crashlandingappdelegate.m

在iPhone OS上使用用Objective-C语言开发的Demo程序

		else
			[self resetGame];
	}
}

// Saves the user's score in the application preferences
- (void)saveScore {
	NSUserDefaults*		defaults = [NSUserDefaults standardUserDefaults];
	NSString*			name = [defaults stringForKey:kUserNameDefaultKey];
	NSDate*				date = [NSDate date];
	NSMutableArray*		scores;
	NSMutableString*	string;
	unsigned			i;
	NSDictionary*		dictionary;
	
	//Dismiss text field
	[_textField endEditing:YES];
	[_textField removeFromSuperview];
	
	//Make sure a player name exists, if only the default
	if(![name length])
		name = @"Player";
	
	//Update the high-scores in the preferences
	scores = [NSMutableArray arrayWithArray:[defaults objectForKey:kHighScoresDefaultKey]];
	[scores addObject:[NSDictionary dictionaryWithObjectsAndKeys:name, @"name", [NSNumber numberWithUnsignedInt:_score], @"score", date, @"date", nil]];
	[scores sortUsingDescriptors:[NSArray arrayWithObject:[[[NSSortDescriptor alloc] initWithKey:@"score" ascending:NO] autorelease]]];
	[defaults setObject:scores forKey:kHighScoresDefaultKey];
	
	//Display high-scores in status texture
	string = [NSMutableString stringWithString:@"       HIGH-SCORES\n"];
	for(i = 0; i < MIN([scores count], 10); ++i) {
		dictionary = [scores objectAtIndex:i];
		[string appendFormat:@"\n%s%i. %@ (%@ Pts)", ([[dictionary objectForKey:@"date"] isEqualToDate:date] ? "> " : "   "), i + 1, [dictionary objectForKey:@"name"], [dictionary objectForKey:@"score"]/*, [[dictionary objectForKey:@"date"] descriptionWithCalendarFormat:@"%m/%d %I:%M %p" timeZone:nil locale:nil]*/];
	}
	[_statusTexture release];
	_statusTexture = [[Texture2D alloc] initWithString:string dimensions:CGSizeMake(256, 256) alignment:UITextAlignmentLeft fontName:kFontName fontSize:kScoreFontSize];
	_state = kState_StandBy;
	
	//Render a frame
	[self renderScene];
}

// Release the status texture and initialized values in preparation for starting a new game
- (void)resetGame {
	CGRect				bounds = [glView bounds];
	
	//Destroy the status texture
	[_statusTexture release];
	_statusTexture = nil;
	
	//Reset the state to running mode
	_state = kState_Running;
	_lastTime = CFAbsoluteTimeGetCurrent();
	_lastThrust = NO;
	
	//Randomize the landing base position
	_basePosition = RANDOM_FLOAT() * (bounds.size.width - kBaseSize) + kBaseSize / 2;
	
	//Set the initial state or the rocket
	_fuel = kInitialFuel;
	_rotation = 0.0;
	_rotationVelocity = 0.0;
	_position.x = RANDOM_FLOAT() * (bounds.size.width - _landerBounds.size.width) + _landerBounds.size.width / 2;
	_position.y = bounds.size.height + _landerBounds.size.height;
	_velocity.x = 0.0;
	_velocity.y = -kInitialVelocity;
	
	//Render a frame immediately
	[self renderScene];
	
	//Start rendering timer
	_timer = [NSTimer scheduledTimerWithTimeInterval:(1.0 / kRenderingFPS) target:self selector:@selector(renderScene) userInfo:nil repeats:YES];
	
	//Play start sound
	SoundEngine_StartEffect( _sounds[kSound_Start]);
}


// Renders one scene of the game
- (void)renderScene {
	CGRect				bounds = [glView bounds];
	float				maxDistance = (kBaseSize - _landerBounds.size.width) / 2.0;
	BOOL				thrust = NO;
	CFTimeInterval		time;
	float				dTime;
	Vector2D			force,
	orientation;
	CGRect				rect;
	float				lateralAcceleration;
	CGSize				size;
	
