GPU: add support for N-many input images and not just exactly one

node-graph/libraries/wgpu-executor/src/shader_runtime/per_pixel_adjust_runtime.rs

@@ -33,7 +33,8 @@
 }
 
 impl ShaderRuntime {
-	pub async fn run_per_pixel_adjust<T: BufferStruct>(&self, shaders: &Shaders<'_>, textures: List<Raster<GPU>>, args: Option<&T>) -> List<Raster<GPU>> {
+	pub async fn run_per_pixel_adjust<T: BufferStruct>(&self, shaders: &Shaders<'_>, textures: &[List<Raster<GPU>>], args: Option<&T>) -> List<Raster<GPU>> {
+		assert_eq!(shaders.input_images, textures.len());
 		let mut cache = self.per_pixel_adjust.pipeline_cache.lock().await;
 		let pipeline = cache
 			.entry(shaders.fragment_shader_name.to_owned())
@@ -54,11 +55,13 @@
 pub struct Shaders<'a> {
 	pub wgsl_shader: &'a str,
 	pub fragment_shader_name: &'a str,
+	pub input_images: usize,
 	pub has_uniform: bool,
 }
 
 pub struct PerPixelAdjustGraphicsPipeline {
 	name: String,
+	input_images: usize,
 	has_uniform: bool,
 	pipeline: wgpu::RenderPipeline,
 }
@@ -76,46 +79,37 @@
 			source: ShaderSource::Wgsl(Cow::Borrowed(info.wgsl_shader)),
 		});
 
-		let entries: &[_] = if info.has_uniform {
-			&[
-				BindGroupLayoutEntry {
-					binding: 0,
-					visibility: ShaderStages::FRAGMENT,
-					ty: BindingType::Buffer {
-						ty: BufferBindingType::Storage { read_only: true },
-						has_dynamic_offset: false,
-						min_binding_size: None,
-					},
-					count: None,
-				},
-				BindGroupLayoutEntry {
-					binding: 1,
-					visibility: ShaderStages::FRAGMENT,
-					ty: BindingType::Texture {
-						sample_type: TextureSampleType::Float { filterable: false },
-						view_dimension: TextureViewDimension::D2,
-						multisampled: false,
-					},
-					count: None,
+		let mut binding_alloc = Counter::default();
+		let mut entries = Vec::new();
+		if info.has_uniform {
+			entries.push(BindGroupLayoutEntry {
+				binding: binding_alloc.alloc(),
+				visibility: ShaderStages::FRAGMENT,
+				ty: BindingType::Buffer {
+					ty: BufferBindingType::Storage { read_only: true },
+					has_dynamic_offset: false,
+					min_binding_size: None,
 				},
-			]
-		} else {
-			&[BindGroupLayoutEntry {
-				binding: 0,
+				count: None,
+			});
+		}
+		for _ in 0..info.input_images {
+			entries.push(BindGroupLayoutEntry {
+				binding: binding_alloc.alloc(),
 				visibility: ShaderStages::FRAGMENT,
 				ty: BindingType::Texture {
 					sample_type: TextureSampleType::Float { filterable: false },
 					view_dimension: TextureViewDimension::D2,
 					multisampled: false,
 				},
 				count: None,
-			}]
-		};
+			});
+		}
 		let pipeline_layout = device.create_pipeline_layout(&PipelineLayoutDescriptor {
 			label: Some(&format!("PerPixelAdjust {name} PipelineLayout")),
 			bind_group_layouts: &[Some(&device.create_bind_group_layout(&BindGroupLayoutDescriptor {
 				label: Some(&format!("PerPixelAdjust {name} BindGroupLayout 0")),
-				entries,
+				entries: &entries,
 			}))],
 			..Default::default()
 		});
@@ -157,61 +151,73 @@
 			pipeline,
 			name,
 			has_uniform: info.has_uniform,
+			input_images: info.input_images,
 		}
 	}
 
-	pub fn dispatch(&self, context: &WgpuContext, textures: List<Raster<GPU>>, arg_buffer: Option<Buffer>) -> List<Raster<GPU>> {
+	pub fn dispatch(&self, context: &WgpuContext, in_textures: &[List<Raster<GPU>>], arg_buffer: Option<Buffer>) -> List<Raster<GPU>> {
 		assert_eq!(self.has_uniform, arg_buffer.is_some());
+		assert_eq!(self.input_images, in_textures.len());
 		let device = &context.device;
 		let name = self.name.as_str();
 
