iOS5是否同时支持GL_STENCIL_INDEX和GL_STENCIL_INDEX8? [英] Does iOS5 support both GL_STENCIL_INDEX and GL_STENCIL_INDEX8?
问题描述
使用以下代码:
GLuint viewRenderbuffer, viewFramebuffer, viewDepthbuffer, stencilBuffer;
// Create the framebuffer object
glGenFramebuffers(1, &viewFramebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, viewFramebuffer);
// Create a render buffer and bind it to the FBO.
glGenRenderbuffers(1, &viewRenderbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, viewRenderbuffer);
[context renderbufferStorage:GL_RENDERBUFFER fromDrawable:(CAEAGLLayer*)self.layer];
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, viewRenderbuffer);
glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &imageWidth);
glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &imageHeight);
// Create a depth buffer and bind it to the FBO.
glGenRenderbuffers(1, &viewDepthbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, viewDepthbuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, imageWidth, imageHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, viewDepthbuffer);
// Create a stencil buffer to crop the rendered scene and bind it to the FBO.
glGenRenderbuffers(1, &stencilBuffer);
glBindRenderbuffer(GL_RENDERBUFFER, stencilBuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_STENCIL_INDEX, imageWidth, imageHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, stencilBuffer);
// Check the FBO.
if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
NSLog(@"Failure with framebuffer generation: %d", glCheckFramebufferStatus(GL_FRAMEBUFFER));
}
使用GL_STENCIL_INDEX
时,出现GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT
错误.使用GL_STENCIL_INDEX8
时,出现GL_FRAMEBUFFER_UNSUPPORTED
错误.两者都是由最后一个glFramebufferRenderbuffer()函数引起的,该函数应该将模板缓冲区绑定到FBO.
With GL_STENCIL_INDEX
, I get the GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT
error. With GL_STENCIL_INDEX8
, I get the GL_FRAMEBUFFER_UNSUPPORTED
error. Both are caused by the last glFramebufferRenderbuffer() function, which should bind the stencil buffer to the FBO.
此外,当我检查GL_RENDERBUFFER_STENCIL_SIZE
值时,使用GL_STENCIL_INDEX8
可以得到正确的值(8),但是使用GL_STENCIL_INDEX
可以得到0.
Furthermore, when I check the GL_RENDERBUFFER_STENCIL_SIZE
value, I get the right value (8) with GL_STENCIL_INDEX8
, but I get 0 with GL_STENCIL_INDEX
.
有了这个,我无法获得带有模板缓冲区的功能齐全的FBO.是由于GL_STENCIL_INDEX
吗?在这里应该使用哪一个?
With this, I can't get a functional and complete FBO with a stencil buffer. Is it due to the GL_STENCIL_INDEX
? Which one should be used here?
推荐答案
似乎在OpenGL ES 2.0中,至少在iOS上(不确定其他OS),您必须结合使用深度缓冲区和模板缓冲区. 我列出了我的设备(带有iOS 5.0.1的iPhone 4)上支持的所有扩展,并且与模板缓冲区有关的唯一扩展是:
It seems that in OpenGL ES 2.0 at least on iOS (not sure for other OS) you have to create combine the depth buffer and the stencil buffer. I listed all the extensions supported on my device (iPhone 4 with iOS 5.0.1) and the only one related to the stencil buffer is :
GL_OES_packed_depth_stencil
这表明您必须创建一个组合深度+模板缓冲区(摘自iPhone 3D编程书)
This suggests that you would have to create a combo depth+stencil buffer (taken from the iPhone 3D Programming book)
// Create a packed depth stencil buffer.
GLuint depthStencil;
glGenRenderbuffersOES(1, &depthStencil);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthStencil);
glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH24_STENCIL8_OES, width, height);
// Create the framebuffer object.
GLuint framebuffer;
glGenFramebuffersOES(1, &framebuffer);
glBindFramebufferOES(GL_FRAMEBUFFER_OES, framebuffer);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES,
GL_RENDERBUFFER_OES, color);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES,
GL_RENDERBUFFER_OES, depthStencil);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_STENCIL_ATTACHMENT_OES,
GL_RENDERBUFFER_OES, depthStencil);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, color);
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