background_image example in python (#46)

Author: catilac

crates/processing_ffi/src/lib.rs

@@ -17,7 +17,7 @@ mod error;
 #[unsafe(no_mangle)]
 pub extern "C" fn processing_init() {
     error::clear_error();
-    error::check(init);
+    error::check(|| init(Config::default()));
 }
 
 /// Create a WebGPU surface from a macOS NSWindow handle.

crates/processing_pyo3/examples/background_image.py

@@ -0,0 +1,12 @@
+from processing import *
+
+def setup():
+    size(800, 600)
+
+def draw():
+    background(220)
+    image("images/logo.png")
+
+
+# TODO: this should happen implicitly on module load somehow
+run()

crates/processing_pyo3/src/graphics.rs

@@ -38,11 +38,13 @@ impl Drop for Graphics {
 #[pymethods]
 impl Graphics {
     #[new]
-    pub fn new(width: u32, height: u32) -> PyResult<Self> {
+    pub fn new(width: u32, height: u32, asset_path: &str) -> PyResult<Self> {
         let glfw_ctx =
             GlfwContext::new(width, height).map_err(|e| PyRuntimeError::new_err(format!("{e}")))?;
 
-        init().map_err(|e| PyRuntimeError::new_err(format!("{e}")))?;
+        let mut config = Config::new();
+        config.set(ConfigKey::AssetRootPath, asset_path.to_string());
+        init(config).map_err(|e| PyRuntimeError::new_err(format!("{e}")))?;
 
         let surface = glfw_ctx
             .create_surface(width, height, 1.0)
@@ -122,6 +124,12 @@ impl Graphics {
         .map_err(|e| PyRuntimeError::new_err(format!("{e}")))
     }
 
+    pub fn image(&self, file: &str) -> PyResult<()> {
+        let image = image_load(file).unwrap();
+        graphics_record_command(self.entity, DrawCommand::BackgroundImage(image))
+            .map_err(|e| PyRuntimeError::new_err(format!("{e}")))
+    }
+
     pub fn push_matrix(&self) -> PyResult<()> {
         graphics_record_command(self.entity, DrawCommand::PushMatrix)
             .map_err(|e| PyRuntimeError::new_err(format!("{e}")))

crates/processing_pyo3/src/lib.rs

@@ -7,13 +7,15 @@
 //! receiver.
 //!
 //! To allow Python users to create a similar experience, we provide module-level
-//! functions that forward to a singleton Graphics object bepub(crate) pub(crate) hind the scenes.
+//! functions that forward to a singleton Graphics object pub(crate) behind the scenes.
 mod glfw;
 mod graphics;
 
 use graphics::{Graphics, get_graphics, get_graphics_mut};
 use pyo3::{exceptions::PyRuntimeError, prelude::*};
 
+use std::env;
+
 #[pymodule]
 fn processing(m: &Bound<'_, PyModule>) -> PyResult<()> {
     m.add_class::<Graphics>()?;
@@ -26,13 +28,36 @@ fn processing(m: &Bound<'_, PyModule>) -> PyResult<()> {
     m.add_function(wrap_pyfunction!(no_stroke, m)?)?;
     m.add_function(wrap_pyfunction!(stroke_weight, m)?)?;
     m.add_function(wrap_pyfunction!(rect, m)?)?;
+    m.add_function(wrap_pyfunction!(image, m)?)?;
     Ok(())
 }
 
+fn get_asset_root() -> PyResult<String> {
+    if let Ok(val) = env::var("PROCESSING_ASSET_ROOT") {
+        return Ok(val);
+    }
+
+    Python::attach(|py| {
+        let sys = PyModule::import(py, "sys")?;
+        let argv: Vec<String> = sys.getattr("argv")?.extract()?;
+        let filename: &str = argv[0].as_str();
+        let os = PyModule::import(py, "os")?;
+        let path = os.getattr("path")?;
+        let dirname = path.getattr("dirname")?.call1((filename,))?;
+        let abspath = path.getattr("abspath")?.call1((dirname,))?;
+        let asset_root = path
+            .getattr("join")?
+            .call1((abspath, "assets"))?
+            .to_string();
+        Ok(asset_root)
+    })
+}
+
 #[pyfunction]
 #[pyo3(pass_module)]
 fn size(module: &Bound<'_, PyModule>, width: u32, height: u32) -> PyResult<()> {
-    let graphics = Graphics::new(width, height)?;
+    let asset_path: String = get_asset_root()?;
+    let graphics = Graphics::new(width, height, asset_path.as_str())?;
     module.setattr("_graphics", graphics)?;
     Ok(())
 }
@@ -122,3 +147,9 @@ fn rect(
 ) -> PyResult<()> {
     get_graphics(module)?.rect(x, y, w, h, tl, tr, br, bl)
 }
+
+#[pyfunction]
+#[pyo3(pass_module, signature = (image_file))]
+fn image(module: &Bound<'_, PyModule>, image_file: &str) -> PyResult<()> {
+    get_graphics(module)?.image(image_file)
+}

