How can I add overbright lighting to Quake engine?

[hondobondo]

Enhanced GlQuake is the only engine that can run SDQuake, besides Darkplaces, and I want to add overbrights to it? Any tuts?

[revelator]

i think mh had some code for that ?.

aye older release before mhquake went d3d controllable to as its used to replace the software gamma code.

[mh]

Simple enough for the world model. Just shift the lightmap by 8 (jnstead of by 7) in R_BuildLightmap, then use glBlendFunc (GL_DST_COLOR, GL_SRC_COLOR); in R_BlendLightmaps or a 2 x RGB combine instead of GL_MODULATE in R_DrawSequentialPoly. If those last items sound like too much you can double your palette values for mipmapped textures instead.

[mh]

BengtOverbrights.zip

Present for you Hondo.

Use gl_overbright 1 (default) to enable. Overbrights are only available if GL_ARB_texture_env_combine is also available. In general that means that they're available on everything aside from old first and second gen 3dfx cards (or other hardware of comparable age).

They could be easily added to the gl_texsort 1 path for brush models on this ancient hardware, as that doesn't depend on combine. Adding them to alias models needs a little more work though.

I've made the whole project Visual C++ 2008 friendly, and removed the need to use gas2masm (just added the generated .asm files to it; ml.exe comes with 2008). The WinQuake builds won't compile successfully though, and I didn't bother with fixing them.

Just search for the word "overbright" in the source and you'll find most of what you need.

Incidentally, there is a third engine that can run SDQuake.

[hondobondo]

BengtOverbrights.zip

Present for you Hondo.

Use gl_overbright 1 (default) to enable. Overbrights are only available if GL_ARB_texture_env_combine is also available. In general that means that they're available on everything aside from old first and second gen 3dfx cards (or other hardware of comparable age).

They could be easily added to the gl_texsort 1 path for brush models on this ancient hardware, as that doesn't depend on combine. Adding them to alias models needs a little more work though.

I've made the whole project Visual C++ 2008 friendly, and removed the need to use gas2masm (just added the generated .asm files to it; ml.exe comes with 2008). The WinQuake builds won't compile successfully though, and I didn't bother with fixing them.

Just search for the word "overbright" in the source and you'll find most of what you need.

Incidentally, there is a third engine that can run SDQuake.

thanks MH

[hondobondo]

BengtOverbrights.zip

Present for you Hondo.

Use gl_overbright 1 (default) to enable. Overbrights are only available if GL_ARB_texture_env_combine is also available. In general that means that they're available on everything aside from old first and second gen 3dfx cards (or other hardware of comparable age).

They could be easily added to the gl_texsort 1 path for brush models on this ancient hardware, as that doesn't depend on combine. Adding them to alias models needs a little more work though.

I've made the whole project Visual C++ 2008 friendly, and removed the need to use gas2masm (just added the generated .asm files to it; ml.exe comes with 2008). The WinQuake builds won't compile successfully though, and I didn't bother with fixing them.

Just search for the word "overbright" in the source and you'll find most of what you need.

Incidentally, there is a third engine that can run SDQuake.

i tried out the code but had some problems:
first i tried merging your changes with mine, but since i use GL_RGBA every level came out with colored splotches everywhere (WTF?)
then i tried adding colored lights to yours but the same thing happened. anyway, i have no idea what you said above with the openGL gibberish(?!)

[revelator]

gl_overbright is just a cvar for enabling/disabling the overbrights nothing to do with opengl as such

shift means the part in R_DrawSequentialPoly where you see << 7 make that << 8 (<< means shift in C).


then use the appropriate blendmodes in R_BlendLightmaps or
R_DrawSequentialPoly.

have a look at the zip mh sent ya

this part in particular

Code: Select all

// mh - set/unset combine modes
void GL_BeginLightBlend (void)
{
	if (gl_usingoverbright)
	{
		// mh - combine mode
		glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
		glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_MODULATE);
		glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE);
		glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB);
		glTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 2.0f);
	}
	else
	{
		// mh - uninverted range
		glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
	}
}

[/code]

[hondobondo]

i'll see what i can make sense of

[r00k]

Oh, is this how QMB made the strobe effect for ammo models?

[revelator]

not sure

btw. this part glTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 2.0f); the 2.0f at the end can actually be replaced by a cvar for scaling the overbrights, just dont go overboard with silly values keep it clamped to some valid ranges.

a range from 0.0f to 2.0f should be fine.

[mh]

not sure

btw. this part glTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 2.0f); the 2.0f at the end can actually be replaced by a cvar for scaling the overbrights, just dont go overboard with silly values keep it clamped to some valid ranges.

a range from 0.0f to 2.0f should be fine.

