Add terrain generation plugin

[vldvoiculescu]

Terrain Generator is a procedural BSP brush generation plugin for NetRadiant-custom. It generates playable geometry (terrain and tunnels) as func_group entities directly inside the editor, using configurable noise-based heightmaps.

Supported shapes: Flat, Hill, Crater, Ridge, Slope, Volcano, Valley, Tunnel, Slope Tunnel

Key features:

• Generate from a selected brush (uses its XYZ bounds as the generation area) or from manual size input
• Adjustable sub-square size, noise type (Perlin/Simplex/Random), variance, frequency, and terrace stepping
• Texture selection integrated with Radiant's texture browser

Build command:

make MAKEFILE_CONF=msys2-Makefile.conf BUILD=debug DEPENDENCIES_CHECK=off DOWNLOAD_GAMEPACKS=no INSTALL_DLLS=no install/plugins/terrain_generator.dll

[Garux]

Found problems:

• repeated show plugin window command shows unlimited number of plugin windows
• generate from selection, undo: original brush is missing
• generate from selected group entity: brush is removed, entity node is not (=empty group entity)
• generate from selection, select different brush, generate - generated from 1st selection AABB; unchecking 'use reference' changes this; checkbox functionality is not clear, possibly should add a tooltip with info; 'generate from current selection' seems to be better behavior default; or if intent is to always use original AABB by default, it should be more clear for user, like do not update shown xyz values, better UI text
• generate from small brush - 'no valid brush' message
• 'pick' button does nothing in layouts w/o floating texture browser; would make sense to explain user what to pick in this case
• click pick twice, tex bro is not auto hidden on selection
• pick already picked shader - tex bro is not auto hidden; i suggest to only useTextureBrowser_show(), as it's good for UX, and remove the hide logic
• weird symbols in feedback: TerrainGenerator: generating tunnel � bounds (1024 x 1024 x 64), step (64 x 64), texture: textures/

Ideas

• it would be good to select generated stuff to make result more clear for user
• if you care to manage texture unwrapping, brush API function accepting UV coords can be added, there is code in radiant to convert UVs to .map texture projection
• it makes sense to flag generated brushes detail

[vldvoiculescu]

Addressed from your list:

✅ Repeated command spawning unlimited plugin windows
✅ Undo leaving the original brush missing
✅ Generating from a group entity leaving an empty group
✅ Confusing "use reference" / wrong AABB on a different brush
✅ "No valid brush" message on a small brush
✅ Pick doing nothing without a floating texture browser
✅ Pick not auto-hiding (twice / already-picked shader)
✅ Weird symbols in console feedback
✅ Idea: select the generated geometry
✅ Idea: flag generated brushes as detail

Biggest refactor — removed the reference-values mechanism. Instead of the confusing "use reference" checkbox (which froze the first brush's AABB for the whole session), each generated func_group now stores its own footprint size as a key. Regeneration reuses that piece's stored size while taking position from the live selection — so it never accumulates, never picks up another brush's size, and follows the terrain if you move it. The checkbox and all the reference state/UI are gone.