Add entry points for GPU

enkou-shaders/src/lib.rs

@@ -5,14 +5,9 @@
 pub mod camera;
 pub mod chaos_game;
 pub mod transform;
-mod variation;
+pub mod variation;
 
-use bytemuck::{Pod, Zeroable};
-use core::f32::consts::PI;
-use glam::{Affine2, Vec3, Vec4, vec2, vec3};
-#[cfg(target_arch = "spirv")]
-use spirv_std::num_traits::Float;
-use spirv_std::spirv;
+use glam::Affine2;
 
 /// Utility trait to convert between `flam3` notation and [`glam`].
 #[allow(missing_docs)]
@@ -39,6 +34,28 @@ pub trait Coefficients2 {
     /// ```
     fn from_coefficients(a: f32, b: f32, c: f32, d: f32, e: f32, f: f32) -> Affine2;
 
+    /// Convert affine transformation coefficients to the [`glam`] representation.
+    /// Parameters use the following form:
+    ///
+    /// ```text
+    /// (a * x + b * y + c, d * x + e * y + f)
+    /// ```
+    ///
+    /// ```
+    /// # use glam::{Affine2, vec2};
+    /// # use crate::enkou_shaders::Coefficients2;
+    /// let coefs = Affine2::from_coefficients_arr([1.0, 2.0, 3.0, 4.0, 5.0, 6.0]);
+    /// let (x, y) = (7.0, 8.0);
+    /// assert_eq!(
+    ///     coefs.transform_point2(vec2(x, y)),
+    ///     vec2(
+    ///         coefs.a() * x + coefs.b() * y + coefs.c(),
+    ///         coefs.d() * x + coefs.e() * y + coefs.f()
+    ///     )
+    /// );
+    /// ```
+    fn from_coefficients_arr(coefficients: [f32; 6]) -> Affine2;
+
     fn a(&self) -> f32;
     fn b(&self) -> f32;
     fn c(&self) -> f32;
@@ -48,10 +65,23 @@ pub trait Coefficients2 {
 }
 
 impl Coefficients2 for Affine2 {
+    #[inline]
     fn from_coefficients(a: f32, b: f32, c: f32, d: f32, e: f32, f: f32) -> Affine2 {
         Affine2::from_cols_array(&[a, d, b, e, c, f])
     }
 
+    #[inline]
+    fn from_coefficients_arr(coefficients: [f32; 6]) -> Affine2 {
+        Affine2::from_coefficients(
+            coefficients[0],
+            coefficients[1],
+            coefficients[2],
+            coefficients[3],
+            coefficients[4],
+            coefficients[5],
+        )
+    }
+
     fn a(&self) -> f32 {
         self.matrix2.x_axis.x
     }
@@ -76,34 +106,3 @@ impl Coefficients2 for Affine2 {
         self.translation.y
     }
 }
-
-#[derive(Copy, Clone, Pod, Zeroable)]
-#[repr(C)]
-#[allow(missing_docs)]
-pub struct ShaderConstants {
-    pub width: u32,
-    pub height: u32,
-    pub time: f32,
-}
-
-#[spirv(fragment)]
-#[allow(missing_docs)]
-pub fn main_fs(vtx_color: Vec3, output: &mut Vec4) {
-    *output = Vec4::from((vtx_color, 1.));
-}
-
-#[spirv(vertex)]
-#[allow(missing_docs)]
-pub fn main_vs(
-    #[spirv(vertex_index)] vert_id: i32,
-    #[spirv(descriptor_set = 0, binding = 0, storage_buffer)] constants: &ShaderConstants,
-    #[spirv(position)] vtx_pos: &mut Vec4,
-    vtx_color: &mut Vec3,
-) {
-    let speed = 0.4;
-    let time = constants.time * speed + vert_id as f32 * (2. * PI * 120. / 360.);
-    let position = vec2(f32::sin(time), f32::cos(time));
-    *vtx_pos = Vec4::from((position, 0.0, 1.0));
-
-    *vtx_color = [vec3(1., 0., 0.), vec3(0., 1., 0.), vec3(0., 0., 1.)][vert_id as usize % 3];
-}