您需要做的就是在启动时使用您想要的 EAGLView 类中的框架调用 [super initWithFrame:frame]。此示例将在左上角创建一个透明的 OpenGL 视图并将其添加到您的控制器视图中。
我的 EAGLView 类中有以下代码:
- (id)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
// get the layer
CAEAGLLayer *eaglLayer = (CAEAGLLayer *)self.layer;
eaglLayer.opaque = NO;
eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:NO],
kEAGLDrawablePropertyRetainedBacking,
kEAGLColorFormatRGBA8,
kEAGLDrawablePropertyColorFormat,
nil];
context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];
if (!context || ![EAGLContext setCurrentContext:context]) {
[self release];
return nil;
}
[EAGLContext setCurrentContext:context];
[self destroyFramebuffer];
[self createFramebuffer];
}
return self;
}
然后我从我的控制器创建 EAGLView,如下所示:
theEAGLView = [[EAGLView alloc] initWithFrame:CGRectMake(30.0f, 30.0f,
90.0f, 70.0f)];
theEAGLView.opaque = NO;
[self.view addSubview:theEAGLView];
在我的 EAGLView 类中进行实际绘图的代码是从控制器调用的,如下所示:
- (void)render {
glViewport(0, 0, backingWidth, backingHeight);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrthof(0.0f, backingWidth, 0.0f, backingHeight, 1000.0f, -1000.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT);
// this is where we draw our stuff
// ...
// ...
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
[context presentRenderbuffer:GL_RENDERBUFFER_OES];
}