Hi, So far, there are two ways of testing for pixel-perfect frames using the Chamelium that are in IGT. The first one grabs a full frame from the Chamelium and compares it pixel-to-pixel with the cairo reference, which works well for DP/HDMI. For VGA, this is probably not the case (because the link is analogue). In that case, I will look into implementing some fuzzy testing, probably inspired by what piglit (probably) does to compare output frames with references. For pixel-perfect testing, grabbing a full frame and testing it with memcmp comes with a significant time penalty (about 2 seconds for 1080p). The Chamelium also provides a CRC mechanism that is faster and does not require retrieving the frame, that IGT currently also supports. It compares the CRC calculated by the Chamelium (implemented in the HDL) with a hardcoded reference value. This approach currently fails for me (the values I get don't match the hardcoded reference). There are reasons why it is not really reasonable: fonts rendering may change between machines (e.g. use of anti-aliasing) and cairo version changes could introduce slight rendering changes too (not to mention changes in the test pattern itself). So instead of comparing the CRC with a hardcoded reference value, I think it would make a lot more sense to actually calculate the CRC based on the cairo image that is the actual reference (and that we should assume may change between runs/machines). I am currently looking into the CRC calculation mechanism used by the Chamelium and trying to reproduce it in C code. Is this a known algorithm for which a reference/optimized implementation exists, or something custom that the folks over at Google came up with? Any thoughts, comments or suggestions? Cheers! -- Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxxxxxx> Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
