C++ opengl 深度缓冲区

GL_DEPTH_BUFFER_BIT 每一次清除之前，都要清空深度缓冲区
启动深度测试glEnable(GL_DEPTH_TEST):离视野近的物体会挡住离视野远的物体。
 

运行截图如下：

源码如下：

void Init() {
	glMatrixMode(GL_PROJECTION);
	gluPerspective(50.0f, 800.0f / 600.0f, 0.1f, 1000.0f);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}

void Draw() {
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
	glClear(GL_COLOR_BUFFER_BIT);
	glBegin(GL_QUADS);
	glColor4ub(200, 50, 0, 255);
	glVertex3f(-0.1f, -0.1f, -0.4f);
	glVertex3f(0.1f, -0.1f, -0.4f);
	glVertex3f(0.1f, 0.1f, -0.4f);
	glVertex3f(-0.1f, 0.1f, -0.4f);

	glColor4ub(0, 50, 200, 255);
	glVertex3f(-0.1f, -0.1f, -0.6f);
	glVertex3f(0.1f, -0.1f, -0.6f);
	glVertex3f(0.1f, 0.1f, -0.6f);
	glVertex3f(-0.1f, 0.1f, -0.6f);
	glEnd();
}

清空缓冲区，和启动深度缓冲测试，程序运行截图如下：

离视野近的物体会挡住离视野远的物体

源码如下：

void Init() {
	glMatrixMode(GL_PROJECTION);
	gluPerspective(50.0f, 800.0f / 600.0f, 0.1f, 1000.0f);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}

void Draw() {
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glEnable(GL_DEPTH_TEST);
	glBegin(GL_QUADS);
	glColor4ub(200, 50, 0, 255);
	glVertex3f(-0.1f, -0.1f, -0.4f);
	glVertex3f(0.1f, -0.1f, -0.4f);
	glVertex3f(0.1f, 0.1f, -0.4f);
	glVertex3f(-0.1f, 0.1f, -0.4f);

	glColor4ub(0, 50, 200, 255);
	glVertex3f(-0.1f, -0.1f, -0.6f);
	glVertex3f(0.1f, -0.1f, -0.6f);
	glVertex3f(0.1f, 0.1f, -0.6f);
	glVertex3f(-0.1f, 0.1f, -0.6f);
	glEnd();
}