| /* |
| * Copyright (C) 2007 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.example.android.lunarlander; |
| |
| import android.content.Context; |
| import android.content.res.Resources; |
| import android.graphics.Bitmap; |
| import android.graphics.BitmapFactory; |
| import android.graphics.Canvas; |
| import android.graphics.Paint; |
| import android.graphics.RectF; |
| import android.graphics.drawable.Drawable; |
| import android.os.Bundle; |
| import android.os.Handler; |
| import android.os.Message; |
| import android.util.AttributeSet; |
| import android.view.KeyEvent; |
| import android.view.SurfaceHolder; |
| import android.view.SurfaceView; |
| import android.view.View; |
| import android.widget.TextView; |
| |
| |
| /** |
| * View that draws, takes keystrokes, etc. for a simple LunarLander game. |
| * |
| * Has a mode which RUNNING, PAUSED, etc. Has a x, y, dx, dy, ... capturing the |
| * current ship physics. All x/y etc. are measured with (0,0) at the lower left. |
| * updatePhysics() advances the physics based on realtime. draw() renders the |
| * ship, and does an invalidate() to prompt another draw() as soon as possible |
| * by the system. |
| */ |
| class LunarView extends SurfaceView implements SurfaceHolder.Callback { |
| class LunarThread extends Thread { |
| /* |
| * Difficulty setting constants |
| */ |
| public static final int DIFFICULTY_EASY = 0; |
| public static final int DIFFICULTY_HARD = 1; |
| public static final int DIFFICULTY_MEDIUM = 2; |
| /* |
| * Physics constants |
| */ |
| public static final int PHYS_DOWN_ACCEL_SEC = 35; |
| public static final int PHYS_FIRE_ACCEL_SEC = 80; |
| public static final int PHYS_FUEL_INIT = 60; |
| public static final int PHYS_FUEL_MAX = 100; |
| public static final int PHYS_FUEL_SEC = 10; |
| public static final int PHYS_SLEW_SEC = 120; // degrees/second rotate |
| public static final int PHYS_SPEED_HYPERSPACE = 180; |
| public static final int PHYS_SPEED_INIT = 30; |
| public static final int PHYS_SPEED_MAX = 120; |
| /* |
| * State-tracking constants |
| */ |
| public static final int STATE_LOSE = 1; |
| public static final int STATE_PAUSE = 2; |
| public static final int STATE_READY = 3; |
| public static final int STATE_RUNNING = 4; |
| public static final int STATE_WIN = 5; |
| |
| /* |
| * Goal condition constants |
| */ |
| public static final int TARGET_ANGLE = 18; // > this angle means crash |
| public static final int TARGET_BOTTOM_PADDING = 17; // px below gear |
| public static final int TARGET_PAD_HEIGHT = 8; // how high above ground |
| public static final int TARGET_SPEED = 28; // > this speed means crash |
| public static final double TARGET_WIDTH = 1.6; // width of target |
| /* |
| * UI constants (i.e. the speed & fuel bars) |
| */ |
| public static final int UI_BAR = 100; // width of the bar(s) |
| public static final int UI_BAR_HEIGHT = 10; // height of the bar(s) |
| private static final String KEY_DIFFICULTY = "mDifficulty"; |
| private static final String KEY_DX = "mDX"; |
| |
| private static final String KEY_DY = "mDY"; |
| private static final String KEY_FUEL = "mFuel"; |
| private static final String KEY_GOAL_ANGLE = "mGoalAngle"; |
| private static final String KEY_GOAL_SPEED = "mGoalSpeed"; |
| private static final String KEY_GOAL_WIDTH = "mGoalWidth"; |
| |
