状态添加Android游戏开发十日通（4）-行走，跳跃，碰撞检测
发一下牢骚和主题无关：
设假游戏渲染的是60FPS， 那么一帧的持续时光就是1/60s = 0.016 s。
textures.png format: RGBA8888 filter: Nearest,Nearest repeat: none block rotate: false xy: 1, 11 size: 48, 48 orig: 48, 48 offset: 0, 0 index: -1 bob-01 rotate: false xy: 51, 31 size: 24, 28 orig: 24, 28 offset: 0, 0 index: -1 /*..omit..*/
package com.me.testgdxgame.model; import com.badlogic.gdx.math.Rectangle; import com.badlogic.gdx.math.Vector2; public class Bob { public enum State { IDLE, WALKING, JUMPING, DYING } public static final float SPEED = 4f; // unit per second static final float JUMP_VELOCITY = 1f; public static final float SIZE = 0.5f; // half a unit Vector2 position = new Vector2(); Vector2 acceleration = new Vector2(); Vector2 velocity = new Vector2(); Rectangle bounds = new Rectangle(); State state = State.IDLE; boolean facingLeft = true; float stateTime = 0; public Bob(Vector2 position) { this.position = position; this.bounds.height = SIZE; this.bounds.width = SIZE; } public boolean isFacingLeft() { return facingLeft; } public void setFacingLeft(boolean facingLeft) { this.facingLeft = facingLeft; } public Vector2 getPosition() { return position; } public Vector2 getAcceleration() { return acceleration; } public Vector2 getVelocity() { return velocity; } public Rectangle getBounds() { return bounds; } public State getState() { return state; } public void setState(State newState) { this.state = newState; } public float getStateTime() { return stateTime; } public void update(float delta) { stateTime += delta; position.add(velocity.cpy().mul(delta)); } }
package com.me.testgdxgame.view; import com.me.testgdxgame.*; import com.me.testgdxgame.model.Block; import com.me.testgdxgame.model.Bob; import com.me.testgdxgame.model.Bob.State; import com.me.testgdxgame.model.World; import com.badlogic.gdx.Gdx; import com.badlogic.gdx.graphics.Color; import com.badlogic.gdx.graphics.GL10; import com.badlogic.gdx.graphics.OrthographicCamera; import com.badlogic.gdx.graphics.Texture; import com.badlogic.gdx.graphics.g2d.Animation; import com.badlogic.gdx.graphics.g2d.SpriteBatch; import com.badlogic.gdx.graphics.g2d.TextureAtlas; import com.badlogic.gdx.graphics.g2d.TextureRegion; import com.badlogic.gdx.graphics.glutils.ShapeRenderer; import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType; import com.badlogic.gdx.math.Rectangle; public class WorldRenderer { private World world; private OrthographicCamera cam; private static final float RUNNING_FRAME_DURATION = 0.06f; private SpriteBatch spriteBatch; private boolean debug=false; private int width; private int height; private float ppuX; // pixels per unit on the X axis private float ppuY; // pixels per unit on the Y axis private static final float CAMERA_WIDTH = 10f; private static final float CAMERA_HEIGHT = 7f; /** Textures **/ private TextureRegion bobIdleLeft; private TextureRegion bobIdleRight; private TextureRegion blockTexture; private TextureRegion bobFrame; /** Animations **/ private Animation walkLeftAnimation; private Animation walkRightAnimation; /** for debug rendering **/ ShapeRenderer debugRenderer = new ShapeRenderer(); public WorldRenderer(World world) { this.world = world; this.cam = new OrthographicCamera(10, 7); this.cam.position.set(5, 3.5f, 0); this.cam.update(); spriteBatch=new SpriteBatch(); loadTextures(); } public void setSize (int w, int h) { this.width = w; this.height = h; ppuX = (float)width / CAMERA_WIDTH; ppuY = (float)height / CAMERA_HEIGHT; } private