ResolveMultisampleFramebufferAPPLE生成INVALID_OPERATION
我想不通，为什么glResolveMultisampleFramebufferAPPLE生成错误1282（0x0502， GL_INVALID_OPERATION ）。
设置代码：
glGenFramebuffers(1, &framebuffer); glBindFramebuffer(GL_FRAMEBUFFER, framebuffer); glGenRenderbuffers(1, &colorRenderbuffer); glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer); [context renderbufferStorage:GL_RENDERBUFFER fromDrawable:(id<EAGLDrawable>)self.layer]; glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorRenderbuffer); glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &backingWidth); glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &backingHeight); GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER); if(status != GL_FRAMEBUFFER_COMPLETE) { NSLog(@"failed to make complete framebuffer object %x", status); } glGenFramebuffers(1, &sampleFramebuffer); glBindFramebuffer(GL_FRAMEBUFFER, sampleFramebuffer); glGenRenderbuffers(1, &sampleColorRenderbuffer); glBindRenderbuffer(GL_RENDERBUFFER, sampleColorRenderbuffer); glRenderbufferStorageMultisampleAPPLE(GL_RENDERBUFFER, 4, GL_RGBA8_OES, backingWidth, backingWidth); glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, sampleColorRenderbuffer); glGenRenderbuffers(1, &sampleDepthRenderbuffer); glBindRenderbuffer(GL_RENDERBUFFER, sampleDepthRenderbuffer); glRenderbufferStorageMultisampleAPPLE(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT16_OES, backingWidth, backingWidth); glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, sampleDepthRenderbuffer);
渲染代码：
glBindFramebuffer(GL_FRAMEBUFFER, sampleFramebuffer); glViewport(0, 0, backingWidth, backingHeight); glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT); GLfloat vertices[] = { 1.0f, 1.0f, 0.0f, 2.0f, 4.0f, 0.0f, 1.0f, 3.0f, 0.0f }; glColor4f(1.0f, 0.0f, 0.0f, 1.0f); glVertexPointer(3, GL_FLOAT, 0, vertices); glDrawArrays(GL_TRIANGLE_STRIP, 0, 3); glBindFramebuffer(GL_READ_FRAMEBUFFER_APPLE, sampleFramebuffer); glBindFramebuffer(GL_DRAW_FRAMEBUFFER_APPLE, framebuffer); glResolveMultisampleFramebufferAPPLE(); NSLog(@"Error: %d", glGetError()); // <<< Here I get 1282 const GLenum discards[] = { GL_DEPTH_ATTACHMENT }; glDiscardFramebufferEXT(GL_READ_FRAMEBUFFER_APPLE, 1, discards); glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer); [context presentRenderbuffer:GL_RENDERBUFFER];
完整的源代码可以在Bitbucket中find： https ： //bitbucket.org/amjaliks/gl2/src
我将backingWidth两次传递给glRenderbufferStorageMultisampleAPPLE 。 因此，我得到了不同大小的renderbuffers，并导致INVALID_OPERATION 。