eaglview.m

一个可以演示OpenGL在xcode里的画点的程序

/*

File: EAGLView.m
Abstract: Convenience class that wraps the CAEAGLLayer from CoreAnimation into a
UIView subclass.

Version: 1.6

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*/

#import <QuartzCore/QuartzCore.h>
#import <OpenGLES/EAGLDrawable.h>

#import "EAGLView.h"

//CLASS IMPLEMENTATIONS:

@implementation EAGLView

@synthesize delegate=_delegate, autoresizesSurface=_autoresize, surfaceSize=_size, framebuffer = _framebuffer, pixelFormat = _format, depthFormat = _depthFormat, context = _context;

+ (Class) layerClass
{
	return [CAEAGLLayer class];
}

- (BOOL) _createSurface
{
	CAEAGLLayer*			eaglLayer = (CAEAGLLayer*)[self layer];
	CGSize					newSize;
	GLuint					oldRenderbuffer;
	GLuint					oldFramebuffer;
	
	if(![EAGLContext setCurrentContext:_context]) {
		return NO;
	}
	
	newSize = [eaglLayer bounds].size;
	newSize.width = roundf(newSize.width);
	newSize.height = roundf(newSize.height);
	
	glGetIntegerv(GL_RENDERBUFFER_BINDING_OES, (GLint *) &oldRenderbuffer);
	glGetIntegerv(GL_FRAMEBUFFER_BINDING_OES, (GLint *) &oldFramebuffer);
	
	glGenRenderbuffersOES(1, &_renderbuffer);
	glBindRenderbufferOES(GL_RENDERBUFFER_OES, _renderbuffer);
	
	if(![_context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(id<EAGLDrawable>)eaglLayer]) {
		glDeleteRenderbuffersOES(1, &_renderbuffer);
		glBindRenderbufferOES(GL_RENDERBUFFER_BINDING_OES, oldRenderbuffer);
		return NO;
	}
	
	glGenFramebuffersOES(1, &_framebuffer);
	glBindFramebufferOES(GL_FRAMEBUFFER_OES, _framebuffer);
	glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, _renderbuffer);
	if (_depthFormat) {
		glGenRenderbuffersOES(1, &_depthBuffer);
		glBindRenderbufferOES(GL_RENDERBUFFER_OES, _depthBuffer);
		glRenderbufferStorageOES(GL_RENDERBUFFER_OES, _depthFormat, newSize.width, newSize.height);
		glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, _depthBuffer);
	}

	_size = newSize;
	if(!_hasBeenCurrent) {
		glViewport(0, 0, newSize.width, newSize.height);
		glScissor(0, 0, newSize.width, newSize.height);
		_hasBeenCurrent = YES;
	}
	else {
		glBindFramebufferOES(GL_FRAMEBUFFER_OES, oldFramebuffer);
	}
	glBindRenderbufferOES(GL_RENDERBUFFER_OES, oldRenderbuffer);
	
	// Error handling here
	
	[_delegate didResizeEAGLSurfaceForView:self];
	
	return YES;
}

- (void) _destroySurface
{
	EAGLContext *oldContext = [EAGLContext currentContext];
	
	if (oldContext != _context)
		[EAGLContext setCurrentContext:_context];
	
	if(_depthFormat) {
		glDeleteRenderbuffersOES(1, &_depthBuffer);
		_depthBuffer = 0;
	}
	
	glDeleteRenderbuffersOES(1, &_renderbuffer);
	_renderbuffer = 0;

	glDeleteFramebuffersOES(1, &_framebuffer);
	_framebuffer = 0;
	
	if (oldContext != _context)
		[EAGLContext setCurrentContext:oldContext];
}

- (id) initWithFrame:(CGRect)frame
{
	return [self initWithFrame:frame pixelFormat:GL_RGB565_OES depthFormat:0 preserveBackbuffer:NO];
}

- (id) initWithFrame:(CGRect)frame pixelFormat:(GLuint)format 
{
	return [self initWithFrame:frame pixelFormat:format depthFormat:0 preserveBackbuffer:NO];
}

- (id) initWithFrame:(CGRect)frame pixelFormat:(GLuint)format depthFormat:(GLuint)depth preserveBackbuffer:(BOOL)retained
{
	if((self = [super initWithFrame:frame])) {
		CAEAGLLayer*			eaglLayer = (CAEAGLLayer*)[self layer];
		
		eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
										[NSNumber numberWithBool:YES], kEAGLDrawablePropertyRetainedBacking, kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat, nil];
		
		_format = format;
		_depthFormat = depth;
		
		_context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];
		if(_context == nil) {
			[self release];
			return nil;
		}
		
		if(![self _createSurface]) {
			[self release];
			return nil;
		}
	}

	return self;
}

- (void) dealloc
{
	[self _destroySurface];
	
	[_context release];
	_context = nil;
	
	[super dealloc];
}

- (void) layoutSubviews
{
	CGRect				bounds = [self bounds];
	
	if(_autoresize && ((roundf(bounds.size.width) != _size.width) || (roundf(bounds.size.height) != _size.height))) {
		[self _destroySurface];
		[self _createSurface];
	}
}

- (void) setAutoresizesEAGLSurface:(BOOL)autoresizesEAGLSurface;
{
	_autoresize = autoresizesEAGLSurface;
	if(_autoresize)
	[self layoutSubviews];
}

- (void) setCurrentContext
{
	if(![EAGLContext setCurrentContext:_context]) {
		printf("Failed to set current context %p in %s\n", _context, __FUNCTION__);
	}
}

- (BOOL) isCurrentContext
{
	return ([EAGLContext currentContext] == _context ? YES : NO);
}

- (void) clearCurrentContext
{
	if(![EAGLContext setCurrentContext:nil])
		printf("Failed to clear current context in %s\n", __FUNCTION__);
}

- (void) swapBuffers
{
	EAGLContext *oldContext = [EAGLContext currentContext];
	GLuint oldRenderbuffer;
	
	if(oldContext != _context)
		[EAGLContext setCurrentContext:_context];
	
	// CHECK_GL_ERROR();
	
	glGetIntegerv(GL_RENDERBUFFER_BINDING_OES, (GLint *) &oldRenderbuffer);
	glBindRenderbufferOES(GL_RENDERBUFFER_OES, _renderbuffer);
	
	if(![_context presentRenderbuffer:GL_RENDERBUFFER_OES])
		printf("Failed to swap renderbuffer in %s\n", __FUNCTION__);

	if(oldContext != _context)
		[EAGLContext setCurrentContext:oldContext];
}

- (CGPoint) convertPointFromViewToSurface:(CGPoint)point
{
	CGRect				bounds = [self bounds];
	
	return CGPointMake((point.x - bounds.origin.x) / bounds.size.width * _size.width, (point.y - bounds.origin.y) / bounds.size.height * _size.height);
}

- (CGRect) convertRectFromViewToSurface:(CGRect)rect
{
	CGRect				bounds = [self bounds];
	
	return CGRectMake((rect.origin.x - bounds.origin.x) / bounds.size.width * _size.width, (rect.origin.y - bounds.origin.y) / bounds.size.height * _size.height, rect.size.width / bounds.size.width * _size.width, rect.size.height / bounds.size.height * _size.height);
}

@end