opsu-dance/src/itdelatrisu/opsu/objects/Slider.java

/*
 * opsu! - an open-source osu! client
 * Copyright (C) 2014, 2015 Jeffrey Han
 *
 * opsu! is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * opsu! is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with opsu!.  If not, see <http://www.gnu.org/licenses/>.
 */

package itdelatrisu.opsu.objects;

import itdelatrisu.opsu.GameImage;
import itdelatrisu.opsu.GameMod;
import itdelatrisu.opsu.GameData;
import itdelatrisu.opsu.OsuFile;
import itdelatrisu.opsu.OsuHitObject;
import itdelatrisu.opsu.Utils;
import itdelatrisu.opsu.audio.MusicController;
import itdelatrisu.opsu.states.Game;

import org.newdawn.slick.Animation;
import org.newdawn.slick.Color;
import org.newdawn.slick.GameContainer;
import org.newdawn.slick.Graphics;
import org.newdawn.slick.Image;

/**
 * Data type representing a slider object.
 */
public class Slider implements HitObject {
	/** Slider ball animation. */
	private static Animation sliderBall;

	/** Slider movement speed multiplier. */
	private static float sliderMultiplier = 1.0f;

	/** Rate at which slider ticks are placed. */
	private static float sliderTickRate = 1.0f;

	/** The associated OsuHitObject. */
	private OsuHitObject hitObject;

	/** The associated Game object. */
	private Game game;

	/** The associated GameData object. */
	private GameData data;

	/** The color of this slider. */
	private Color color;

	/** The underlying Bezier object. */
	private Bezier bezier;

	/** The time duration of the slider, in milliseconds. */
	private float sliderTime = 0f;

	/** The time duration of the slider including repeats, in milliseconds. */
	private float sliderTimeTotal = 0f;

	/** Whether or not the result of the initial hit circle has been processed. */
	private boolean sliderClicked = false;

	/** Whether or not to show the follow circle. */
	private boolean followCircleActive = false;

	/** Whether or not the slider result ends the combo streak. */
	private boolean comboEnd;

	/** The number of repeats that have passed so far. */
	private int currentRepeats = 0;

	/** The t values of the slider ticks. */
	private float[] ticksT;

	/** The tick index in the ticksT[] array. */
	private int tickIndex = 0;

	/** Number of ticks hit and tick intervals so far. */
	private int ticksHit = 0, tickIntervals = 1;

	/**
	 * Representation of a Bezier curve, the main component of a slider.
	 *
	 * @author Alex Gheorghiu (http://html5tutorial.com/how-to-draw-n-grade-bezier-curve-with-canvas-api/)
	 * @author pictuga (https://github.com/pictuga/osu-web)
	 */
	private class Bezier {
		/** The order of the Bezier curve. */
		private int order;

		/** The step size (used for drawing). */
		private float step;

		/** The curve points for drawing with step size given by 'step'. */
		private float[] curveX, curveY;

		/** The angles of the first and last control points. */
		private float startAngle, endAngle;

		/**
		 * Constructor.
		 */
		public Bezier() {
			this.order = hitObject.getSliderX().length + 1;
			this.step = 5 / hitObject.getPixelLength();

			// calculate curve points for drawing
			int N = (int) (1 / step);
			this.curveX = new float[N + 1];
			this.curveY = new float[N + 1];
			float t = 0f;
			for (int i = 0; i < N; i++, t += step) {
				float[] c = pointAt(t);
				curveX[i] = c[0];
				curveY[i] = c[1];
			}
			curveX[N] = getX(order - 1);
			curveY[N] = getY(order - 1);

			// calculate angles (if needed)
			if (hitObject.getRepeatCount() > 1) {
				float[] c1 = pointAt(0f);
				float[] c2 = pointAt(step);
				startAngle = (float) (Math.atan2(c2[1] - c1[1], c2[0] - c1[0]) * 180 / Math.PI);
				c1 = pointAt(1f);
				c2 = pointAt(1f - step);
				endAngle = (float) (Math.atan2(c2[1] - c1[1], c2[0] - c1[0]) * 180 / Math.PI);
			}
		}

