Raycast against all visible scene nodes. Returns the closest hit.
(
scene: &SceneGraph,
origin: &[f32; 3],
direction: &[f32; 3],
)
| 78 | |
| 79 | /// Raycast against all visible scene nodes. Returns the closest hit. |
| 80 | pub fn raycast_scene( |
| 81 | scene: &SceneGraph, |
| 82 | origin: &[f32; 3], |
| 83 | direction: &[f32; 3], |
| 84 | ) -> PickResult { |
| 85 | let mut best = PickResult::miss(); |
| 86 | let mut best_dist = f32::MAX; |
| 87 | |
| 88 | for (handle, node) in scene.nodes.iter() { |
| 89 | if !node.visible || node.indices.is_empty() { |
| 90 | continue; |
| 91 | } |
| 92 | |
| 93 | // Transform ray into node's local space via inverse transform |
| 94 | let inv_transform = mat4_inverse_local(&node.transform); |
| 95 | let local_origin = mat4_transform_point(&inv_transform, origin); |
| 96 | let local_dir = mat4_transform_dir(&inv_transform, direction); |
| 97 | |
| 98 | // Test against all triangles |
| 99 | for tri in node.indices.chunks(3) { |
| 100 | if tri.len() < 3 { continue; } |
| 101 | let v0 = &node.vertices[tri[0] as usize]; |
| 102 | let v1 = &node.vertices[tri[1] as usize]; |
| 103 | let v2 = &node.vertices[tri[2] as usize]; |
| 104 | |
| 105 | if let Some((t, u, v)) = ray_triangle_intersection( |
| 106 | &local_origin, &local_dir, |
| 107 | &v0.position, &v1.position, &v2.position, |
| 108 | ) { |
| 109 | if t > 0.0 && t < best_dist { |
| 110 | best_dist = t; |
| 111 | |
| 112 | // Compute hit point in world space |
| 113 | let hit_local = [ |
| 114 | local_origin[0] + local_dir[0] * t, |
| 115 | local_origin[1] + local_dir[1] * t, |
| 116 | local_origin[2] + local_dir[2] * t, |
| 117 | ]; |
| 118 | let hit_world = mat4_transform_point(&node.transform, &hit_local); |
| 119 | |
| 120 | // Interpolate normal |
| 121 | let w = 1.0 - u - v; |
| 122 | let normal = [ |
| 123 | v0.normal[0] * w + v1.normal[0] * u + v2.normal[0] * v, |
| 124 | v0.normal[1] * w + v1.normal[1] * u + v2.normal[1] * v, |
| 125 | v0.normal[2] * w + v1.normal[2] * u + v2.normal[2] * v, |
| 126 | ]; |
| 127 | let nl = (normal[0]*normal[0] + normal[1]*normal[1] + normal[2]*normal[2]).sqrt(); |
| 128 | let normal = if nl > 1e-6 { |
| 129 | [normal[0]/nl, normal[1]/nl, normal[2]/nl] |
| 130 | } else { |
| 131 | [0.0, 1.0, 0.0] |
| 132 | }; |
| 133 | |
| 134 | best = PickResult { |
| 135 | hit: true, |
| 136 | handle, |
| 137 | distance: t, |
no test coverage detected