Renderers: Set premultipliedAlpha to true when using SubtractiveBlending/MultiplyBlending.

Author: mrdoob

src/renderers/webgl-fallback/utils/WebGLState.js

@@ -338,6 +338,17 @@ class WebGLState {
 
 				}
 
+				if ( premultipliedAlpha === false ) {
+
+					if ( blending === SubtractiveBlending || blending === MultiplyBlending ) {
+
+						warnOnce( 'WebGLState: Material premultipliedAlpha was set to true because MultiplyBlending and SubtractiveBlending require it.' );
+						premultipliedAlpha = true;
+
+					}
+
+				}
+
 				if ( premultipliedAlpha ) {
 
 					switch ( blending ) {
@@ -376,16 +387,6 @@ class WebGLState {
 							gl.blendFuncSeparate( gl.SRC_ALPHA, gl.ONE, gl.ONE, gl.ONE );
 							break;
 
-						case SubtractiveBlending:
-							warnOnce( 'WebGLState: SubtractiveBlending works best with material.premultipliedAlpha = true.' );
-							gl.blendFuncSeparate( gl.ZERO, gl.ONE_MINUS_SRC_COLOR, gl.ZERO, gl.ONE );
-							break;
-
-						case MultiplyBlending:
-							warnOnce( 'WebGLState: MultiplyBlending works best with material.premultipliedAlpha = true.' );
-							gl.blendFuncSeparate( gl.DST_COLOR, gl.ONE_MINUS_SRC_ALPHA, gl.ZERO, gl.ONE );
-							break;
-
 						default:
 							error( 'WebGLState: Invalid blending: ', blending );
 							break;

src/renderers/webgl/WebGLState.js

@@ -651,6 +651,17 @@ function WebGLState( gl, extensions ) {
 
 				}
 
+				if ( premultipliedAlpha === false ) {
+
+					if ( blending === SubtractiveBlending || blending === MultiplyBlending ) {
+
+						warnOnce( 'WebGLState: Material premultipliedAlpha was set to true because MultiplyBlending and SubtractiveBlending require it.' );
+						premultipliedAlpha = true;
+
+					}
+
+				}
+
 				if ( premultipliedAlpha ) {
 
 					switch ( blending ) {
@@ -689,16 +700,6 @@ function WebGLState( gl, extensions ) {
 							gl.blendFuncSeparate( gl.SRC_ALPHA, gl.ONE, gl.ONE, gl.ONE );
 							break;
 
-						case SubtractiveBlending:
-							warnOnce( 'WebGLState: SubtractiveBlending works best with material.premultipliedAlpha = true.' );
-							gl.blendFuncSeparate( gl.ZERO, gl.ONE_MINUS_SRC_COLOR, gl.ZERO, gl.ONE );
-							break;
-
-						case MultiplyBlending:
-							warnOnce( 'WebGLState: MultiplyBlending works best with material.premultipliedAlpha = true.' );
-							gl.blendFuncSeparate( gl.DST_COLOR, gl.ONE_MINUS_SRC_ALPHA, gl.ZERO, gl.ONE );
-							break;
-
 						default:
 							error( 'WebGLState: Invalid blending: ', blending );
 							break;

src/renderers/webgpu/utils/WebGPUPipelineUtils.js

@@ -413,6 +413,17 @@ class WebGPUPipelineUtils {
 
 			};
 
+			if ( premultipliedAlpha === false ) {
+
+				if ( blending === SubtractiveBlending || blending === MultiplyBlending ) {
+
+					warnOnce( 'WebGPURenderer: Material premultipliedAlpha was set to true because MultiplyBlending and SubtractiveBlending require it.' );
+					premultipliedAlpha = true;
+
+				}
+
+			}
+
 			if ( premultipliedAlpha ) {
 
 				switch ( blending ) {
@@ -447,16 +458,6 @@ class WebGPUPipelineUtils {
 						setBlend( GPUBlendFactor.SrcAlpha, GPUBlendFactor.One, GPUBlendFactor.One, GPUBlendFactor.One );
 						break;
 
-					case SubtractiveBlending:
-						warnOnce( 'WebGPURenderer: SubtractiveBlending works best with material.premultipliedAlpha = true.' );
-						setBlend( GPUBlendFactor.Zero, GPUBlendFactor.OneMinusSrc, GPUBlendFactor.Zero, GPUBlendFactor.One );
-						break;
-
-					case MultiplyBlending:
-						warnOnce( 'WebGPURenderer: MultiplyBlending works best with material.premultipliedAlpha = true.' );
-						setBlend( GPUBlendFactor.Dst, GPUBlendFactor.OneMinusSrcAlpha, GPUBlendFactor.Zero, GPUBlendFactor.One );
-						break;
-
 				}
 
 			}