[ts][pixi] Fix parent alpha not working for dark tint. Aligned DarkTintMaterial shader with the Batcher one.

spine-ts/spine-pixi/src/darkTintMesh/DarkTintMaterial.ts

@@ -191,11 +191,9 @@ export class DarkTintMaterial extends Shader {
 	public update(): void {
 		if (this._colorDirty) {
 			this._colorDirty = false;
-			const baseTexture = this.texture.baseTexture;
-			const applyToChannels = baseTexture.alphaMode as unknown as boolean;
-
-			Color.shared.setValue(this._tintColor).premultiply(this._alpha, applyToChannels).toArray(this.uniforms.uColor);
-			Color.shared.setValue(this._darkTintColor).premultiply(this._alpha, applyToChannels).toArray(this.uniforms.uDarkColor);
+			const missingAlphaInPMAColor = this._alpha / this._tintColor.alpha;
+			Color.shared.setValue(this._tintColor).premultiply(missingAlphaInPMAColor, true).premultiply(this._alpha, false).toArray(this.uniforms.uColor);
+			Color.shared.setValue(this._darkTintColor).premultiply(missingAlphaInPMAColor, true).premultiply(1, false).toArray(this.uniforms.uDarkColor);
 		}
 		if (this.uvMatrix.update()) {
 			this.uniforms.uTextureMatrix = this.uvMatrix.mapCoord;

spine-ts/spine-pixi/src/darkTintMesh/DarkTintMesh.ts

@@ -43,6 +43,7 @@ export interface IDarkTintElement {
 	_tintRGB: number;
 	// eslint-disable-next-line @typescript-eslint/naming-convention
 	_darkTintRGB: number;
+	alpha: number;
 	blendMode: BLEND_MODES;
 }
 

spine-ts/spine-pixi/src/darkTintMesh/DarkTintRenderer.ts

@@ -98,14 +98,10 @@ export class DarkTintRenderer extends BatchRenderer {
 		const indicies = element.indices;
 		const vertexData = element.vertexData;
 		const textureId = element._texture.baseTexture._batchLocation;
-		const alpha = Math.min(element.worldAlpha, 1.0);
-
-		const alphaInt = Math.round(alpha * 255) & 0xFF;
-		const tintRGB = element._tintRGB & 0xFFFFFF;
-		const argb = (alphaInt << 24) | tintRGB;
-
-		const darkTintRGB = element._darkTintRGB & 0xFFFFFF;
-		const darkargb = (0xFF << 24) | darkTintRGB;
+		const worldAlpha = Math.min(element.worldAlpha, 1.0);
+		const missingAlphaInPMAColor = worldAlpha / element.alpha;
+		const argb = Color.shared.setValue(element._tintRGB).premultiply(missingAlphaInPMAColor, true).toPremultiplied(worldAlpha, false);
+		const darkargb = Color.shared.setValue(element._darkTintRGB).premultiply(missingAlphaInPMAColor, true).toPremultiplied(1, false);
 
 		// lets not worry about tint! for now..
 		for (let i = 0; i < vertexData.length; i += 2) {