在OpenGL ES 3.0或2.0 Android中渲染立体3D

Question

I am working with 3D objects and I'm using OpenGL ES for Android. What I am trying to do is to implement two GLES20.glViewport() so I can have the same object twice, one in the left and one in the right. I've seen tutorials for OpenGL and C++, and this is possible. But in Android it is different, because I need to call GLES20.glViewport() in the onSurfaceChanged() method. Can someone help me please? Thanks.

Answer 1

Well, I know now how to do this. If someone wants to implement this then here is my solution.

1.- Define your glViewPort() in onSurfaceChanged() method. This can have the full resolution of your screen.

2.- In the method that draws your left object put at the top of it:

GLES20.glEnable(GLES20.GL_SCISSOR_TEST);
GLES20.glScissor(0, 0, width/2, height);
GLES20.glViewport(0, 0, width/2, height);

Then all that is needed for drawing, and finally at the end of the method you disable the scissor test.

GLES20.glDisable(GLES20.GL_SCISSOR_TEST);

3.- You do the same for the right object, but changing the parameters of the functions.

GLES20.glEnable(GLES20.GL_SCISSOR_TEST);
GLES20.glScissor(width/2, 0, width/2, height);
GLES20.glViewport(width/2, 0, width/2, height);
...
GLES20.glDisable(GLES20.GL_SCISSOR_TEST);