Implemented "Flashlight" mod.

- Restricted view area using alpha maps and offscreen drawing. (credits: davedes)
- Added silver grades.

Signed-off-by: Jeffrey Han <itdelatrisu@gmail.com>

src/itdelatrisu/opsu/objects/Slider.java

@@ -94,6 +94,9 @@ public class Slider implements HitObject {
 	/** Number of ticks hit and tick intervals so far. */
 	private int ticksHit = 0, tickIntervals = 1;
 
+	/** Container dimensions. */
+	private static int containerWidth, containerHeight;
+
 	/**
 	 * Initializes the Slider data type with images and dimensions.
 	 * @param container the game container
@@ -101,6 +104,9 @@ public class Slider implements HitObject {
 	 * @param osu the associated OsuFile object
 	 */
 	public static void init(GameContainer container, float circleSize, OsuFile osu) {
+		containerWidth = container.getWidth();
+		containerHeight = container.getHeight();
+
 		int diameter = (int) (104 - (circleSize * 8));
 		diameter = (int) (diameter * OsuHitObject.getXMultiplier());  // convert from Osupixels (640x480)
 
@@ -192,7 +198,7 @@ public class Slider implements HitObject {
 		color.a = oldAlpha;
 
 		// repeats
-		for(int tcurRepeat = currentRepeats; tcurRepeat<=currentRepeats+1; tcurRepeat++){
+		for (int tcurRepeat = currentRepeats; tcurRepeat <= currentRepeats + 1; tcurRepeat++) {
 			if (hitObject.getRepeatCount() - 1 > tcurRepeat) {
 				Image arrow = GameImage.REVERSEARROW.getImage();
 				if (tcurRepeat != currentRepeats) {
@@ -232,8 +238,18 @@ public class Slider implements HitObject {
 			sliderBallFrame.drawCentered(c[0], c[1]);
 
 			// follow circle
-			if (followCircleActive)
+			if (followCircleActive) {
 				GameImage.SLIDER_FOLLOWCIRCLE.getImage().drawCentered(c[0], c[1]);
+
+				// "flashlight" mod: dim the screen
+				if (GameMod.FLASHLIGHT.isActive()) {
+					float oldAlphaBlack = Utils.COLOR_BLACK_ALPHA.a;
+					Utils.COLOR_BLACK_ALPHA.a = 0.75f;
+					g.setColor(Utils.COLOR_BLACK_ALPHA);
+					g.fillRect(0, 0, containerWidth, containerHeight);
+					Utils.COLOR_BLACK_ALPHA.a = oldAlphaBlack;
+				}
+			}
 		}
 	}