Add upscaling support and refactor rendering pipeline

README.md

@@ -68,6 +68,7 @@ Continue with the [RHI Guide](https://qian-o.github.io/Zenith.NET/docs/) or buil
 [![ImageSharp](https://img.shields.io/nuget/v/Zenith.NET.Extensions.ImageSharp.svg?label=ImageSharp&style=flat-square)](https://www.nuget.org/packages/Zenith.NET.Extensions.ImageSharp)
 [![ImGui](https://img.shields.io/nuget/v/Zenith.NET.Extensions.ImGui.svg?label=ImGui&style=flat-square)](https://www.nuget.org/packages/Zenith.NET.Extensions.ImGui)
 [![Skia](https://img.shields.io/nuget/v/Zenith.NET.Extensions.Skia.svg?label=Skia&style=flat-square)](https://www.nuget.org/packages/Zenith.NET.Extensions.Skia)
+[![Upscaling](https://img.shields.io/nuget/v/Zenith.NET.Extensions.Upscaling.svg?label=Upscaling&style=flat-square)](https://www.nuget.org/packages/Zenith.NET.Extensions.Upscaling)
 
 ### Views
 

Zenith.NET.slnx

@@ -10,6 +10,7 @@
     <Project Path="sources/Extensions/Zenith.NET.Extensions.ImageSharp/Zenith.NET.Extensions.ImageSharp.csproj" />
     <Project Path="sources/Extensions/Zenith.NET.Extensions.ImGui/Zenith.NET.Extensions.ImGui.csproj" />
     <Project Path="sources/Extensions/Zenith.NET.Extensions.Skia/Zenith.NET.Extensions.Skia.csproj" />
+    <Project Path="sources/Extensions/Zenith.NET.Extensions.Upscaling/Zenith.NET.Extensions.Upscaling.csproj" />
   </Folder>
   <Folder Name="/Solution Items/">
     <File Path="sources/Directory.Build.props" />

documents/docs/fundamentals/commands.md

@@ -41,7 +41,11 @@ commandBuffer.Draw(vertexCount, 1, 0, 0);
 commandBuffer.EndRenderPass();
 ```
 
-`BeginRenderPass` initializes viewports and scissors from the attachment size. Set them afterward when rendering to a smaller region.
+`BeginRenderPass` resets the viewport and scissor state to one pair, regardless of the number of color attachments. The pair covers the selected mip level of the first color attachment. When there are no color attachments, its dimensions come from the depth/stencil attachment's selected mip level instead.
+
+`SetViewports` and `SetScissors` replace the corresponding active arrays, including their counts. Call them after `BeginRenderPass` to change the rendering region or configure multiple viewports. Both arrays must be nonempty and within the device's supported limits, and their counts must match before drawing. Using more than one pair requires device support for multiple viewports.
+
+The array indices identify viewport/scissor slots, not color attachments. See [MRT and Viewports](../workloads/rasterization.md#mrt-and-viewports) for the distinction.
 
 ## Transfer Data
 

documents/docs/workloads/rasterization.md

@@ -53,10 +53,16 @@ commandBuffer.Draw(vertexCount, 1, 0, 0);
 commandBuffer.EndRenderPass();
 ```
 
-Choose `Load`, `Clear`, or `DontCare` for each attachment according to whether previous contents are needed. `BeginRenderPass` initializes the viewport and scissor from the attachment size.
+Choose `Load`, `Clear`, or `DontCare` for each attachment according to whether previous contents are needed. `BeginRenderPass` initializes one viewport/scissor pair, independent of the color attachment count. Its dimensions come from the first color attachment's selected mip level, or the depth/stencil attachment's selected mip level when there are no color attachments.
 
-Set a smaller viewport and scissor after beginning the pass when rendering to only part of an attachment.
+Set a smaller viewport and scissor after beginning the pass when rendering to only part of an attachment. To change the number of active viewports, set both arrays with matching counts before drawing. See [Commands](../fundamentals/commands.md#record-a-render-pass) for the count and device requirements.
 
 Use `Draw` for non-indexed geometry and `DrawIndexed` for indexed geometry. `DrawIndirect` and `DrawIndexedIndirect` read commands from a buffer created with `BufferUsages.Indirect`.
 
+## MRT and Viewports
+
+Multiple render targets (MRT) use fragment shader outputs `SV_Target0`, `SV_Target1`, and so on to write to color attachments at the corresponding indices. Keep the output indices aligned with both `AttachmentFormats.ColorFormats` and the `colorAttachments` array passed to `BeginRenderPass`. These outputs share the viewport transform and scissor selected for the primitive. Multiple color attachments do not require multiple viewports or scissors.
+
+Multiple viewports instead let different primitives select different viewport transforms and scissor rectangles. The pre-rasterization shader output `SV_ViewportArrayIndex` selects the viewport/scissor pair for a primitive, not a color attachment. Without this output, primitives use pair zero. Setting multiple viewports does not duplicate geometry or create additional render targets.
+
 See [Bindless Resources](../fundamentals/bindless-resources.md) for shader-visible resources and [Synchronization](../fundamentals/synchronization.md) when GPU work produces indirect arguments.

