在 iPhone 的 OpenGL ES 中请求 DepthBuffer [英] Request a DepthBuffer in OpenGL ES for iPhone

问题描述

我正在 iPhone 上创建一个 3D OpenGL ES 视图并想设置一个深度缓冲区，以便我可以使用它.我正在调用 glEnable(GL_DEPTH_TEST) 等，但是因为我没有设置 z-buffer，所以它什么也没做.

I'm creating a 3D OpenGL ES view on the iPhone and want to set up a depth buffer, so I can use it. I'm calling glEnable(GL_DEPTH_TEST) and such, but because I haven't set up the z-buffer, it does nothing.

我正在寻找对等的调用glutInitDisplayMode(GLUT_DEPTH)

非常欢迎任何帮助.谢谢！

Any help would be most welcome. Thanks!

推荐答案

正如您所怀疑的，您没有深度缓冲区.您需要在您创建的使用 CAEAGLLayer 作为其层的任何 UIView 子类中将深度缓冲区附加到帧缓冲区.

As you suspect, you've no depth buffer. You'll need to attach a depth buffer to your frame buffer in whatever UIView subclass you've created that uses a CAEAGLLayer as its layer.

假设您使用 Apple 的 OpenGL ES Xcode 模板，相关的 UIView 子类是 EAGLView.那里有一个方法，createFramebuffer，它负责创建帧缓冲区.最初它会说:

Supposing you're working with Apple's OpenGL ES Xcode template, the relevant UIView subclass is EAGLView. There's a method in there, createFramebuffer, that is responsible for creating the frame buffer. Initially it'll say:

- (void)createFramebuffer
{
    if (context && !defaultFramebuffer)
    {
        [EAGLContext setCurrentContext:context];

        // Create default framebuffer object.
        glGenFramebuffers(1, &defaultFramebuffer);
        glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebuffer);

        // Create color render buffer and allocate backing store.
        glGenRenderbuffers(1, &colorRenderbuffer);
        glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer);
        [context renderbufferStorage:GL_RENDERBUFFER fromDrawable:(CAEAGLLayer *)self.layer];
        glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &framebufferWidth);
        glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &framebufferHeight);

        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorRenderbuffer);

        if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
            NSLog(@"Failed to make complete framebuffer object %x", glCheckFramebufferStatus(GL_FRAMEBUFFER));
    }
}

它所做的是生成并绑定一个帧缓冲区，然后它生成并绑定一个颜色渲染缓冲区，为颜色缓冲区提供 CAEAGLLayer 附带的固有存储，为以后获取帧尺寸并将颜色缓冲区附加到渲染缓冲区.

What that does is generates and binds a frame buffer, then it generates and binds a colour render buffer, gifts the colour buffer the inherent storage that comes with a CAEAGLLayer, grabs the frame dimensions for later and attaches the colour buffer to the render buffer.

您还需要创建并附加一个深度缓冲区.应该很简单(为 depthRenderbuffer 添加合适的实例变量；直接在此处输入):

You need also to create and attach a depth buffer. Which should be as simple as (with a suitable instance variable added for depthRenderbuffer; typing directly in here):

glGenRenderbuffers(1, &depthRenderbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, depthRenderbuffer);

glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, framebufferWidth, framebufferHeight);

glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthRenderbuffer);

它看起来像它所做的那样 - 生成并绑定一个渲染缓冲区，将其分配为与颜色缓冲区相同尺寸的 16 位深度缓冲区，然后将其附加到帧缓冲区.

Which does what it looks like it does — generates and binds a render buffer, allocates it storage to be a 16bit depth buffer of the same dimensions as the colour buffer and then attaches it to the frame buffer.

因此，总共(未经测试):

So, in total (untested):

- (void)createFramebuffer
{
    if (context && !defaultFramebuffer)
    {
        [EAGLContext setCurrentContext:context];

        // Create default framebuffer object.
        glGenFramebuffers(1, &defaultFramebuffer);
        glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebuffer);

        // Create color render buffer and allocate backing store.
        glGenRenderbuffers(1, &colorRenderbuffer);
        glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer);
        [context renderbufferStorage:GL_RENDERBUFFER fromDrawable:(CAEAGLLayer *)self.layer];
        glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &framebufferWidth);
        glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &framebufferHeight);

        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorRenderbuffer);

        // Create depth render buffer and allocate backing store.
        glGenRenderbuffers(1, &depthRenderbuffer);
        glBindRenderbuffer(GL_RENDERBUFFER, depthRenderbuffer);

        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, framebufferWidth, framebufferHeight);

        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthRenderbuffer);

        if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
            NSLog(@"Failed to make complete framebuffer object %x", glCheckFramebufferStatus(GL_FRAMEBUFFER));
    }
}

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