		/**
		 * Returns the x coordinate of the control point at index i.
		 */
		private float getX(int i) {
			return (i == 0) ? hitObject.getX() : hitObject.getSliderX()[i - 1];
		}

		/**
		 * Returns the y coordinate of the control point at index i.
		 */
		private float getY(int i) {
			return (i == 0) ? hitObject.getY() : hitObject.getSliderY()[i - 1];
		}

		/**
		 * Returns the angle of the first control point.
		 */
		private float getStartAngle() { return startAngle; }

		/**
		 * Returns the angle of the last control point.
		 */
		private float getEndAngle() { return endAngle; }

		/**
		 * Calculates the factorial of a number.
		 */
		private long factorial(int n) {
			return (n <= 1 || n > 20) ? 1 : n * factorial(n - 1);
		}

		/**
		 * Calculates the Bernstein polynomial.
		 * @param i the index
		 * @param n the degree of the polynomial (i.e. number of points)
		 * @param t the t value [0, 1]
		 */
		private double bernstein(int i, int n, float t) {
			return factorial(n) / (factorial(i) * factorial(n-i)) *
					Math.pow(t, i) * Math.pow(1-t, n-i);
		}

		/**
		 * Returns the point on the Bezier curve at a value t.
		 * For curves of order greater than 4, points will be generated along
		 * a path of overlapping cubic (at most) Beziers.
		 * @param t the t value [0, 1]
		 * @return the point [x, y]
		 */
		public float[] pointAt(float t) {
			float[] c = { 0f, 0f };
			int n = order - 1;
			if (n < 4) {  // normal curve
				for (int i = 0; i <= n; i++) {
					c[0] += getX(i) * bernstein(i, n, t);
					c[1] += getY(i) * bernstein(i, n, t);
				}
			} else {  // split curve into path
				// TODO: this is probably wrong...
				int segmentCount = (n / 3) + 1;
				int segment = (int) Math.floor(t * segmentCount);
				int startIndex = 3 * segment;
				int segmentOrder = Math.min(startIndex + 3, n) - startIndex;
				float segmentT = (t * segmentCount) - segment;
				for (int i = 0; i <= segmentOrder; i++) {
					c[0] += getX(i + startIndex) * bernstein(i, segmentOrder, segmentT);
					c[1] += getY(i + startIndex) * bernstein(i, segmentOrder, segmentT);
				}
			}
			return c;
		}

		/**
		 * Draws the full Bezier curve to the graphics context.
		 */
		public void draw() {
			Image hitCircle = GameImage.HITCIRCLE.getImage();
			Image hitCircleOverlay = GameImage.HITCIRCLE_OVERLAY.getImage();

			// draw overlay and hit circle
			for (int i = curveX.length - 1; i >= 0; i--)
				Utils.drawCentered(hitCircleOverlay, curveX[i], curveY[i], Utils.COLOR_WHITE_FADE);
			for (int i = curveX.length - 1; i >= 0; i--)
				Utils.drawCentered(hitCircle, curveX[i], curveY[i], color);
		}
	}

	/**
	 * Initializes the Slider data type with images and dimensions.
	 * @param container the game container
	 * @param circleSize the map's circleSize value
	 * @param osu the associated OsuFile object
	 */
	public static void init(GameContainer container, float circleSize, OsuFile osu) {
		int diameter = (int) (96 - (circleSize * 8));
		diameter = diameter * container.getWidth() / 640;  // convert from Osupixels (640x480)

		// slider ball
		Image[] sliderBallImages;
		if (GameImage.SLIDER_BALL.hasSkinImages() ||
		    (!GameImage.SLIDER_BALL.hasSkinImage() && GameImage.SLIDER_BALL.getImages() != null))
			sliderBallImages = GameImage.SLIDER_BALL.getImages();
		else
			sliderBallImages = new Image[]{ GameImage.SLIDER_BALL.getImage() };
		for (int i = 0; i < sliderBallImages.length; i++)
			sliderBallImages[i] = sliderBallImages[i].getScaledCopy(diameter * 118 / 128, diameter * 118 / 128);
		sliderBall = new Animation(sliderBallImages, 60);

