[Patch] Fixed Shading

[Ian]

I've honestly no idea what the translator map does

[HarryTuttle]

Ian, I've finally sorted it all.

As it turns out, Step 1.5 have the shade "base" value set to 2.0 for *everything* self-illuminated (even non fixed shaded), so the corresponding poly color gets its value doubled, then fixed shading is added to the value like this: for illuminated polys spans from -0.5 to +0.5, for self-illuminated polys spans from -1.0 to +1.0, finally for ambient light == 0.0 (and only in this particular case) the shade *is* the value of fixed-shading ranging from 0.0 to 1.0.

Now it all makes sense. And the much more clearer code is like this:

Code: Select all

if (m_step == 0x15) {
  if (!ph.LightEnabled()) {
    shade = 2.0f;
  }
}
float divisor = ph.LightEnabled() ? 255.0f : 127.0f;
float offset = ph.LightEnabled() ? 0.5f : 1.0f;
shade += 2.0f * (float)((UINT8)(ix & 0xFF)) / divisor - offset;
if (vp_ambient == 0.0f)
  shade = (float)((UINT8)(ix & 0xFF)) / 127.0f;


[Ian]

I'll give this one a spin tomorrow

[Bart]

What was the final determination on this? Is it correct and has it been incorporated into the source tree?

[Ian]

As far as I can work out .. this is the basic formula

FinalColour.r = FixedShade * polyColour.r
FinalColour.g = FixedShade * polyColour.g
FinalColour.b = FixedShade * polyColour.b

When lighting is enabled it becomes

FinalColour.r = FixedShade + polyColour.r
FinalColour.g = FixedShade + polyColour.g
FinalColour.b = FixedShade + polyColour.b

Where the fixed shade value comes from the signed 8 bit normal vector. Where -1 = 0 and +1 = 255

Personally I wouldn't have thought the shading values be conditional on certain viewport ambient values .. but I could be wrong. The model3 is crazy :p anything is possible.

[scd]

hi ian. is this fixed shading already a part of the new engine, or it will be a part of it soon?

[HarryTuttle]

I've done some adjustments to fixed shading (as well as other things like light on fog). I'm currently making some tidying up work to my private messy Supermodel tree. As soon as possible I'll review/update my submitted patches before (I hope) next major release.

[Bart]

hi ian. is this fixed shading already a part of the new engine, or it will be a part of it soon?

I believe the fixed shading changes have already all been incorporated into the SVN tree.

[Ian]

I had a bit of a debug of mag truck, since never looked at fixed shading in this game

Arcade looks like this ( really poor quality ) anyone got any better caps?



Supermodel ..


Ground is clearly the wrong colour. Comes out black, should come out with full brightness ..

Changing the code from

Code: Select all

float shade = (((ix + 128) & 0xFF) / 255.f) + offset;

to

Code: Select all

float shade = (((ix + 127) & 0xFF) / 255.f) + offset;

Produces ..


Personally I would think the first formula to be the correct one. Since signed int8 starts at -128 and ends at 127 but it produces the wrong colour entirely

The black values have the hex value 0x80
0x80 + 128 = 0
0x80 + 127 = 255

Needs more testing .. really only tested mag truck with this code.

[Ian]

well that modification was definitely wrong :/