-[EAGLContext呈现缓冲区存储:来自fromDrawable：]第二次失败？

Question

我正在开发一个iOS openGL ES应用程序。

我正在做通常的EAGLView / ES2Render的事情。

在启动时，使用以下代码成功创建框架缓冲区：

- (BOOL) createFramebuffers
{
    [EAGLContext setCurrentContext:_mainContext];

    // [ A ] On-screen  

    // 1. Framebuffer
    glGenFramebuffers(1, &_mainFramebuffer);
    bindFramebuffer(_mainFramebuffer);

    // 2. Color buffer
    glGenRenderbuffers(1, &_mainColorbuffer);
    bindRenderbuffer(_mainColorbuffer);

    // Adjust size to view's layer:
    CAEAGLLayer* layer = (CAEAGLLayer*)[_view layer];

    if (![_mainContext renderbufferStorage:GL_RENDERBUFFER fromDrawable:layer]) {
        // something went horribly wrong
        NSLog(@"-[ES2Renderer createFramebuffers]: Failed to obtain renderbuffer storage from layer!");
        return NO;
    }

    // Query new size:
    glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH,  &_backingWidth);
    glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &_backingHeight);

    // Attach to color:
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, _mainColorbuffer);

    // 3. Depth buffer
    glGenRenderbuffers(1, &_depthBuffer);
    bindRenderbuffer(_depthBuffer);

    if (_useStencilBuffer) {
        // Depth + Stencil

        // Allocate storage:
        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8_OES, _backingWidth, _backingHeight);

        // Attach to depth:
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, _depthBuffer);

        // Attach to stencil:
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, _depthBuffer);
    }
    else{
        // Depth only

        // Allocate storage:
        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24_OES, _backingWidth, _backingHeight);

        // Attachto depth:
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, _depthBuffer);

    }

    // 4. Validate the set:
    GLenum framebufferStatus = glCheckFramebufferStatus(GL_FRAMEBUFFER);

    if (framebufferStatus != GL_FRAMEBUFFER_COMPLETE) {
        // Something went wrong!

        NSLog(@"-[ES2Renderer createFramebuffers]: Failed to make complete framebuffer object: %@",
              [self stringFromFramebufferStauts:framebufferStatus]);

        return NO;
    }

    // [ B ] Off-screen (Render-to-texture)

    // 1. Framebuffer
    glGenFramebuffers(1, &_transFramebuffer);
    bindFramebuffer(_transFramebuffer);

    // 2. Depth buffer
    glGenRenderbuffers(1, &_transDepthBuffer);
    bindRenderbuffer(_transDepthBuffer);

    if (_useStencilBuffer) {
        // Allocate storage:
        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8_OES, _backingWidth, _backingHeight);

        // Attach to depth:
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, _transDepthBuffer);

        // Attach to stencil:
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, _transDepthBuffer);
    }
    else{
        // Allocate storage
        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24_OES, _backingWidth, _backingHeight);

        // Attach to depth:
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, _transDepthBuffer);
   }


    // 3. Textures (color buffers)

    GLuint* texPtrs[2] = {&_transTexture1, &_transTexture2};

    for (NSUInteger i=0; i < 2; i++) {

        GLuint* texPtr = texPtrs[i];

        // Create:
        glGenTextures(1, texPtr);

        // Bind:
        bindTexture2D(*texPtr);

        // Configure for pixel-aligned use:
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

        // Allocate storage:
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, _backingWidth, _backingHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);

        // Attach:
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, *texPtr, 0);

        framebufferStatus = glCheckFramebufferStatus(GL_FRAMEBUFFER);

        // Validate:
        if ( framebufferStatus != GL_FRAMEBUFFER_COMPLETE) {
            // Something went wrong!

            NSLog(@"-[ES2Renderer createFramebuffers]: Failed to make complete framebuffer object: %@",
                  [self stringFromFramebufferStauts:framebufferStatus]);

            return NO;
        }
    }

    // Final State:

    bindFramebuffer(_mainFramebuffer);
    bindRenderbuffer(_mainColorbuffer);
    bindTexture2D(0);


    NSLog(@"-[ES2Renderer createFramebuffers] Succeeded.");
    return YES;
}

不久，UIView的-layoutSubviews就会被调用，而我又会执行-resizeFromLayer:。

- (BOOL) resizeFromLayer:(CAEAGLLayer *)layer
{
    // [ A ] On screen framebuffer

    bindFramebuffer(_mainFramebuffer);

    // 1. Resize color buffer
    bindRenderbuffer(_mainColorbuffer);

    if (![_mainContext renderbufferStorage:GL_RENDERBUFFER fromDrawable:layer]) {
        // Something went wrong
        return NO; // <-- SECOND TIME ON, THIS HAPPENS
    }

    // Query new size:
    glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH,  &_backingWidth);
    glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &_backingHeight);

    // 2. Resize depth buffer
    bindRenderbuffer(_depthBuffer);

    if (_useStencilBuffer) {
        // (Depth & Stencil)

        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8_OES, _backingWidth, _backingHeight);
    }
    else{
        // (Depth only)

        glRenderbufferStorage(GL_FRAMEBUFFER, GL_DEPTH_COMPONENT24_OES, _backingWidth, _backingHeight);
    }

    // ...Validate:
    GLenum framebufferStatus = glCheckFramebufferStatus(GL_FRAMEBUFFER);

    if (framebufferStatus != GL_FRAMEBUFFER_COMPLETE) {
        // Something went wrong!

