在OpenGL ES for iPhone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，并且想要设置一个深度缓冲区，所以我可以使用它。我正在调用 glEnable（GL_DEPTH_TEST）等等，但由于我没有设置z-buffer，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.

我正在寻找等价于
的电话 glutInitDisplayMode（GLUT_DEPTH）

欢迎任何帮助。谢谢！

推荐答案

正如您所怀疑的那样，您没有深度缓冲区。您需要在您创建的任何UIView子类中将深度缓冲区附加到帧缓冲区，该子类使用 CAEAGLLayer 作为其图层。

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.

假设您正在使用Apple的OpenGL ES Xcode模板，相关的UIView子类是EAGLView。其中有一个方法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));
    }
}

它的作用是生成并绑定帧缓冲区，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，抓取帧尺寸以供日后使用，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深度缓冲区。这应该很简单（为depthRenderbuffer添加了一个合适的实例变量;直接在这里输入）：

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);

它看起来像是什么 - 生成并绑定渲染缓冲区，将其存储分配为与颜色缓冲区尺寸相同的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，总计（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));
    }
}

这篇关于在OpenGL ES for iPhone中请求DepthBuffer的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！