You need rust.
Run cargo build for the CLI, cargo build --bin heightmap_gui --features gui for the gui.
Compile or download from releases.
heightmap.exe --help for usage instructions:
USAGE:
heightmap.exe [FLAGS] [OPTIONS] <INPUT>...
FLAGS:
--cull Automatically remove bottom level bricks and fully transparent bricks
--glow Make the heightmap glow at 0 intensity
--greedy Use greedy optimization
-h, --help Prints help information
--hdmap Using a high detail rgb color encoded heightmap
-i, --img Make the heightmap flat and render an image
--lrgb Use linear rgb input color instead of sRGB
--micro Render bricks as micro bricks
--nocollide Disable brick collision
--snap Snap bricks to the brick grid
--stud Render bricks as stud cubes
--tile Render bricks as tiles
-V, --version Prints version information
OPTIONS:
-c, --colormap <colormap> Input colormap image (PNG/JPG)
-o, --output <output> Output file (BRDB, BRZ)
-s, --size <size> Brick stud size (default 1)
-v, --vertical <vertical> Vertical scale multiplier (default 1)
ARGS:
<INPUT>... Input heightmap image files (PNG/JPG)
An example command for generating the GTA V map would be:
heightmap example_maps/gta5_fixed2_height.png -c example_maps/gta5_fixed2_color.png -s 4 -v 20 --tile -o gta5.brz
To use stacked heightmap for increased resolution, simply provide more input files. See the stacked_N.png files in the example_maps directory for example stacked heightmaps.
heightmap ./example_maps/stacked_1.png ./example_maps/stacked_2.png ./example_maps/stacked_3.png ./example_maps/stacked_4.png --tile
To generate HD heightmaps for the --hdmap flag, check out Kmschr's GeoTIFF2Heightmap tool.


