[Patch] Fixed Shading

[HarryTuttle]

Ian, since those comparisons are a bit time consuming to prepare, if you need specific cases let me know.

[Ian]

Well ..
any that look obviously broken (with the current code) compared to the real h/w would be really useful

[Bart]

How about Scud Race -- in particular, the bridge and castle walls, the airport terminal, and the waterfalls on the medium stage? These have bedeviled us for some time.

[HarryTuttle]

How about Scud Race -- in particular, the bridge and castle walls, the airport terminal, and the waterfalls on the medium stage?

Ok, They're coming. I'll update this post.

Update #1: Scud Race - Waterfalls (Left: Abe's video, Middle: Supermodel post-fx, Right: Supermodel with marked fixed-shaded polys)

Blue = self-illuminated fixed shaded polys

sr1.jpeg (253.07 KiB) Viewed 7676 times

Update #2: Scud Race - Terminal

Blue = self-illuminated fixed shaded polys

sr2.jpeg (245.36 KiB) Viewed 7672 times

Update #3: Scud Race - Bridge & Castle

Blue = self-illuminated fixed shaded polys
Red = illuminated fixed shaded polys

sr3.jpeg (241.34 KiB) Viewed 7662 times

[Ian]

looks basically the same?

[HarryTuttle]

I've to confirm. However here's your formula for self-illuminated fixed-shaded polys and, following, mine:

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shade = (((ix + 128) & 0xFF) / 255.f) + 1.f


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// For step 1.5 games
shade = 1.f + (float)((UINT8)(ix & 0xFF)) / 128.f;


[Ian]

the +1 means it 100% brightness. Anything further than that further increases brightness, so you won't really get any dark areas

This is the part I wasn't sure was shaded correctly (thought mine was too bright), or rather not enough contrast

[HarryTuttle]

Ian, I just updated my previous post with that image of the bridge.

the +1 means it 100% brightness. Anything further than that further increases brightness

I think It's perfectly "legal" for Real3D to multiply poly RGB values by (1.0 + Shading), since the final texel.rgb will be:

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final.rgb = texel.rgb * poly.rgb;


In case of scud's sky texture, it will bring an over-brightened sky, that's - I think - the intended behavior as you can see from the videos.

[HarryTuttle]

This is the part I wasn't sure was shaded correctly (thought mine was too bright), or rather not enough contrast

Judging from the formulae, we'll obtain, in that specific case, the same value.

Update: I've to correct my last sentence, we'll obtain different results, your shading value will be higher and yes, your poly will be brighter.

[Ian]

So what do you think the correct formula is?