Reputation: 1934
Android bitmap animation
I am adding bitmap animations into my simple 2D android game engine(if you can call it one yet.. :D) and I am facing problem of cycling through frames at pre defined FPS/rate.
What I have done for now is simply use System to get currentTimeMillis and use it as reference but I am pretty sure that's not the best decision.. I was thinking I could pass current frame to the drawing method and use that to the drawing method.
Currently I have object that you get the drawable from and I use it on renderer like this:
canvas.drawBitmap(animation.getDrawable(), (int)x, (int)y, null);
and getDrawable() returns current frame of the animation or the only frame if its still image and heres the code
if(frames.size() > 1) {
long current = System.currentTimeMillis();
if (currentFrame == frames.size() - 1 && frameDirection == 1) {
frameDirection = -1;
} else if (currentFrame == 0 && frameDirection == -1) {
frameDirection = 1;
}
if ((current - lastFrame) > delay) {
currentFrame += frameDirection;
lastFrame = current;
}
}
return frames.get(currentFrame);
and in my eyes that just looks so bad and unefficient.. What can I do about this? Is the only way to go passing current frame to getDrawable or how should this be done?
Upvotes: 0
Views: 1913
Answers (1)
Reputation: 9599
If I understand this right, you want to create an animation class for you game engine?
In my Game Engine I've got a class called SpriteSheetAnimation, which basically iterates through every frame of the animation when the update method is called - I'm sure you'll understand the logic behind it and you'll find a way to use it:
public class SpriteSheetAnimation extends GameObjectTemplate {
int animationSheetLength;
int animationSheetHeight;
int columns;
int rows;
Rect srcRect;
int left;
int bottom;
int lengthOfSpriteInSheet;
int heightOfSpriteInSheet;
boolean repeatAnimation;
boolean animationCompleted;
boolean animationStarted;
Bitmap bitmap;
/**
* You input a bitmap and the number of sprites (by defining the number of rows and columns), and this class will
* take care of animating the sheet.
*
*/
public SpriteSheetAnimation(WorldTemplate world, Bitmap animationSheet, int amountOfRows, int amountOfColumns) {
super(world);
this.animationSheetLength = animationSheet.getWidth();
this.animationSheetHeight = animationSheet.getHeight();
this.columns = amountOfColumns;
this.rows = amountOfRows;
this.lengthOfSpriteInSheet = this.animationSheetLength/this.columns;
this.heightOfSpriteInSheet = this.animationSheetHeight/this.rows;
srcRect = new Rect();
left = 0;
bottom = this.heightOfSpriteInSheet;
repeatAnimation = false;
animationCompleted = false;
animationStarted = false;
this.bitmap = animationSheet;
this.drawShapesOfSprites = true;
this.gameObjectShape.addRectangle(new Rect(0, 0, 0 + this.heightOfSpriteInSheet, 0 + this.lengthOfSpriteInSheet));
}
@Override
public void defineGameObjectPositionShape() {
this.gameObjectShape.addRectangle(new Rect());
}
/**
* <b><i>public Rect getSrcRect()</i></b>
* <br>
* Since: API 1
* <br>
* <br>
* Retrieve the rect that will cover the current source of the sheet.
*
* @return
* The current rect that will cover the current source of the sheet.
*
*/
public Rect getSrcRect() {
return srcRect;
}
/**
* <b><i>public Rect getDstRect()</i></b>
* <br>
* Since: API 1
* <br>
* <br>
* Retrieve the rect where the bitmap will be scaled to fit into.
*
* @return
* The current rect where the bitmap will be scaled to fit into.
*
*/
public Rect getDstRect() {
return this.getGameObjectPositionRect();
}
/**
* <b><i>public void repeatAnimation(boolean repetition)</i></b>
* <br>
* Since: API 1
* <br>
* <br>
* This method will set if the animation should be repeated or not.
*
* @param state
* <br><br>
* 1. True = The animation will repeat once completed and keep on doing so.
* <br><br>
* 2. False = The animation will play only once.
*
*
*/
public void repeatAnimation(boolean repetition) {
this.repeatAnimation = repetition;
}
/**
* <b><i>public boolean isAnimationFinished()</i></b>
* <br>
* Since: API 1
* <br>
* <br>
* Retrieve if the animation has finished.
*
* @return
* If the animation has finished.
*
*/
public boolean isAnimationFinished() {
return animationCompleted;
}
/**
* <b><i>public boolean hasBeenStarted()</i></b>
* <br>
* Since: API 1
* <br>
* <br>
* Retrieve if the animation has started.
*
* @return
* If the animation has started.
*
*/
public boolean hasBeenStarted() {
return animationStarted;
}
/**
* <b><i>public void render()</i></b>
* <br>
* Since: API 1
* <br>
* <br>
* This method will render the animation (the current picture of the sheet).
*
*/
public void render() {
world.game.getGraphics().getCanvasGameScreen().drawBitmap(this.bitmap, this.getSrcRect(), this.getGameObjectPositionRect(), null);
}
/**
* <b><i>public void update()</i></b>
* <br>
* Since: API 1
* <br>
* <br>
* This method will update the animation.
*
*/
@Override
public void update() {
// Every update will advance to the next frame of the animation
// Set if animation has started
if(!animationStarted) {
animationStarted = true;
}
// Set the frame
srcRect.set(left, (bottom - this.heightOfSpriteInSheet), (left + this.lengthOfSpriteInSheet), bottom);
// Change the location, so the next time the frame is set, it will be set accordingly
left = left + this.lengthOfSpriteInSheet;
if(left == this.animationSheetLength && bottom == this.animationSheetHeight) {
if(repeatAnimation == true) {
left = 0;
bottom = 0;
}
else {
animationCompleted = true;
}
}
if(left == this.animationSheetLength) {
bottom = bottom + this.heightOfSpriteInSheet;
left = 0;
}
}
}
I hope this helps you and gets you started.
Upvotes: 1