appcontroller.m

一个可以演示OpenGL在xcode里的画点的程序

/*

File: AppController.m
Abstract: The UIApplication  delegate class, which is the central controller of
the application.

Version: 1.6

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APPLE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Copyright (C) 2008 Apple Inc. All Rights Reserved.

*/

#import "AppController.h"

//CONSTANTS:

#define kPaletteHeight					30
#define kPaletteSize				    5
#define kAccelerometerFrequency			25 //Hz
#define kFilteringFactor				0.1
#define kMinEraseInterval				0.5
#define kEraseAccelerationThreshold		2.0

// Padding for margins
#define kLeftMargin				10.0
#define kTopMargin				10.0
#define kRightMargin			10.0
 
//FUNCTIONS:
/*
   HSL2RGB Converts hue, saturation, luminance values to the equivalent red, green and blue values.
   For details on this conversion, see Fundamentals of Interactive Computer Graphics by Foley and van Dam (1982, Addison and Wesley)
   You can also find HSL to RGB conversion algorithms by searching the Internet.
   See also http://en.wikipedia.org/wiki/HSV_color_space for a theoretical explanation
 */
static void HSL2RGB(float h, float s, float l, float* outR, float* outG, float* outB)
{
	float			temp1,
					temp2;
	float			temp[3];
	int				i;
	
	// Check for saturation. If there isn't any just return the luminance value for each, which results in gray.
	if(s == 0.0) {
		if(outR)
			*outR = l;
		if(outG)
			*outG = l;
		if(outB)
			*outB = l;
		return;
	}
	
	// Test for luminance and compute temporary values based on luminance and saturation 
	if(l < 0.5)
		temp2 = l * (1.0 + s);
	else
		temp2 = l + s - l * s;
		temp1 = 2.0 * l - temp2;
	
	// Compute intermediate values based on hue
	temp[0] = h + 1.0 / 3.0;
	temp[1] = h;
	temp[2] = h - 1.0 / 3.0;

	for(i = 0; i < 3; ++i) {
		
		// Adjust the range
		if(temp[i] < 0.0)
			temp[i] += 1.0;
		if(temp[i] > 1.0)
			temp[i] -= 1.0;
		
		
		if(6.0 * temp[i] < 1.0)
			temp[i] = temp1 + (temp2 - temp1) * 6.0 * temp[i];
		else {
			if(2.0 * temp[i] < 1.0)
				temp[i] = temp2;
			else {
				if(3.0 * temp[i] < 2.0)
					temp[i] = temp1 + (temp2 - temp1) * ((2.0 / 3.0) - temp[i]) * 6.0;
				else
					temp[i] = temp1;
			}
		}
	}
	
	// Assign temporary values to R, G, B
	if(outR)
		*outR = temp[0];
	if(outG)
		*outG = temp[1];
	if(outB)
		*outB = temp[2];
}

//CLASS IMPLEMENTATIONS:

@implementation AppController

- (void) applicationDidFinishLaunching:(UIApplication*)application
{
	CGRect					rect = [[UIScreen mainScreen] applicationFrame];
	CGFloat					components[3];
	
	//Create a full-screen window
	window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
	[window setBackgroundColor:[UIColor blackColor]];
	
	//Create the OpenGL drawing view and add it to the window
	drawingView = [[PaintingView alloc] initWithFrame:CGRectMake(rect.origin.x, rect.origin.y, rect.size.width, rect.size.height)]; // - kPaletteHeight 
	[window addSubview:drawingView];
	
	// Create a segmented control so that the user can choose the brush color.
	UISegmentedControl *segmentedControl = [[UISegmentedControl alloc] initWithItems:
											[NSArray arrayWithObjects:
												[UIImage imageNamed:@"Red.png"],
												[UIImage imageNamed:@"Yellow.png"],
												[UIImage imageNamed:@"Green.png"],
												[UIImage imageNamed:@"Blue.png"],
												[UIImage imageNamed:@"Purple.png"],
												nil]];
	
