Function QueryPrePostModPixelValues

renderdoc/driver/gl/gl_pixelhistory.cpp:1205–1382

}

void QueryPrePostModPixelValues(WrappedOpenGL *driver, GLPixelHistoryResources &resources,
                                const rdcarray<EventUsage> &modEvents, int x, int y,
                                rdcarray<PixelModification> &history, uint32_t numSamples,
                                uint32_t sampleIndex)
{
  GLMarkerRegion region("QueryPrePostModPixelValues");
  driver->ReplayLog(0, modEvents[0].eventId, eReplay_WithoutDraw);
  CopyFramebuffer premodCopyFramebuffer = {};
  premodCopyFramebuffer.framebufferId = ~0u;
  CopyFramebuffer postmodCopyFramebuffer = {};
  postmodCopyFramebuffer.framebufferId = ~0u;
  int preModLastIdx = 0, postModLastIdx = 0;

  for(size_t i = 0; i < modEvents.size(); i++)
  {
    uint32_t colIdx = getFramebufferColIndex(driver, resources.target);

    {
      GLint savedReadFramebuffer, savedDrawFramebuffer;
      driver->glGetIntegerv(eGL_DRAW_FRAMEBUFFER_BINDING, &savedDrawFramebuffer);
      driver->glGetIntegerv(eGL_READ_FRAMEBUFFER_BINDING, &savedReadFramebuffer);

      GLuint copySourceFramebuffer = savedDrawFramebuffer;

      if(isDirectWrite(modEvents[i].usage))
      {
        copySourceFramebuffer = resources.copySourceFramebuffer;

        // bind this as the framebuffer so the below code which expects to duplicate based on bound
        // framebuffer will work. We've already saved teh real one
        driver->glBindFramebuffer(eGL_FRAMEBUFFER, copySourceFramebuffer);
      }

      if(numSamples > 1)
      {
        premodCopyFramebuffer =
            getCopyFramebuffer(driver, colIdx, resources.copyFramebuffers, ModType::PreMod,
                               numSamples, int(modEvents.size()));

        driver->glBindFramebuffer(eGL_DRAW_FRAMEBUFFER, premodCopyFramebuffer.framebufferId);
        driver->glBindFramebuffer(eGL_READ_FRAMEBUFFER, copySourceFramebuffer);

        GLenum savedReadBuffer;
        driver->glGetIntegerv(eGL_READ_BUFFER, (GLint *)&savedReadBuffer);

        driver->glReadBuffer(GLenum(eGL_COLOR_ATTACHMENT0 + colIdx));
        SafeBlitFramebuffer(x, y, x + 1, y + 1, 0, 0, 1, 1, getFramebufferCopyMask(driver),
                            eGL_NEAREST);
        readPixelValuesMS(driver, resources, premodCopyFramebuffer, sampleIndex, 0, 0, history, i,
                          ModType::PreMod, true);

        driver->glReadBuffer(savedReadBuffer);
      }
      else
      {
        CopyFramebuffer newCopyFramebuffer =
            getCopyFramebuffer(driver, colIdx, resources.copyFramebuffers, ModType::PreMod,
                               1 /*single sampled*/, int(modEvents.size()));