[英]Is it possible to render an Android View to an OpenGL FBO or texture?
是否可以将视图(例如,WebView)渲染到 FBO,以便它可以用作 OpenGL 组合中的纹理?
我汇集了一个完整的演示项目,它以一种有效的方式实时渲染 GL 纹理的视图,可以在这个 repo 中找到。 它以如何将 WebView 实时渲染为 GL 纹理为例。
还有一个简短的代码如下(取自上述 repo 的演示项目):
public class GLWebView extends WebView {
private ViewToGLRenderer mViewToGLRenderer;
...
// drawing magic
@Override
public void draw( Canvas canvas ) {
//returns canvas attached to gl texture to draw on
Canvas glAttachedCanvas = mViewToGLRenderer.onDrawViewBegin();
if(glAttachedCanvas != null) {
//translate canvas to reflect view scrolling
float xScale = glAttachedCanvas.getWidth() / (float)canvas.getWidth();
glAttachedCanvas.scale(xScale, xScale);
glAttachedCanvas.translate(-getScrollX(), -getScrollY());
//draw the view to provided canvas
super.draw(glAttachedCanvas);
}
// notify the canvas is updated
mViewToGLRenderer.onDrawViewEnd();
}
...
}
public class ViewToGLRenderer implements GLSurfaceView.Renderer{
private SurfaceTexture mSurfaceTexture;
private Surface mSurface;
private int mGlSurfaceTexture;
private Canvas mSurfaceCanvas;
...
@Override
public void onDrawFrame(GL10 gl){
synchronized (this){
// update texture
mSurfaceTexture.updateTexImage();
}
}
@Override
public void onSurfaceChanged(GL10 gl, int width, int height){
releaseSurface();
mGlSurfaceTexture = createTexture();
if (mGlSurfaceTexture > 0){
//attach the texture to a surface.
//It's a clue class for rendering an android view to gl level
mSurfaceTexture = new SurfaceTexture(mGlSurfaceTexture);
mSurfaceTexture.setDefaultBufferSize(mTextureWidth, mTextureHeight);
mSurface = new Surface(mSurfaceTexture);
}
}
public Canvas onDrawViewBegin(){
mSurfaceCanvas = null;
if (mSurface != null) {
try {
mSurfaceCanvas = mSurface.lockCanvas(null);
}catch (Exception e){
Log.e(TAG, "error while rendering view to gl: " + e);
}
}
return mSurfaceCanvas;
}
public void onDrawViewEnd(){
if(mSurfaceCanvas != null) {
mSurface.unlockCanvasAndPost(mSurfaceCanvas);
}
mSurfaceCanvas = null;
}
}
演示输出截图:
是的,这当然可能,我在这里写了一个操作方法; http://www.felixjones.co.uk/neo%20website/Android_View/
但是对于不会改变的静态元素,位图选项可能更好。
至少有人设法以这种方式呈现文本:
它描述了我使用 OpenGL ES 1.0 和 TrueType/OpenType 字体文件高效渲染高质量动态文本的方法。
[...]
整个过程其实很简单。 我们生成位图(作为纹理),计算并存储每个字符的大小,以及它在纹理上的位置(UV 坐标)。 还有一些其他更精细的细节,但我们会谈到这一点。
OpenGL ES 2.0 版本: https : //github.com/d3kod/Texample2
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