		GameImage.SLIDER_FOLLOWCIRCLE.setImage(GameImage.SLIDER_FOLLOWCIRCLE.getImage().getScaledCopy(diameter * 259 / 128, diameter * 259 / 128));
		GameImage.REVERSEARROW.setImage(GameImage.REVERSEARROW.getImage().getScaledCopy(diameter, diameter));
		GameImage.SLIDER_TICK.setImage(GameImage.SLIDER_TICK.getImage().getScaledCopy(diameter / 4, diameter / 4));

		sliderMultiplier = osu.sliderMultiplier;
		sliderTickRate = osu.sliderTickRate;
	}

	/**
	 * Constructor.
	 * @param hitObject the associated OsuHitObject
	 * @param game the associated Game object
	 * @param data the associated GameData object
	 * @param color the color of this circle
	 * @param comboEnd true if this is the last hit object in the combo
	 */
	public Slider(OsuHitObject hitObject, Game game, GameData data, Color color, boolean comboEnd) {
		this.hitObject = hitObject;
		this.game = game;
		this.data = data;
		this.color = color;
		this.comboEnd = comboEnd;

		this.bezier = new Bezier();
	}

	@Override
	public void draw(int trackPosition, boolean currentObject, Graphics g) {
		float x = hitObject.getX(), y = hitObject.getY();
		float[] sliderX = hitObject.getSliderX(), sliderY = hitObject.getSliderY();
		int timeDiff = hitObject.getTime() - trackPosition;

		float approachScale = (timeDiff >= 0) ? 1 + (timeDiff * 2f / game.getApproachTime()) : 1f;
		float alpha = (approachScale > 3.3f) ? 0f : 1f - (approachScale - 1f) / 2.7f;
		float oldAlpha = color.a;
		float oldAlphaFade = Utils.COLOR_WHITE_FADE.a;
		color.a = alpha;
		Utils.COLOR_WHITE_FADE.a = alpha;

		// bezier
		bezier.draw();

		// ticks
		if (currentObject && ticksT != null) {
			Image tick = GameImage.SLIDER_TICK.getImage();
			for (int i = 0; i < ticksT.length; i++) {
				float[] c = bezier.pointAt(ticksT[i]);
				tick.drawCentered(c[0], c[1]);
			}
		}

		Image hitCircleOverlay = GameImage.HITCIRCLE_OVERLAY.getImage();
		Image hitCircle = GameImage.HITCIRCLE.getImage();

		// end circle
		int lastIndex = sliderX.length - 1;
		Utils.drawCentered(hitCircleOverlay, sliderX[lastIndex], sliderY[lastIndex], Utils.COLOR_WHITE_FADE);
		Utils.drawCentered(hitCircle, sliderX[lastIndex], sliderY[lastIndex], color);

		// start circle
		Utils.drawCentered(hitCircleOverlay, x, y, Utils.COLOR_WHITE_FADE);
		Utils.drawCentered(hitCircle, x, y, color);
		if (sliderClicked)
			;  // don't draw current combo number if already clicked
		else
			data.drawSymbolNumber(hitObject.getComboNumber(), x, y,
					hitCircle.getWidth() * 0.40f / data.getDefaultSymbolImage(0).getHeight());

		color.a = oldAlpha;
		Utils.COLOR_WHITE_FADE.a = oldAlphaFade;

		// repeats
		if (hitObject.getRepeatCount() - 1 > currentRepeats) {
			Image arrow = GameImage.REVERSEARROW.getImage();
			arrow.setAlpha(alpha);
			if (currentRepeats % 2 == 0) {  // last circle
				arrow.setRotation(bezier.getEndAngle());
				arrow.drawCentered(sliderX[lastIndex], sliderY[lastIndex]);
			} else {  // first circle
				arrow.setRotation(bezier.getStartAngle());
				arrow.drawCentered(x, y);
			}
			arrow.setAlpha(1f);
		}

		if (timeDiff >= 0) {
			// approach circle
			Utils.drawCentered(GameImage.APPROACHCIRCLE.getImage().getScaledCopy(approachScale), x, y, color);
		} else {
			float[] c = bezier.pointAt(getT(trackPosition, false));

			// slider ball
			Utils.drawCentered(sliderBall, c[0], c[1]);

