Fix objects with alpha below 141 are invisible

[FileEX]

Summary

This PR fixes a bug where objects with alpha < 141 are not rendered.

This issue has two stages: the first is the alpha threshold (rwRENDERSTATEALPHATESTFUNCTIONREF) set to 140 in the function CRenderer::RenderEverythingBarRoads - this is the direct cause of #425. The next stage is in the function CVisibilityPlugins::RenderEntity, where the alpha threshold is set to 100, and then objects with alpha < 101 are not rendered.

Is it safe to just set this to 0?

These settings were R*’s attempts to fix the halo effect around trees and bushes, which, as can be seen in the game, did not work.

            //!PC - required to minimize alpha halo problems outside (bushes & trees mainly)
            if ((CGame::currArea==AREA_MAIN_MAP) && (!pModelInfo->GetDontWriteZBuffer()))
            {
                RwRenderStateSet(rwRENDERSTATEALPHATESTFUNCTIONREF, (void*)100);
            }
            else
            {
                RwRenderStateSet(rwRENDERSTATEALPHATESTFUNCTIONREF, (void*)0);
            }

I did not observe any new or worse rendering bugs with plants after setting these values to 0.

Alpha halo bugs "fixed" by R*:

Motivation

Fixes #425

Test plan

1. crun o = createObject(1337, me.position)
2. crun o.alpha = 140

Checklist

• Your code should follow the coding guidelines.
• Smaller pull requests are easier to review. If your pull request is beefy, your pull request should be reviewable commit-by-commit.

[Dutchman101]

This would be ok, unless we get a bunch of user reports from different trees (or tree mods, or any unchecked scenario) that there's worsened visual glitches. Time will tell and we got to pay attention.

[rifleh700]

FYI
http://gta.rockstarvision.com/skygfx/skygfx.html#SAatest
https://github.com/aap/skygfx/blob/master/src/main.cpp#L1569