private static boolean onScreen(int x, int y, int z) {
		int l = y * curveSineX + x * curveCosineX >> 16;
		int i1 = y * curveCosineX - x * curveSineX >> 16;
		int j1 = z * curveSineY + i1 * curveCosineY >> 16;
		int k1 = z * curveCosineY - i1 * curveSineY >> 16;
		if (j1 < 50 || j1 > 3500)
			return false;
		int l1 = midX + (l << 9) / j1;
		int i2 = midY + (k1 << 9) / j1;
		return l1 >= left && l1 <= right && i2 >= top && i2 <= bottom;
	}