Tutorials
Transparent Texture Shadows
In this tutorial you will learn how you can make the opaque parts of a transparent texture on a model cast shadows.
You may be wondering "What does alpha mean?" Alpha - or more specifically the alpha channel, is what defines transparency in an image. For example, glass textures have an alpha channel that makes them transparent.
For example: a fence
The fence's grating has an alpha channel that allows you to see through it. This is great for visual looks like looking through it, but source has no idea what to do about lighting for the alpha channel for props, and it simply uses the collision model as a shadow reference. This would be okay, but it looks really unrealistic when a light is near it.
In the days of the HL2 Source engine and the HL2:EP1 engine you had to make a grating yourself, by taking a blocklight texture and cutting it out. Nobody ever wanted to do this because it was pointless and very time consuming (And the shadows looked blocky)
Then came the Orangebox engine, and at first, we could use projectedtextures to create our dynamic lights, but then nVidia complained about the shadows from these entities and resulted in nVidia users getting these nasty grainy-edged shadows. Yes, they were dynamic (And partially better than what i'm about to teach you about), but they are really bad looking.
Skip forward to now, where we have learned that the light compiler (vrad) now has an option to allow the alpha channel to allow light through. That command? -TextureShadows.
This command, combined with -StaticPropPolys, can allow your alpha channels to create shadows. This is better than before, but there are still some flaws. These shadows are lightmap shadows, so they cannot be moved and thus, are static.
But if you're using a static prop you shouldn't care anyways.
Anyways, you may be wondering "Alright, this sounds cool, how do I accomplish this?".
Basic requirements
Orangebox /Source 2009 Engine Game (Half-Life 2 Episode 2 or Left 4 Dead)
Prop with texture that has alpha channel (In this case we'll be using a fence model)
Step 1 - Create a lights.rad file
First of all, go into notepad and copy this
lights/fluorescentcool001a 189 231 232 350 lights/fluorescentcool001b 236 255 182 350 lights/fluorescentcool002a 189 231 232 400 lights/fluorescentcool002b 236 255 182 400 lights/fluorescentcool003a 189 231 232 300 lights/fluorescentwarm001a 239 216 193 350 lights/fluorescentwarm002a 239 216 193 400 lights/fluorescentwhite001a 245 245 245 350 lights/fluorescentwhite002a 245 245 245 400 lights/hazzardred001a 228 37 0 300 lights/hazzardyellow001a 250 215 74 300 lights/HIDcool001a 145 222 172 650 lights/HIDcool001b 205 232 255 650 lights/HIDwarm001a 255 201 116 650 lights/white001 250 240 205 100 lights/white002 189 233 247 425 lights/white003 232 246 190 350 lights/white004 170 228 247 425 lights/white005 234 235 220 375 lights/white006 234 235 220 100 lights/blue001 166 180 196 200 166 180 196 100 lights/blue002 141 176 203 200 141 176 203 100 lights/red001 63 1 1 200 63 1 1 100 lights/white001_nochop 250 240 205 100 lights/white002_nochop 189 233 247 425 lights/white003_nochop 232 246 190 350 lights/white004_nochop 170 228 247 425 lights/white005_nochop 234 235 220 375 lights/white006_nochop 234 235 220 100 lights/incandescentcool001a 235 235 235 300 lights/incandescentwarm001a 250 226 129 300 glass/glassscreen001a 172 192 161 225 glass/glasspipe001f 214 72 44 200 glass/glassscreen001c 172 192 161 225 glass/glassscreen001d 211 187 134 225 glass/glassblock001a 70 194 209 200 composite/citadelfloor001a 103 143 203 200 props/tvscreen006a 196 0 0 200 shadertest/gooinglass 149 49 15 50 glass/glasswindow002e 189 233 247 425 glass/glasswindow035a 145 222 172 100 dev/DEV_INTERIORLIGHT02B 151 176 204 225 plaster/plasterwall029h 189 223 227 125 building_template/Building_Trainstation_Template001d 230 230 200 65 building_template/Building_Trainstation_Template001e 230 230 200 150 building_template/Building_Trainstation_window002d 230 230 200 300 building_template/Building_Trainstation_window002e 230 230 200 300 lights/physgunlight 189 231 232 20 noshadow tree_deciduous_01a_branches.vmt noshadow tree_deciduous_01a_leaves.vmt noshadow tree_deciduous_01a_lod.vmt noshadow tree_deciduous_01a_lod-leaves.vmt forcetextureshadow props_foliage/tree_dead01.mdl forcetextureshadow props_foliage/tree_dead02.mdl forcetextureshadow props_foliage/tree_dead03.mdl forcetextureshadow props_foliage/tree_dead04.mdl forcetextureshadow props_foliage/tree_dry01.mdl forcetextureshadow props_foliage/tree_dry02.mdl forcetextureshadow props_foliage/tree_pine_large.mdl forcetextureshadow props_foliage/tree_pine04.mdl forcetextureshadow props_foliage/tree_pine05.mdl forcetextureshadow props_foliage/tree_pine06.mdl forcetextureshadow props_foliage/tree_deciduous_01a.mdl