Nexus 10 - 渲染到外部渲染目标仅适用于横向

Question

Nexus 10 - 渲染到外部渲染目标仅适用于横向

kea*_*ine 5 android framebuffer glsl opengl-es-2.0 nexus-10

我们正在使用Nexus 10上的OpenGL ES 2.0开发动态壁纸.

动态壁纸使用2个小型(128x128)外部帧缓冲器在它们之间进行乒乓渲染以模糊图像.

虽然这在任何设备上都能正常工作(即使是在老化的摩托罗拉里程碑上),但Nexus 10存在一个奇怪的问题.仅当设备处于横向时才有效.如果设备在任何其他位置(90度,180度或270度)旋转,则帧缓冲区仅具有清晰的颜色.我已经设置glClearColor为红色,因此可以清楚地看到这些帧缓冲区被清除但没有任何内容被渲染到它们中.

我在Tegra 2,Tegra 3,Adreno 200,Adreno 320,2 PowerVR GPU上进行了测试,它运行得很好.

这看起来像一些奇怪的驱动程序错误,但也可能是Mali驱动程序的一些细节.请指教.

代码摘录.

Init帧缓冲区:

private void initBloomStuff() {
    mBloomTextureID = loadTexture("textures/empty128.png");
    mBloomVertTextureID = loadTexture("textures/empty128.png");

    mBloomFBHeight = 128;
    mBloomFBWidth = 128;

    float blurSize = 1.0f;

    // Texel offset for blur filter kernel
    m_fTexelOffset = 1.0f / mBloomFBWidth / blurSize;

    ByteBuffer tmpFB, tmpRB;
    IntBuffer handle, renderbuffers;
    int result;

    tmpFB = ByteBuffer.allocateDirect(4);
    tmpFB.order(ByteOrder.nativeOrder());
    handle = tmpFB.asIntBuffer();
    GLES20.glGenFramebuffers(1, handle);
    framebufferHandle = handle.get(0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mBloomTextureID);
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, framebufferHandle);
    GLES20.glFramebufferTexture2D(GLES20.GL_FRAMEBUFFER, GLES20.GL_COLOR_ATTACHMENT0, GLES20.GL_TEXTURE_2D, mBloomTextureID, 0);

    checkGlError("FB 1");
    tmpRB = ByteBuffer.allocateDirect(4);
    renderbuffers = tmpRB.asIntBuffer();
    GLES20.glGenRenderbuffers(1, renderbuffers);
    checkGlError("FB 1 - glGenRenderbuffers");
    depthbufferHandle = renderbuffers.get(0);
    GLES20.glBindRenderbuffer(GLES20.GL_RENDERBUFFER, depthbufferHandle);
    checkGlError("FB 1 - glBindRenderbuffer");
    GLES20.glRenderbufferStorage(GLES20.GL_RENDERBUFFER, GLES20.GL_DEPTH_COMPONENT16, mBloomFBWidth, mBloomFBHeight);
    checkGlError("FB 1 - glRenderbufferStorage");
    GLES20.glFramebufferRenderbuffer(GLES20.GL_FRAMEBUFFER, GLES20.GL_DEPTH_ATTACHMENT, GLES20.GL_RENDERBUFFER, depthbufferHandle);
    checkGlError("FB 1 - glFramebufferRenderbuffer");

    result = GLES20.glCheckFramebufferStatus(GLES20.GL_FRAMEBUFFER);
    if (result != GLES20.GL_FRAMEBUFFER_COMPLETE) {
        Log.d(TAG, "Error creating framebufer 1: " + result);
    } else {
        Log.d(TAG, "Created framebufer 1: " + result);
    }

    GLES20.glBindRenderbuffer(GLES20.GL_RENDERBUFFER, 0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0);
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);

    tmpFB = ByteBuffer.allocateDirect(4);
    tmpFB.order(ByteOrder.nativeOrder());
    handle = tmpFB.asIntBuffer();
    GLES20.glGenFramebuffers(1, handle);
    framebufferVertHandle = handle.get(0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mBloomVertTextureID);
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, framebufferVertHandle);
    GLES20.glFramebufferTexture2D(GLES20.GL_FRAMEBUFFER, GLES20.GL_COLOR_ATTACHMENT0, GLES20.GL_TEXTURE_2D, mBloomVertTextureID, 0);

    checkGlError("FB 2");
    tmpRB = ByteBuffer.allocateDirect(4);
    renderbuffers = tmpRB.asIntBuffer();
    GLES20.glGenRenderbuffers(1, renderbuffers);
    checkGlError("FB 2 - glGenRenderbuffers");
    depthbufferVertHandle = renderbuffers.get(0);
    GLES20.glBindRenderbuffer(GLES20.GL_RENDERBUFFER, depthbufferVertHandle);
    checkGlError("FB 2 - glBindRenderbuffer");
    GLES20.glRenderbufferStorage(GLES20.GL_RENDERBUFFER, GLES20.GL_DEPTH_COMPONENT16, mBloomFBWidth, mBloomFBHeight);
    checkGlError("FB 2 - glRenderbufferStorage");
    GLES20.glFramebufferRenderbuffer(GLES20.GL_FRAMEBUFFER, GLES20.GL_DEPTH_ATTACHMENT, GLES20.GL_RENDERBUFFER, depthbufferVertHandle);
    checkGlError("FB 2 - glFramebufferRenderbuffer");

    result = GLES20.glCheckFramebufferStatus(GLES20.GL_FRAMEBUFFER);
    if (result != GLES20.GL_FRAMEBUFFER_COMPLETE) {
        Log.d(TAG, "Error creating framebufer 2: " + result);
    } else {
        Log.d(TAG, "Created framebufer 2: " + result);
    }

