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Split xform stack out into its own type.

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This is mainly just to make the tracer code read more cleanly.
All of the pushing and popping logic obscured the big picture
and made things a bit confusing.
This commit is contained in:
Nathan Vegdahl 2016-05-28 14:15:05 -07:00
parent 56b5267b7a
commit ef31093dcb
1 changed files with 81 additions and 28 deletions
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109
src/tracer.rs
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@ -11,8 +11,7 @@ use surface::SurfaceIntersection;
pub struct Tracer<'a> {
root: &'a Assembly,
rays: UnsafeCell<Vec<Ray>>, // Should only be used from trace(), not any other methods
xform_stack: Vec<Matrix4x4>,
xform_stack_indices: Vec<usize>,
xform_stack: TransformStack,
isects: Vec<SurfaceIntersection>,
}
@ -21,8 +20,7 @@ impl<'a> Tracer<'a> {
Tracer {
root: assembly,
rays: UnsafeCell::new(Vec::new()),
xform_stack: Vec::new(),
xform_stack_indices: vec![0],
xform_stack: TransformStack::new(),
isects: Vec::new(),
}
}
@ -63,23 +61,10 @@ impl<'a> Tracer<'a> {
// Transform rays if needed
if let Some((xstart, xend)) = inst.transform_indices {
// Push transforms to stack
let mut combined = Vec::new();
if self.xform_stack.len() == 0 {
self.xform_stack.extend(&assembly.xforms[xstart..xend]);
} else {
let x2start = self.xform_stack_indices[self.xform_stack_indices.len() - 2];
let x2end = self.xform_stack_indices[self.xform_stack_indices.len() - 1];
multiply_matrix_slices(&self.xform_stack[x2start..x2end],
&assembly.xforms[xstart..xend],
&mut combined);
self.xform_stack.extend(&combined);
}
self.xform_stack_indices.push(self.xform_stack.len());
self.xform_stack.push(&assembly.xforms[xstart..xend]);
// Do transforms
let xstart = self.xform_stack_indices[self.xform_stack_indices.len() - 2];
let xend = self.xform_stack_indices[self.xform_stack_indices.len() - 1];
let xforms = &self.xform_stack[xstart..xend];
let xforms = self.xform_stack.top();
for ray in &mut rs[..] {
let id = ray.id;
let t = ray.time;
@ -102,17 +87,11 @@ impl<'a> Tracer<'a> {
// Un-transform rays if needed
if let Some(_) = inst.transform_indices {
// Pop transforms off stack
let xstart = self.xform_stack_indices[self.xform_stack_indices.len() - 2];
let xend = self.xform_stack_indices[self.xform_stack_indices.len() - 1];
let l = self.xform_stack.len();
self.xform_stack.resize(l - (xend - xstart), Matrix4x4::new());
self.xform_stack_indices.pop();
self.xform_stack.pop();
// Undo transforms
if self.xform_stack.len() > 0 {
let xstart = self.xform_stack_indices[self.xform_stack_indices.len() - 2];
let xend = self.xform_stack_indices[self.xform_stack_indices.len() - 1];
let xforms = &self.xform_stack[xstart..xend];
let xforms = self.xform_stack.top();
if xforms.len() > 0 {
for ray in &mut rs[..] {
let id = ray.id;
let t = ray.time;
@ -138,3 +117,77 @@ impl<'a> Tracer<'a> {
}
}
}
struct TransformStack {
stack: Vec<Matrix4x4>,
stack_indices: Vec<usize>,
scratch_space: Vec<Matrix4x4>,
}
impl TransformStack {
fn new() -> TransformStack {
let mut ts = TransformStack {
stack: Vec::new(),
stack_indices: Vec::new(),
scratch_space: Vec::new(),
};
ts.stack_indices.push(0);
ts.stack_indices.push(0);
ts
}
fn with_capacity(capacity: usize) -> TransformStack {
let mut ts = TransformStack {
stack: Vec::with_capacity(capacity),
stack_indices: Vec::with_capacity(capacity),
scratch_space: Vec::with_capacity(capacity),
};
ts.stack_indices.push(0);
ts.stack_indices.push(0);
ts
}
fn push(&mut self, xforms: &[Matrix4x4]) {
assert!(xforms.len() > 0);
if self.stack.len() == 0 {
self.stack.extend(xforms);
} else {
let sil = self.stack_indices.len();
let i1 = self.stack_indices[sil - 2];
let i2 = self.stack_indices[sil - 1];
self.scratch_space.clear();
multiply_matrix_slices(&self.stack[i1..i2], xforms, &mut self.scratch_space);
self.stack.extend(&self.scratch_space);
}
self.stack_indices.push(self.stack.len());
}
fn pop(&mut self) {
assert!(self.stack_indices.len() > 1);
let sl = self.stack.len();
let sil = self.stack_indices.len();
let i1 = self.stack_indices[sil - 2];
let i2 = self.stack_indices[sil - 1];
self.stack.truncate(sl - (i2 - i1));
self.stack_indices.pop();
}
fn top<'a>(&'a self) -> &'a [Matrix4x4] {
let sil = self.stack_indices.len();
let i1 = self.stack_indices[sil - 2];
let i2 = self.stack_indices[sil - 1];
&self.stack[i1..i2]
}
}