| private static final String KEY_GOAL_X = "mGoalX"; |
| private static final String KEY_HEADING = "mHeading"; |
| private static final String KEY_LANDER_HEIGHT = "mLanderHeight"; |
| private static final String KEY_LANDER_WIDTH = "mLanderWidth"; |
| private static final String KEY_WINS = "mWinsInARow"; |
| |
| private static final String KEY_X = "mX"; |
| private static final String KEY_Y = "mY"; |
| |
| /* |
| * Member (state) fields |
| */ |
| /** The drawable to use as the background of the animation canvas */ |
| private Bitmap mBackgroundImage; |
| |
| /** |
| * Current height of the surface/canvas. |
| * |
| * @see #setSurfaceSize |
| */ |
| private int mCanvasHeight = 1; |
| |
| /** |
| * Current width of the surface/canvas. |
| * |
| * @see #setSurfaceSize |
| */ |
| private int mCanvasWidth = 1; |
| |
| /** What to draw for the Lander when it has crashed */ |
| private Drawable mCrashedImage; |
| |
| /** |
| * Current difficulty -- amount of fuel, allowed angle, etc. Default is |
| * MEDIUM. |
| */ |
| private int mDifficulty; |
| |
| /** Velocity dx. */ |
| private double mDX; |
| |
| /** Velocity dy. */ |
| private double mDY; |
| |
| /** Is the engine burning? */ |
| private boolean mEngineFiring; |
| |
| /** What to draw for the Lander when the engine is firing */ |
| private Drawable mFiringImage; |
| |
| /** Fuel remaining */ |
| private double mFuel; |
| |
| /** Allowed angle. */ |
| private int mGoalAngle; |
| |
| /** Allowed speed. */ |
| private int mGoalSpeed; |
| |
| /** Width of the landing pad. */ |
| private int mGoalWidth; |
| |
| /** X of the landing pad. */ |
| private int mGoalX; |
| |
| /** Message handler used by thread to interact with TextView */ |
| private Handler mHandler; |
| |
| /** |
| * Lander heading in degrees, with 0 up, 90 right. Kept in the range |
| * 0..360. |
| */ |
| private double mHeading; |
| |
| /** Pixel height of lander image. */ |
| private int mLanderHeight; |
| |
| /** What to draw for the Lander in its normal state */ |
| private Drawable mLanderImage; |
| |
| /** Pixel width of lander image. */ |
| private int mLanderWidth; |
| |
| /** Used to figure out elapsed time between frames */ |
| private long mLastTime; |
| |
| /** Paint to draw the lines on screen. */ |
| private Paint mLinePaint; |
| |
| /** "Bad" speed-too-high variant of the line color. */ |
| private Paint mLinePaintBad; |
| |
| /** The state of the game. One of READY, RUNNING, PAUSE, LOSE, or WIN */ |
| private int mMode; |
| |
| /** Currently rotating, -1 left, 0 none, 1 right. */ |
| private int mRotating; |
| |
| /** Indicate whether the surface has been created & is ready to draw */ |
| private boolean mRun = false; |
| |
| /** Scratch rect object. */ |
| private RectF mScratchRect; |
| |
| /** Handle to the surface manager object we interact with */ |
| private SurfaceHolder mSurfaceHolder; |
| |
| /** Number of wins in a row. */ |
| private int mWinsInARow; |
| |
| /** X of lander center. */ |
| private double mX; |
| |
| /** Y of lander center. */ |
| private double mY; |
| |
| public LunarThread(SurfaceHolder surfaceHolder, Context context, |
| Handler handler) { |
| // get handles to some important objects |
| mSurfaceHolder = surfaceHolder; |
| mHandler = handler; |
| mContext = context; |
| |
| Resources res = context.getResources(); |
| // cache handles to our key sprites & other drawables |
