Method lerp

src/main/java/emu/grasscutter/utils/Utils.java:273–299

Performs a linear interpolation using a table of fixed points to create an effective piecewise f(x) = y function. @param x The x value. @param xyArray Array of points in [[x0,y0], ... [xN, yN]] format @return f(x) = y

(int x, int[][] xyArray)

	 * @return f(x) = y
	 */
	public static int lerp(int x, int[][] xyArray) {
		try {
			if (x <= xyArray[0][0]){  // Clamp to first point
				return xyArray[0][1];
			} else if (x >= xyArray[xyArray.length-1][0]) {  // Clamp to last point
				return xyArray[xyArray.length-1][1];
			}
			// At this point we're guaranteed to have two lerp points, and pity be somewhere between them.
			for (int i=0; i < xyArray.length-1; i++) {
				if (x == xyArray[i+1][0]) {
					return xyArray[i+1][1];
				}
				if (x < xyArray[i+1][0]) {
					// We are between [i] and [i+1], interpolation time!
					// Using floats would be slightly cleaner but we can just as easily use ints if we're careful with order of operations.
					int position = x - xyArray[i][0];
					int fullDist = xyArray[i+1][0] - xyArray[i][0];
					int prevValue = xyArray[i][1];
					int fullDelta = xyArray[i+1][1] - prevValue;
					return prevValue + ( (position * fullDelta) / fullDist );
				}
			}
		} catch (IndexOutOfBoundsException e) {
			Grasscutter.getLogger().error("Malformed lerp point array. Must be of form [[x0, y0], ..., [xN, yN]].");
		}
		return 0;
	}

	/**
	 * Checks if an int is in an int[]