TSL: UVNode - Move to TSL approach #28511
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| export const bitangentWorld = varying( getBitangent( normalWorld.cross( tangentWorld ) ) ).normalize(); | ||
| export const transformedBitangentView = getBitangent( transformedNormalView.cross( transformedTangentView ) ).normalize(); | ||
| export const transformedBitangentWorld = transformedBitangentView.transformDirection( cameraViewMatrix ).normalize(); | ||
| export const bitangentGeometry = /*#__PURE__*/ varying( getBitangent( normalGeometry.cross( tangentGeometry ) ), 'v_bitangentGeometry' ).normalize().toVar( 'bitangentGeometry' ); |
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What's the difference between varying() and toVar()?
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toVar( name = null ) will create a variable, the first parameter is used to add a name to it, otherwise the node system will name it automatically, it can be useful in debugging or access using wgslFn.
varying( node, name = null ) this node is very interesting, let's suppose you want to optimize some calculation in the vertex stage but are using it in a slot like material.colorNode, with varying this is possible. For example:
// multiplication will be executed in vertex stage
const inVertexStage = varying( modelNormalMatrix.mul( normalLocal ) ); // normalView
// normalize will be executed in fragment stage
// because .colorNode is a fragment stage slot as default
material.colorNode = inVertexStage.normalize();The first parameter of varying( modelNormalMatrix.mul( normalLocal ) ) will be executed in vertex stage, and the return from varying() will be a varying as we are used in WGSL/GLSL, this can optimize extra calculations in the fragment stage. The second parameter allows you to add a custom name to varying.
If varying() is added only to .positionNode, it will only return a simple variable and varying will not be created.
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Sounds good! Thanks for explaining 🙏
I've started a wiki page for TSL.
Any chance you can spend some time completing it?
Related issue: #28408
Improved too: Normal/Tangent/Bitangent revisions