    GLES20.glBindRenderbuffer(GLES20.GL_RENDERBUFFER, 0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0);
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);

    mTriangleVerticesVignette = ByteBuffer.allocateDirect(mQuadTriangles.length * FLOAT_SIZE_BYTES).order(ByteOrder.nativeOrder()).asFloatBuffer();
    mTriangleVerticesVignette.put(mQuadTriangles).position(0);
}

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渲染到FB:

    GLES20.glUseProgram(mProgram);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mStemTextureID);
    drawBird();
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mSphereTextureID);
    drawSphere();

    GLES20.glViewport(0, 0, mBloomFBWidth, mBloomFBHeight);
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, framebufferHandle);
    // GLES20.glBindRenderbuffer(GLES20.GL_FRAMEBUFFER, depthbufferHandle);

    GLES20.glClearColor(1.0f, 0.5f, 0.5f, 1.0f);
    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mStemTextureID);
    drawBird();
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mSphereTextureID);
    drawSphere();

    GLES20.glViewport(0, 0, screenWidth, screenHeight);
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);
    // GLES20.glBindRenderbuffer(GLES20.GL_FRAMEBUFFER, 0);

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2个FB之间的乒乓渲染模糊图像:

    GLES20.glUseProgram(mBloomProgram);
    GLES20.glUniform1i(mBloom_sTexture, 0);
    GLES20.glUniform1f(mBloom_bloomFactor, 0.8f);

    GLES20.glActiveTexture(GL10.GL_TEXTURE0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mBloomTextureID);
    GLES20.glViewport(0, 0, mBloomFBWidth, mBloomFBHeight);
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, framebufferVertHandle);
    GLES20.glUniform1f(mBloom_TexelOffsetX, m_fTexelOffset);
    GLES20.glUniform1f(mBloom_TexelOffsetY, 0.0f);
    GLES20.glActiveTexture(GL10.GL_TEXTURE0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mBloomTextureID);
    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
    drawBloom();
    GLES20.glViewport(0, 0, screenWidth, screenHeight);
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);

    GLES20.glActiveTexture(GL10.GL_TEXTURE0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mBloomVertTextureID);
    GLES20.glViewport(0, 0, mBloomFBWidth, mBloomFBHeight);
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, framebufferHandle);
    GLES20.glUniform1f(mBloom_TexelOffsetX, 0.0f);
    GLES20.glUniform1f(mBloom_TexelOffsetY, m_fTexelOffset);
    GLES20.glActiveTexture(GL10.GL_TEXTURE0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mBloomVertTextureID);
    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
    drawBloom();
    GLES20.glViewport(0, 0, screenWidth, screenHeight);
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);

    GLES20.glActiveTexture(GL10.GL_TEXTURE0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mBloomTextureID);
    GLES20.glViewport(0, 0, mBloomFBWidth, mBloomFBHeight);
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, framebufferVertHandle);
    GLES20.glUniform1f(mBloom_TexelOffsetX, m_fTexelOffset / 2);
    GLES20.glUniform1f(mBloom_TexelOffsetY, m_fTexelOffset / 2);
    GLES20.glActiveTexture(GL10.GL_TEXTURE0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mBloomTextureID);
    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
    drawBloom();
    GLES20.glViewport(0, 0, screenWidth, screenHeight);
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);

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测试应用程序来重现bug

你可以在这里下载测试APK:https://dl.dropboxusercontent.com/u/7197208/LiveWallpaperAnimTest.apk 这是一个动态壁纸应用程序,安装它并选择'测试'动态壁纸(有玫瑰图标).

正如您所看到的,在默认的横向方向上,您将看到围绕鸟的一些"绽放"效果,这是通过两个帧缓冲区之间的乒乓渲染实现的.在任何其他设备方向,它不起作用,并用明亮的颜色(红色)填充FB.

其他链接

我还将此问题发布到了Mali开发人员中心和Google代码:

http://forums.arm.com/index.php?/topic/16894-nexus-10-render-to-external-rendertarget-works-only-in-landscape/

http://code.google.com/p/android/issues/detail?id=57391

Answer 1

kea*_*ine 1

Mali 驱动程序支持团队确认这是一个驱动程序错误，并将在下一个驱动程序版本中修复它。glViewport作为临时解决方法，他们建议在后致电glBindFramebuffer。此解决方法有效 - 在更改调用顺序后，我设法实现了正确的渲染。

我建议 Google 联系 ARM，一旦固定驱动程序可用，就为 Nexus 10 提供固定的 OpenGL ES 驱动程序。如果有人愿意让这种情况更快发生，您可以在 Android bug 跟踪器中为问题加注星标：http://code.google.com/p/android/issues/detail ?id=57391

链接到我已提交此问题的马里开发者中心论坛： http://forums.arm.com/index.php ?/topic/16894-nexus-10-render-to-external-rendertarget-works-only-in -景观/

由于此驱动程序错误已得到 ARM 的验证和确认，请前往Android 问题 #57391并加注星标，而不是为这个 SO 问题投票。希望这能迫使 Google 重视问题并发布固件更新，让 Nexus 10 变得更好。这就是我为这个问题分配赏金的原因。

编辑。这个bug终于在Android 4.4中得到修复。

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