| mLanderImage = context.getResources().getDrawable( |
| R.drawable.lander_plain); |
| mFiringImage = context.getResources().getDrawable( |
| R.drawable.lander_firing); |
| mCrashedImage = context.getResources().getDrawable( |
| R.drawable.lander_crashed); |
| |
| // load background image as a Bitmap instead of a Drawable b/c |
| // we don't need to transform it and it's faster to draw this way |
| mBackgroundImage = BitmapFactory.decodeResource(res, |
| R.drawable.earthrise); |
| |
| // Use the regular lander image as the model size for all sprites |
| mLanderWidth = mLanderImage.getIntrinsicWidth(); |
| mLanderHeight = mLanderImage.getIntrinsicHeight(); |
| |
| // Initialize paints for speedometer |
| mLinePaint = new Paint(); |
| mLinePaint.setAntiAlias(true); |
| mLinePaint.setARGB(255, 0, 255, 0); |
| |
| mLinePaintBad = new Paint(); |
| mLinePaintBad.setAntiAlias(true); |
| mLinePaintBad.setARGB(255, 120, 180, 0); |
| |
| mScratchRect = new RectF(0, 0, 0, 0); |
| |
| mWinsInARow = 0; |
| mDifficulty = DIFFICULTY_MEDIUM; |
| |
| // initial show-up of lander (not yet playing) |
| mX = mLanderWidth; |
| mY = mLanderHeight * 2; |
| mFuel = PHYS_FUEL_INIT; |
| mDX = 0; |
| mDY = 0; |
| mHeading = 0; |
| mEngineFiring = true; |
| } |
| |
| /** |
| * Starts the game, setting parameters for the current difficulty. |
| */ |
| public void doStart() { |
| synchronized (mSurfaceHolder) { |
| // First set the game for Medium difficulty |
| mFuel = PHYS_FUEL_INIT; |
| mEngineFiring = false; |
| mGoalWidth = (int) (mLanderWidth * TARGET_WIDTH); |
| mGoalSpeed = TARGET_SPEED; |
| mGoalAngle = TARGET_ANGLE; |
| int speedInit = PHYS_SPEED_INIT; |
| |
| // Adjust difficulty params for EASY/HARD |
| if (mDifficulty == DIFFICULTY_EASY) { |
| mFuel = mFuel * 3 / 2; |
| mGoalWidth = mGoalWidth * 4 / 3; |
| mGoalSpeed = mGoalSpeed * 3 / 2; |
| mGoalAngle = mGoalAngle * 4 / 3; |
| speedInit = speedInit * 3 / 4; |
| } else if (mDifficulty == DIFFICULTY_HARD) { |
| mFuel = mFuel * 7 / 8; |
| mGoalWidth = mGoalWidth * 3 / 4; |
| mGoalSpeed = mGoalSpeed * 7 / 8; |
| speedInit = speedInit * 4 / 3; |
| } |
| |
| // pick a convenient initial location for the lander sprite |
| mX = mCanvasWidth / 2; |
| mY = mCanvasHeight - mLanderHeight / 2; |
| |
| // start with a little random motion |
| mDY = Math.random() * -speedInit; |
| mDX = Math.random() * 2 * speedInit - speedInit; |
| mHeading = 0; |
| |
| // Figure initial spot for landing, not too near center |
| while (true) { |
| mGoalX = (int) (Math.random() * (mCanvasWidth - mGoalWidth)); |
| if (Math.abs(mGoalX - (mX - mLanderWidth / 2)) > mCanvasHeight / 6) |
| break; |
| } |
| |
| mLastTime = System.currentTimeMillis() + 100; |
| setState(STATE_RUNNING); |
| } |
| } |
| |
| /** |
| * Pauses the physics update & animation. |
| */ |
| public void pause() { |
| synchronized (mSurfaceHolder) { |
| if (mMode == STATE_RUNNING) setState(STATE_PAUSE); |
| } |
| } |
| |
| /** |
| * Restores game state from the indicated Bundle. Typically called when |
| * the Activity is being restored after having been previously |
| * destroyed. |
| * |
| * @param savedState Bundle containing the game state |
| */ |
| public synchronized void restoreState(Bundle savedState) { |
| synchronized (mSurfaceHolder) { |
| setState(STATE_PAUSE); |
| mRotating = 0; |