void loadTextures() { TextureAtlas atlas = new TextureAtlas(Gdx.files.internal("images/textures/textures.pack")); bobIdleLeft = atlas.findRegion("bob-01"); bobIdleRight = new TextureRegion(bobIdleLeft); bobIdleRight.flip(true, false); blockTexture = atlas.findRegion("block"); TextureRegion[] walkLeftFrames = new TextureRegion[5]; for (int i = 0; i < 5; i++) { walkLeftFrames[i] = atlas.findRegion("bob-0" + (i + 2)); } walkLeftAnimation = new Animation(RUNNING_FRAME_DURATION, walkLeftFrames); TextureRegion[] walkRightFrames = new TextureRegion[5]; for (int i = 0; i < 5; i++) { walkRightFrames[i] = new TextureRegion(walkLeftFrames[i]); walkRightFrames[i].flip(true, false); } walkRightAnimation = new Animation(RUNNING_FRAME_DURATION, walkRightFrames); } public void render() { spriteBatch.begin(); drawBlocks(); drawBob(); spriteBatch.end(); if(debug) drawDebug(); } private void drawBlocks(){ for (Block block : world.getBlocks()) { spriteBatch.draw(blockTexture, block.getPosition().x * ppuX, block.getPosition().y * ppuY, Block.SIZE * ppuX, Block.SIZE * ppuY); } } private void drawBob(){ Bob bob = world.getBob(); bobFrame = bob.isFacingLeft() ? bobIdleLeft : bobIdleRight; //spriteBatch.draw(bobIdleLeft, bob.getPosition().x * ppuX, bob.getPosition().y * ppuY, Bob.SIZE * ppuX, Bob.SIZE * ppuY); if(bob.getState().equals(State.WALKING)){ bobFrame = bob.isFacingLeft() ? walkLeftAnimation.getKeyFrame(bob.getStateTime(),true):walkRightAnimation.getKeyFrame(bob.getStateTime(),true); } spriteBatch.draw(bobFrame, bob.getPosition().x * ppuX, bob.getPosition().y * ppuY, Bob.SIZE * ppuX, Bob.SIZE * ppuY); } private void drawDebug(){ // render blocks debugRenderer.setProjectionMatrix(cam.combined); debugRenderer.begin(ShapeType.Rectangle); for (Block block : world.getBlocks()) { Rectangle rect = block.getBounds(); float x1 = block.getPosition().x + rect.x; float y1 = block.getPosition().y + rect.y; debugRenderer.setColor(new Color(1, 0, 0, 1)); debugRenderer.rect(x1, y1, rect.width, rect.height); } // render Bob Bob bob = world.getBob(); Rectangle rect = bob.getBounds(); float x1 = bob.getPosition().x + rect.x; float y1 = bob.getPosition().y + rect.y; debugRenderer.setColor(new Color(0, 1, 0, 1)); debugRenderer.rect(x1, y1, rect.width, rect.height); debugRenderer.end(); } }
跑一下mian.java,键盘左键右就能够控制君子跑了。
第必定律：倘物体处于动运状态，或呈等速直线动运，只要没外力作用，物体将持保动运状态，或呈等速直线动运之状态。这定律又称为惯性定律。
第二定律：物体的加速度，与所受的净外力成正比。加速度的方向与净外力的方向同相。即 ；其中，是加速度， 是净外力， 是量质。
第三定律：两个物体的互相作使劲老是小大等相，方向相反，同时涌现或消逝。强版第三定律还外额要求两支作使劲的方向都处于一同直线。
package com.me.testgdxgame.controller; import java.util.HashMap; import java.util.Map; import com.me.testgdxgame.model.Bob; import com.me.testgdxgame.model.Bob.State; import com.me.testgdxgame.model.World; public class WorldController { enum Keys{ LEFT,RIGHT,JUMP,FIRE } private World world; private Bob bob; private long jumpPressedTime; private boolean jumpingPressed; static Map<Keys,Boolean> keys = new HashMap<WorldController.Keys,Boolean>(); static { keys.put(Keys.LEFT, false); keys.put(Keys.RIGHT, false); keys.put(Keys.JUMP, false); keys.put(Keys.FIRE, false); }; private static final long LONG_JUMP_PRESS = 150l; private static final float ACCELERATION = 20f; private static final float GRAVITY = -20f; private static final float MAX_JUMP_SPEED = 7f; private static final float DAMP = 0.8f; private static final float MAX_VEL = 4f; private static final float WIDTH =10f; public WorldController(World w){ world=w; bob=world.getBob(); } //Key presses and