sources/Directory.Packages.props

@@ -5,23 +5,23 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageVersion Include="Avalonia" Version="12.1.1" />
+        <PackageVersion Include="Avalonia" Version="12.1.2" />
         <PackageVersion Include="Hexa.NET.ImGui" Version="2.2.9" />
         <PackageVersion Include="Metal.NET" Version="2.4.0" />
-        <PackageVersion Include="Microsoft.Maui.Controls" Version="10.0.90" />
-        <PackageVersion Include="Microsoft.WindowsAppSDK" Version="2.3.1" />
-        <PackageVersion Include="Roslynator.Analyzers" Version="4.15.0" />
+        <PackageVersion Include="Microsoft.Maui.Controls" Version="10.0.101" />
+        <PackageVersion Include="Microsoft.WindowsAppSDK" Version="2.4.0" />
+        <PackageVersion Include="Roslynator.Analyzers" Version="5.0.0" />
         <PackageVersion Include="Silk.NET.Direct3D11" Version="2.23.0" />
         <PackageVersion Include="Silk.NET.Direct3D12" Version="2.23.0" />
         <PackageVersion Include="Silk.NET.Direct3D9" Version="2.23.0" />
         <PackageVersion Include="Silk.NET.Vulkan" Version="2.23.0" />
         <PackageVersion Include="Silk.NET.Vulkan.Extensions.ANDROID" Version="2.23.0" />
         <PackageVersion Include="Silk.NET.Vulkan.Extensions.EXT" Version="2.23.0" />
         <PackageVersion Include="Silk.NET.Vulkan.Extensions.KHR" Version="2.23.0" />
-        <PackageVersion Include="SixLabors.ImageSharp" Version="4.0.0" />
-        <PackageVersion Include="SkiaSharp" Version="4.151.0" />
-        <PackageVersion Include="Slangc.NET" Version="2026.14.1" />
-        <PackageVersion Include="Uno.WinUI" Version="6.6.184" />
+        <PackageVersion Include="SixLabors.ImageSharp" Version="4.1.1" />
+        <PackageVersion Include="SkiaSharp" Version="4.152.0" />
+        <PackageVersion Include="Slangc.NET" Version="2026.16.1" />
+        <PackageVersion Include="Uno.WinUI" Version="6.7.103" />
     </ItemGroup>
 
 </Project>

sources/Experiments/CornellBox/App.cs

@@ -114,7 +114,7 @@ static App()
 
     public static void Run()
     {
-        window.Update += delta =>
+        window.Update += static delta =>
         {
             if (Width is 0 || Height is 0)
             {
@@ -129,14 +129,14 @@ public static void Run()
 
             ImGui.GetBackgroundDrawList().AddImage(imGui.Binding(activeRenderer.Color), new(0, 0), new(Width / DpiScale.X, Height / DpiScale.Y));
 
-            ImGuiHelper.Overlay(() =>
+            ImGuiHelper.Overlay(static () =>
             {
                 ImGui.Text(Context.Capabilities.DeviceName);
                 ImGui.Text($"GraphicsApi: {Context.GraphicsApi}");
                 ImGui.Text($"FPS: {ImGui.GetIO().Framerate:F1}");
             });
 
-            ImGuiHelper.Settings(() =>
+            ImGuiHelper.Settings(static () =>
             {
                 ImGui.Text("Render Mode:");
 
@@ -168,7 +168,7 @@ public static void Run()
             });
         };
 
-        window.Render += _ =>
+        window.Render += static _ =>
         {
             if (Width is 0 || Height is 0)
             {
@@ -181,17 +181,15 @@ public static void Run()
             activeRenderer.Render(commandBuffer);
 
             commandBuffer.Transition(swapChain.Drawable, default, TextureLayout.Undefined, TextureLayout.ColorAttachment);
-
-            imGui.Render(commandBuffer, ColorAttachment.DontCare(swapChain.Drawable));
-
+            imGui.Render(commandBuffer, ColorAttachment.Clear(swapChain.Drawable, default));
             commandBuffer.Transition(swapChain.Drawable, default, TextureLayout.ColorAttachment, TextureLayout.Present);
 
             commandBuffer.Submit().Wait();
 
             swapChain.Present();
         };
 
-        window.Resize += _ =>
+        window.Resize += static _ =>
         {
             if (Width is 0 || Height is 0)
             {

sources/Experiments/CornellBox/Assets/Shaders/PathTracing.slang

@@ -338,7 +338,8 @@ float3 TracePath(float3 origin, float3 direction, inout uint rng)
 
         if (query.CommittedStatus() == COMMITTED_NOTHING)
         {
-            float3 skyColor = lerp(float3(0.15, 0.12, 0.10), float3(0.30, 0.35, 0.45), saturate(direction.y * 0.5 + 0.5));
+            float3 skyColor =
+                lerp(float3(0.15, 0.12, 0.10), float3(0.30, 0.35, 0.45), saturate(direction.y * 0.5 + 0.5));
             radiance += throughput * skyColor;
 
             break;
@@ -472,7 +473,8 @@ void CSMain(uint3 dispatchThreadID: SV_DispatchThreadID)
         return;
     }
 
-    uint rng = PCGHash(pixel.x + pixel.y * pathTracing.Width + pathTracing.FrameCount * pathTracing.Width * pathTracing.Height);
+    uint rng = PCGHash(pixel.x + pixel.y * pathTracing.Width +
+                       pathTracing.FrameCount * pathTracing.Width * pathTracing.Height);
 
     uint sampleIndex = pathTracing.FrameCount + 1;
     float hx = Halton(sampleIndex, 2);