| mEngineFiring = false; |
| |
| mDifficulty = savedState.getInt(KEY_DIFFICULTY); |
| mX = savedState.getDouble(KEY_X); |
| mY = savedState.getDouble(KEY_Y); |
| mDX = savedState.getDouble(KEY_DX); |
| mDY = savedState.getDouble(KEY_DY); |
| mHeading = savedState.getDouble(KEY_HEADING); |
| |
| mLanderWidth = savedState.getInt(KEY_LANDER_WIDTH); |
| mLanderHeight = savedState.getInt(KEY_LANDER_HEIGHT); |
| mGoalX = savedState.getInt(KEY_GOAL_X); |
| mGoalSpeed = savedState.getInt(KEY_GOAL_SPEED); |
| mGoalAngle = savedState.getInt(KEY_GOAL_ANGLE); |
| mGoalWidth = savedState.getInt(KEY_GOAL_WIDTH); |
| mWinsInARow = savedState.getInt(KEY_WINS); |
| mFuel = savedState.getDouble(KEY_FUEL); |
| } |
| } |
| |
| @Override |
| public void run() { |
| while (mRun) { |
| Canvas c = null; |
| try { |
| c = mSurfaceHolder.lockCanvas(null); |
| synchronized (mSurfaceHolder) { |
| if (mMode == STATE_RUNNING) updatePhysics(); |
| doDraw(c); |
| } |
| } finally { |
| // do this in a finally so that if an exception is thrown |
| // during the above, we don't leave the Surface in an |
| // inconsistent state |
| if (c != null) { |
| mSurfaceHolder.unlockCanvasAndPost(c); |
| } |
| } |
| } |
| } |
| |
| /** |
| * Dump game state to the provided Bundle. Typically called when the |
| * Activity is being suspended. |
| * |
| * @return Bundle with this view's state |
| */ |
| public Bundle saveState(Bundle map) { |
| synchronized (mSurfaceHolder) { |
| if (map != null) { |
| map.putInt(KEY_DIFFICULTY, Integer.valueOf(mDifficulty)); |
| map.putDouble(KEY_X, Double.valueOf(mX)); |
| map.putDouble(KEY_Y, Double.valueOf(mY)); |
| map.putDouble(KEY_DX, Double.valueOf(mDX)); |
| map.putDouble(KEY_DY, Double.valueOf(mDY)); |
| map.putDouble(KEY_HEADING, Double.valueOf(mHeading)); |
| map.putInt(KEY_LANDER_WIDTH, Integer.valueOf(mLanderWidth)); |
| map.putInt(KEY_LANDER_HEIGHT, Integer |
| .valueOf(mLanderHeight)); |
| map.putInt(KEY_GOAL_X, Integer.valueOf(mGoalX)); |
| map.putInt(KEY_GOAL_SPEED, Integer.valueOf(mGoalSpeed)); |
| map.putInt(KEY_GOAL_ANGLE, Integer.valueOf(mGoalAngle)); |
| map.putInt(KEY_GOAL_WIDTH, Integer.valueOf(mGoalWidth)); |
| map.putInt(KEY_WINS, Integer.valueOf(mWinsInARow)); |
| map.putDouble(KEY_FUEL, Double.valueOf(mFuel)); |
| } |
| } |
| return map; |
| } |
| |
| /** |
| * Sets the current difficulty. |
| * |
| * @param difficulty |
| */ |
| public void setDifficulty(int difficulty) { |
| synchronized (mSurfaceHolder) { |
| mDifficulty = difficulty; |
| } |
| } |
| |
| /** |
| * Sets if the engine is currently firing. |
| */ |
| public void setFiring(boolean firing) { |
| synchronized (mSurfaceHolder) { |
| mEngineFiring = firing; |
| } |
| } |
| |
| /** |
| * Used to signal the thread whether it should be running or not. |
| * Passing true allows the thread to run; passing false will shut it |
| * down if it's already running. Calling start() after this was most |
| * recently called with false will result in an immediate shutdown. |
| * |
| * @param b true to run, false to shut down |
| */ |
| public void setRunning(boolean b) { |
| mRun = b; |
| } |
| |
| /** |
| * Sets the game mode. That is, whether we are running, paused, in the |
| * failure state, in the victory state, etc. |
| * |
| * @see #setState(int, CharSequence) |
| * @param mode one of the STATE_* constants |
| */ |