			// follow circle
			if (followCircleActive)
				GameImage.SLIDER_FOLLOWCIRCLE.getImage().drawCentered(c[0], c[1]);
		}
	}

	/**
	 * Calculates the slider hit result.
	 * @param time the hit object time (difference between track time)
	 * @param lastCircleHit true if the cursor was held within the last circle
	 * @return the hit result (GameData.HIT_* constants)
	 */
	private int hitResult() {
		int lastIndex = hitObject.getSliderX().length - 1;
		float tickRatio = (float) ticksHit / tickIntervals;

		int result;
		if (tickRatio >= 1.0f)
			result = GameData.HIT_300;
		else if (tickRatio >= 0.5f)
			result = GameData.HIT_100;
		else if (tickRatio > 0f)
			result = GameData.HIT_50;
		else
			result = GameData.HIT_MISS;

		if (currentRepeats % 2 == 0)  // last circle
			data.hitResult(hitObject.getTime() + (int) sliderTimeTotal, result,
					hitObject.getSliderX()[lastIndex], hitObject.getSliderY()[lastIndex],
					color, comboEnd, hitObject.getHitSoundType());
		else  // first circle
			data.hitResult(hitObject.getTime() + (int) sliderTimeTotal, result,
					hitObject.getX(), hitObject.getY(), color, comboEnd, hitObject.getHitSoundType());

		return result;
	}

	@Override
	public boolean mousePressed(int x, int y) {
		if (sliderClicked)  // first circle already processed
			return false;

		double distance = Math.hypot(hitObject.getX() - x, hitObject.getY() - y);
		int circleRadius = GameImage.HITCIRCLE.getImage().getWidth() / 2;
		if (distance < circleRadius) {
			int trackPosition = MusicController.getPosition();
			int timeDiff = Math.abs(trackPosition - hitObject.getTime());
			int[] hitResultOffset = game.getHitResultOffsets();

			int result = -1;
			if (timeDiff < hitResultOffset[GameData.HIT_50]) {
				result = GameData.HIT_SLIDER30;
				ticksHit++;
			} else if (timeDiff < hitResultOffset[GameData.HIT_MISS])
				result = GameData.HIT_MISS;
			//else not a hit

			if (result > -1) {
				sliderClicked = true;
				data.sliderTickResult(hitObject.getTime(), result,
						hitObject.getX(), hitObject.getY(), hitObject.getHitSoundType());
				return true;
			}
		}
		return false;
	}

	@Override
	public boolean update(boolean overlap, int delta, int mouseX, int mouseY) {
		int repeatCount = hitObject.getRepeatCount();

		// slider time and tick calculations
		if (sliderTimeTotal == 0f) {
			// slider time
			this.sliderTime = game.getBeatLength() * (hitObject.getPixelLength() / sliderMultiplier) / 100f;
			this.sliderTimeTotal = sliderTime * repeatCount;

			// ticks
			float tickLengthDiv = 100f * sliderMultiplier / sliderTickRate / game.getTimingPointMultiplier();
			int tickCount = (int) Math.ceil(hitObject.getPixelLength() / tickLengthDiv) - 1;
			if (tickCount > 0) {
				this.ticksT = new float[tickCount];
				float tickTOffset = 1f / (tickCount + 1);
				float t = tickTOffset;
				for (int i = 0; i < tickCount; i++, t += tickTOffset)
					ticksT[i] = t;
			}
		}

		byte hitSound = hitObject.getHitSoundType();
		int trackPosition = MusicController.getPosition();
		int[] hitResultOffset = game.getHitResultOffsets();
		int lastIndex = hitObject.getSliderX().length - 1;
		boolean isAutoMod = GameMod.AUTO.isActive();

		if (!sliderClicked) {
			int time = hitObject.getTime();

			// start circle time passed
			if (trackPosition > time + hitResultOffset[GameData.HIT_50]) {
				sliderClicked = true;
				if (isAutoMod) {  // "auto" mod: catch any missed notes due to lag
					ticksHit++;
					data.sliderTickResult(time, GameData.HIT_SLIDER30,
							hitObject.getX(), hitObject.getY(), hitSound);
				} else
					data.sliderTickResult(time, GameData.HIT_MISS,
							hitObject.getX(), hitObject.getY(), hitSound);
			}

