Add entry points for GPU

enkou-shaders/src/transform.rs

@@ -5,7 +5,7 @@
 //! but produce more interesting images once we add variations.
 use crate::variation::Variation;
 use bytemuck::{Pod, Zeroable};
-use glam::{Affine2, Vec2};
+use glam::{Affine2, UVec2, Vec2};
 use rand::Rng;
 
 /// Affine transform for use in the [`chaos_game`](crate::chaos_game).
@@ -13,12 +13,12 @@ use rand::Rng;
 #[repr(C)]
 pub struct Transform {
     coefficients: Affine2,
-    variation_range: [u16; 2],
+    variation_range: UVec2,
 }
 
 impl Transform {
     /// Create a new transform from an affine transformation matrix
-    pub fn new(coefficients: Affine2, variation_range: [u16; 2]) -> Self {
+    pub fn new(coefficients: Affine2, variation_range: UVec2) -> Self {
         Transform {
             coefficients,
             variation_range,
@@ -35,8 +35,11 @@ impl Transform {
         let point = self.coefficients.transform_point2(point);
 
         let mut point_output = Vec2::ZERO;
-        let variation_range = self.variation_range[0] as usize..self.variation_range[1] as usize;
-        for variation in variations[variation_range].iter() {
+
+        let variation_start = self.variation_range.x;
+        let variation_end = self.variation_range.y;
+        for variation_index in variation_start..variation_end {
+            let ref variation = variations[variation_index as usize];
             point_output += variation.transform_point(point, rng, &self.coefficients)
         }