touches public void leftPressed(){ keys.get(keys.put(Keys.LEFT, true)); } public void rightPressed() { keys.get(keys.put(Keys.RIGHT, true)); } public void jumpPressed() { keys.get(keys.put(Keys.JUMP, true)); } public void firePressed() { keys.get(keys.put(Keys.FIRE, false)); } public void leftReleased() { keys.get(keys.put(Keys.LEFT, false)); } public void rightReleased() { keys.get(keys.put(Keys.RIGHT, false)); } public void jumpReleased() { keys.get(keys.put(Keys.JUMP, false)); jumpingPressed = false; } public void fireReleased() { keys.get(keys.put(Keys.FIRE, false)); } public void update(float delta){ processInput(); bob.getAcceleration().y = GRAVITY; bob.getAcceleration().mul(delta); bob.getVelocity().add(bob.getAcceleration().x, bob.getAcceleration().y); if (bob.getAcceleration().x == 0) bob.getVelocity().x *= DAMP; if (bob.getVelocity().x > MAX_VEL) { bob.getVelocity().x = MAX_VEL; } if (bob.getVelocity().x < -MAX_VEL) { bob.getVelocity().x = -MAX_VEL; } bob.update(delta); //Set Bob's state to State.IDLE when Bob touch edge if (bob.getPosition().y < 0) { bob.getPosition().y = 0f; bob.setPosition(bob.getPosition()); if (bob.getState().equals(State.JUMPING)) { bob.setState(State.IDLE); } } if (bob.getPosition().x < 0) { bob.getPosition().x = 0; bob.setPosition(bob.getPosition()); if (!bob.getState().equals(State.JUMPING)) { bob.setState(State.IDLE); } } if (bob.getPosition().x > WIDTH - bob.getBounds().width ) { bob.getPosition().x = WIDTH - bob.getBounds().width; bob.setPosition(bob.getPosition()); if (!bob.getState().equals(State.JUMPING)) { bob.setState(State.IDLE); } } } private boolean processInput(){ if (keys.get(Keys.JUMP)) { if (!bob.getState().equals(State.JUMPING)) { jumpingPressed = true; jumpPressedTime = System.currentTimeMillis(); bob.setState(State.JUMPING); bob.getVelocity().y = MAX_JUMP_SPEED; } else { if (jumpingPressed && ((System.currentTimeMillis() - jumpPressedTime) >= LONG_JUMP_PRESS)) { jumpingPressed = false; } else { if (jumpingPressed) { bob.getVelocity().y = MAX_JUMP_SPEED; } } } } if(keys.get(Keys.LEFT)){ bob.setFacingLeft(true); if(!bob.getState().equals(State.JUMPING)){ bob.setState(State.WALKING); } bob.getVelocity().x=-ACCELERATION; }else if (keys.get(Keys.RIGHT)) { // left is pressed bob.setFacingLeft(false); if(!bob.getState().equals(State.JUMPING)){ bob.setState(State.WALKING); } bob.getVelocity().x=ACCELERATION; }else { if(!bob.getState().equals(State.JUMPING)){ bob.setState(State.IDLE); } ; // acceleration is 0 on the x bob.getAcceleration().x = 0; } return false; } }
在WorldRender中还要需添加与跃跳对应的纹理还有修改drawBob数函。
private void loadTextures() { TextureAtlas atlas = new TextureAtlas(Gdx.files.internal("images/textures/textures.pack")); bobJumpLeft = atlas.findRegion("bob-up"); bobJumpRight = new TextureRegion(bobJumpLeft); bobJumpRight.flip(true, false); bobFallLeft=atlas.findRegion("bob-down"); bobFallRight = new TextureRegion(bobFallLeft); bobFallRight.flip(true, false); bobIdleLeft = atlas.findRegion("bob-01"); bobIdleRight = new TextureRegion(bobIdleLeft); bobIdleRight.flip(true, false); blockTexture = atlas.findRegion("block"); TextureRegion[] walkLeftFrames = new TextureRegion[5]; for (int i = 0; i < 5; i++) { walkLeftFrames[i] = atlas.findRegion("bob-0" + (i + 2)); } walkLeftAnimation = new Animation(RUNNING_FRAME_DURATION, walkLeftFrames); TextureRegion[] walkRightFrames = new TextureRegion[5]; for (int i = 0; i < 5; i++) { walkRightFrames[i] = new TextureRegion(walkLeftFrames[i]); walkRightFrames[i].flip(true, false); } walkRightAnimation = new Animation(RUNNING_FRAME_DURATION, walkRightFrames); }
