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Bug in grid indexing.

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This commit is contained in:
mindv0rtex
2021-03-01 11:29:32 -05:00
parent 74a588046a
commit 82833748f4
3 changed files with 34 additions and 14 deletions
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7
src/grid.rs
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@@ -18,7 +18,7 @@ impl Grid {
/// Create a new grid filled with random floats in the [0.0..1.0) range.
pub fn new(width: usize, height: usize) -> Self {
if !width.is_power_of_two() || !height.is_power_of_two() {
panic!("Grid dimensitions must be a power of two.");
panic!("Grid dimensions must be a power of two.");
}
let rng = rand::thread_rng();
let range = Uniform::from(0.0..1.0);
@@ -35,8 +35,9 @@ impl Grid {
/// Truncate x and y and return a corresponding index into the data slice.
fn index(&self, x: f32, y: f32) -> usize {
let i = (x as usize + self.width) & (self.width - 1);
let j = (y as usize + self.height) & (self.height - 1);
// x/y can come in negative, hence we shift them by width/height.
let i = (x + self.width as f32) as usize & (self.width - 1);
let j = (y + self.height as f32) as usize & (self.height - 1);
j * self.width + i
}