	//Update game state
	if(_state == kState_Running) {
		time = CFAbsoluteTimeGetCurrent();
		dTime = time - _lastTime;
		
		//Update lander position
		_position.x += _velocity.x * dTime;
		_position.y += _velocity.y * dTime;
		
		//Wrap the lander horizontal position
		if(_position.x < 0.0)
			_position.x = bounds.size.width + _position.x;
		else if(_position.x > bounds.size.width)
			_position.x = bounds.size.width - _position.x;
		
		//Clamp the lander top vertical position
		if(_position.y > bounds.size.height - _landerBounds.size.height / 2) {
			_position.y = bounds.size.height - _landerBounds.size.height / 2;
			_velocity.y = 0.0;
		}
		
		//Update the rocket orientation
		_rotation += _rotationVelocity * dTime;
		
		//Check to see if the rocket  touched the ground
		orientation.x = sinf(DEGREES_TO_RADIANS(_rotation));
		orientation.y = cosf(DEGREES_TO_RADIANS(_rotation));
		rect = CGRectApplyAffineTransform(_landerBounds, CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(_rotation)));
		if(_position.y + CGRectGetMinY(rect) <= kBaseOffset + (GLfloat)[_textures[kTexture_Base] pixelsHigh] / 2) {
			//Check whether the landing is successful  or not
			if((_velocity.y >= -kMaxVelocity) && (fabsf(_rotation) <= kMaxRotation) && (fabsf(_position.x - _basePosition) < maxDistance)) {
				SoundEngine_StartEffect(_sounds[kSound_Success]);
				_state = kState_Success;
				_score = kScoreVelocity * (1.0 - _velocity.y / -kMaxVelocity) + kScoreFuel * (_fuel / kInitialFuel) + kScoreRotation * (1.0 - _rotation / kMaxRotation) + kScoreDistance * (1.0 - fabsf(_position.x - _basePosition) / maxDistance);
				_statusTexture = [[Texture2D alloc] initWithString:[NSString stringWithFormat:@"SUCCESS!\nYou scored %i Points\n\nEnter your name:", _score] dimensions:CGSizeMake(256, 128) alignment:UITextAlignmentCenter fontName:kFontName fontSize:kStatusFontSize];
				
				//Show text field that allows the user to enter a name for the score
				[_textField setText:[[NSUserDefaults standardUserDefaults] stringForKey:kUserNameDefaultKey]];
				[window addSubview:_textField];
			}
			else {  // The landing is not successful; the rocket crashed!
				SoundEngine_Vibrate();
				SoundEngine_SetEffectPosition(_sounds[kSound_Failure], 2.0 * (_position.x / bounds.size.width) - 1.0, 0.0, 0.0);
				SoundEngine_StartEffect(_sounds[kSound_Failure]);
				_state = kState_Failure;
				_statusTexture = [[Texture2D alloc] initWithString:@"YOU CRASHED!" dimensions:CGSizeMake(256, 32) alignment:UITextAlignmentCenter fontName:kFontName fontSize:kStatusFontSize];
			}
			
			//Stop rendering timer
			[_timer invalidate];
			_timer = nil;
		}
		//Update lander velocity, rotation speed and fuel
		else {
			thrust = (_accelerometer[1] <= kMainThrustThreshold ? YES : NO);
			
			force.x = 0.0;
			force.y = -kMass * kGravity;
			if(thrust && (_fuel > 0.0)) {
				force.x = -orientation.x * kMainThrust;
				force.y = orientation.y * kMainThrust;
			}
			else
				thrust = NO;
			
			_velocity.x += force.x / kMass * dTime;
			_velocity.y += force.y / kMass * dTime;
			
			lateralAcceleration = _accelerometer[0];
			if(fabsf(lateralAcceleration) >= kLateralThrustThreshold) {
				_velocity.x += (lateralAcceleration > 0.0 ? lateralAcceleration - kLateralThrustThreshold : lateralAcceleration + kLateralThrustThreshold) * kLateralSpeed;
				_rotationVelocity = -(lateralAcceleration > 0.0 ? lateralAcceleration - kLateralThrustThreshold : lateralAcceleration + kLateralThrustThreshold) * kRotationSpeed;
			}
			
			if(thrust) {  // Update the fuel level
				_fuel -= dTime;
				if(_fuel < 0.0)
					_fuel = 0.0;
			}
			
