Question

嗨，我对ios和OpenGL很新。我正在尝试按照iPhone 3d编程中的说明进行操作。我只是想从OpenGL渲染一个灰色的屏幕。

我真的不知道我做错了什么，而且我需要明白为什么在我冒险之前我没有得到我的OpenGL窗口。

如果我可以提供更多帮助，只需发表评论：）

GLView.h：

#import <UIKit/UIKit.h>
#import <OpenGLES/EAGL.h>
#import <QuartzCore/QuartzCore.h>
#import <OpenGLES/ES1/gl.h>
#import <OpenGLES/ES1/glext.h>

@interface GLView : UIView {
    // Protected fields
    EAGLContext* m_context;
}

// public fields
-(void)drawWiew;

@end

GLView.mm：

#import "GLView.h"

@implementation GLView

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

- (id)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {
        CAEAGLLayer* eaglLayer = (CAEAGLLayer*) super.layer;
        eaglLayer.opaque = YES;

        m_context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];
        if (!m_context || ![EAGLContext setCurrentContext:m_context]) {
            [self release];
            return nil;
        }

        // Initialization code
        GLuint framebuffer, renderbuffer;
        glGenFramebuffersOES(1, &framebuffer);
        glGenRenderbuffersOES(1, &renderbuffer);

        glBindFramebufferOES(GL_FRAMEBUFFER_OES, framebuffer);
        glBindRenderbufferOES(GL_RENDERBUFFER_OES, renderbuffer);

        [m_context
         renderbufferStorage:GL_RENDERBUFFER_OES
         fromDrawable:eaglLayer];

        glFramebufferRenderbufferOES(
                                     GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES,
                                     GL_RENDERBUFFER_OES, renderbuffer);

        glViewport(0, 0, CGRectGetWidth(frame), CGRectGetHeight(frame));        

        [self drawWiew];
    }
    return self;
}

-(void)drawWiew {
    glClearColor(0.5f, 0.5f, 0.5f, 1);
    glClear(GL_COLOR_BUFFER_BIT);

    [m_context presentRenderbuffer:GL_RENDERBUFFER_OES];

    NSLog(@"drawView called");
}

-(void)dealloc {
    if ([EAGLContext currentContext] == m_context) 
        [EAGLContext setCurrentContext:nil];

    [m_context release];
    [super dealloc];
}

/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
    // Drawing code
}
*/

@end

HellowArrowAppDelegate.h：

#import <UIKit/UIKit.h>
#import "GLView.h"

@interface HelloArrowAppDelegate : UIResponder <UIApplicationDelegate> {
    UIWindow* window;
    GLView* view;
}

@property (strong, nonatomic) UIWindow *window;

@end

HellowArrowAppDelegate.mm：

#import "HelloArrowAppDelegate.h"

@implementation HelloArrowAppDelegate

@synthesize window = _window;

- (void)dealloc
{
    [_window release];
    [super dealloc];
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    CGRect screenBounds = [[UIScreen mainScreen] bounds];

    _window = [[UIWindow alloc] initWithFrame:screenBounds];
    view = [[GLView alloc] initWithFrame:screenBounds];   

    [_window addSubview:view];
    [_window makeKeyWindow];

//    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
//    // Override point for customization after application launch.
//    self.window.backgroundColor = [UIColor whiteColor];
//    [self.window makeKeyAndVisible];
    return YES;
}

- (void)applicationWillResignActive:(UIApplication *)application
{
    /*
     Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
     Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
     */
}

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    /*
     Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
     If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
     */
}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
    /*
     Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
     */
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    /*
     Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
     */
}

- (void)applicationWillTerminate:(UIApplication *)application
{
    /*
     Called when the application is about to terminate.
     Save data if appropriate.
     See also applicationDidEnterBackground:.
     */
}

@end

Answer 1

OpenGL屏幕可能会变黑，具体取决于所用操作系统的版本，以及所绘制的屏幕窗口的大小。例如，在4.0,4.1和4.3上运行正常的代码可以在4.2中显示黑色。或者，如果您将OpenGL窗口的大小加倍，它就可以工作。有时固件会妨碍使用 - 尝试使用更新版本的操作系统，看看它是否更好。

窗口在OpenGL中变黑

1 个答案: