Added methods to check for transparent pixels in images.

This is currently being used for the logo/play/exit buttons in the main menu.

Also fixed bug where mod multipliers weren't being read.

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

src/itdelatrisu/opsu/GameMod.java

@@ -226,7 +226,7 @@ public enum GameMod {
 	 */
 	GameMod(Category category, int categoryIndex, GameImage image, String abbrev,
 			int bit, int key, float multiplier, String description) {
-		this(category, categoryIndex, image, abbrev, bit, key, 1f, true, description);
+		this(category, categoryIndex, image, abbrev, bit, key, multiplier, true, description);
 	}
 
 	/**
@@ -355,16 +355,6 @@ public enum GameMod {
 	 */
 	public boolean contains(float x, float y) { return button.contains(x, y); }
 
-	/**
-	 * Returns the center x coordinate of the button.
-	 */
-	public float getButtonX() { return button.getX(); }
-
-	/**
-	 * Returns the center y coordinate of the button.
-	 */
-	public float getButtonY() { return button.getY(); }
-
 	/**
 	 * Resets the hover fields for the button.
 	 */
@@ -378,4 +368,12 @@ public enum GameMod {
 	 * @param y the y coordinate
 	 */
 	public void hoverUpdate(int delta, float x, float y) { button.hoverUpdate(delta, x, y); }
+
+	/**
+	 * Updates the scale of the button depending on whether or not the cursor
+	 * is hovering over the button.
+	 * @param delta the delta interval
+	 * @param isHover true if the cursor is currently hovering over the button
+	 */
+	public void hoverUpdate(int delta, boolean isHover) { button.hoverUpdate(delta, isHover); }
 }

src/itdelatrisu/opsu/MenuButton.java

@@ -242,6 +242,24 @@ public class MenuButton {
 				(cy > y - yRadius && cy < y + yRadius));
 	}
 
+	/**
+	 * Returns true if the coordinates are within the button bounds and the
+	 * pixel at the specified location has an alpha level above the given bound.
+	 * @param cx the x coordinate
+	 * @param cy the y coordinate
+	 * @param alpha the alpha level lower bound
+	 */
+	public boolean contains(float cx, float cy, float alpha) {
+		Image image = this.img;
+		if (image == null)
+			image = anim.getCurrentFrame();
+		float xRad = img.getWidth() / 2f, yRad = img.getHeight() / 2f;
+
+		return ((cx > x - xRad && cx < x + xRad) &&
+				(cy > y - yRad && cy < y + yRad) &&
+				image.getAlphaAt((int) (cx - (x - xRad)), (int) (cy - (y - yRad))) > alpha);
+	}
+
 	/**
 	 * Resets the hover fields for the button.
 	 */
@@ -325,9 +343,31 @@ public class MenuButton {
 	 * @param cy the y coordinate
 	 */
 	public void hoverUpdate(int delta, float cx, float cy) {
+		hoverUpdate(delta, contains(cx, cy));
+	}
+
+	/**
+	 * Processes a hover action depending on whether or not the cursor
+	 * is hovering over the button, only if the specified pixel of the
+	 * image has an alpha level above the given bound.
+	 * @param delta the delta interval
+	 * @param cx the x coordinate
+	 * @param cy the y coordinate
+	 * @param alpha the alpha level lower bound
+	 */
+	public void hoverUpdate(int delta, float cx, float cy, float alpha) {
+		hoverUpdate(delta, contains(cx, cy, alpha));
+	}
+
+	/**
+	 * Processes a hover action depending on whether or not the cursor
+	 * is hovering over the button.
+	 * @param delta the delta interval
+	 * @param isHover true if the cursor is currently hovering over the button
+	 */
+	public void hoverUpdate(int delta, boolean isHover) {
 		if (hoverEffect == 0)
 			return;
-		boolean isHover = contains(cx, cy);
 
 		// scale the button
 		if ((hoverEffect & EFFECT_EXPAND) > 0) {

src/itdelatrisu/opsu/states/ButtonMenu.java

@@ -179,12 +179,8 @@ public class ButtonMenu extends BasicGameState {
 			@Override
 			public void update(GameContainer container, int delta, int mouseX, int mouseY) {
 				super.update(container, delta, mouseX, mouseY);
-				for (GameMod mod : GameMod.values()) {
+				for (GameMod mod : GameMod.values())
-					if (mod.isActive())
+					mod.hoverUpdate(delta, mod.isActive());
-						mod.hoverUpdate(delta, mod.getButtonX(), mod.getButtonY());
-					else
-						mod.hoverUpdate(delta, -1, -1);
-				}
 			}
 