			_lastTime = time;
		}
		
		//Start or stop thurst sound & update its position
		if(thrust && !_lastThrust)
			SoundEngine_StartEffect( _sounds[kSound_Thrust]);
		else if(!thrust && _lastThrust)
			 SoundEngine_StopEffect(_sounds[kSound_Thrust], false);
		if(thrust)
			SoundEngine_SetEffectPosition(_sounds[kSound_Thrust], 2.0 * (_position.x / bounds.size.width) - 1.0, 0.0, 0.0);
		_lastThrust = thrust;
	}
	
	//Draw background
	glDisable(GL_BLEND);
	[_textures[kTexture_Background] drawInRect:bounds];
	glEnable(GL_BLEND);
	
	//Draw the game elements
	if(_state != kState_StandBy) {
		//Draw the landing base
		[_textures[kTexture_Base] drawAtPoint:CGPointMake(_basePosition, kBaseOffset)];
		
		//Draw the lander
		glPushMatrix();
		glTranslatef(_position.x, _position.y, 0);
		if(_rotation)
			glRotatef(_rotation, 0, 0, 1);
		[_textures[kTexture_Lander] drawAtPoint:CGPointZero];
		if(_state == kState_Running) {
			if(thrust)
				[_textures[kTexture_MainThrust] drawAtPoint:CGPointMake(0, -56)];
			if(lateralAcceleration > kLateralThrustThreshold)
				[_textures[kTexture_LeftThrust] drawAtPoint:CGPointMake(-35.5, -48)];
			if(lateralAcceleration < -kLateralThrustThreshold)
				[_textures[kTexture_RightThrust] drawAtPoint:CGPointMake(35.5, -48)];
		}
		glPopMatrix();
		
		//Draw the status lights
		[_textures[(_velocity.y >= -kMaxVelocity ? kTexture_LightGreen : kTexture_LightRed)] drawAtPoint:CGPointMake(kSpeedX, kLightY)];
		[_textures[(fabsf(_rotation) <= kMaxRotation ? kTexture_LightGreen : kTexture_LightRed)] drawAtPoint:CGPointMake(kAngleX, kLightY)];
		[_textures[(fabsf(_position.x - _basePosition) < maxDistance ? kTexture_LightGreen : kTexture_LightRed)] drawAtPoint:CGPointMake(kPositionX, kLightY)];
		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
		[_textures[kTexture_LabelSpeed] drawAtPoint:CGPointMake(kSpeedX + kLabelOffset, kLabelY)];
		[_textures[kTexture_LabelAngle] drawAtPoint:CGPointMake(kAngleX + kLabelOffset, kLabelY)];
		[_textures[kTexture_LabelPosition] drawAtPoint:CGPointMake(kPositionX + kLabelOffset, kLabelY)];
		glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
		
		//Draw the explosion if the lander is crashed
		if(_state == kState_Failure)
			[_textures[kTexture_Explosion] drawAtPoint:CGPointMake(_position.x, _position.y)];
		
		//Draw the fuel bar
		if(_state == kState_Running) {
			size = [_textures[kTexture_FuelBar] contentSize];
			[_textures[kTexture_FuelBar] drawAtPoint:CGPointMake(kFuelBarX, kFuelBarY)];
			if(_fuel > 0)
				[_textures[kTexture_FuelLevel] drawInRect:CGRectMake(kFuelBarX - size.width / 2 + 1, kFuelBarY - size.height / 2 + 1, size.width - 2, _fuel / kInitialFuel * (size.height - 2))];
		}
	}
	
	//Draw the overlay status texture
	if(_statusTexture) {
		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
		[_statusTexture drawAtPoint:CGPointMake(bounds.size.width / 2, bounds.size.height * 2 / 3)];
		glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
	}
	
	//Swap the framebuffer
	[glView swapBuffers];
}

@end