在Android上使用帧缓冲区时，场景不会渲染

问题描述

我正尝试将我的应用程序切换到使用帧缓冲区/渲染缓冲区对象(希望稍后渲染到纹理)，但每当我使用帧缓冲区/渲染缓冲区时，什么都不渲染。如果默认帧缓冲区处于打开状态(默认情况下)，则渲染效果良好；所有与颜色、深度和模具相关的功能均可完全按照预期工作。

初始化代码：

if(frameBuffer == 0 || !GLES20.glIsFramebuffer(frameBuffer)){
    int[] retVal = new int[1];
    GLES20.glGenFramebuffers(1, retVal, 0);
    frameBuffer = retVal[0];
    retVal[0] = 0;

    if(renderBufferColour != 0 || !GLES20.glIsRenderbuffer(renderBufferColour)){
        GLES20.glGenRenderbuffers(1, retVal, 0);
        renderBufferColour = retVal[0];
    }

    if(renderBufferDepth != 0 || !GLES20.glIsRenderbuffer(renderBufferDepth)){
        GLES20.glGenRenderbuffers(1, retVal, 0);
        renderBufferDepth = retVal[0];
    }

    if(renderBufferStencil != 0 || !GLES20.glIsRenderbuffer(renderBufferStencil)){
        GLES20.glGenRenderbuffers(1, retVal, 0);
        renderBufferStencil = retVal[0];
    }
}

FrameBuffer启用代码(将此注释掉允许使用默认缓冲区进行渲染)：

GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, frameBuffer);

GLES20.glBindRenderbuffer(GLES20.GL_RENDERBUFFER, renderBufferColour);
GLES20.glRenderbufferStorage(GLES20.GL_RENDERBUFFER, GLES20.GL_RGBA4, width, height);
GLES20.glFramebufferRenderbuffer(
        GLES20.GL_FRAMEBUFFER,
        GLES20.GL_COLOR_ATTACHMENT0,
        GLES20.GL_RENDERBUFFER,
        renderBufferColour);

GLES20.glBindRenderbuffer(GLES20.GL_RENDERBUFFER, renderBufferDepth);
GLES20.glRenderbufferStorage(GLES20.GL_RENDERBUFFER, GLES20.GL_DEPTH_COMPONENT16, width, height);
GLES20.glFramebufferRenderbuffer(
        GLES20.GL_FRAMEBUFFER,
        GLES20.GL_DEPTH_ATTACHMENT,
        GLES20.GL_RENDERBUFFER,
        renderBufferDepth);

GLES20.glBindRenderbuffer(GLES20.GL_RENDERBUFFER, renderBufferStencil);
GLES20.glRenderbufferStorage(GLES20.GL_RENDERBUFFER, GLES20.GL_STENCIL_INDEX8, width, height);
GLES20.glFramebufferRenderbuffer(
        GLES20.GL_FRAMEBUFFER,
        GLES20.GL_STENCIL_ATTACHMENT,
        GLES20.GL_RENDERBUFFER,
        renderBufferStencil);

if (GLES20.glCheckFramebufferStatus(GLES20.GL_FRAMEBUFFER) != GLES20.GL_FRAMEBUFFER_COMPLETE)
    throw new RuntimeException(String.format("Failed to make complete framebuffer object %x", GLES20.glCheckFramebufferStatus(GLES20.GL_FRAMEBUFFER)));

不抛出结尾处的异常，在每一步后检查glGetError()时，不返回错误。我是不是错过了什么？

推荐答案

好的，在阅读了OpenGLES2.0手册后，我看到了这一段：

By allowing the images of a renderbuffer to be attached to a framebuffer,
OpenGL ES provides a mechanism to support off-screen rendering. Further, by
allowing the images of a texture to be attached to a framebuffer, OpenGL ES provides
a mechanism to support render to texture.

在我看来，应用程序呈现缓冲区始终在屏幕外而不是像我预期的在屏幕上。如果我没有读错的话，这就是屏幕上没有图像的原因。

这篇关于在Android上使用帧缓冲区时，场景不会渲染的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！