Is there a way to make this lightmode in gzdoom?

[ibm5155]

I belive it's something similar to the software lightmode, but it start decreasing the light in a far distance, and later everything is black.
So? (at least some tip about where is the software lightmode is so I could play with it )

[Rachael]

Yes, there is. You will have to use the shader system, though.

I don't know if there's a cleaner way to do this, but you can target the following shader:

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gzdoom.pk3/shaders/glsl/main.fp - function R_DoomLightingEquation

And use this MAPINFO definition:

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lightmode = 8

Graf might have an idea of how it could/should be done differently, though. I've played with that shader some good bit, though, but nothing that's actually published into a project because main.fp is always changing.

[ibm5155]

Yes, there is. You will have to use the shader system, though.

I don't know if there's a cleaner way to do this, but you can target the following shader:

Code: Select all

gzdoom.pk3/shaders/glsl/main.fp - function R_DoomLightingEquation

And use this MAPINFO definition:

Code: Select all

lightmode = 8

Graf might have an idea of how it could/should be done differently, though. I've played with that shader some good bit, though, but nothing that's actually published into a project because main.fp is always changing.

Thanks Eruanna, that did the trick

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float R_DoomLightingEquation(float light)
{
	// Calculated from r_visibility. It differs between walls, floor and sprites.
	//
	// Wall: globVis = r_WallVisibility
	// Floor: r_FloorVisibility / abs(plane.Zat0 - ViewPos.Z)
	// Sprite: same as wall
	// All are calculated in R_SetVisibility and seem to be decided by the
	// aspect ratio amongst other things.

	lightscale = clamp(min(pixelpos.w,500.0) / 500.0, 0.0, 1.0);
	return lightscale;
}

[Rachael]

You're welcome.

Just remember that main.fp changes with every GZDoom version. If this function does not get exported to its own file, you will have to include a script with your distribution that rewrites the user's current main.fp with your custom function, and then stores the changes inside your mod. Otherwise, GZDoom's shaders will fail to compile (with other GZDoom versions) - and in some cases might not even start.

[ibm5155]

uh, I belive for now the new shader option will just be enabled under my separated port, and for gzdoom people will just use the normal software lightmode

[ibm5155]

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	/* L is the integer light level used in the game */
	float L = 255 - light * 255.0;

	//Spooky house Light Equation
	float lightscale;
	lightscale = clamp((  min(pixelpos.w  * L , 76500.0)) / 76500.0, 0.0, 1.0);

so, with that code it should the fog distance should be based on the light, so, if the sector bright is 255, you can see everything, but if the sector light is zero, you should see nothing.
But for somehow it's not doing that (I belive it should end in something like min ( x * 0, 76500.0), and anything * 0 is 0, unless I'm missing some importante thing here and the minimal valua is a bit higher than 0 (ie 1)

[dpJudas]

Light and color values in GLSL are in the 0-1 range, with 0 being black and 1 being max. If you look at the code in getLightColor you have this code:

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		float newlightlevel = 1.0 - R_DoomLightingEquation(uLightLevel);
		color.rgb *= newlightlevel;

This means that if R_DoomLightingEquation return 0 it will be 1-0 = 1 -> full bright. While if it returns 1 then it will be 1-1 = 0 -> black. uLightLevel is in the range 0-1 as well. So if the sector has a value of 255 in the map, then uLightLevel will be 1. 128 is 0.5 and so on.

The code you're seeing in R_DoomLightingEquation is relatively complex because it maps the value back to 0-255 (by multiplying light by 255) so that the 'zdoom light equation' can be an exact match to what I grabbed out of the zdoom codebase. You don't have to do that. To get the effect you're asking, you can make the function much simpler. Something like this should do the trick:

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float R_DoomLightingEquation(float light)
{
	float fullDarkDistance = 100.0; // Adjust this value to what distance you want it to get fully dark.
	return clamp(pixelpos.w / fullDarkDistance, 0.0, 1.0) * (1.0 - light);
}

[dpJudas]

Damn, think that's also actually wrong. It should look like this:

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float R_DoomLightingEquation(float light)
{
	float fullDarkDistance = 100.0; // Adjust this value to what distance you want it to get fully dark.
	return 1.0 - max((1.0 - pixelpos.w / fullDarkDistance) * light, 0.0);
}

[ibm5155]

just wondering, what the .w value is used for?

[dpJudas]

It is the depth (Z) value of the pixel/fragment in view/eye space (the camera's point of view).