psychopath/src/surface/triangle_mesh.rs

261 lines
9.9 KiB
Rust

#![allow(dead_code)]
use kioku::Arena;
use crate::{
accel::BVH4,
bbox::BBox,
boundable::Boundable,
color::Color,
lerp::lerp_slice,
math::{cross, dot, Normal, Point, XformFull},
ray::{LocalRay, Ray},
shading::{SimpleSurfaceShader, SurfaceShader},
};
use super::{triangle, Surface, SurfaceIntersection, SurfaceIntersectionData};
const MAX_LEAF_TRIANGLE_COUNT: usize = 3;
#[derive(Copy, Clone, Debug)]
pub struct TriangleMesh<'a> {
pub shader_idx: Option<usize>,
time_sample_count: usize,
vertices: &'a [Point], // Vertices, with the time samples for each vertex stored contiguously
normals: Option<&'a [Normal]>, // Vertex normals, organized the same as `vertices`
indices: &'a [(u32, u32, u32, u32)], // (v0_idx, v1_idx, v2_idx, original_tri_idx)
accel: BVH4<'a>,
}
impl<'a> TriangleMesh<'a> {
pub fn from_verts_and_indices<'b>(
arena: &'b Arena,
shader_idx: Option<usize>,
verts: &[Vec<Point>],
vert_normals: &Option<Vec<Vec<Normal>>>,
tri_indices: &[(usize, usize, usize)],
) -> TriangleMesh<'b> {
let vert_count = verts[0].len();
let time_sample_count = verts.len();
// Copy verts over to a contiguous area of memory, reorganizing them
// so that each vertices' time samples are contiguous in memory.
let vertices = {
let vertices = arena.alloc_array_uninit(vert_count * time_sample_count);
for vi in 0..vert_count {
for ti in 0..time_sample_count {
unsafe {
*vertices[(vi * time_sample_count) + ti].as_mut_ptr() = verts[ti][vi];
}
}
}
unsafe { std::mem::transmute(vertices) }
};
// Copy vertex normals, if any, organizing them the same as vertices
// above.
let normals = match vert_normals {
Some(ref vnors) => {
let normals = arena.alloc_array_uninit(vert_count * time_sample_count);
for vi in 0..vert_count {
for ti in 0..time_sample_count {
unsafe {
*normals[(vi * time_sample_count) + ti].as_mut_ptr() = vnors[ti][vi];
}
}
}
unsafe { Some(std::mem::transmute(&normals[..])) }
}
None => None,
};
// Copy triangle vertex indices over, appending the triangle index itself to the tuple
let indices: &mut [(u32, u32, u32, u32)] = {
let indices = arena.alloc_array_uninit(tri_indices.len());
for (i, tri_i) in tri_indices.iter().enumerate() {
unsafe {
*indices[i].as_mut_ptr() =
(tri_i.0 as u32, tri_i.2 as u32, tri_i.1 as u32, i as u32);
}
}
unsafe { std::mem::transmute(indices) }
};
// Create bounds array for use during BVH construction
let bounds = {
let mut bounds = Vec::with_capacity(indices.len() * time_sample_count);
for tri in tri_indices {
for ti in 0..time_sample_count {
let p0 = verts[ti][tri.0];
let p1 = verts[ti][tri.1];
let p2 = verts[ti][tri.2];
let minimum = p0.min(p1.min(p2));
let maximum = p0.max(p1.max(p2));
bounds.push(BBox::from_points(minimum, maximum));
}
}
bounds
};
// Build BVH
let accel = BVH4::from_objects(arena, &mut indices[..], MAX_LEAF_TRIANGLE_COUNT, |tri| {
&bounds
[(tri.3 as usize * time_sample_count)..((tri.3 as usize + 1) * time_sample_count)]
});
TriangleMesh {
shader_idx: shader_idx,
time_sample_count: time_sample_count,
vertices: vertices,
normals: normals,
indices: indices,
accel: accel,
}
}
}
impl<'a> Boundable for TriangleMesh<'a> {
fn bounds(&self) -> &[BBox] {
self.accel.bounds()
}
}
impl<'a> Surface for TriangleMesh<'a> {
fn intersect_ray(
&self,
ray: &mut Ray,
local_ray: &LocalRay,
space: &XformFull,
isect: &mut SurfaceIntersection,
shaders: &[&dyn SurfaceShader],
) {
let unassigned_shader = SimpleSurfaceShader::Emit {
color: Color::new_xyz(color::rec709_to_xyz((1.0, 0.0, 1.0))),
};
let shader = if let Some(idx) = self.shader_idx {
shaders[idx]
} else {
&unassigned_shader
};
self.accel.traverse(ray, local_ray, |idx_range, ray| {
// Iterate through the triangles and test the ray against them.
