似乎無法在模擬器上使用opengl es 1.1進行渲染

Question

我對OpenGL完全陌生，我一直在嘗試將這段簡單的代碼呈現在iphone模擬器上，它可以正常啟動，顯示初始屏幕，然后……什么都沒有……只是黑暗，我可以不能告訴我我所缺少的，請幫忙一下嗎？ 我還沒有為旋轉做任何事情，等着看我首先渲染的內容，然后再繼續旋轉等等。

如果這很重要，我正在使用Xcode 4.2。

這是我的代碼：

IRenderEngine.cpp

#ifndef HelloArrow_IRenderingEngine_hpp
#define HelloArrow_IRenderingEngine_hpp

#import <OpenGLES/ES1/gl.h>
#import <OpenGLES/ES1/glext.h>

//Physical Orientation of a handheld device, equivalent to UIDeviceOrientation
enum DeviceOrientation{
DeviceOrientationUnknown,
DeviceOrientationPortrait,
DeviceOrientationPortraitUpsideDown,
DeviceOrientationLandscapeLeft,
DeviceOrientationLandscapeRight,
DeviceOrientationFaceUp,
DeviceOrientationFaceDown
};

//Creates an instance of a renderer and sets up various openGL state
struct IRenderingEngine *CreateRenderer1();

//Interface to OpenGL ES renderer; consumed by GLView
struct IRenderingEngine{
virtual void Initialize(int width, int height)=0;
virtual void Render() = 0;
virtual void UpdateAnimation(float timeStep) = 0;
virtual void OnRotate(DeviceOrientation newOrientation) = 0;
virtual ~IRenderingEngine(){};
};

RenderingEngine.cpp

#include <iostream>

#include <OpenGLES/ES1/gl.h>

#include <OpenGLES/ES1/glext.h>

#include "IRenderingEngine.hpp"


class RenderingEngine1 : public IRenderingEngine{
public:
RenderingEngine1();
void Initialize(int width, int height);
void Render();
void UpdateAnimation(float timeStep){}
void OnRotate(DeviceOrientation newOrientation){}
private:
GLuint m_framebuffer;
GLuint m_renderbuffer;
};

IRenderingEngine * CreateRenderer1(){
return new RenderingEngine1;
}

struct Vertex {
float Position[2];
float Color[4];
};

//Define the position and colors of the 2 triangles
const struct Vertex Vertices[6] = {
{{-0.5, -0.866},{1, 1, 0.5f, 1}},
{{0.5, -0.866},{1,1,0.5f,1}},
{{0,1},{1,1,0.5f,1}},
{{-0.5, -0.866},{0.5f,0.5f,0.5f}},
{{0.5, -0.866},{0.5f,0.5f,0.5f}},
{{0,-0.4f},{0.5f,0.5f,0.5f}}
};
RenderingEngine1::RenderingEngine1(){
glGenRenderbuffersOES(1, &m_renderbuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, m_renderbuffer);
}

void RenderingEngine1::Initialize(int width, int height){
//Create the framebuffer object and attache the renderbuffer    
glGenFramebuffersOES(1, &m_framebuffer);
glBindFramebufferOES(GL_FRAMEBUFFER_OES, m_framebuffer);

glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES,     GL_RENDERBUFFER_OES, m_renderbuffer);

glViewport(0, 0, width, height);

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

const float maxX = 2;
const float maxY = 3;

glOrthof(-maxX,+maxX,-maxY,+maxY,-1,1);


glMatrixMode(GL_MODELVIEW);

glLoadIdentity();

}

void RenderingEngine1::Render(){

glClearColor(0.5f, 0.5f, 0.5f, 1);


glClear(GL_COLOR_BUFFER_BIT);


glEnableClientState(GL_VERTEX_ARRAY);


glEnableClientState(GL_COLOR_ARRAY);
glVertexPointer(2,GL_FLOAT,4,&Vertices[0].Position);


glColorPointer(4,GL_FLOAT,2,&Vertices[0].Color);

GLsizei vertexcount = sizeof(Vertices)/sizeof(Vertex);
glDrawArrays(GL_TRIANGLES, 0, vertexcount);
glFlush();
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_COLOR_ARRAY);
}

