compute_postprocess

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compute_postprocess

Overview

This sample takes the postprocess rendering flow from Chapter 20 and applies the effect with a compute shader instead of a fragment-shader FullscreenPass
Without changing the webg core, it integrates a compute pass using only the WebGPU device obtained from WebgApp and Screen.createRenderTarget()
The 3D scene is rendered to an offscreen RenderTarget, then the compute shader reads that color texture and writes to a storage texture
Finally, FullscreenPass displays the compute-output texture on the canvas, while the operation guide stays in the Help Panel and editable current values are collected in CommandPalette

Open ./compute_postprocess.html
Use a browser with WebGPU support, and check the help panel and CommandPalette together with the sample when needed

WebgApp(autoDrawScene: false): lets the sample side control the 3D-scene draw destination and the postprocess order
RenderTarget: stores the textures for scene color/depth and compute output
FullscreenPass: copies the storage texture written by the compute shader to the canvas
Shape / Primitive: builds a standard 3D scene for inspecting the postprocess appearance
buildHelpPanelOptions() + showOverlayPanel(): shows the operation guide in a collapsible panel at the upper left

Confirm that the 3D scene is first drawn to an offscreen target and only then displayed after going through the compute pass
Press C to toggle Compute Postprocess on or off and confirm that only the postprocess changes while the scene itself stays the same
Press V to switch the view between composite / scene / output and compare the original scene with the compute output
When changing edge strength with 1 / 2, local-contrast sharpness with 3 / 4, white vignette with 5 / 6, and red-blue chromatic offset with 7 / 8, confirm that the CommandPalette values and the visual changes match
Press M to switch the mode between film / edge / heat and confirm that the appearance can change by branching inside the same compute shader
Confirm that even when the viewport size changes, the scene target and compute output follow the screen size correctly