我正在开发一个iOS openGL ES应用程序。
我正在做通常的EAGLView / ES2Render东西。
启动时,使用以下代码成功创建frambuffer:
- (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;
}
不久之后,UIView
的-layoutSubviews
叫,我又执行-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;
}
我在做什么都没什么特别的。我有一个单独的帧缓冲区来渲染场景过渡,其中两个纹理分别附加到颜色和深度上。
第二次-renderbufferStorage:fromDrawable:
称为(-layoutSubviews
-> resizeFromLayer:
),它总是失败(返回NO
);glGetError()
在此之前立即调用不会导致任何错误,但在return之后立即调用它不会导致错误GL_INVALID_OPERATION
。如果我忽略这一点并继续进行操作,glGetRenderbufferParameteriv()
仍然可以让我获得正确的宽度和高度(在iPhone 5上分别为640和1136),但是glCheckFramebufferStatus()
会返回GL_FRAMEBUFFER_UNSUPPORTED
。
另外,我跳过了上述内容,resizeFromLayer:
并用以下内容替换了它:
- (BOOL) resizeFromLayer:(CAEAGLLayer *)layer
{
[self destroyFramebuffers];
return [self createFramebuffers];
}
...但是相同的错误仍然存在(-renderStorage:fromDrawable:
失败;这次是内部-createFramebuffers
)。
现在,我只是返回YES
(我的应用程序仅支持纵向,因此实际上没有发生任何屏幕尺寸更改),但是我真的想修复它,因为有一天我需要支持横向等等。
一个可能因此renderbufferStorage:fromDrawable:
失败是,_mainContext
是不是当时的当前上下文。即使似乎没有其他上下文可以窃取“当前”状态,我还是建议在对与该上下文关联的对象进行操作的[EAGLContext setCurrentContext:_mainContext]
任何代码gl
或EAGL
代码之前进行调用(例如,在resizeFromLayer:
方法的开头)。
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我来说两句