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SURFACE.INI

Text-based INI configuration file that defines per-texture-index blend behavior and surface-type sound remapping for the terrain renderer.

Shipped sample path: /Redguard/surface.ini (e.g. .../GOG Galaxy/Redguard/Redguard/surface.ini).

Engine string analysis confirms the engine expects this file at startup, requires a surfaces section/header, and validates surface type values plus texture set/index bounds (with some sound-section validation).

File Structure

Top-level sections:

  1. [surfaces] section: texture-set/index to surface-type assignments
  2. Sound remap sections: [unknown], [water], [deepwater], [scapewater], [scapedeepwater], [lava], [sand], [wood], [tile], [scape], [rock], [gloop]

Surface Assignment Records ([surfaces])

  • set, index, type
  • set, all, type

Where:

  • set: texture set id, documented range 0..511
  • index: texture index inside the set
  • type: case-insensitive token from {WATER, DEEPWATER, LAVA, SAND, WOOD, TILE, ROCK, GLOOP}

Sound Remap Records

Each sound section contains entries of the form:

  • <sound_id> = <remap_sound_id>

Behavior/constraints from shipped comments and runtime validation strings:

  • Sound ids are 0..255 at animation-system call sites; remaps may point to other effect ids.
  • Separate water/scapewater and deepwater/scapedeepwater sections are expected.
  • Empty sections are valid (for example [unknown], [lava], [scape] in shipped sample).
  • The file is parser-tolerant regarding token case (WOOD and wood both appear).

Terrain Texture Blending

SURFACE.INI drives a pixel-level alpha-blending system for terrain tile transitions. The blend system uses a 64-entry type table (one per texture index) with these categories:

Blend typeBehavior
None (default)Tile rendered as fully opaque; no transition blending.
FullTile is always fully blended (alpha = 256). Used for index 0 (default/empty tile).
GradientAlpha ramps linearly across the tile based on pixel position. Used for indices 6 and 52.
Hard edgeSharp alpha cutoff at a fixed distance into the tile. Used for index 31.
Custom patternPer-pixel alpha from a 256x256 lookup buffer, configured by .CFG files loaded via SURFACE.INI. Used for indices 5, 7, 30, and 32.

Complete shipped-runtime taxonomy for terrain texture indices 0..63:

  • Explicit special indices are {0, 5, 6, 7, 30, 31, 32, 52}.
  • Water-surface shortcut set is {0, 5, 30, 31} (all four tile corners in this set trigger water-surface rendering).
  • All other indices in 0..63 use the default non-special blend/type behavior (no additional hardcoded special handling).

The file also defines a palette-remap table per texture type, mapping source palette indices to blended output indices.

This blending is a pixel-level renderer effect. It does not affect geometry, UVs, or material assignment — it only controls how adjacent terrain textures cross-fade at their shared edges.

Relationships to Other Formats

  • WLD terrain Map 3 texture indices are the primary consumer of the blend type table and surface-type assignments.
  • TEXBSI supplies the texture images referenced by the 64-entry terrain texture table.

External References