| public void setState(int mode) { |
| synchronized (mSurfaceHolder) { |
| setState(mode, null); |
| } |
| } |
| |
| /** |
| * Sets the game mode. That is, whether we are running, paused, in the |
| * failure state, in the victory state, etc. |
| * |
| * @param mode one of the STATE_* constants |
| * @param message string to add to screen or null |
| */ |
| public void setState(int mode, CharSequence message) { |
| /* |
| * This method optionally can cause a text message to be displayed |
| * to the user when the mode changes. Since the View that actually |
| * renders that text is part of the main View hierarchy and not |
| * owned by this thread, we can't touch the state of that View. |
| * Instead we use a Message + Handler to relay commands to the main |
| * thread, which updates the user-text View. |
| */ |
| synchronized (mSurfaceHolder) { |
| mMode = mode; |
| |
| if (mMode == STATE_RUNNING) { |
| Message msg = mHandler.obtainMessage(); |
| Bundle b = new Bundle(); |
| b.putString("text", ""); |
| b.putInt("viz", View.INVISIBLE); |
| msg.setData(b); |
| mHandler.sendMessage(msg); |
| } else { |
| mRotating = 0; |
| mEngineFiring = false; |
| Resources res = mContext.getResources(); |
| CharSequence str = ""; |
| if (mMode == STATE_READY) |
| str = res.getText(R.string.mode_ready); |
| else if (mMode == STATE_PAUSE) |
| str = res.getText(R.string.mode_pause); |
| else if (mMode == STATE_LOSE) |
| str = res.getText(R.string.mode_lose); |
| else if (mMode == STATE_WIN) |
| str = res.getString(R.string.mode_win_prefix) |
| + mWinsInARow + " " |
| + res.getString(R.string.mode_win_suffix); |
| |
| if (message != null) { |
| str = message + "\n" + str; |
| } |
| |
| if (mMode == STATE_LOSE) mWinsInARow = 0; |
| |
| Message msg = mHandler.obtainMessage(); |
| Bundle b = new Bundle(); |
| b.putString("text", str.toString()); |
| b.putInt("viz", View.VISIBLE); |
| msg.setData(b); |
| mHandler.sendMessage(msg); |
| } |
| } |
| } |
| |
| /* Callback invoked when the surface dimensions change. */ |
| public void setSurfaceSize(int width, int height) { |
| // synchronized to make sure these all change atomically |
| synchronized (mSurfaceHolder) { |
| mCanvasWidth = width; |
| mCanvasHeight = height; |
| |
| // don't forget to resize the background image |
| mBackgroundImage = Bitmap.createScaledBitmap( |
| mBackgroundImage, width, height, true); |
| } |
| } |
| |
| /** |
| * Resumes from a pause. |
| */ |
| public void unpause() { |
| // Move the real time clock up to now |
| synchronized (mSurfaceHolder) { |
| mLastTime = System.currentTimeMillis() + 100; |
| } |
| setState(STATE_RUNNING); |
| } |
| |
| /** |
| * Handles a key-down event. |
| * |
| * @param keyCode the key that was pressed |
| * @param msg the original event object |
| * @return true |
| */ |
| boolean doKeyDown(int keyCode, KeyEvent msg) { |
| synchronized (mSurfaceHolder) { |
| boolean okStart = false; |
| if (keyCode == KeyEvent.KEYCODE_DPAD_UP) okStart = true; |
| if (keyCode == KeyEvent.KEYCODE_DPAD_DOWN) okStart = true; |
| if (keyCode == KeyEvent.KEYCODE_S) okStart = true; |
| |
| if (okStart |
| && (mMode == STATE_READY || mMode == STATE_LOSE || mMode == STATE_WIN)) { |
| // ready-to-start -> start |
| doStart(); |
| return true; |
| } else if (mMode == STATE_PAUSE && okStart) { |
| // paused -> running |
| unpause(); |
