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Merged
sunag merged 2 commits into from
Jun 10, 2025
+17 −15
Merged

Renderers: Correct the blending formulas #31246

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4ab29b4
Correct the blending formulas
WestLangley Jun 8, 2025
d7631a1
Update examples that use MultiplyBlending
WestLangley Jun 9, 2025
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2 changes: 1 addition & 1 deletion examples/misc_exporter_usdz.html
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Original file line number Diff line number Diff line change
Expand Up @@ -145,7 +145,7 @@

const geometry = new THREE.PlaneGeometry();
const material = new THREE.MeshBasicMaterial( {
map: shadowTexture, blending: THREE.MultiplyBlending, toneMapped: false
map: shadowTexture, blending: THREE.MultiplyBlending, toneMapped: false, premultipliedAlpha: true
} );

const mesh = new THREE.Mesh( geometry, material );
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2 changes: 2 additions & 0 deletions examples/webgl_materials_blending.html
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Expand Up @@ -102,6 +102,8 @@
material.transparent = true;
material.blending = blending.constant;

material.premultipliedAlpha = true;

const x = ( i - blendings.length / 2 ) * 110;
const z = 0;

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2 changes: 1 addition & 1 deletion examples/webgl_materials_car.html
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Original file line number Diff line number Diff line change
Expand Up @@ -171,7 +171,7 @@
const mesh = new THREE.Mesh(
new THREE.PlaneGeometry( 0.655 * 4, 1.3 * 4 ),
new THREE.MeshBasicMaterial( {
map: shadow, blending: THREE.MultiplyBlending, toneMapped: false, transparent: true
map: shadow, blending: THREE.MultiplyBlending, toneMapped: false, transparent: true, premultipliedAlpha: true
} )
);
mesh.rotation.x = - Math.PI / 2;
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2 changes: 1 addition & 1 deletion examples/webgl_materials_envmaps_groundprojected.html
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Expand Up @@ -112,7 +112,7 @@
const mesh = new THREE.Mesh(
new THREE.PlaneGeometry( 0.655 * 4, 1.3 * 4 ),
new THREE.MeshBasicMaterial( {
map: shadow, blending: THREE.MultiplyBlending, toneMapped: false, transparent: true
map: shadow, blending: THREE.MultiplyBlending, toneMapped: false, transparent: true, premultipliedAlpha: true
} )
);
mesh.rotation.x = - Math.PI / 2;
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8 changes: 4 additions & 4 deletions src/renderers/webgl-fallback/utils/WebGLState.js
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Expand Up @@ -339,7 +339,7 @@ class WebGLState {
break;

case MultiplyBlending:
gl.blendFuncSeparate( gl.ZERO, gl.SRC_COLOR, gl.ZERO, gl.SRC_ALPHA );
gl.blendFuncSeparate( gl.DST_COLOR, gl.ONE_MINUS_SRC_ALPHA, gl.ZERO, gl.ONE );
break;

default:
Expand All @@ -357,15 +357,15 @@ class WebGLState {
break;

case AdditiveBlending:
gl.blendFunc( gl.SRC_ALPHA, gl.ONE );
gl.blendFuncSeparate( gl.SRC_ALPHA, gl.ONE, gl.ONE, gl.ONE );
break;

case SubtractiveBlending:
gl.blendFuncSeparate( gl.ZERO, gl.ONE_MINUS_SRC_COLOR, gl.ZERO, gl.ONE );
console.error( 'THREE.WebGLState: SubtractiveBlending requires material.premultipliedAlpha = true' );
break;

case MultiplyBlending:
gl.blendFunc( gl.ZERO, gl.SRC_COLOR );
console.error( 'THREE.WebGLState: MultiplyBlending requires material.premultipliedAlpha = true' );
break;

default:
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8 changes: 4 additions & 4 deletions src/renderers/webgl/WebGLState.js
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Expand Up @@ -667,7 +667,7 @@ function WebGLState( gl, extensions ) {
break;

case MultiplyBlending:
gl.blendFuncSeparate( gl.ZERO, gl.SRC_COLOR, gl.ZERO, gl.SRC_ALPHA );
gl.blendFuncSeparate( gl.DST_COLOR, gl.ONE_MINUS_SRC_ALPHA, gl.ZERO, gl.ONE );
break;

default:
Expand All @@ -685,15 +685,15 @@ function WebGLState( gl, extensions ) {
break;

case AdditiveBlending:
gl.blendFunc( gl.SRC_ALPHA, gl.ONE );
gl.blendFuncSeparate( gl.SRC_ALPHA, gl.ONE, gl.ONE, gl.ONE );
break;

case SubtractiveBlending:
gl.blendFuncSeparate( gl.ZERO, gl.ONE_MINUS_SRC_COLOR, gl.ZERO, gl.ONE );
console.error( 'THREE.WebGLState: SubtractiveBlending requires material.premultipliedAlpha = true' );
break;

case MultiplyBlending:
gl.blendFunc( gl.ZERO, gl.SRC_COLOR );
console.error( 'THREE.WebGLState: MultiplyBlending requires material.premultipliedAlpha = true' );
break;

default:
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8 changes: 4 additions & 4 deletions src/renderers/webgpu/utils/WebGPUPipelineUtils.js
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Expand Up @@ -389,7 +389,7 @@ class WebGPUPipelineUtils {
break;

case MultiplyBlending:
setBlend( GPUBlendFactor.Zero, GPUBlendFactor.Src, GPUBlendFactor.Zero, GPUBlendFactor.SrcAlpha );
setBlend( GPUBlendFactor.Dst, GPUBlendFactor.OneMinusSrcAlpha, GPUBlendFactor.Zero, GPUBlendFactor.One );
break;

}
Expand All @@ -403,15 +403,15 @@ class WebGPUPipelineUtils {
break;

case AdditiveBlending:
setBlend( GPUBlendFactor.SrcAlpha, GPUBlendFactor.One, GPUBlendFactor.SrcAlpha, GPUBlendFactor.One );
setBlend( GPUBlendFactor.SrcAlpha, GPUBlendFactor.One, GPUBlendFactor.One, GPUBlendFactor.One );
break;

case SubtractiveBlending:
setBlend( GPUBlendFactor.Zero, GPUBlendFactor.OneMinusSrc, GPUBlendFactor.Zero, GPUBlendFactor.One );
console.error( 'THREE.WebGPURenderer: SubtractiveBlending requires material.premultipliedAlpha = true' );
break;

case MultiplyBlending:
setBlend( GPUBlendFactor.Zero, GPUBlendFactor.Src, GPUBlendFactor.Zero, GPUBlendFactor.Src );
console.error( 'THREE.WebGPURenderer: MultiplyBlending requires material.premultipliedAlpha = true' );
break;

}
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