let mut non_shadow_hit = false;
let mut hit_tri = std::mem::MaybeUninit::uninit();
let mut hit_tri_indices = std::mem::MaybeUninit::uninit();
let mut hit_tri_data = std::mem::MaybeUninit::uninit();
let ray_pre = triangle::RayTriPrecompute::new(ray.dir);
for tri_idx in idx_range.clone() {
let tri_indices = self.indices[tri_idx];
// Get triangle.
let mut tri = if self.time_sample_count == 1 {
// No deformation motion blur, so fast-path it.
(
self.vertices[tri_indices.0 as usize],
self.vertices[tri_indices.1 as usize],
self.vertices[tri_indices.2 as usize],
)
} else {
// Deformation motion blur, need to interpolate.
let p0_slice = &self.vertices[(tri_indices.0 as usize * self.time_sample_count)
..((tri_indices.0 as usize + 1) * self.time_sample_count)];
let p1_slice = &self.vertices[(tri_indices.1 as usize * self.time_sample_count)
..((tri_indices.1 as usize + 1) * self.time_sample_count)];
let p2_slice = &self.vertices[(tri_indices.2 as usize * self.time_sample_count)
..((tri_indices.2 as usize + 1) * self.time_sample_count)];
let p0 = lerp_slice(p0_slice, ray.time);
let p1 = lerp_slice(p1_slice, ray.time);
let p2 = lerp_slice(p2_slice, ray.time);
(p0, p1, p2)
};
// Transform triangle into world space.
tri.0 = tri.0.xform(space);
tri.1 = tri.1.xform(space);
tri.2 = tri.2.xform(space);
// Test ray against triangle
if let Some((t, b0, b1, b2)) =
triangle::intersect_ray(ray.orig, ray_pre, ray.max_t, tri)
{
if ray.is_occlusion() {
*isect = SurfaceIntersection::Occlude;
ray.mark_done();
break;
} else {
non_shadow_hit = true;
ray.max_t = t;
unsafe {
*hit_tri.as_mut_ptr() = tri;
*hit_tri_indices.as_mut_ptr() = tri_indices;
*hit_tri_data.as_mut_ptr() = (t, b0, b1, b2);
}
}
}
}
// Calculate intersection data if necessary.
if non_shadow_hit {
let hit_tri = unsafe { hit_tri.assume_init() };
let (t, b0, b1, b2) = unsafe { hit_tri_data.assume_init() };
// Calculate intersection point and error magnitudes
let (pos, pos_err) = triangle::surface_point(hit_tri, (b0, b1, b2));
// Calculate geometric surface normal
let geo_normal = cross(hit_tri.0 - hit_tri.1, hit_tri.0 - hit_tri.2).into_normal();
// Calculate interpolated surface normal, if any
let shading_normal = if let Some(normals) = self.normals {
let hit_tri_indices = unsafe { hit_tri_indices.assume_init() };
let n0_slice = &normals[(hit_tri_indices.0 as usize * self.time_sample_count)
..((hit_tri_indices.0 as usize + 1) * self.time_sample_count)];
let n1_slice = &normals[(hit_tri_indices.1 as usize * self.time_sample_count)
..((hit_tri_indices.1 as usize + 1) * self.time_sample_count)];
let n2_slice = &normals[(hit_tri_indices.2 as usize * self.time_sample_count)
..((hit_tri_indices.2 as usize + 1) * self.time_sample_count)];
let n0 = lerp_slice(n0_slice, ray.time).normalized();
let n1 = lerp_slice(n1_slice, ray.time).normalized();
let n2 = lerp_slice(n2_slice, ray.time).normalized();
let s_nor = ((n0 * b0) + (n1 * b1) + (n2 * b2)).xform_fast(&space);
if dot(s_nor, geo_normal) >= 0.0 {
s_nor
} else {
-s_nor
}
} else {
geo_normal
};
let intersection_data = SurfaceIntersectionData {
incoming: ray.dir,
t: t,
pos: pos,
pos_err: pos_err,
nor: shading_normal,
nor_g: geo_normal,
local_space: *space,
sample_pdf: 0.0,
};
// Fill in intersection data
*isect = SurfaceIntersection::Hit {
intersection_data: intersection_data,
closure: shader.shade(&intersection_data, ray.time),
};
}
});
}
}