private void drawBob(){ Bob bob = world.getBob(); bobFrame = bob.isFacingLeft() ? bobIdleLeft : bobIdleRight; if(bob.getState().equals(State.WALKING)) { bobFrame = bob.isFacingLeft() ? walkLeftAnimation.getKeyFrame(bob.getStateTime(), true) : walkRightAnimation.getKeyFrame(bob.getStateTime(), true); } else if (bob.getState().equals(State.JUMPING)) { if (bob.getVelocity().y > 0) { bobFrame = bob.isFacingLeft() ? bobJumpLeft : bobJumpRight; } else { bobFrame = bob.isFacingLeft() ? bobFallLeft : bobFallRight; } } spriteBatch.draw(bobFrame, bob.getPosition().x * ppuX, bob.getPosition().y * ppuY, Bob.SIZE * ppuX, Bob.SIZE * ppuY); }
运行一下：
碰撞测检
package com.me.testgdxgame.model; import com.badlogic.gdx.math.Vector2; public class Level { private int width; private int height; private Block[][] blocks; public int getWidth() { return width; } public void setWidth(int width) { this.width = width; } public int getHeight() { return height; } public void setHeight(int height) { this.height = height; } public Block[][] getBlocks() { return blocks; } public void setBlocks(Block[][] blocks) { this.blocks = blocks; } public Level() { loadDemoLevel(); } public Block get(int x, int y) { return blocks[x][y]; } private void loadDemoLevel() { width = 10; height = 7; blocks = new Block[width][height]; for (int col = 0; col < width; col++) { for (int row = 0; row < height; row++) { blocks[col][row] = null; } } for (int col = 0; col < 10; col++) { blocks[col][0] = new Block(new Vector2(col, 0)); blocks[col][6] = new Block(new Vector2(col, 6)); if (col > 2) { blocks[col][1] = new Block(new Vector2(col, 1)); } } blocks[9][2] = new Block(new Vector2(9, 2)); blocks[9][3] = new Block(new Vector2(9, 3)); blocks[9][4] = new Block(new Vector2(9, 4)); blocks[9][5] = new Block(new Vector2(9, 5)); blocks[6][3] = new Block(new Vector2(6, 3)); blocks[6][4] = new Block(new Vector2(6, 4)); blocks[6][5] = new Block(new Vector2(6, 5)); } }
World类做对应的修改：
package com.me.testgdxgame.model; import java.util.ArrayList; import java.util.List; import com.badlogic.gdx.math.Rectangle; import com.badlogic.gdx.math.Vector2; import com.badlogic.gdx.utils.Array; public class World { /** Our player controlled hero **/ Bob bob; /** A world has a level through which Bob needs to go through **/ Level level; /** The collision boxes **/ Array<Rectangle> collisionRects = new Array<Rectangle>(); // Getters ----------- public Array<Rectangle> getCollisionRects() { return collisionRects; } public Bob getBob() { return bob; } public Level getLevel() { return level; } /** Return only the blocks that need to be drawn **/ public List<Block> getDrawableBlocks(int width, int height) { int x = (int)bob.getPosition().x - width; int y = (int)bob.getPosition().y - height; if (x < 0) { x = 0; } if (y < 0) { y = 0; } int x2 = x + 2 * width; int y2 = y + 2 * height; if (x2 > level.getWidth()) { x2 = level.getWidth() - 1; } if (y2 > level.getHeight()) { y2 = level.getHeight() - 1; } List<Block> blocks = new ArrayList<Block>(); Block block; for (int col = x; col <= x2; col++) { for (int row = y; row <= y2; row++) { block = level.getBlocks()[col][row]; if (block != null) { blocks.add(block); } } } return blocks; } // -------------------- public World() { createDemoWorld(); } private void createDemoWorld() { bob = new Bob(new Vector2(7, 2)); level = new Level(); } }
