Support reversed depth (#31496)

Author: WestLangley

src/lights/LightShadow.js

@@ -206,12 +206,25 @@ class LightShadow {
 		_projScreenMatrix.multiplyMatrices( shadowCamera.projectionMatrix, shadowCamera.matrixWorldInverse );
 		this._frustum.setFromProjectionMatrix( _projScreenMatrix );
 
-		shadowMatrix.set(
-			0.5, 0.0, 0.0, 0.5,
-			0.0, 0.5, 0.0, 0.5,
-			0.0, 0.0, 0.5, 0.5,
-			0.0, 0.0, 0.0, 1.0
-		);
+		if ( shadowCamera.reversedDepth ) {
+
+			shadowMatrix.set(
+				0.5, 0.0, 0.0, 0.5,
+				0.0, 0.5, 0.0, 0.5,
+				0.0, 0.0, 1.0, 0.0,
+				0.0, 0.0, 0.0, 1.0
+			);
+
+		} else {
+
+			shadowMatrix.set(
+				0.5, 0.0, 0.0, 0.5,
+				0.0, 0.5, 0.0, 0.5,
+				0.0, 0.0, 0.5, 0.5,
+				0.0, 0.0, 0.0, 1.0
+			);
+
+		}
 
 		shadowMatrix.multiply( _projScreenMatrix );