OpenGL MSAA多采樣中的蒙版（stencil）使用

在OpenGL中進行MSAA多采樣時，需要進行如下設置FBO

glGenFramebuffers(1, &mfbo);
		glBindFramebuffer(GL_FRAMEBUFFER, mfbo);
		//create color render buffer
		glGenRenderbuffers(1, &colorBuffer);
		glBindRenderbuffer(GL_RENDERBUFFER, colorBuffer);
		glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4 /* 4 samples */, GL_RGBA8, width, height);
		glBindRenderbuffer(GL_RENDERBUFFER, 0);
		glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorBuffer);
		// multi sampled depth buffer
		glGenRenderbuffers(1, &depthBuffer);
		glBindRenderbuffer(GL_RENDERBUFFER, depthBuffer);
		glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4 /* 4 samples */, GL_RGBA8, width, height);
		glBindRenderbuffer(GL_RENDERBUFFER, 0);
		glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthBuffer);


		GLenum result = glCheckFramebufferStatus(GL_FRAMEBUFFER);

		if (result == GL_FRAMEBUFFER_COMPLETE) {
			isMultiFBODone = true;
		}
		else {
			isMultiFBODone = false;
		}

		glBindFramebuffer(GL_FRAMEBUFFER, 0);

如果程序中還需要使用蒙版緩衝（stencil buffer），則需要將此FBO設置爲如下格式：

glGenFramebuffers(1, &mfbo);
		glBindFramebuffer(GL_FRAMEBUFFER, mfbo);
		//create color render buffer
		glGenRenderbuffers(1, &colorBuffer);
		glBindRenderbuffer(GL_RENDERBUFFER, colorBuffer);
		glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4 /* 4 samples */, GL_RGBA8, width, height);
		glBindRenderbuffer(GL_RENDERBUFFER, 0);
		glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorBuffer);
		// multi sampled depth buffer
		glGenRenderbuffers(1, &depthBuffer);
		glBindRenderbuffer(GL_RENDERBUFFER, depthBuffer);
		glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4 /* 4 samples */, GL_DEPTH24_STENCIL8, width, height);
		glBindRenderbuffer(GL_RENDERBUFFER, 0);
		glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, depthBuffer);


		GLenum result = glCheckFramebufferStatus(GL_FRAMEBUFFER);

		if (result == GL_FRAMEBUFFER_COMPLETE) {
			isMultiFBODone = true;
		}
		else {
			isMultiFBODone = false;
		}

		glBindFramebuffer(GL_FRAMEBUFFER, 0);

然後在根據需要寫關於蒙版的代碼即可