package com.me.testgdxgame.controller; import java.util.HashMap; import java.util.Map; import com.badlogic.gdx.math.Rectangle; import com.badlogic.gdx.utils.Array; import com.badlogic.gdx.utils.Pool; import com.me.testgdxgame.model.Block; import com.me.testgdxgame.model.Bob; import com.me.testgdxgame.model.Bob.State; import com.me.testgdxgame.model.World; public class WorldController { enum Keys { LEFT, RIGHT, JUMP, FIRE } private static final long LONG_JUMP_PRESS = 150l; private static final float ACCELERATION = 20f; private static final float GRAVITY = -20f; private static final float MAX_JUMP_SPEED = 7f; private static final float DAMP = 0.90f; private static final float MAX_VEL = 4f; private World world; private Bob bob; private long jumpPressedTime; private boolean jumpingPressed; private boolean grounded = false; // This is the rectangle pool used in collision detection // Good to avoid instantiation each frame private Pool<Rectangle> rectPool = new Pool<Rectangle>() { @Override protected Rectangle newObject() { return new Rectangle(); } }; static Map<Keys, Boolean> keys = new HashMap<WorldController.Keys, Boolean>(); static { keys.put(Keys.LEFT, false); keys.put(Keys.RIGHT, false); keys.put(Keys.JUMP, false); keys.put(Keys.FIRE, false); }; // Blocks that Bob can collide with any given frame private Array<Block> collidable = new Array<Block>(); public WorldController(World world) { this.world = world; this.bob = world.getBob(); } // ** Key presses and touches **************** // public void leftPressed() { keys.get(keys.put(Keys.LEFT, true)); } public void rightPressed() { keys.get(keys.put(Keys.RIGHT, true)); } public void jumpPressed() { keys.get(keys.put(Keys.JUMP, true)); } public void firePressed() { keys.get(keys.put(Keys.FIRE, false)); } public void leftReleased() { keys.get(keys.put(Keys.LEFT, false)); } public void rightReleased() { keys.get(keys.put(Keys.RIGHT, false)); } public void jumpReleased() { keys.get(keys.put(Keys.JUMP, false)); jumpingPressed = false; } public void fireReleased() { keys.get(keys.put(Keys.FIRE, false)); } /** The main update method **/ public void update(float delta) { // Processing the input - setting the states of Bob processInput(); // If Bob is grounded then reset the state to IDLE if (grounded && bob.getState().equals(State.JUMPING)) { bob.setState(State.IDLE); } // Setting initial vertical acceleration bob.getAcceleration().y = GRAVITY; // Convert acceleration to frame time bob.getAcceleration().mul(delta); // apply acceleration to change velocity bob.getVelocity().add(bob.getAcceleration().x, bob.getAcceleration().y); // checking collisions with the surrounding blocks depending on Bob's velocity checkCollisionWithBlocks(delta); // apply damping to halt Bob nicely bob.getVelocity().x *= DAMP; // ensure terminal velocity is not exceeded if (bob.getVelocity().x > MAX_VEL) { bob.getVelocity().x = MAX_VEL; } if (bob.getVelocity().x < -MAX_VEL) { bob.getVelocity().x = -MAX_VEL; } // simply updates the state time bob.update(delta); } /** Collision checking **/ private void checkCollisionWithBlocks(float delta) { // scale velocity to frame units bob.getVelocity().mul(delta); // Obtain the rectangle from the pool instead of instantiating it Rectangle bobRect = rectPool.obtain(); // set the rectangle to bob's bounding box bobRect.set(bob.getBounds().x, bob.getBounds().y, bob.getBounds().width, bob.getBounds().height); // we first check the movement on the horizontal X axis int startX, endX; int startY = (int) bob.getBounds().y; int endY = (int) (bob.getBounds().y + bob.getBounds().height); // if Bob is heading left then we check if he collides with the block on his left // we check the block on his right otherwise if (bob.getVelocity().x < 0) { startX = endX = (int) Math.floor(bob.getBounds().x + bob.getVelocity().x); } else { startX = endX = (int) Math.floor(bob.getBounds().x + bob.getBounds().width + bob.getVelocity().x); } // get the block(s) bob can collide with populateCollidableBlocks(startX, startY, endX, endY); // simulate bob's movement on the X bobRect.x += bob.getVelocity().x; // clear collision boxes in world world.getCollisionRects().clear(); // if bob collides, make his horizontal velocity 0 for (Block block : collidable) { if (block == null) continue; if (bobRect.overlaps(block.getBounds())) { bob.getVelocity().x = 0; world.getCollisionRects().add(block.getBounds()); break; } } // reset the x position of the collision box bobRect.x = bob.getPosition().x; // the same thing but on the vertical Y axis startX = (int) bob.getBounds().x; endX = (int) (bob.getBounds().x + bob.getBounds().width); if (bob.getVelocity().y < 0) { startY = endY = (int) Math.floor(bob.getBounds().y + bob.getVelocity().y); } else { startY = endY = (int) Math.floor(bob.getBounds().y + bob.getBounds().height + bob.getVelocity().y); } populateCollidableBlocks(startX, startY, endX, endY); bobRect.y += bob.getVelocity().y; for (Block block : collidable) { if (block == null) continue; if (bobRect.overlaps(block.getBounds())) { if (bob.getVelocity().y < 0) { grounded = true; } bob.getVelocity().y = 0; world.getCollisionRects().add(block.getBounds()); break; } } // reset the collision box's position on Y bobRect.y = bob.getPosition().y; // update Bob's position bob.getPosition().add(bob.getVelocity()); bob.getBounds().x = bob.getPosition().x; bob.getBounds().y = bob.getPosition().y; // un-scale velocity (not in frame time) bob.getVelocity().mul(1 / delta); } /** populate the collidable array with the blocks found in the enclosing coordinates **/ private void populateCollidableBlocks(int startX, int startY, int endX, int endY) { collidable.clear(); for (int x = startX; x <= endX; x++) { for (int y = startY; y <= endY; y++) { if (x >= 0 && x < world.getLevel().getWidth() && y >=0 && y < world.getLevel().getHeight()) { collidable.add(world.getLevel().get(x, y)); } } } } /** Change Bob's state and parameters based on input controls **/ private boolean processInput() { if (keys.get(Keys.JUMP)) { if (!bob.getState().equals(State.JUMPING)) { jumpingPressed = true; jumpPressedTime = System.currentTimeMillis(); bob.setState(State.JUMPING); bob.getVelocity().y = MAX_JUMP_SPEED; grounded = false; } else { if (jumpingPressed && ((System.currentTimeMillis() - jumpPressedTime) >= LONG_JUMP_PRESS)) { jumpingPressed = false; } else { if (jumpingPressed) { bob.getVelocity().y = MAX_JUMP_SPEED; } } } } if (keys.get(Keys.LEFT)) { // left is pressed bob.setFacingLeft(true); if (!bob.getState().equals(State.JUMPING)) { bob.setState(State.WALKING); } bob.getAcceleration().x = -ACCELERATION; } else if (keys.get(Keys.RIGHT)) { // left is pressed bob.setFacingLeft(false); if (!bob.getState().equals(State.JUMPING)) { bob.setState(State.WALKING); } bob.getAcceleration().x = ACCELERATION; } else { if (!bob.getState().equals(State.JUMPING)) { bob.setState(State.IDLE); } bob.getAcceleration().x = 0; } return false; } }
运行截图：
总结
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