        NSLog(@"-[ES2Renderer resizeFromLayer:]: Failed to make complete framebuffer object: %@",
              [self stringFromFramebufferStauts:glCheckFramebufferStatus(GL_FRAMEBUFFER)]);

        return NO;
    }

    // [ B ] Off screen (render-to-terxture) framebuffer

    bindFramebuffer(_transFramebuffer);

    // 1. Resize depth buffer

    bindRenderbuffer(_transDepthBuffer);

    if (_useStencilBuffer) {
        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8_OES, _backingWidth, _backingHeight);
    }
    else{
        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24_OES, _backingWidth, _backingHeight);        
    }


    // 2. Resize textures

    GLuint* texPtrs[2] = {&_transTexture1, &_transTexture2};

    for (NSUInteger i=0; i < 2; i++) {

        GLuint* texPtr = texPtrs[i];

        // Bind:
        bindTexture2D(*texPtr);

        // Configure for pixel-aligned use:
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

        // Allocate storage:
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, _backingWidth, _backingHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);

        // Attach:
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, *texPtr, 0);


        // Validate:
        if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
            // Something went wrong!
            NSString* statusString = [self stringFromFramebufferStauts:glCheckFramebufferStatus(GL_FRAMEBUFFER)];
            NSLog(@"-[ES2Renderer resizeFromLayer:]: Failed to make complete framebuffer object: %@", statusString);
            return NO;
        }
    }

    bindFramebuffer(_mainFramebuffer);
    bindRenderbuffer(_mainColorbuffer);


    // Pass new ortho projection to shaders
    [self initializeModelViewMatrix];
    [self initializeSpriteProgram];

    // Set new viewport
    glViewport(0, 0, _backingWidth, _backingHeight);

    NSLog(@"-[ES2Renderer resizeFromLayer:]: Succeeded.");

    return YES;
}

我所做的一切都不是特别的。我有一个单独的框架缓冲区来呈现场景转换，两个纹理附加到颜色和深度。

第二次调用-renderbufferStorage:fromDrawable: (-layoutSubviews -> resizeFromLayer:)时，它总是失败(返回NO)；在此之前调用glGetError()不会导致错误，但在返回GL_INVALID_OPERATION后立即调用。如果我忽略了这一点并继续，glGetRenderbufferParameteriv()仍然给我正确的宽度和高度(在iPhone 5上分别为640和1136 )，但是glCheckFramebufferStatus()将返回GL_FRAMEBUFFER_UNSUPPORTED。

或者，我跳过了上面的resizeFromLayer:并将其替换为：

- (BOOL) resizeFromLayer:(CAEAGLLayer *)layer
{
    [self destroyFramebuffers];

    return [self createFramebuffers];
}

...but仍然存在相同的错误(-renderStorage:fromDrawable:失败；这一次在-createFramebuffers中)。

现在，我只返回YES (我的应用程序只支持肖像画，所以屏幕大小的变化从来没有发生过)，但我真的想修复它，因为有一天我需要支持景观，等等……

Answer 1

renderbufferStorage:fromDrawable:失败的一个可能原因是_mainContext不是当时的当前上下文。尽管似乎没有其他上下文能够窃取“当前”状态，但我建议在对与该上下文关联的对象(例如，在[EAGLContext setCurrentContext:_mainContext]方法的开头)进行操作的任何gl或EAGL代码之前调用resizeFromLayer:。

Answer 2

另一个可能的原因是你的层太大了。此外，请确保每次都使用新的框架缓冲区和呈现缓冲区。在创造新的之前你已经摧毁了你的旧的。

你可以这样删除它们

if let displayFramebuffer = self.displayFramebuffer {
    var temporaryFramebuffer = displayFramebuffer
    glDeleteFramebuffers(1, &temporaryFramebuffer)
    self.displayFramebuffer = nil
}

if let displayRenderbuffer = self.displayRenderbuffer {
    var temporaryRenderbuffer = displayRenderbuffer
    glDeleteRenderbuffers(1, &temporaryRenderbuffer)
    self.displayRenderbuffer = nil
}

Answer 3

Josh Bernfeld的回答启发了我。我检查了MyView的大小，它的边界是CGRect.zero。CAEAGLLayer也是如此。对我来说，init MyView使用非零的CGRect解决了这个问题。

希望它对你有用。