 			width, height,
 			&prevPos,
 			mtxs);
+#else
+		aten::vec4 prevPos = centerPrevPos;
+#endif
 
 		// [0, 1]͈͓̔ɓĂ邩.
 		bool isInsideX = (0.0 <= prevPos.x) && (prevPos.x <= 1.0);

	static const float zThreshold = 0.05f;
	static const float nThreshold = 0.98f;

	for (int y = -1; y <= 1; y++) {
		for (int x = -1; x <= 1; x++) {
			int xx = clamp(ix + x, 0, width - 1);

				&prevPos,
				mtxs);

			if (x == 0 && y == 0) {
				centerPrevPos = prevPos;
			}

			// [0, 1]͈͓̔ɓĂ邩.
			bool isInsideX = (0.0 <= prevPos.x) && (prevPos.x <= 1.0);
			bool isInsideY = (0.0 <= prevPos.y) && (prevPos.y <= 1.0);
