在opengl中， 可以开启模板测试功能，来限定某一部分是可画的，某一部分是不可画的。这可通过设置模板模式来控制哪部分是可画的， 有点类似在墙上喷字。

虽说剪刀测试也可以限定蓝屏的某一部分可画，但不适用于不规则的区域，不如模板测试灵活。下面提供一个Android模板测试的实例代码：

public class MyRenderer implements Renderer {private Square square1 = null;private FloatBuffer vertices = null;// Step size in x and y directions// (number of pixels to move each time)private float x = 0;private float y = 0;private float xstep = 1.0f;private float ystep = 1.0f;// Keep track of windows changing width and heightprivate float windowWidth;private float windowHeight;public MyRenderer(Context ctx) {square1 = new Square(ctx, false);}private void makeStencilPattern(GL10 gl) {float dRadius = 0.1f;ByteBuffer bb = ByteBuffer.allocateDirect(4000 * 4 * 2);bb.order(ByteOrder.nativeOrder());vertices = bb.asFloatBuffer();vertices.position(0);for(float dAngle = 0; dAngle < 400.0; dAngle += 0.1){vertices.put((float) (dRadius * Math.cos(dAngle)));vertices.put((float) (dRadius * Math.sin(dAngle)));dRadius *= 1.002;}vertices.position(0);}@Overridepublic void onDrawFrame(GL10 gl) {gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_STENCIL_BUFFER_BIT);// Replace the current matrix with the identity matrixgl.glMatrixMode(GL10.GL_MODELVIEW);gl.glLoadIdentity();gl.glStencilFunc(GL10.GL_NEVER, 0x0, 0x0);gl.glStencilOp(GL10.GL_INCR, GL10.GL_INCR, GL10.GL_INCR);gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);gl.glVertexPointer(2, GL10.GL_FLOAT, 0, vertices);gl.glColor4f(0, 1, 1, 1);gl.glDrawArrays(GL10.GL_LINE_STRIP, 0, 4000 * 2);gl.glStencilFunc(GL10.GL_NOTEQUAL, 0x1, 0x1);gl.glStencilOp(GL10.GL_KEEP, GL10.GL_KEEP, GL10.GL_KEEP);gl.glColor4f(1, 0, 0, 1);// Reverse direction when you reach left or right edgeif(x > windowWidth-20 || x < -windowWidth)xstep = -xstep;// Reverse direction when you reach top or bottom edgeif(y > windowHeight || y < -windowHeight + 20)ystep = -ystep;// Check bounds. This is in case the window is made// smaller while the rectangle is bouncing and the // rectangle suddenly finds itself outside the new// clipping volumeif(x > windowWidth-20)x = windowWidth-20-1;if(y > windowHeight)y = windowHeight-1; // Actually move the squarex += xstep;y += ystep;gl.glTranslatef(x, y, 0);square1.draw(gl);}@Overridepublic void onSurfaceChanged(GL10 gl, int w, int h) {float aspectRatio;// Prevent a divide by zeroif(h == 0)h = 1;// Set Viewport to window dimensionsgl.glViewport(0, 0, w, h);// Reset coordinate systemgl.glMatrixMode(GL10.GL_PROJECTION);gl.glLoadIdentity();// Establish clipping volume (left, right, bottom, top, near, far)aspectRatio = (float)w / (float)h;if (w <= h) {windowWidth = 100;windowHeight = 100 / aspectRatio;gl.glOrthof(-100.0f, 100.0f, -windowHeight, windowHeight, 1.0f, -1.0f);}else {windowWidth = 100 * aspectRatio;windowHeight = 100;gl.glOrthof(-windowWidth, windowWidth, -100.0f, 100.0f, 1.0f, -1.0f);}gl.glMatrixMode(GL10.GL_MODELVIEW);gl.glLoadIdentity();}@Overridepublic void onSurfaceCreated(GL10 gl, EGLConfig config) {// TODO Auto-generated method stubgl.glClearColor(0.0f, 0.0f, 1.0f, 0.0f);  // Enable Smooth Shading, default not really needed.gl.glShadeModel(GL10.GL_SMOOTH);gl.glEnable(GL10.GL_STENCIL_TEST);gl.glClearStencil(0);makeStencilPattern(gl);}}