psychopath/src/tracer.rs
2022-07-31 17:50:54 -07:00

130 lines
4.1 KiB
Rust

use crate::{
color::{rec709_to_xyz, Color},
lerp::lerp_slice,
math::XformFull,
ray::{LocalRay, Ray},
scene::{Assembly, InstanceType, Object},
shading::{SimpleSurfaceShader, SurfaceShader},
surface::SurfaceIntersection,
};
pub struct Tracer<'a> {
root: &'a Assembly<'a>,
ray_trace_count: u64,
}
impl<'a> Tracer<'a> {
pub fn from_assembly(assembly: &'a Assembly) -> Tracer<'a> {
Tracer {
root: assembly,
ray_trace_count: 0,
}
}
pub fn rays_traced(&self) -> u64 {
self.ray_trace_count
}
pub fn trace(&mut self, ray: &mut Ray, isect: &mut SurfaceIntersection) {
self.ray_trace_count += 1;
let local_ray = ray.to_local();
let space = XformFull::identity();
self.trace_assembly(self.root, ray, &local_ray, &space, isect);
}
fn trace_assembly(
&mut self,
assembly: &Assembly,
ray: &mut Ray,
local_ray: &LocalRay,
space: &XformFull,
isect: &mut SurfaceIntersection,
) {
assembly
.object_accel
.traverse(ray, local_ray, |idx_range, ray| {
for inst_idx in idx_range {
let inst = &assembly.instances[inst_idx];
// Handle transforms if needed.
let (local_space, local_ray) = if let Some((xstart, xend)) =
inst.transform_indices
{
let instance_xform = lerp_slice(&assembly.xforms[xstart..xend], ray.time);
let combined_xform = instance_xform.compose(&space.fwd);
if let Some(xform) = combined_xform.to_full() {
(xform, ray.to_local_xform(&xform))
} else {
// Invalid transform, so skip traversing into this instance.
continue;
}
} else {
(*space, *local_ray)
};
// Trace ray.
match inst.instance_type {
InstanceType::Object => {
self.trace_object(
&assembly.objects[inst.data_index],
inst.surface_shader_index
.map(|i| assembly.surface_shaders[i]),
ray,
&local_ray,
&local_space,
isect,
);
}
InstanceType::Assembly => {
self.trace_assembly(
&assembly.assemblies[inst.data_index],
ray,
&local_ray,
&local_space,
isect,
);
}
}
if ray.is_done() {
return;
}
}
});
}
fn trace_object<'b>(
&mut self,
obj: &Object,
surface_shader: Option<&dyn SurfaceShader>,
ray: &mut Ray,
local_ray: &LocalRay,
space: &XformFull,
isect: &mut SurfaceIntersection,
) {
match *obj {
Object::Surface(surface) => {
let unassigned_shader = SimpleSurfaceShader::Emit {
color: Color::new_xyz(rec709_to_xyz((1.0, 0.0, 1.0))),
};
let shader = surface_shader.unwrap_or(&unassigned_shader);
surface.intersect_ray(ray, local_ray, space, isect, shader);
}
Object::SurfaceLight(surface) => {
// Lights don't use shaders
let bogus_shader = SimpleSurfaceShader::Emit {
color: Color::new_xyz(rec709_to_xyz((1.0, 0.0, 1.0))),
};
surface.intersect_ray(ray, local_ray, space, isect, &bogus_shader);
}
}
}
}