https://github.com/WWBN/AVideo/issues/8713

node_modules/three/examples/js/shaders/MirrorShader.js

@@ -0,0 +1,56 @@
+/**
+ * Mirror Shader
+ * Copies half the input to the other half
+ *
+ * side: side of input to mirror (0 = left, 1 = right, 2 = top, 3 = bottom)
+ */
+
+THREE.MirrorShader = {
+
+	uniforms: {
+
+		'tDiffuse': { value: null },
+		'side': { value: 1 }
+
+	},
+
+	vertexShader: [
+
+		'varying vec2 vUv;',
+
+		'void main() {',
+
+		'	vUv = uv;',
+		'	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );',
+
+		'}'
+
+	].join( '\n' ),
+
+	fragmentShader: [
+
+		'uniform sampler2D tDiffuse;',
+		'uniform int side;',
+
+		'varying vec2 vUv;',
+
+		'void main() {',
+
+		'	vec2 p = vUv;',
+		'	if (side == 0){',
+		'		if (p.x > 0.5) p.x = 1.0 - p.x;',
+		'	}else if (side == 1){',
+		'		if (p.x < 0.5) p.x = 1.0 - p.x;',
+		'	}else if (side == 2){',
+		'		if (p.y < 0.5) p.y = 1.0 - p.y;',
+		'	}else if (side == 3){',
+		'		if (p.y > 0.5) p.y = 1.0 - p.y;',
+		'	} ',
+		'	vec4 color = texture2D(tDiffuse, p);',
+		'	gl_FragColor = color;',
+
+		'}'
+
+	].join( '\n' )
+
+};