WebGPURenderer: Support for access previous frame textures using pass()

[sunag]

Related issue: #29058 (comment)

Description

Add support for accessing previous textures, without needing special configuration, just like the syntax below:

const scenePass = pass( scene, camera );

const currentTexture = scenePass.getTextureNode();
const previousTexture = scenePass.getPreviousTextureNode();

postProcessing.outputNode = mix( currentTexture, previousTexture, .5 ); // simple motion blur

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

Filesize dev	Filesize PR	Diff
685.1 kB (169.6 kB)	685.1 kB (169.6 kB)	+0 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

Filesize dev	Filesize PR	Diff
462 kB (111.5 kB)	462 kB (111.5 kB)	+0 B

[sunag]

Several revisions have been made, now MRT is working on WebGLBackend as shown in the screenshots.

[cmhhelgeson]

I'm getting an error on this code ( just modifying the after image sample ):

const scenePass = pass( scene, camera );
const scenePassColor = scenePass.getTextureNode();
const scenePassPrevColor = scenePass.getPreviousTextureNode();

// combinedPass = scenePassColor;
// combinedPass = combinedPass.afterImage( params.damp );

postProcessing.outputNode = scenePassPrevColor; //combinedPass;

three.js.examples.-.Google.Chrome.2024-08-05.23-05-57.mp4

Full error is as follows. As expected, the error and flickering goes away when antialiasing is turned off since the default sample count for the WebGPUBackend is 1.

The depth stencil attachment [TextureView of Texture "depth"] sample count (4) does not match the sample count of the other attachments (1).
 - While validating depthStencilAttachment.
 - While encoding [CommandEncoder "renderContext_1"].BeginRenderPass([null]).

[sunag]

I think it is { antialias: true }, WebGPURenderer does not yet fully support this