Image_Load_Store graphical glitches (GT3 and GT4)

[RAZORXKHARA33]

PCSX2 version: v1.5.0-dev-2194-gada0d5745, but also happens on earlier GIT builds, stable 1.4.0, and earlier.

• Notes: Got worse with build v1.5.0-dev-2184-ga0aa585af, but existed before that. If necessary, I can submit a GS Dump, but it happens throughout gameplay, rather than when something suddenly draws into view.

PCSX2 options: EE Round: Chop/Zero EE Clamping: Full VU Round: Chop/Zero VU Clamping: Extra + Preserve Sign Frame limiting and Frame skipping disabled Vsync setting: Forced on thru Nvidia Control Panel, set to Adaptive in PCSX2 EE Cyclerate: Default VU Cycle Stealing: None INTC Spin Detection: Enabled Wait Loop Detection: Enabled Fast CDVD: Enabled mVU Flag Hack: Enabled MTVU: Enabled Manual Game Fixes: Disabled

Plugins used:

GSdx Settings: Adapter: NVIDIA GeForce GTX 1080 Renderer: OpenGL (Hardware) Interlacing: Bob tff Texture Filtering: Bilinear (PS2) Allow 8-bit textures: Enabled Large Framebuffer: Enabled (issue persists regardless of setting) Internal Resolution: 3x Native Mipmapping (Ins): Basic CRC Hack Level: Partial (OpenGL Recommended) HW Hacks: Disabled Accurate Date: Enabled Blending Unit Accuracy (High)

SPU-2X Settings: Interpolation: Catmull-Rom Disable Effects Processing: Disabled Use de-alias filter: Disabled Debug Options: Disabled Module: XAudio2 Volume: 100% Latency: 30ms Synchronizing Mode: Async Mix Audio Expansion Mode: Stereo (none, default) Use a Winamp DSP Plugin: Disabled

Description of the issue: Car bodies shimmer/flicker during races (some track textures in GT4 as well, like the roads in Opera Paris). This issue has existed ever since I started using PCSX2, but got worse with the build mentioned above in the notes. Disabling Image_Load_Store in the HW Hacks fixes the problem, but makes the game run noticeably slower in places that would already slow down, and it would slow down in places it wouldn't normally do so. I know that this is because Image_Load_Store speeds things up, but it also causes graphical glitches.

How to reproduce the issue: Use settings above and make sure Image_Load_Store, Accurate Date, and High-Accuracy Blending are enabled. Then load any race in GT3 or GT4. Most noticeable when using chase cam or roof/hood cam.

Last known version to work: None

PC specifications: CPU: Intel Core i7 4790K (4.4 GHz) RAM: 32 GB DDR3 1600 MHz GPU: Nvidia GeForce GTX 1080 Boot SSD: Samsung 950 Pro 256 GB (PCSX2 loads off of this drive) Mass Storage 1: WD Blue 1 TB 7200 RPM (games, inis, and memory cards load off of this). Windows 10 Pro 64-bit, Creators Update

[MrCK1]

Try using Forced Texture Filtering. IIRC, this is similar to the issue I used to encounter.

[lightningterror]

Set mipmapping to off. I was able to reproduce the issue with mipmapping on. GT4 doesn't need mipmapping.

edit: Actually I take that back. The road flickering is caused by mipmapping but the car flickering is a separate issue which I was able to reproduce.

[gregory38]

Do you have the issue with a lower level of accurate blending ?

[lightningterror]

Disabling blending fixes it. Basic blending still causes the issue.

[gregory38]

So it is likely a bad interaction between DATE (with load/store image) and accurate blending. Could you confirm that it works fine without load/store image extensions

[lightningterror]

Yes it works fine with image load store disabled. Here is a gs dump just in case. https://drive.google.com/open?id=0B8cQAq-Ko9-uVzV4cVFtdFZoMWc

I was able to reproduce the issue only on my ntsc disc. Pal doesn't experience the issue.

[RAZORXKHARA33]

Also, there seems to be something strange about the way cars in GT3 and GT4 are rendered in the garage, GT Auto, pre-race (GT4 only), showroom, etc, as the both GT3 and GT4 slow to a crawl in those scenarios when using high-accuracy blending. Medium or lower doesn't have this problem, but in races, the reflection vibrance on cars and the road surfaces is noticeably lower. That's likely for another issue, though, if it hasn't been reported yet.

I can also confirm that force-disabling Image_Load_Store in HW Hacks fixes the glitchy shimmering with high-accuracy blending and accurate date both enabled, but of course results in a slowdown.

[MrCK1]

Does the other issue look similar to #1796 ? Might be the one you're thinking of.

[gregory38]

Interesting, accurate blend should be disabled in draw call that use image load/store (aka DATE42 in the code). I guess I failed to do it correctly.

High level of accuracy blending could be slow.

[RAZORXKHARA33]

@MrCK1 Issue #1796 only occurs if I pause the emulator and then resume. The other issue I mentioned is that the game slows to <50% speed in garage, event halls, etc. (whenever the car is shown rotating or being prepped for oil change), which has to do with something in the High-Accuracy blending. It may or may not be related to this issue (likely not).

[MrCK1]

Best solution for the slowdown is to lower blending accuracy and/or resolution scaling.

[mirh]

Does any of the tips here improve situation?

[FlatOutPS2]

Does any of the tips here improve situation?

See @lightningterror 's first comment in this issue

[gregory38]

Debug is still on-going.

So far bad draw call seems to be 1188 (LT dump). This draw calls does a DATE_GL45 + sw blending (with destination alpha). A rough guess is that we use a wrong alpha value somewhere in the shader.

[gregory38]

A quick note, it is potentially not a bug. Accurate DATE will enable accurate blending for the draw call too. The game uses destination alpha blending which is wrong (except in high blending accuraccy mode).So acccurate DATE mix, correct and bad blending which give us some flickering.

As a side note, il could be nice to implement 2 mode for accurate date

• A fast mode that will take only the first pixel (equivalent to date_one in the code). It isn't accurate per se but severals game seems to use it this way (it is the case for this dump)
• A slow mode (current code)