Merge "Performance optimizations" into rvc-dev am: 73e0f350

status_t BlurFilter::prepare() {

    ATRACE_NAME("BlurFilter::prepare");

    blit(mCompositionFbo, mPingFbo);

    // Kawase is an approximation of Gaussian, but it behaves differently from it.

    // A radius transformation is required for approximating them, and also to introduce

    // non-integer steps, necessary to smoothly interpolate large radii.

    auto radius = mRadius / 6.0f;

    const auto radius = mRadius / 6.0f;

    // Calculate how many passes we'll do, based on the radius.

    // Too many passes will make the operation expensive.

    auto passes = min(kMaxPasses, (uint32_t)ceil(radius));

    const auto passes = min(kMaxPasses, (uint32_t)ceil(radius));

    // We'll ping pong between our textures, to accumulate the result of various offsets.

    const float radiusByPasses = radius / (float)passes;

    const float stepX = radiusByPasses / (float)mCompositionFbo.getBufferWidth();

    const float stepY = radiusByPasses / (float)mCompositionFbo.getBufferHeight();

    // Let's start by downsampling and blurring the composited frame simultaneously.

    mBlurProgram.useProgram();

    glActiveTexture(GL_TEXTURE0);

    glUniform1i(mBTextureLoc, 0);

    glBindTexture(GL_TEXTURE_2D, mCompositionFbo.getTextureName());

    glUniform2f(mBOffsetLoc, stepX, stepY);

    glViewport(0, 0, mPingFbo.getBufferWidth(), mPingFbo.getBufferHeight());

    mPingFbo.bind();

    drawMesh(mBUvLoc, mBPosLoc);

    // And now we'll ping pong between our textures, to accumulate the result of various offsets.

    GLFramebuffer* read = &mPingFbo;

    GLFramebuffer* draw = &mPongFbo;

    float stepX = radius / (float)mCompositionFbo.getBufferWidth() / (float)passes;

    float stepY = radius / (float)mCompositionFbo.getBufferHeight() / (float)passes;

    glViewport(0, 0, draw->getBufferWidth(), draw->getBufferHeight());

    glActiveTexture(GL_TEXTURE0);

    glUniform1i(mBTextureLoc, 0);

    for (auto i = 0; i < passes; i++) {

    for (auto i = 1; i < passes; i++) {

        ATRACE_NAME("BlurFilter::renderPass");

        draw->bind();

    }

    mLastDrawTarget = read;

    // Cleanup

    glBindFramebuffer(GL_FRAMEBUFFER, 0);

    return NO_ERROR;

}

        glBlitFramebuffer(0, 0, mLastDrawTarget->getBufferWidth(),

                          mLastDrawTarget->getBufferHeight(), 0, 0, mDisplayWidth, mDisplayHeight,

                          GL_COLOR_BUFFER_BIT, GL_LINEAR);

        glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);

        return NO_ERROR;

    }

}

void BlurFilter::blit(GLFramebuffer& read, GLFramebuffer& draw) const {

    ATRACE_NAME("BlurFilter::blit");

    read.bindAsReadBuffer();

    draw.bindAsDrawBuffer();

    glBlitFramebuffer(0, 0, read.getBufferWidth(), read.getBufferHeight(), 0, 0,

                      draw.getBufferWidth(), draw.getBufferHeight(), GL_COLOR_BUFFER_BIT,

                      GL_LINEAR);

    glBindFramebuffer(GL_FRAMEBUFFER, 0);

}

} // namespace gl