forcetextureshadow props_foliage/tree_deciduous_02a.mdl forcetextureshadow props_wasteland/interior_fence001a.mdl forcetextureshadow props_wasteland/interior_fence001b.mdl forcetextureshadow props_wasteland/interior_fence001c.mdl forcetextureshadow props_wasteland/interior_fence001d.mdl forcetextureshadow props_wasteland/interior_fence001e.mdl forcetextureshadow props_wasteland/interior_fence001g.mdl forcetextureshadow props_wasteland/interior_fence002a.mdl forcetextureshadow props_wasteland/interior_fence002b.mdl forcetextureshadow props_wasteland/interior_fence002c.mdl forcetextureshadow props_wasteland/interior_fence002d.mdl forcetextureshadow props_wasteland/interior_fence002e.mdl forcetextureshadow props_wasteland/interior_fence002f.mdl forcetextureshadow props_wasteland/interior_fence003a.mdl forcetextureshadow props_wasteland/interior_fence003b.mdl forcetextureshadow props_wasteland/interior_fence003d.mdl forcetextureshadow props_wasteland/interior_fence003e.mdl forcetextureshadow props_wasteland/interior_fence003f.mdl forcetextureshadow props_wasteland/interior_fence004a.mdl forcetextureshadow props_wasteland/interior_fence004b.mdl forcetextureshadow props_forest/fence_barb_256.mdl forcetextureshadow props_forest/fence_barb_512.mdl forcetextureshadow props_forest/fence_border_128.mdl forcetextureshadow props_forest/fence_border_256.mdl forcetextureshadow props_forest/fence_border_512.mdl forcetextureshadow props_forest/fence_trail_128.mdl forcetextureshadow props_forest/fence_trail_256.mdl forcetextureshadow props_forest/fence_trail_512.mdl forcetextureshadow props_wasteland/exterior_fence_notbarbed002a.mdl forcetextureshadow props_wasteland/exterior_fence_notbarbed002b.mdl forcetextureshadow props_wasteland/exterior_fence_notbarbed002c.mdl forcetextureshadow props_wasteland/exterior_fence_notbarbed002d.mdl forcetextureshadow props_wasteland/exterior_fence_notbarbed002e.mdl forcetextureshadow props_wasteland/exterior_fence_notbarbed002f.mdl forcetextureshadow props_wasteland/exterior_fence001a.mdl forcetextureshadow props_wasteland/exterior_fence001b.mdl forcetextureshadow props_wasteland/exterior_fence002a.mdl forcetextureshadow props_wasteland/exterior_fence002b.mdl forcetextureshadow props_wasteland/exterior_fence002c.mdl forcetextureshadow props_wasteland/exterior_fence002d.mdl forcetextureshadow props_wasteland/exterior_fence002e.mdl forcetextureshadow props_wasteland/exterior_fence003a.mdl forcetextureshadow props_wasteland/exterior_fence003b.mdl forcetextureshadow props_foliage/fern01.mdl forcetextureshadow props_foliage/ferns01.mdl forcetextureshadow props_foliage/ferns02.mdl forcetextureshadow props_foliage/ferns03.mdl forcetextureshadow props_forest/fern01.mdl forcetextureshadow props_forest/fern01lg.mdl forcetextureshadow props_c17/fence03a.mdl
This is Episode 2's lights file. It tells what textures give off light, and at the bottom, tells which models create shadows from their alpha channel.
You should add in your own models if they have an alpha channel if you want to. Simply create a new line and put in "forcetextureshadow" (without quotes) and then the path to your model (without the models part, so if you had "ep2/models/props_lol/lolball.mdl" you would put in "props_lol/lolball.mdl")
Save this file as lights.rad (not lights.rad.txt, make sure of this) in your Episode 2 / left 4 dead directory (c:\program files\steam\steamapps\username\Half Life 2 Episode 2\ep2\ or c:\program files\steam\steamapps\common\left4dead\l4d\)
Step 2 - Placing models and fulfilling requirements
Now, the fun part. Place your models you added into the list (or the ones that are already on the list) into your map. (For the sake of this tutorial, i'm using the one i added into the lights.rad file for everyone, models/props_c17/fence03a.mdl.)These models must be prop_static!. After you've placed your models where you want them, make sure there's a nearby light source. Having no light is pointless, and it strains your processor to compile what you can't even see.
Once you've done this, set the lightmaps around your fence/model down very low (2 is what seems to work the best, 4 is the minimum requirement). This will allow you to see the shadows, since they are fairly faint.
Step 3 - Compiling
Now that you've done this, it's time to compile! Press F9 and go to the button that says "Expert..."
Now you'll see a list of things like $bsp_exe and such. Click on $light_exe.
Now in the parameters section on the right, select all text there and replace it with the following
-StaticPropPolys -TextureShadows -game $gamedir $path\$file
And that's it! You're now ready to compile. Press "Go!" from the box (DO NOT SWITCH BACK TO NORMAL MODE) And after a compile (It may take a lot longer because it's very processor intensive) you'll hopefully have pretty shadows.
- Jimmy422