render basic test pattern

.gitignore

@@ -1,5 +1,8 @@
 /target
 
+# test artifacts
+*.png
+
 # Byte-compiled / optimized / DLL files
 __pycache__/
 .pytest_cache/

Cargo.lock

@@ -8,12 +8,27 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26"
 
+[[package]]
+name = "bytemuck"
+version = "1.22.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6b1fc10dbac614ebc03540c9dbd60e83887fda27794998c6528f1782047d540"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "glam"
+version = "0.30.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d0e9b6647e9b41d3a5ef02964c6be01311a7f2472fea40595c635c6d046c259e"
+dependencies = [
+ "bytemuck",
+]
+
 [[package]]
 name = "heck"
 version = "0.5.0"
@@ -35,11 +50,16 @@ checksum = "d750af042f7ef4f724306de029d18836c26c1765a54a6a3f094cbd23a7267ffa"
 [[package]]
 name = "mechthild_core"
 version = "0.1.0"
+dependencies = [
+ "bytemuck",
+ "glam",
+]
 
 [[package]]
 name = "mechthild_py"
 version = "0.1.0"
 dependencies = [
+ "bytemuck",
  "mechthild_core",
  "pyo3",
 ]

core/Cargo.toml

@@ -7,3 +7,9 @@ license.workspace = true
 repository.workspace = true
 
 [dependencies]
+bytemuck = { version = "1.22.0", optional = true }
+glam = "0.30.2"
+
+[features]
+fast-math = ["glam/fast-math"]
+bytemuck = ["dep:bytemuck", "glam/bytemuck"]

core/src/color.rs

@@ -0,0 +1,29 @@
+use std::fmt;
+
+#[derive(Clone, Copy)]
+#[repr(C)]
+pub struct Rgba {
+    r: f32,
+    g: f32,
+    b: f32,
+    a: f32,
+}
+
+impl Rgba {
+    pub const BLACK: Self = Self::new(0.0, 0.0, 0.0, 1.0);
+
+    pub const fn new(r: f32, g: f32, b: f32, a: f32) -> Self {
+        Self { r, g, b, a }
+    }
+}
+
+impl fmt::Debug for Rgba {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_tuple(stringify!(Rgba))
+            .field(&self.r)
+            .field(&self.g)
+            .field(&self.b)
+            .field(&self.a)
+            .finish()
+    }
+}

core/src/impl_bytemuck.rs

@@ -0,0 +1,6 @@
+use bytemuck::{Pod, Zeroable};
+
+use crate::color::Rgba;
+
+unsafe impl Pod for Rgba {}
+unsafe impl Zeroable for Rgba {}

core/src/lib.rs

@@ -1,14 +1,38 @@
-pub fn add(left: usize, right: usize) -> usize {
-    left + right
-}
+#[cfg(feature = "bytemuck")]
+pub mod impl_bytemuck;
 
-#[cfg(test)]
-mod tests {
-    use super::*;
+pub mod color;
 
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
+use color::Rgba;
+
+pub struct Scene;
+
+impl Scene {
+    pub fn new() -> Self {
+        Self
+    }
+
+    pub fn render(&self, width: usize, height: usize) -> Box<[Rgba]> {
+        let mut data = Box::new_uninit_slice(width * height);
+
+        for (i, pixel) in data.iter_mut().enumerate() {
+            let x = (i % width) as f32;
+            let y = (i / width) as f32;
+
+            pixel.write(Rgba::new(
+                x / (width - 1) as f32,
+                y / (height - 1) as f32,
+                0.5,
+                1.0,
+            ));
+        }
+
+        unsafe { data.assume_init() }
+    }
+}
+
+impl Default for Scene {
+    fn default() -> Self {
+        Self::new()
     }
 }

examples/basic.py

@@ -0,0 +1,11 @@
+from PIL import Image
+from mechthild import Scene
+
+WIDTH = 800
+HEIGHT = 600
+
+render_result = Scene().render(WIDTH, HEIGHT)
+rgba = bytes([int(v * 255) for v in render_result])
+
+img = Image.frombuffer('RGBA', (WIDTH, HEIGHT), rgba)
+img.save("test.png")

py/Cargo.toml

@@ -13,4 +13,5 @@ crate-type = ["cdylib"]
 
 [dependencies]
 pyo3 = "0.24.0"
-mechthild_core = { path = "../core" }
+mechthild_core = { path = "../core", features = ["bytemuck"] }
+bytemuck = { version = "1.22.0", features = ["extern_crate_alloc"] }

py/src/lib.rs

@@ -1,14 +1,27 @@
+use bytemuck::allocation::cast_slice_box;
+use mechthild_core::{Scene, color::Rgba};
 use pyo3::prelude::*;
 
-/// Formats the sum of two numbers as string.
-#[pyfunction]
-fn sum_as_string(a: usize, b: usize) -> PyResult<String> {
-    Ok(mechthild_core::add(a, b).to_string())
+#[pyclass(name = "Scene")]
+struct PyScene(Scene);
+
+#[pymethods]
+impl PyScene {
+    #[new]
+    pub fn new() -> Self {
+        Self(Scene::new())
+    }
+
+    pub fn render(&self, width: usize, height: usize) -> Vec<f32> {
+        let result = self.0.render(width, height);
+
+        cast_slice_box::<Rgba, f32>(result).into_vec()
+    }
 }
 
 /// A Python module implemented in Rust.
 #[pymodule]
 fn mechthild(m: &Bound<'_, PyModule>) -> PyResult<()> {
-    m.add_function(wrap_pyfunction!(sum_as_string, m)?)?;
+    m.add_class::<PyScene>()?;
     Ok(())
 }