Custom maps

[sultim-t]

Note: this is intended to tweak maps; if modifying becomes too complex for a mod, it might be worth to wait for Half-Life RTX (another project that adds path tracing to HL1: a full mod support is claimed), or NVIDIA RTX Remix

Note: Texture replacements is expected to be read first

In HL1, each map contains static (walls, floors etc) and dynamic objects (characters. particles etc).
In HL1RT, static objects and static light sources can be exported to gITF2 format via RTGL1 devmode (more about devmode here).
With gITF, we can modify existing light sources, geometry; and even add new ones.

The overall workflow for a new map:

1. Export a map to gITF
2. Modify the glTF file (e.g. in Blender)
3. When the game renders a map, the corresponding gITF2 file is loaded and being rendered instead of the original map
4. Optional per-map properties can be tweaked in data/scenes,json

Details

For example, we would like to make this map RT-compatible

Install it, by unzipping it to Half-Life/valve folder, so dm_dust2_hl1.bsp is inside Half-Life/valve/maps. Launch the game, load into it.

Export

Ensure that No server cull is enabled (otherwise not all lights/objects will be exported).

In devmode window, click Export frame geometry

Open

Open the exported glTF in Blender

Tip: Enable viewport shading mode (to see the lighting/textures), and set sampling to 1 (so it's less laggy)

Now we should see the map

Modify

All the objects must be inside rtgl1_main_root (as HL1 uses non-metric system)

Let's make sun green

Export

HL1RT hot-reloads glTF files, so a game can just run in background, and as soon we export glTF, we should see the changes in the game instantly (if there are no errors, and if devmode is enabled).

Click File->Export->glTF 2.0 (it's useful to keybind it, e.g. Ctrl-E)

Find the existing file, select it

glTF export settings must be:

1. Format = glTF Separate
2. Keep original = True
3. Include - Custom Properties = True
4. Include - Punctual Lights = True
5. Mesh - Tangents = True

Tip: it's useful to save such export settings:

The name line will be red, as we replace existing file. Click Export

We would see a message in HL1 console

and the sun is green now

Cleaning

HLT1RT exporter juts works.

glTF doesn't support polygon lights, so they are approximated by spotlights, and usually the HL1RT exporter produces too many unnecessary lights around polygons. They should be removed (less lights = less noise)

Example: remove three unnecessary spotlights and leave only one point light

Just works

Per-scene properties

There's a limited set of optional properties that can be set for a scene: Half-Life/rt/data/scenes.json contains the properties. If a property is not found in scenes.json, then values from cvars are used.

For custom maps, add an entry with a specified sceneName.

Note: HL1 map names have format maps/c0a0.bsp, but sceneName is only c0a0
Warning: there are bugs related to spaces in the JSON-parser, specifically, spaces around : in arrays are interpreted as errors. Remove spaces and look into the console logs for parser errors!

Per-object properties

glTF allows extra fields on objects. We can utilize that to provide more info to the renderer. For example, make a light volumetric, or mark a mesh as mirror.

Lights:

• lightstyle -- use dynamic intensity mu;tiplier from original HL1 map lightstyles
• isVolumetric -- only one light can be marked as volumetric per map; if none of the glTF lights have this property, sun is used
• todo

Meshes:

• isGlass
• isMirror
• isWater
• todo

Adding custom objects

To add a new mesh, just create it in Blender and put it inside rtgl1_main_root.
Custom textures (TGA/PNG) should exist in the same folder as its .gltf file.
Never use textures from mat_junction folder for new objects.

Light leaks

When using volumtrics, light might leak throw thin walls or if nothing obstructs the light source (e.g. a building doesn't have a roof). To prevent such leaks, walls should be thicker (or rt_volume_far smaller, so the grid voxels are smaller) / add geometry to obstruct the light source.

Publish

Only distribute scenes.json, .gltf, .bin and your own textures.
Never include mat_junction folder as it contains original HL1 textures, and used only to display textures in Blender.

Screenshots

Editing

Different light setups

[THG327]

I converted the Hazard-Course and it was surprisingly easy to do following this guide.
rt-training.zip
I also noticed that you can have individual textures.json files for scenes. Would it be possible to have the per-scene properties loaded from those individual folders instead of overwriting the main scenes.json file?

[cinder-block-garry]

HOW DO I GO IN DEVMODE

[cinder-block-garry]

[cinder-block-garry]

@sultim-t never mind blender is ok but HOW DO I GO IN DEVMODE I FORGOT

[Muxinio]

u need create one #124

[cinder-block-garry]

u need create one #124

what do you mean

[cinder-block-garry]

its been almost 2 years WHERE ARE YOU?