spine_runtime 0.2.2

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//! World-space vertices for vertex attachments (meshes, paths, bounding
//! boxes, clipping polygons).

use crate::data::{SlotId, VertexData};
use crate::skeleton::Skeleton;

impl Skeleton {
    /// Writes world `x, y` pairs for `vertex_data` into `world`, starting at
    /// `offset` and `stride` floats apart. `start` and `count` are in floats
    /// (twice the vertex index and count). A non-empty applied deform on the
    /// slot replaces unweighted vertices and offsets weighted ones.
    #[allow(clippy::too_many_arguments, clippy::many_single_char_names)]
    pub(crate) fn compute_world_vertices(
        &self,
        vertex_data: &VertexData,
        slot_id: SlotId,
        start: usize,
        count: usize,
        world: &mut [f32],
        offset: usize,
        stride: usize,
    ) {
        let end = offset + (count >> 1) * stride;
        let bones = &vertex_data.bones;
        let vertices = &vertex_data.vertices;
        let deform = &self.slots[slot_id.index()].applied().deform;

        if bones.is_empty() {
            let verts: &[f32] = if deform.is_empty() { vertices } else { deform };
            let slot_bone = self.data.slots[slot_id.index()].bone;
            let b = self.bones[slot_bone.index()].applied();
            let (x, y, a, bb, c, d) = (b.world_x, b.world_y, b.a, b.b, b.c, b.d);
            let mut vv = start;
            let mut w = offset;
            while w < end {
                let vx = verts[vv];
                let vy = verts[vv + 1];
                world[w] = vx * a + vy * bb + x;
                world[w + 1] = vx * c + vy * d + y;
                vv += 2;
                w += stride;
            }
            return;
        }

        // Skip the first `start / 2` vertices: `v` indexes `bones`, `skip`
        // counts bone influences passed.
        let mut v = 0_usize;
        let mut skip = 0_usize;
        let mut i = 0_usize;
        while i < start {
            let n = bones[v] as usize;
            v += n + 1;
            skip += n;
            i += 2;
        }

        if deform.is_empty() {
            let mut w = offset;
            let mut b_idx = skip * 3;
            while w < end {
                let mut wx = 0.0_f32;
                let mut wy = 0.0_f32;
                let n_here = bones[v] as usize;
                v += 1;
                let n_end = v + n_here;
                while v < n_end {
                    let bone_index = bones[v] as usize;
                    let bone = self.bones[bone_index].applied();
                    let vx = vertices[b_idx];
                    let vy = vertices[b_idx + 1];
                    let weight = vertices[b_idx + 2];
                    wx += (vx * bone.a + vy * bone.b + bone.world_x) * weight;
                    wy += (vx * bone.c + vy * bone.d + bone.world_y) * weight;
                    v += 1;
                    b_idx += 3;
                }
                world[w] = wx;
                world[w + 1] = wy;
                w += stride;
            }
        } else {
            let mut w = offset;
            let mut b_idx = skip * 3;
            let mut f = skip << 1;
            while w < end {
                let mut wx = 0.0_f32;
                let mut wy = 0.0_f32;
                let n_here = bones[v] as usize;
                v += 1;
                let n_end = v + n_here;
                while v < n_end {
                    let bone_index = bones[v] as usize;
                    let bone = self.bones[bone_index].applied();
                    let vx = vertices[b_idx] + deform[f];
                    let vy = vertices[b_idx + 1] + deform[f + 1];
                    let weight = vertices[b_idx + 2];
                    wx += (vx * bone.a + vy * bone.b + bone.world_x) * weight;
                    wy += (vx * bone.c + vy * bone.d + bone.world_y) * weight;
                    v += 1;
                    b_idx += 3;
                    f += 2;
                }
                world[w] = wx;
                world[w + 1] = wy;
                w += stride;
            }
        }
    }
}