| return true; |
| } else if (mMode == STATE_RUNNING) { |
| // center/space -> fire |
| if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER |
| || keyCode == KeyEvent.KEYCODE_SPACE) { |
| setFiring(true); |
| return true; |
| // left/q -> left |
| } else if (keyCode == KeyEvent.KEYCODE_DPAD_LEFT |
| || keyCode == KeyEvent.KEYCODE_Q) { |
| mRotating = -1; |
| return true; |
| // right/w -> right |
| } else if (keyCode == KeyEvent.KEYCODE_DPAD_RIGHT |
| || keyCode == KeyEvent.KEYCODE_W) { |
| mRotating = 1; |
| return true; |
| // up -> pause |
| } else if (keyCode == KeyEvent.KEYCODE_DPAD_UP) { |
| pause(); |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| } |
| |
| /** |
| * Handles a key-up event. |
| * |
| * @param keyCode the key that was pressed |
| * @param msg the original event object |
| * @return true if the key was handled and consumed, or else false |
| */ |
| boolean doKeyUp(int keyCode, KeyEvent msg) { |
| boolean handled = false; |
| |
| synchronized (mSurfaceHolder) { |
| if (mMode == STATE_RUNNING) { |
| if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER |
| || keyCode == KeyEvent.KEYCODE_SPACE) { |
| setFiring(false); |
| handled = true; |
| } else if (keyCode == KeyEvent.KEYCODE_DPAD_LEFT |
| || keyCode == KeyEvent.KEYCODE_Q |
| || keyCode == KeyEvent.KEYCODE_DPAD_RIGHT |
| || keyCode == KeyEvent.KEYCODE_W) { |
| mRotating = 0; |
| handled = true; |
| } |
| } |
| } |
| |
| return handled; |
| } |
| |
| /** |
| * Draws the ship, fuel/speed bars, and background to the provided |
| * Canvas. |
| */ |
| private void doDraw(Canvas canvas) { |
| // Draw the background image. Operations on the Canvas accumulate |
| // so this is like clearing the screen. |
| canvas.drawBitmap(mBackgroundImage, 0, 0, null); |
| |
| int yTop = mCanvasHeight - ((int) mY + mLanderHeight / 2); |
| int xLeft = (int) mX - mLanderWidth / 2; |
| |
| // Draw the fuel gauge |
| int fuelWidth = (int) (UI_BAR * mFuel / PHYS_FUEL_MAX); |
| mScratchRect.set(4, 4, 4 + fuelWidth, 4 + UI_BAR_HEIGHT); |
| canvas.drawRect(mScratchRect, mLinePaint); |
| |
| // Draw the speed gauge, with a two-tone effect |
| double speed = Math.sqrt(mDX * mDX + mDY * mDY); |
| int speedWidth = (int) (UI_BAR * speed / PHYS_SPEED_MAX); |
| |
| if (speed <= mGoalSpeed) { |
| mScratchRect.set(4 + UI_BAR + 4, 4, |
| 4 + UI_BAR + 4 + speedWidth, 4 + UI_BAR_HEIGHT); |
| canvas.drawRect(mScratchRect, mLinePaint); |
| } else { |
| // Draw the bad color in back, with the good color in front of |
| // it |
| mScratchRect.set(4 + UI_BAR + 4, 4, |
| 4 + UI_BAR + 4 + speedWidth, 4 + UI_BAR_HEIGHT); |
| canvas.drawRect(mScratchRect, mLinePaintBad); |
| int goalWidth = (UI_BAR * mGoalSpeed / PHYS_SPEED_MAX); |
| mScratchRect.set(4 + UI_BAR + 4, 4, 4 + UI_BAR + 4 + goalWidth, |
| 4 + UI_BAR_HEIGHT); |
| canvas.drawRect(mScratchRect, mLinePaint); |
| } |
| |
| // Draw the landing pad |
| canvas.drawLine(mGoalX, 1 + mCanvasHeight - TARGET_PAD_HEIGHT, |
| mGoalX + mGoalWidth, 1 + mCanvasHeight - TARGET_PAD_HEIGHT, |
| mLinePaint); |
| |
| |
| // Draw the ship with its current rotation |
| canvas.save(); |
| canvas.rotate((float) mHeading, (float) mX, mCanvasHeight |
| - (float) mY); |
| if (mMode == STATE_LOSE) { |
| mCrashedImage.setBounds(xLeft, yTop, xLeft + mLanderWidth, yTop |
| + mLanderHeight); |
| mCrashedImage.draw(canvas); |