+		// Assumption: when we have multiple input images to our node, each input's List of images can have a different
+		// length. Only process the minimum between all input images, same as `impl Blend<Color> for List<Raster<CPU>>`.
+		let dispatch_cnt = match in_textures.iter().map(|t| t.len()).min() {
+			None => {
+				return List::new();
+			}
+			Some(e) => e,
+		};
+
 		let mut cmd = device.create_command_encoder(&wgpu::CommandEncoderDescriptor {
 			label: Some(&format!("{name} cmd encoder")),
 		});
-		let out = (0..textures.len())
-			.map(|index| {
-				let element = textures.element(index).unwrap();
-				let tex_in = &element.texture;
-				let view_in = tex_in.create_view(&TextureViewDescriptor::default());
-				let format = tex_in.format();
-
-				let entries: &[_] = if let Some(arg_buffer) = arg_buffer.as_ref() {
-					&[
-						BindGroupEntry {
-							binding: 0,
-							resource: BindingResource::Buffer(BufferBinding {
-								buffer: arg_buffer,
-								offset: 0,
-								size: None,
-							}),
-						},
-						BindGroupEntry {
-							binding: 1,
-							resource: BindingResource::TextureView(&view_in),
-						},
-					]
-				} else {
-					&[BindGroupEntry {
-						binding: 0,
+		let out = (0..dispatch_cnt)
+			.map(|dispatch_id| {
+				let mut binding_alloc = Counter::default();
+				let mut entries = Vec::new();
+				if let Some(arg_buffer) = arg_buffer.as_ref() {
+					entries.push(BindGroupEntry {
+						binding: binding_alloc.alloc(),
+						resource: BindingResource::Buffer(BufferBinding {
+							buffer: arg_buffer,
+							offset: 0,
+							size: None,
+						}),
+					});
+				}
+				let in_texture_views = in_textures.iter().map(|texture| {
+					let element = texture.element(dispatch_id).unwrap();
+					element.texture.create_view(&TextureViewDescriptor::default())
+				}).collect::<Vec<_>>();
+				for view_in in &in_texture_views {
+					entries.push(BindGroupEntry {
+						binding: binding_alloc.alloc(),
 						resource: BindingResource::TextureView(&view_in),
-					}]
-				};
+					});
+				}
+
 				let bind_group = device.create_bind_group(&BindGroupDescriptor {
 					label: Some(&format!("{name} bind group")),
 					// `get_bind_group_layout` allocates unnecessary memory, we could create it manually to not do that
 					layout: &self.pipeline.get_bind_group_layout(0),
-					entries,
+					entries: &entries,
 				});
 
+				// Assumption: The output texture has the same size and format as the first input texture. Like the
+				// blend node, that writes the output directly back into the first texture.
+				let outref_list = &in_textures[0];
+				let outref_tex = &outref_list.element(dispatch_id).unwrap().texture;
 				let tex_out = device.create_texture(&TextureDescriptor {
 					label: Some(&format!("{name} texture out")),
-					size: tex_in.size(),
+					size: outref_tex.size(),
 					mip_level_count: 1,
 					sample_count: 1,
 					dimension: TextureDimension::D2,
-					format,
+					format: outref_tex.format(),
 					usage: wgpu::TextureUsages::TEXTURE_BINDING | wgpu::TextureUsages::COPY_DST | wgpu::TextureUsages::COPY_SRC | wgpu::TextureUsages::RENDER_ATTACHMENT,
-					view_formats: &[format],
+					view_formats: &[outref_tex.format()],
 				});
 
 				let view_out = tex_out.create_view(&TextureViewDescriptor::default());
@@ -233,11 +239,22 @@
 				rp.set_bind_group(0, Some(&bind_group), &[]);
 				rp.draw(0..3, 0..1);
 
-				let attributes = textures.clone_item_attributes(index);
+				let attributes = outref_list.clone_item_attributes(dispatch_id);
 				Item::from_parts(Raster::new(GPU { texture: tex_out }), attributes)
 			})
 			.collect::<List<_>>();
 		context.queue.submit([cmd.finish()]);
 		out
 	}
 }
+
+#[derive(Clone, Debug, Default)]
+pub struct Counter(pub u32);
+
+impl Counter {
+	pub fn alloc(&mut self) -> u32 {
+		let out = self.0;
+		self.0 += 1;
+		out
+	}
+}

node-graph/node-macro/src/shader_nodes/per_pixel_adjust.rs

@@ -248,16 +248,15 @@ impl PerPixelAdjustCodegen<'_> {
 			is_data_field: false,
 		});
 
-		// find exactly one gpu_image field, runtime doesn't support more than 1 atm
-		let gpu_image_field = {
-			let mut iter = fields.iter().filter(|f| matches!(f.ty, ParsedFieldType::Regular(RegularParsedField { gpu_image: true, .. })));
-			match (iter.next(), iter.next()) {
-				(Some(v), None) => Ok(v),
-				(Some(_), Some(more)) => Err(syn::Error::new_spanned(&more.pat_ident, "No more than one parameter must be annotated with `#[gpu_image]`")),
-				(None, _) => Err(syn::Error::new_spanned(&self.parsed.fn_name, "At least one parameter must be annotated with `#[gpu_image]`")),
-			}?
-		};
-		let gpu_image = &gpu_image_field.pat_ident.ident;
+		// find gpu_image fields
+		let gpu_images = fields
+			.iter()
+			.filter_map(|f| match f.ty {
+				ParsedFieldType::Regular(RegularParsedField { gpu_image: true, .. }) => Some(&f.pat_ident.ident),
+				_ => None,
+			})
+			.collect::<Vec<_>>();
+		let input_images = gpu_images.len();
 
 		// uniform buffer struct construction
 		let has_uniform = self.has_uniform;
@@ -287,7 +286,8 @@ impl PerPixelAdjustCodegen<'_> {
 					wgsl_shader: crate::WGSL_SHADER,
 					fragment_shader_name: super::#entry_point_name,
 					has_uniform: #has_uniform,
-				}, #gpu_image, #uniform_buffer).await
+					input_images: #input_images,
+				}, &[#(#gpu_images),*], #uniform_buffer).await
 			}
 		};
 

node-graph/nodes/raster/src/blending_nodes.rs

@@ -141,7 +141,7 @@ pub fn apply_blend_mode(foreground: Color, background: Color, blend_mode: BlendM
 	}
 }
 
-#[node_macro::node(category("Raster"), cfg(feature = "std"))]
+#[node_macro::node(category("Raster"), shader_node(PerPixelAdjust))]
 fn mix<T: Blend<Color> + Send>(
 	_: impl Ctx,
 	#[implementations(