	// Compute a rectangle that is positioned correctly for the segmented control you'll use as a brush color palette
	CGRect frame = CGRectMake(rect.origin.x + kLeftMargin, rect.size.height - kPaletteHeight - kTopMargin, rect.size.width - (kLeftMargin + kRightMargin), kPaletteHeight);
	segmentedControl.frame = frame;
	// When the user chooses a color, the method changeBrushColor: is called.
	[segmentedControl addTarget:self action:@selector(changeBrushColor:) forControlEvents:UIControlEventValueChanged];
	segmentedControl.segmentedControlStyle = UISegmentedControlStyleBar;
	// Make sure the color of the color complements the black background
	segmentedControl.tintColor = [UIColor darkGrayColor];
	// Set the third color (index values start at 0)
	segmentedControl.selectedSegmentIndex = 2;
	
	// Add the control to the window
	[window addSubview:segmentedControl];
	// Now that the control is added, you can release it
	[segmentedControl release];
	
    // Define a starting color 
	HSL2RGB((CGFloat) 2.0 / (CGFloat)kPaletteSize, kSaturation, kLuminosity, &components[0], &components[1], &components[2]);
	// Set the color using OpenGL
	glColor4f(components[0], components[1], components[2], kBrushOpacity);
	
	//Show the window
	[window makeKeyAndVisible];	
	// Look in the Info.plist file and you'll see the status bar is hidden
	// Set the style to black so it matches the background of the application
	[application setStatusBarStyle:UIStatusBarStyleBlackTranslucent animated:NO];
	// Now show the status bar, but animate to the style.
	[application setStatusBarHidden:NO animated:YES];
	
	//Configure and enable the accelerometer
	[[UIAccelerometer sharedAccelerometer] setUpdateInterval:(1.0 / kAccelerometerFrequency)];
	[[UIAccelerometer sharedAccelerometer] setDelegate:self];
	
	//Load the sounds
	 NSBundle *mainBundle = [NSBundle mainBundle];	
	erasingSound = [[SoundEffect alloc] initWithContentsOfFile:[mainBundle pathForResource:@"Erase" ofType:@"caf"]];
	selectSound =  [[SoundEffect alloc] initWithContentsOfFile:[mainBundle pathForResource:@"Select" ofType:@"caf"]];
}

// Release resources when they are no longer needed,
- (void) dealloc
{
	[selectSound release];
	[erasingSound release];
	[drawingView release];
	[window release];
	
	[super dealloc];
}

// Change the brush color
- (void)changeBrushColor:(id)sender
{
 	CGFloat					components[3];
 
	//Play sound
 	[selectSound play];
	
	//Set the new brush color
 	HSL2RGB((CGFloat)[sender selectedSegmentIndex] / (CGFloat)kPaletteSize, kSaturation, kLuminosity, &components[0], &components[1], &components[2]);
 	glColor4f(components[0], components[1], components[2], kBrushOpacity);
 }

// Called when the accelerometer detects motion; plays the erase sound and redraws the view if the motion is over a threshold.
- (void) accelerometer:(UIAccelerometer*)accelerometer didAccelerate:(UIAcceleration*)acceleration
{
	UIAccelerationValue				length,
									x,
									y,
									z;
	
	//Use a basic high-pass filter to remove the influence of the gravity
	myAccelerometer[0] = acceleration.x * kFilteringFactor + myAccelerometer[0] * (1.0 - kFilteringFactor);
	myAccelerometer[1] = acceleration.y * kFilteringFactor + myAccelerometer[1] * (1.0 - kFilteringFactor);
	myAccelerometer[2] = acceleration.z * kFilteringFactor + myAccelerometer[2] * (1.0 - kFilteringFactor);
	// Compute values for the three axes of the acceleromater
	x = acceleration.x - myAccelerometer[0];
	y = acceleration.y - myAccelerometer[0];
	z = acceleration.z - myAccelerometer[0];
	
	//Compute the intensity of the current acceleration 
	length = sqrt(x * x + y * y + z * z);
	// If above a given threshold, play the erase sounds and erase the drawing view
	if((length >= kEraseAccelerationThreshold) && (CFAbsoluteTimeGetCurrent() > lastTime + kMinEraseInterval)) {
		[erasingSound play];
		[drawingView erase];
		lastTime = CFAbsoluteTimeGetCurrent();
	}
}

@end