opengl FrameBuffer的使用

1.创建framebuffer

GLES20.glGenFramebuffers(1,framebuffer,0);

2.创建纹理

//初始化纹理,一个绑定fbo
GLES20.glGenTextures(textur.length, textur, 0);        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textur[0]);        GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_RGB,
                1000, 1000,
                0, GLES20.GL_RGB,
                GLES20.GL_UNSIGNED_BYTE, null);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR);

3.绑定纹理

 GLES20.glBindTexture(GLES20.GL_TEXTURE_2D,textur[0]);

4.绑定framebuffer

 GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, framebuffer[0]);

5.framebuffer绑定纹理

GLES20.glFramebufferTexture2D(GLES20.GL_FRAMEBUFFER, GLES20.GL_COLOR_ATTACHMENT0,
                GLES20.GL_TEXTURE_2D, textur[0], 0);
        

6.绘制,与其他的绘制一样

 super.render();

7.解绑framebuffer

     GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);

8.解绑纹理

 GLES20.glBindTexture(GLES20.GL_TEXTURE_2D,0);

9.绘制framebuffer中的东西，抛开前面，现在绘制纹理，上面创建的texture