| } else if (mEngineFiring) { |
| mFiringImage.setBounds(xLeft, yTop, xLeft + mLanderWidth, yTop |
| + mLanderHeight); |
| mFiringImage.draw(canvas); |
| } else { |
| mLanderImage.setBounds(xLeft, yTop, xLeft + mLanderWidth, yTop |
| + mLanderHeight); |
| mLanderImage.draw(canvas); |
| } |
| canvas.restore(); |
| } |
| |
| /** |
| * Figures the lander state (x, y, fuel, ...) based on the passage of |
| * realtime. Does not invalidate(). Called at the start of draw(). |
| * Detects the end-of-game and sets the UI to the next state. |
| */ |
| private void updatePhysics() { |
| long now = System.currentTimeMillis(); |
| |
| // Do nothing if mLastTime is in the future. |
| // This allows the game-start to delay the start of the physics |
| // by 100ms or whatever. |
| if (mLastTime > now) return; |
| |
| double elapsed = (now - mLastTime) / 1000.0; |
| |
| // mRotating -- update heading |
| if (mRotating != 0) { |
| mHeading += mRotating * (PHYS_SLEW_SEC * elapsed); |
| |
| // Bring things back into the range 0..360 |
| if (mHeading < 0) |
| mHeading += 360; |
| else if (mHeading >= 360) mHeading -= 360; |
| } |
| |
| // Base accelerations -- 0 for x, gravity for y |
| double ddx = 0.0; |
| double ddy = -PHYS_DOWN_ACCEL_SEC * elapsed; |
| |
| if (mEngineFiring) { |
| // taking 0 as up, 90 as to the right |
| // cos(deg) is ddy component, sin(deg) is ddx component |
| double elapsedFiring = elapsed; |
| double fuelUsed = elapsedFiring * PHYS_FUEL_SEC; |
| |
| // tricky case where we run out of fuel partway through the |
| // elapsed |
| if (fuelUsed > mFuel) { |
| elapsedFiring = mFuel / fuelUsed * elapsed; |
| fuelUsed = mFuel; |
| |
| // Oddball case where we adjust the "control" from here |
| mEngineFiring = false; |
| } |
| |
| mFuel -= fuelUsed; |
| |
| // have this much acceleration from the engine |
| double accel = PHYS_FIRE_ACCEL_SEC * elapsedFiring; |
| |
| double radians = 2 * Math.PI * mHeading / 360; |
| ddx = Math.sin(radians) * accel; |
| ddy += Math.cos(radians) * accel; |
| } |
| |
| double dxOld = mDX; |
| double dyOld = mDY; |
| |
| // figure speeds for the end of the period |
| mDX += ddx; |
| mDY += ddy; |
| |
| // figure position based on average speed during the period |
| mX += elapsed * (mDX + dxOld) / 2; |
| mY += elapsed * (mDY + dyOld) / 2; |
| |
| mLastTime = now; |
| |
| // Evaluate if we have landed ... stop the game |
| double yLowerBound = TARGET_PAD_HEIGHT + mLanderHeight / 2 |
| - TARGET_BOTTOM_PADDING; |
| if (mY <= yLowerBound) { |
| mY = yLowerBound; |
| |
| int result = STATE_LOSE; |
| CharSequence message = ""; |
| Resources res = mContext.getResources(); |
| double speed = Math.sqrt(mDX * mDX + mDY * mDY); |
| boolean onGoal = (mGoalX <= mX - mLanderWidth / 2 && mX |
| + mLanderWidth / 2 <= mGoalX + mGoalWidth); |
| |
| // "Hyperspace" win -- upside down, going fast, |
| // puts you back at the top. |
| if (onGoal && Math.abs(mHeading - 180) < mGoalAngle |
| && speed > PHYS_SPEED_HYPERSPACE) { |
| result = STATE_WIN; |
| mWinsInARow++; |
| doStart(); |
| |
| return; |
| // Oddball case: this case does a return, all other cases |
| // fall through to setMode() below. |
| } else if (!onGoal) { |
| message = res.getText(R.string.message_off_pad); |
| } else if (!(mHeading <= mGoalAngle || mHeading >= 360 - mGoalAngle)) { |
