feat: yaaay first stem

packages/utils/src/geometry/extrude_path.rs

@@ -1 +1,115 @@
-pub fn extrude_path(path: &[i32]) {}
+use crate::log;
+
+use super::create_empty_geometry;
+use glam::{Mat4, Quat, Vec3};
+
+fn create_circle(res: usize) -> Vec<f32> {
+    let angle = (2.0 * std::f32::consts::PI) / res as f32;
+    let mut circle = Vec::new();
+    for i in 0..res {
+        circle.push((angle * i as f32).cos());
+        circle.push((angle * i as f32).sin());
+    }
+    circle
+}
+
+#[rustfmt::skip]
+pub fn extrude_path(input_path: &[i32], res_x: usize) -> Vec<i32> {
+    let point_amount = input_path.len() / 4;
+    let face_amount = (point_amount - 1) * res_x * 2;
+    let vertices_amount = point_amount * res_x;
+
+    let circle = create_circle(res_x);
+
+    let mut geometry = create_empty_geometry(vertices_amount, face_amount);
+
+    let (_header,rest) = geometry.split_at_mut(5);
+    let (indices, rest) = rest.split_at_mut(face_amount*3);
+    let (_positions, _normals) =  rest.split_at_mut(vertices_amount*3);
+    let positions: &mut [f32];
+    let normals: &mut [f32];
+    let path: &[f32];
+    unsafe {
+        path = std::slice::from_raw_parts(input_path.as_ptr() as *const f32, input_path.len());
+        positions = std::slice::from_raw_parts_mut(_positions.as_mut_ptr() as *mut f32, _positions.len());
+        normals = std::slice::from_raw_parts_mut(_normals.as_mut_ptr() as *mut f32, _normals.len());
+    }
+
+    normals[0] = 0.0;
+
+    for i in 0..point_amount {
+
+        let index_offset = i * res_x * 6;
+        let position_offset = i * res_x;
+
+        let point = Vec3::from_slice(&path[i*4..i*4+3]);
+        let thickness = path[i*4+3];
+        let next_point = if i == point_amount - 1 { point } else { Vec3::from_slice(&path[(i+1)*4..(i+1)*4+3]) };
+        let prev_point = if i == 0 { point } else { Vec3::from_slice(&path[(i-1)*4..(i-1)*4+3]) };
+
+        let mut v = if i == 0 {
+            point - next_point
+        } else if i == point_amount - 1 {
+            prev_point - point
+        } else {
+            prev_point - next_point
+        };
+        v = v.normalize();
+
+        let n = Vec3::new(0.0, 1.0, 0.0); // Assuming 'n' is the up vector or similar
+        let axis = n.cross(v);
+        let angle = n.dot(v).acos();
+
+        let quat = Quat::from_axis_angle(axis, angle);
+        let mat = Mat4::IDENTITY * Mat4::from_quat(quat);
+
+        for j in 0..res_x {
+
+            if i < point_amount - 1 {
+
+                let i_index_offset = index_offset + j * 6;
+                let i_position_offset = position_offset + j;
+
+                if j == res_x - 1 {
+                    indices[i_index_offset    ] = (i_position_offset + 1) as i32;
+                    indices[i_index_offset + 1] = (i_position_offset - res_x + 1) as i32;
+                    indices[i_index_offset + 2] = (i_position_offset) as i32;
+                    indices[i_index_offset + 3] = (i_position_offset) as i32;
+                    indices[i_index_offset + 4] = (i_position_offset + res_x) as i32;
+                    indices[i_index_offset + 5] = (i_position_offset + 1) as i32;
+                } else {
+                    indices[i_index_offset    ] = (i_position_offset + res_x + 1) as i32;
+                    indices[i_index_offset + 1] = (i_position_offset + 1) as i32;
+                    indices[i_index_offset + 2] = (i_position_offset) as i32;
+                    indices[i_index_offset + 3] = (i_position_offset) as i32;
+                    indices[i_index_offset + 4] = (i_position_offset + res_x) as i32;
+                    indices[i_index_offset + 5] = (i_position_offset + res_x + 1) as i32;
+                }
+            }
+
+            // construct the points
+            let idx = i * res_x * 3 + j * 3;
+
+            let circle_x = circle[j * 2    ] * thickness;
+            let circle_y = circle[j * 2 + 1] * thickness;
+
+            let _pt = Vec3::new(
+                point[0] + circle_x,
+                point[1],
+                point[2] + circle_y,
+            );
+
+            let pt = Mat4::transform_point3(&mat, _pt) + point;
+
+            normals[idx    ] = circle_x;
+            normals[idx + 1] = 0.0;
+            normals[idx + 2] = circle_y;
+
+            positions[idx    ] = pt[0];
+            positions[idx + 1] = pt[1];
+            positions[idx + 2] = pt[2];
+        }
+    }
+
+    geometry
+}