GLView.h

#import "IRenderingEngine.hpp"
#import <UIKit/UIKit.h>
#import <OpenGLES/EAGL.h>
#import <QuartzCore/QuartzCore.h>


@interface GLView : UIView
{
EAGLContext *m_context;
struct IRenderingEngine *m_renderingEngine;
float m_timestamp;
}

-(void) drawView:(CADisplayLink*) displayLink;
-(void) didRotate: (NSNotification*) notification;

@end

GLView.mm

#import <OpenGLES/EAGLDrawable.h>
#import <OpenGLES/ES1/gl.h> //<- for GL_RENDERBUFFER only
#import "GLView.h"
#import "mach/mach_time.h"
#import "IRenderingEngine.hpp"

@implementation GLView

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

- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
    // Initialization code
    CAEAGLLayer *eaglLayer = (CAEAGLLayer*) super.layer;
    eaglLayer.opaque = YES;
    m_context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];

    if(!m_context || ![EAGLContext setCurrentContext:m_context]){
        return nil;
    }

    m_renderingEngine = CreateRenderer1();    

    [m_context renderbufferStorage:GL_RENDERBUFFER fromDrawable:eaglLayer];

    m_renderingEngine->Initialize(CGRectGetWidth(frame), CGRectGetHeight(frame));
    [self drawView:nil];
    m_timestamp = CACurrentMediaTime();
    CADisplayLink *displayLink;
    displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(drawView:)];
    [displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(didRotate:) name:UIDeviceOrientationDidChangeNotification object:nil];

}
return self;
}

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

-(void) drawView: (CADisplayLink *) displayLink{

if(displayLink != nil){
    float elapsedseconds = [displayLink timestamp] - m_timestamp;
    m_timestamp = [displayLink timestamp];
    m_renderingEngine->UpdateAnimation(elapsedseconds);
}
m_renderingEngine->Render();

[m_context presentRenderbuffer:GL_RENDERBUFFER_OES];

}

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

-(void) didRotate:(NSNotification *)notification{
UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation];
m_renderingEngine->OnRotate((DeviceOrientation) orientation);
[self drawView:nil];
}

@end

AppDelegate.h

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

@class ViewController;

@interface AppDelegate : UIResponder <UIApplicationDelegate>{
UIWindow *m_window;
GLView *m_view;
}

@property (strong, nonatomic) IBOutlet UIWindow *m_window;

@end

最后是AppDelegate.mm

#import "AppDelegate.h"
#import "OpenGLVC.h"
#import <UIKit/UIKit.h>

@implementation AppDelegate

@synthesize m_window = _window;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
CGRect screenBounds = [[UIScreen mainScreen] bounds];
self.m_window = [[UIWindow alloc] initWithFrame:screenBounds];
m_view = [[GLView alloc] initWithFrame:screenBounds];
[m_window addSubview:m_view];
[application setStatusBarHidden:YES withAnimation:UIStatusBarAnimationNone];
OpenGLVC *oglvc = [[OpenGLVC alloc] init];
self.m_window.rootViewController = oglvc;
// Override point for customization after application launch.
[self.m_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

嘗試改變

glVertexPointer(2,GL_FLOAT,4,&Vertices[0].Position);
glColorPointer(4,GL_FLOAT,2,&Vertices[0].Color);

至

glVertexPointer(2,GL_FLOAT,sizeof(Vertex),&Vertices[0].Position);
glColorPointer(4,GL_FLOAT,sizeof(Vertex),&Vertices[0].Color);

這兩個函數中的第三個參數應該是跨度，即Vertices [0] .Position和Vertices [1] .Position之間的字節偏移量之差。

換句話說，如果您站在Vertices [i] .Position上並花了一個大步，然后站在Vertices [i + 1] .Position上，則您的步幅必須以字節為單位（而不是浮點數） 。 這並不是說你必須跳過從頂點結束[I] .POSITION去頂點開始第[i + 1] .POSITION的差距。

此外，跨度始終以字節表示，而不是浮點數或整數。

看到：

http://www.opengl.org/sdk/docs/man/xhtml/glVertexPointer.xml

http://www.opengl.org/sdk/docs/man/xhtml/glColorPointer.xml