| message = res.getText(R.string.message_bad_angle); |
| } else if (speed > mGoalSpeed) { |
| message = res.getText(R.string.message_too_fast); |
| } else { |
| result = STATE_WIN; |
| mWinsInARow++; |
| } |
| |
| setState(result, message); |
| } |
| } |
| } |
| |
| /** Handle to the application context, used to e.g. fetch Drawables. */ |
| private Context mContext; |
| |
| /** Pointer to the text view to display "Paused.." etc. */ |
| private TextView mStatusText; |
| |
| /** The thread that actually draws the animation */ |
| private LunarThread thread; |
| |
| public LunarView(Context context, AttributeSet attrs) { |
| super(context, attrs); |
| |
| // register our interest in hearing about changes to our surface |
| SurfaceHolder holder = getHolder(); |
| holder.addCallback(this); |
| |
| // create thread only; it's started in surfaceCreated() |
| thread = new LunarThread(holder, context, new Handler() { |
| @Override |
| public void handleMessage(Message m) { |
| mStatusText.setVisibility(m.getData().getInt("viz")); |
| mStatusText.setText(m.getData().getString("text")); |
| } |
| }); |
| |
| setFocusable(true); // make sure we get key events |
| } |
| |
| /** |
| * Fetches the animation thread corresponding to this LunarView. |
| * |
| * @return the animation thread |
| */ |
| public LunarThread getThread() { |
| return thread; |
| } |
| |
| /** |
| * Standard override to get key-press events. |
| */ |
| @Override |
| public boolean onKeyDown(int keyCode, KeyEvent msg) { |
| return thread.doKeyDown(keyCode, msg); |
| } |
| |
| /** |
| * Standard override for key-up. We actually care about these, so we can |
| * turn off the engine or stop rotating. |
| */ |
| @Override |
| public boolean onKeyUp(int keyCode, KeyEvent msg) { |
| return thread.doKeyUp(keyCode, msg); |
| } |
| |
| /** |
| * Standard window-focus override. Notice focus lost so we can pause on |
| * focus lost. e.g. user switches to take a call. |
| */ |
| @Override |
| public void onWindowFocusChanged(boolean hasWindowFocus) { |
| if (!hasWindowFocus) thread.pause(); |
| } |
| |
| /** |
| * Installs a pointer to the text view used for messages. |
| */ |
| public void setTextView(TextView textView) { |
| mStatusText = textView; |
| } |
| |
| /* Callback invoked when the surface dimensions change. */ |
| public void surfaceChanged(SurfaceHolder holder, int format, int width, |
| int height) { |
| thread.setSurfaceSize(width, height); |
| } |
| |
| /* |
| * Callback invoked when the Surface has been created and is ready to be |
| * used. |
| */ |
| public void surfaceCreated(SurfaceHolder holder) { |
| // start the thread here so that we don't busy-wait in run() |
| // waiting for the surface to be created |
| thread.setRunning(true); |
| thread.start(); |
| } |
| |
| /* |
| * Callback invoked when the Surface has been destroyed and must no longer |
| * be touched. WARNING: after this method returns, the Surface/Canvas must |
| * never be touched again! |
| */ |
| public void surfaceDestroyed(SurfaceHolder holder) { |
| // we have to tell thread to shut down & wait for it to finish, or else |
| // it might touch the Surface after we return and explode |
| boolean retry = true; |
| thread.setRunning(false); |
| while (retry) { |
| try { |
| thread.join(); |
| retry = false; |
| } catch (InterruptedException e) { |
| } |
| } |
| } |
| } |
