GFX rendering performance issues in release v2.1.5.140 on MacOS

Issue:

• The GFX rendering loop which was optimized in 2.1.5.140 according to the changelog is non-performant and causes MacOS input lag

Setup:

Hardware Overview:

Model Name: MacBook Pro
Model Identifier: MacBookPro10,2
Processor Name: Dual-Core Intel Core i5
Processor Speed: 2,6 GHz
Number of Processors: 1
Total Number of Cores: 2
L2 Cache (per Core): 256 KB
L3 Cache: 3 MB
Hyper-Threading Technology: Enabled
Memory: 8 GB

Intel HD Graphics 4000:

Chipset Model: Intel HD Graphics 4000
Type: GPU
Bus: Built-In
VRAM (Dynamic, Max): 1536 MB
Vendor: Intel
Device ID: 0x0166
Revision ID: 0x0009
Metal: Supported, feature set macOS GPUFamily1 v4

Steps to reproduce:

1. Run a version before v2.1.5.140
2. 2560x1600 in window mode
3. Observe no freezes of stalling of the Mac OS
4. Update to v2.1.5.140
5. Restart the game
6. Observe freezes at the very startup of the game
7. Changing the resolution to 1024x768 (lowest resolution) shows that the main rendering loop becomes less hammered and int

What happens:

At step 6, the observation is:

• The main render loop causing the game to run at less than 30fps when running 2560x1600 in window mode which was not a problem on previous versions;
• This is slowness and frame dropping is already apparent when the PlayDek introduction animation is shown before getting to the main menu;
• The rendering loop makes a lot of hardware calls that actually causes Mac OS itself to start having input lag: mouse movement stutters outside of Lord of Waterdeep & character input lag while writing this bug report on a keyboard become impossible.

After step 7:

• The MacOS input lag is somewhat improved. The animations are also a bit smoother

Expected behavior:

• Ability to run at 2560x1600 in window mode as before on MacOS
• Render loop is not to stall or freeze the game nor the MacOS
• Move heavy/intense computations to a background thread