nexus_mpm3d 0.5.0

Cross-platform 3D GPU-accelerated MPM physics.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57

use crate::mpm_shaders::solver::particle::{Position, RigidParticleIndices};
use glamx::UVec2;
use rapier::geometry::{Polyline, Segment};

/// Type alias for backward compatibility.
pub type GpuSampleIds = RigidParticleIndices;

#[derive(Copy, Clone, Debug)]
#[repr(C)]
pub struct SamplingParams {
    pub base_vid: u32,
    pub collider_id: u32,
    pub sampling_step: f32,
}

#[derive(Default, Clone)]
pub struct SamplingBuffers {
    pub samples: Vec<Position>,
    pub samples_ids: Vec<GpuSampleIds>,
}

pub fn sample_polyline(
    polyline: &Polyline,
    params: &SamplingParams,
    buffers: &mut SamplingBuffers,
) {
    for seg_idx in polyline.indices() {
        let seg = Segment::new(
            polyline.vertices()[seg_idx[0] as usize],
            polyline.vertices()[seg_idx[1] as usize],
        );
        let sample_id = GpuSampleIds {
            segment: UVec2::new(params.base_vid + seg_idx[0], params.base_vid + seg_idx[1]),
            collider: params.collider_id,
            _pad: 0,
        };
        buffers.samples.push(Position { pt: seg.a });
        buffers.samples_ids.push(sample_id);

        if let Some(dir) = seg.direction() {
            for i in 0.. {
                let shift = (i as f32) * params.sampling_step;
                if shift > seg.length() {
                    break;
                }

                buffers.samples.push(Position {
                    pt: seg.a + dir * shift,
                });
                buffers.samples_ids.push(sample_id);
            }

            buffers.samples.push(Position { pt: seg.b });
            buffers.samples_ids.push(sample_id);
        }
    }
}