			// "auto" mod: send a perfect hit result
			else if (isAutoMod) {
				if (Math.abs(trackPosition - time) < hitResultOffset[GameData.HIT_300]) {
					ticksHit++;
					sliderClicked = true;
					data.sliderTickResult(time, GameData.HIT_SLIDER30,
							hitObject.getX(), hitObject.getY(), hitSound);
				}
			}
		}

		// end of slider
		if (overlap || trackPosition > hitObject.getTime() + sliderTimeTotal) {
			tickIntervals++;

			// "auto" mod: send a perfect hit result
			if (isAutoMod)
				ticksHit++;

			// check if cursor pressed and within end circle
			else if (Utils.isGameKeyPressed()) {
				float[] c = bezier.pointAt(getT(trackPosition, false));
				double distance = Math.hypot(c[0] - mouseX, c[1] - mouseY);
				int followCircleRadius = GameImage.SLIDER_FOLLOWCIRCLE.getImage().getWidth() / 2;
				if (distance < followCircleRadius)
					ticksHit++;
			}

			// calculate and send slider result
			hitResult();
			return true;
		}

		// repeats
		boolean isNewRepeat = false;
		if (repeatCount - 1 > currentRepeats) {
			float t = getT(trackPosition, true);
			if (Math.floor(t) > currentRepeats) {
				currentRepeats++;
				tickIntervals++;
				isNewRepeat = true;
			}
		}

		// ticks
		boolean isNewTick = false;
		if (ticksT != null &&
			tickIntervals < (ticksT.length * (currentRepeats + 1)) + repeatCount &&
			tickIntervals < (ticksT.length * repeatCount) + repeatCount) {
			float t = getT(trackPosition, true);
			if (t - Math.floor(t) >= ticksT[tickIndex]) {
				tickIntervals++;
				tickIndex = (tickIndex + 1) % ticksT.length;
				isNewTick = true;
			}
		}

		// holding slider...
		float[] c = bezier.pointAt(getT(trackPosition, false));
		double distance = Math.hypot(c[0] - mouseX, c[1] - mouseY);
		int followCircleRadius = GameImage.SLIDER_FOLLOWCIRCLE.getImage().getWidth() / 2;
		if ((Utils.isGameKeyPressed() && distance < followCircleRadius) || isAutoMod) {
			// mouse pressed and within follow circle
			followCircleActive = true;
			data.changeHealth(delta * GameData.HP_DRAIN_MULTIPLIER);

			// held during new repeat
			if (isNewRepeat) {
				ticksHit++;
				if (currentRepeats % 2 > 0)  // last circle
					data.sliderTickResult(trackPosition, GameData.HIT_SLIDER30,
							hitObject.getSliderX()[lastIndex], hitObject.getSliderY()[lastIndex], hitSound);
				else  // first circle
					data.sliderTickResult(trackPosition, GameData.HIT_SLIDER30,
							c[0], c[1], hitSound);
			}

			// held during new tick
			if (isNewTick) {
				ticksHit++;
				data.sliderTickResult(trackPosition, GameData.HIT_SLIDER10,
						c[0], c[1], (byte) -1);
			}
		} else {
			followCircleActive = false;

			if (isNewRepeat)
				data.sliderTickResult(trackPosition, GameData.HIT_MISS, 0, 0, (byte) -1);
			if (isNewTick)
				data.sliderTickResult(trackPosition, GameData.HIT_MISS, 0, 0, (byte) -1);
		}

		return false;
	}

	/**
	 * Returns the t value based on the given track position.
	 * @param trackPosition the current track position
	 * @param raw if false, ensures that the value lies within [0, 1] by looping repeats
	 * @return the t value: raw [0, repeats] or looped [0, 1]
	 */
	private float getT(int trackPosition, boolean raw) {
		float t = (trackPosition - hitObject.getTime()) / sliderTime;
		if (raw)
			return t;
		else {
			float floor = (float) Math.floor(t);
			return (floor % 2 == 0) ? t - floor : floor + 1 - t;
		}
	}
}