr
 
 	RID default_sampler = material_storage->sampler_rd_get_default(RS::CANVAS_ITEM_TEXTURE_FILTER_LINEAR, RS::CANVAS_ITEM_TEXTURE_REPEAT_DISABLED);
 
+	float base_variance = 1.1f;
+	float base_variance_min = 0.75f;
+	float base_variance_max = 1.00f;
+	float variance_scale = 1080.0f / p_resolution.height; // 1080p taken as baseline for calculation, as this is most commonly used resolution
+
 	TAAResolvePushConstant push_constant;
 	memset(&push_constant, 0, sizeof(TAAResolvePushConstant));
 	push_constant.resolution_width = p_resolution.width;
 	push_constant.resolution_height = p_resolution.height;
 	push_constant.disocclusion_threshold = 2.5f; // If velocity changes by less than this amount of texels we can retain the accumulation buffer.
-	push_constant.disocclusion_scale = 0.01f; // Scale the weight of this pixel calculated as (change in velocity - threshold) * scale.
+	push_constant.variance_dynamic = CLAMP(base_variance * variance_scale, base_variance_min, base_variance_max); // Variance dynamically scales based on resolution
 
 	RD::ComputeListID compute_list = RD::get_singleton()->compute_list_begin();
 	RD::get_singleton()->compute_list_bind_compute_pipeline(compute_list, pipeline);

servers/rendering/renderer_rd/effects/taa.h

@@ -47,7 +47,7 @@ private:
 		float resolution_width;
 		float resolution_height;
 		float disocclusion_threshold;
-		float disocclusion_scale;
+		float variance_dynamic;
 	};
 
 	TaaResolveShaderRD taa_shader;

servers/rendering/renderer_rd/shaders/effects/taa_resolve.glsl

@@ -19,6 +19,7 @@
 // CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 ///////////////////////////////////////////////////////////////////////////////////
 // File changes (yyyy-mm-dd)
+// 2025-11-05: Jakub Brzyski: Added dynamic variance, base variance value adjusted to reduce ghosting
 // 2022-05-06: Panos Karabelas: first commit
 // 2020-12-05: Joan Fons: convert to Vulkan and Godot
 ///////////////////////////////////////////////////////////////////////////////////
@@ -38,6 +39,8 @@
 #define RPC_9 0.11111111111
 #define RPC_16 0.0625
 
+#define DISOCCLUSION_SCALE 0.01 // Scale the weight of this pixel calculated as (change in velocity - threshold) * scale.
+
 layout(local_size_x = GROUP_SIZE, local_size_y = GROUP_SIZE, local_size_z = 1) in;
 
 layout(rgba16f, set = 0, binding = 0) uniform restrict readonly image2D color_buffer;
@@ -49,8 +52,8 @@ layout(rgba16f, set = 0, binding = 5) uniform restrict writeonly image2D output_
 
 layout(push_constant, std430) uniform Params {
 	vec2 resolution;
-	float disocclusion_threshold; // 0.1 / max(params.resolution.x, params.resolution.y
+	float disocclusion_threshold; // 0.1 / max(params.resolution.x, params.resolution.y)
-	float disocclusion_scale;
+	float variance_dynamic;
 }
 params;
 
@@ -273,7 +276,8 @@ vec3 clip_history_3x3(uvec2 group_pos, vec3 color_history, vec2 velocity_closest
 	// Compute min and max (with an adaptive box size, which greatly reduces ghosting)
 	vec3 color_avg = (s1 + s2 + s3 + s4 + s5 + s6 + s7 + s8 + s9) * RPC_9;
 	vec3 color_avg2 = ((s1 * s1) + (s2 * s2) + (s3 * s3) + (s4 * s4) + (s5 * s5) + (s6 * s6) + (s7 * s7) + (s8 * s8) + (s9 * s9)) * RPC_9;
-	float box_size = mix(0.0f, 2.5f, smoothstep(0.02f, 0.0f, length(velocity_closest)));
+	// Use variance clipping as described in https://developer.download.nvidia.com/gameworks/events/GDC2016/msalvi_temporal_supersampling.pdf
+	float box_size = mix(0.0f, params.variance_dynamic, smoothstep(0.02f, 0.0f, length(velocity_closest)));
 	vec3 dev = sqrt(abs(color_avg2 - (color_avg * color_avg))) * box_size;
 	vec3 color_min = color_avg - dev;
 	vec3 color_max = color_avg + dev;
@@ -304,7 +308,7 @@ float get_factor_disocclusion(vec2 uv_reprojected, vec2 velocity) {
 	vec2 velocity_texels = velocity * params.resolution;
 	vec2 prev_velocity_texels = velocity_previous * params.resolution;
 	float disocclusion = length(prev_velocity_texels - velocity_texels) - params.disocclusion_threshold;
-	return clamp(disocclusion * params.disocclusion_scale, 0.0, 1.0);
+	return clamp(disocclusion * DISOCCLUSION_SCALE, 0.0, 1.0);
 }
 
 vec3 temporal_antialiasing(uvec2 pos_group_top_left, uvec2 pos_group, uvec2 pos_screen, vec2 uv, sampler2D tex_history) {