 			@Override

src/itdelatrisu/opsu/states/MainMenu.java

@@ -267,9 +267,9 @@ public class MainMenu extends BasicGameState {
 		Utils.updateCursor(delta);
 		Utils.updateVolumeDisplay(delta);
 		int mouseX = input.getMouseX(), mouseY = input.getMouseY();
-		logo.hoverUpdate(delta, mouseX, mouseY);
+		logo.hoverUpdate(delta, mouseX, mouseY, 0.25f);
-		playButton.hoverUpdate(delta, mouseX, mouseY);
+		playButton.hoverUpdate(delta, mouseX, mouseY, 0.25f);
-		exitButton.hoverUpdate(delta, mouseX, mouseY);
+		exitButton.hoverUpdate(delta, mouseX, mouseY, 0.25f);
 		if (repoButton != null)
 			repoButton.hoverUpdate(delta, mouseX, mouseY);
 		downloadsButton.hoverUpdate(delta, mouseX, mouseY);
@@ -337,11 +337,11 @@ public class MainMenu extends BasicGameState {
 			throws SlickException {
 		// reset button hover states if mouse is not currently hovering over the button
 		int mouseX = input.getMouseX(), mouseY = input.getMouseY();
-		if (!logo.contains(mouseX, mouseY))
+		if (!logo.contains(mouseX, mouseY, 0.25f))
 			logo.resetHover();
-		if (!playButton.contains(mouseX, mouseY))
+		if (!playButton.contains(mouseX, mouseY, 0.25f))
 			playButton.resetHover();
-		if (!exitButton.contains(mouseX, mouseY))
+		if (!exitButton.contains(mouseX, mouseY, 0.25f))
 			exitButton.resetHover();
 		if (!musicPlay.contains(mouseX, mouseY))
 			musicPlay.resetHover();
@@ -418,7 +418,7 @@ public class MainMenu extends BasicGameState {
 
 		// start moving logo (if clicked)
 		else if (!logoClicked) {
-			if (logo.contains(x, y)) {
+			if (logo.contains(x, y, 0.25f)) {
 				logoClicked = true;
 				logoTimer = 0;
 				playButton.getImage().setAlpha(0f);
@@ -429,10 +429,10 @@ public class MainMenu extends BasicGameState {
 
 		// other button actions (if visible)
 		else if (logoClicked) {
-			if (logo.contains(x, y) || playButton.contains(x, y)) {
+			if (logo.contains(x, y, 0.25f) || playButton.contains(x, y, 0.25f)) {
 				SoundController.playSound(SoundEffect.MENUHIT);
 				game.enterState(Opsu.STATE_SONGMENU, new FadeOutTransition(Color.black), new FadeInTransition(Color.black));
-			} else if (exitButton.contains(x, y))
+			} else if (exitButton.contains(x, y, 0.25f))
 				container.exit();
 		}
 	}

src/org/newdawn/slick/Image.java

@@ -1408,6 +1408,36 @@ public class Image implements Renderable {
 		}
 	}
 
+	/**
+	 * Get the alpha value of a pixel at a specified location in this image,
+	 * or 1f if the image does not support transparency.
+	 * 
+	 * @param x The x coordinate of the pixel
+	 * @param y The y coordinate of the pixel
+	 * @return The alpha level of the pixel at the specified location
+	 */
+	public float getAlphaAt(int x, int y) {
+		if (!texture.hasAlpha())
+			return 1f;
+
+		if (pixelData == null)
+			pixelData = texture.getTextureData();
+
+		// scale coordinates based on the image scale
+		x = x * texture.getImageWidth() / width;
+		y = y * texture.getImageHeight() / height;
+
+		int xo = (int) (textureOffsetX * texture.getTextureWidth());
+		int yo = (int) (textureOffsetY * texture.getTextureHeight());
+
+		x = (textureWidth < 0) ? xo - x : xo + x;
+		y = (textureHeight < 0) ? yo - y : yo + y;
+
+		int offset = x + (y * texture.getTextureWidth());
+		offset *= 4;
+		return (offset + 3 >= pixelData.length) ? 1f : translate(pixelData[offset + 3]) / 255f;
+	}
+	
 	/**
 	 * Check if this image has been destroyed
 	 *