Actually it can't; the only legal values are 1, 2 or 4: http://www.opengl.org/sdk/docs/man/xhtml/glTexEnv.xml

GL_INVALID_VALUE is generated if the params value for GL_RGB_SCALE or GL_ALPHA_SCALE are not one of 1.0, 2.0, or 4.0.

Also http://msdn.microsoft.com/en-us/library ... 85%29.aspx which tends to more accurately represent what the hardware can actually do (at the expense of having it explode in your face if you try to do something it can't! )

It would probably work on NVIDIA hardware though, but don't expect it to work on anything else.

(Aside: I have done some experiments with 4 x overbrighting in the past. It does give a slightly better light range, but only very slightly, and the stair-step effect becomes very strong (due to >> 9). It's fine if you can do 64-bit or 128-bit textures, but not really that big a deal overall.)

[revelator]

limited cvar usage then well could probably round those values somehow but aye would be a bit messy if the user wrote 1.5 should it then be 1 or 2

idea actually came from a quake2 engine that used a cvar that way allthough the menu item for it was clamped at 2 highest 1 normal.

[hondobondo]

Simple enough for the world model. Just shift the lightmap by 8 (jnstead of by 7) in R_BuildLightmap, then use glBlendFunc (GL_DST_COLOR, GL_SRC_COLOR); in R_BlendLightmaps or a 2 x RGB combine instead of GL_MODULATE in R_DrawSequentialPoly. If those last items sound like too much you can double your palette values for mipmapped textures instead.

i'm laughing because all of this is gibberish to me. i think i can do the first part in R_BuildLightMap (change all the <<= 7s and >>= 7s to 8s). but i don't know what 2xRGB combine is.

I DO MATH! but poor at OPENGL

[mh]

Simple enough for the world model. Just shift the lightmap by 8 (jnstead of by 7) in R_BuildLightmap, then use glBlendFunc (GL_DST_COLOR, GL_SRC_COLOR); in R_BlendLightmaps or a 2 x RGB combine instead of GL_MODULATE in R_DrawSequentialPoly. If those last items sound like too much you can double your palette values for mipmapped textures instead.

i'm laughing because all of this is gibberish to me. i think i can do the first part in R_BuildLightMap (change all the <<= 7s and >>= 7s to 8s). but i don't know what 2xRGB combine is.

I DO MATH! but poor at OPENGL

Find this:

Code: Select all

		glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

and replace it with this:

Code: Select all

		glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);
		glTexEnvi (GL_TEXTURE_ENV, GL_COMBINE_RGB, GL_MODULATE);
		glTexEnvi (GL_TEXTURE_ENV, GL_SOURCE0_RGB, GL_TEXTURE);
		glTexEnvi (GL_TEXTURE_ENV, GL_SOURCE1_RGB, GL_PRIMARY_COLOR);
		glTexEnvf (GL_TEXTURE_ENV, GL_RGB_SCALE, 2.0f);

When shutting down the state at the end of your draw function you'll also need this:

Code: Select all

	glTexEnvf (GL_TEXTURE_ENV, GL_RGB_SCALE, 1.0f);
	glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

But beware! Your code may use glTexEnvf where I use glTexEnvi. No practical difference though.

You'll also need these in your glquake.h:

Code: Select all

#define GL_COMBINE                        0x8570
#define GL_COMBINE_RGB                    0x8571
#define GL_COMBINE_ALPHA                  0x8572
#define GL_SOURCE0_RGB                    0x8580
#define GL_SOURCE1_RGB                    0x8581
#define GL_SOURCE2_RGB                    0x8582
#define GL_SOURCE0_ALPHA                  0x8588
#define GL_SOURCE1_ALPHA                  0x8589
#define GL_SOURCE2_ALPHA                  0x858A
#define GL_OPERAND0_RGB                   0x8590
#define GL_OPERAND1_RGB                   0x8591
#define GL_OPERAND2_RGB                   0x8592
#define GL_OPERAND0_ALPHA                 0x8598
#define GL_OPERAND1_ALPHA                 0x8599
#define GL_OPERAND2_ALPHA                 0x859A
#define GL_RGB_SCALE                      0x8573
#define GL_ADD_SIGNED                     0x8574
#define GL_INTERPOLATE                    0x8575
#define GL_SUBTRACT                       0x84E7
#define GL_CONSTANT                       0x8576
#define GL_PRIMARY_COLOR                  0x8577
#define GL_PREVIOUS                       0x8578
#define GL_DOT3_RGB                       0x86AE
#define GL_DOT3_RGBA                      0x86AF

[Baker]

To hell with the death of Quakesrc.org

MH is his own Quakesrc.org galaxy.