我是OpenGL的完全菜鸟，我一直在尝试让这段简单的代码在iPhone模拟器上渲染，它启动正常，启动画面显示，然后......无。。。只是黑暗，我说不出我错过了什么，可以帮忙吗？我还没有为旋转做任何事情，等着看我先渲染了什么，然后继续旋转等等......
我正在使用Xcode 4.2，如果这很重要的话。
这是我的代码：
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(){};
};
渲染引擎.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，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
尝试更改
glVertexPointer(2,GL_FLOAT,4,&Vertices[0].Position);
glColorPointer(4,GL_FLOAT,2,&Vertices[0].Color);
自
glVertexPointer(2,GL_FLOAT,sizeof(Vertex),&Vertices[0].Position);
glColorPointer(4,GL_FLOAT,sizeof(Vertex),&Vertices[0].Color);
这两个函数中的第三个参数应该是步幅，即顶点[0]之间的字节偏移量之差。位置和顶点[1]。位置。
换句话说，如果你站在顶点[i]。位置并大步走，然后站在顶点[i+1]。位置，您的步幅必须以字节为单位（而不是浮点数）多长时间。 这不是你必须跳过的间隙才能从顶点[i]的末尾获得。顶点起点的位置[i+1]。位置。
此外，步幅始终以字节表示，而不是浮点数或整数。
看：
http://www.opengl.org/sdk/docs/man/xhtml/glVertexPointer.xml
http://www.opengl.org/sdk/docs/man/xhtml/glColorPointer.xml