1 unstable release
0.1.0 | May 10, 2023 |
---|
#1824 in Game dev
120KB
3K
SLoC
recast-rs
Rust bindings for Recast from recastnavigation
.
Getting started
Recast is essentially a toolbox for generating navigation meshes from geometry. A good starting point for generating navigation meshes is:
- Create a
Heightfield
. - Rasterize triangles into the
Heightfield
. Consider marking triangles as walkable. - Create a
CompactHeightfield
from theHeightfield
. - (Optional) Erode the walkable area.
- (Optional) Mark areas using boxes, cylinders, or convex polygons.
- Build regions for the
CompactHeightfield
. - Create a
ContourSet
from theCompactHeightfield
(with regions). - Create a
PolyMesh
from theContourSet
. - Use the
PolyMesh
data as a navigation mesh.
As a simple example of this process:
use recast_rs::*;
fn generate_nav_mesh(
vertices: &[Vec3<f32>],
triangles: &[Vec3<i32>],
) -> Result<Vec<Vec<Vec3<f32>>>, ()> {
let mut context = Context::new();
let (min_bounds, max_bounds) = util::calculate_bounds(vertices);
let mut heightfield = Heightfield::new(
&mut context,
min_bounds,
max_bounds,
/* cell_horizontal_size */ 1.0,
/* cell_height= */ 1.0,
)?;
let mut area_ids = vec![0; triangles.len()];
util::mark_walkable_triangles(
&mut context,
/* walkable_slope_angle= */ 45.0,
vertices,
triangles,
&mut area_ids,
);
heightfield.rasterize_indexed_triangles_i32(
&mut context,
vertices,
triangles,
&area_ids,
/* flag_merge_threshold= */ 1,
)?;
let mut compact_heightfield = CompactHeightfield::<NoRegions>::new(
&heightfield,
&mut context,
/* walkable_height= */ 3,
/* walkable_climb= */ 1,
)?;
compact_heightfield
.erode_walkable_area(&mut context, /* radius= */ 1)?;
let compact_heightfield = compact_heightfield.build_regions(
&mut context,
/* border_size= */ 0,
/* min_region_area= */ 0,
/* merge_region_area= */ 0,
)?;
let contour_set = ContourSet::new(
&compact_heightfield,
&mut context,
/* max_error= */ 1.0,
/* max_edge_len= */ 10,
ContourBuildFlags {
tessellate_wall_edges: true,
tessellate_area_edges: false,
},
)?;
let poly_mesh = PolyMesh::new(
&contour_set,
&mut context,
/* max_vertices_per_polygon= */ 8,
)?;
Ok(
poly_mesh
.polygons_iter()
.map(|polygon| {
polygon
.valid_vertices()
.iter()
.map(|&vertex_index| poly_mesh.vertex(vertex_index as usize).as_f32())
.collect()
})
.collect(),
)
}
Note in this example we just create a Vec for each polygon filled with the vertices that make up that polygon. In practice, you likely want to extract the neighbour information for each polygon to use this as a navigation mesh.
License
Licensed under the MIT license.
Dependencies
~1.6–3.5MB
~82K SLoC