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Improve transmission when background is transparent #26003

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WestLangley wants to merge 1 commit into from
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Improve transmission when background is transparent #26003

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11 changes: 11 additions & 0 deletions src/renderers/WebGLRenderer.js
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@ import {
UnsignedShort4444Type,
UnsignedShort5551Type
} from '../constants.js';
import { Color } from '../math/Color.js';
import { Frustum } from '../math/Frustum.js';
import { Matrix4 } from '../math/Matrix4.js';
import { Vector3 } from '../math/Vector3.js';
Expand Down Expand Up @@ -174,6 +175,9 @@ class WebGLRenderer {
const _currentScissor = new Vector4();
let _currentScissorTest = null;

const _currentClearColor = new Color( 0x000000 );
let _currentClearAlpha = 0;

//

let _width = canvas.width;
Expand Down Expand Up @@ -1359,6 +1363,11 @@ class WebGLRenderer {

const currentRenderTarget = _this.getRenderTarget();
_this.setRenderTarget( _transmissionRenderTarget );

_this.getClearColor( _currentClearColor );
_currentClearAlpha = _this.getClearAlpha();
if ( _currentClearAlpha < 1 ) _this.setClearColor( 0x7f7f7f, 0.8 );
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@WestLangley WestLangley May 7, 2023

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Based on my experiments, values greater than 0x7f7f7f are too bright. This seems to be a good compromise.

The clear alpha value of 0.8 allows the CSS background to show through when the scene background is transparent. This is a subjective value.


_this.clear();

// Turn off the features which can affect the frag color for opaque objects pass.
Expand Down Expand Up @@ -1409,6 +1418,8 @@ class WebGLRenderer {

_this.setRenderTarget( currentRenderTarget );

_this.setClearColor( _currentClearColor, _currentClearAlpha );

_this.toneMapping = currentToneMapping;

}
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2 changes: 1 addition & 1 deletion src/renderers/shaders/ShaderChunk/output_fragment.glsl.js
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Expand Up @@ -5,7 +5,7 @@ diffuseColor.a = 1.0;

// https://github.com/mrdoob/three.js/pull/22425
#ifdef USE_TRANSMISSION
diffuseColor.a *= material.transmissionAlpha + 0.1;
diffuseColor.a *= material.transmissionAlpha;
#endif

gl_FragColor = vec4( outgoingLight, diffuseColor.a );
Expand Down