crates/processing_render/Cargo.toml

@@ -32,4 +32,4 @@ windows = { version = "0.58", features = ["Win32_Foundation", "Win32_System_Libr
 wasm-bindgen = "0.2"
 wasm-bindgen-futures = "0.4"
 js-sys = "0.3"
-web-sys = { version = "0.3", features = ["Window", "Document", "HtmlCanvasElement"] }
+web-sys = { version = "0.3", features = ["Window", "Document", "HtmlCanvasElement"] }

crates/processing_render/src/config.rs

@@ -0,0 +1,48 @@
+//! Options object for configuring various aspects of libprocessing.
+//!
+//! To add a new Config just add a new enum with associated value
+
+use bevy::prelude::Resource;
+use std::collections::HashMap;
+
+#[derive(Clone, Hash, Eq, PartialEq)]
+pub enum ConfigKey {
+    AssetRootPath,
+}
+
+// TODO: Consider Box<dyn Any> instead of String
+#[derive(Resource)]
+pub struct Config {
+    map: HashMap<ConfigKey, String>,
+}
+
+impl Clone for Config {
+    fn clone(&self) -> Self {
+        Config {
+            map: self.map.clone(),
+        }
+    }
+}
+
+impl Config {
+    pub fn new() -> Self {
+        // TODO consider defaults
+        Config {
+            map: HashMap::new(),
+        }
+    }
+
+    pub fn get(&self, k: ConfigKey) -> Option<&String> {
+        self.map.get(&k)
+    }
+
+    pub fn set(&mut self, k: ConfigKey, v: String) {
+        self.map.insert(k, v);
+    }
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self::new()
+    }
+}

crates/processing_render/src/image.rs

@@ -5,7 +5,8 @@ use std::path::PathBuf;
 
 use bevy::{
     asset::{
-        LoadState, RenderAssetUsages, handle_internal_asset_events, io::embedded::GetAssetServer,
+        AssetPath, LoadState, RenderAssetUsages, handle_internal_asset_events,
+        io::{AssetSourceId, embedded::GetAssetServer},
     },
     ecs::{entity::EntityHashMap, system::RunSystemOnce},
     prelude::*,
@@ -23,6 +24,7 @@ use bevy::{
 };
 use half::f16;
 
+use crate::config::{Config, ConfigKey};
 use crate::error::{ProcessingError, Result};
 
 pub struct ImagePlugin;
@@ -138,7 +140,16 @@ pub fn from_handle(
 }
 
 pub fn load(In(path): In<PathBuf>, world: &mut World) -> Result<Entity> {
+    let config = world.resource_mut::<Config>();
+    let path: AssetPath = match config.get(ConfigKey::AssetRootPath) {
+        Some(_) => {
+            AssetPath::from_path_buf(path).with_source(AssetSourceId::from("assets_directory"))
+        }
+        None => AssetPath::from_path_buf(path),
+    };
+
     let handle: Handle<bevy::image::Image> = world.get_asset_server().load(path);
+
     while let LoadState::Loading = world.get_asset_server().load_state(&handle) {
         world.run_system_once(handle_internal_asset_events).unwrap();
     }

crates/processing_render/src/lib.rs

@@ -1,3 +1,4 @@
+pub mod config;
 pub mod error;
 mod graphics;
 pub mod image;
@@ -6,11 +7,13 @@ mod surface;
 
 use std::{cell::RefCell, num::NonZero, path::PathBuf, sync::OnceLock};
 
+use config::*;
+
 #[cfg(not(target_arch = "wasm32"))]
 use bevy::log::tracing_subscriber;
 use bevy::{
     app::{App, AppExit},
-    asset::AssetEventSystems,
+    asset::{AssetEventSystems, io::AssetSourceBuilder},
     prelude::*,
     render::render_resource::{Extent3d, TextureFormat},
 };
@@ -202,9 +205,11 @@ pub fn surface_resize(graphics_entity: Entity, width: u32, height: u32) -> error
     })
 }
 
-fn create_app() -> App {
+fn create_app(config: Config) -> App {
     let mut app = App::new();
 
+    app.insert_resource(config.clone());
+
     #[cfg(not(target_arch = "wasm32"))]
     let plugins = DefaultPlugins
         .build()
@@ -227,6 +232,13 @@ fn create_app() -> App {
             ..default()
         });
 
+    if let Some(asset_path) = config.get(ConfigKey::AssetRootPath) {
+        app.register_asset_source(
+            "assets_directory",
+            AssetSourceBuilder::platform_default(asset_path, None),
+        );
+    }
+
     app.add_plugins(plugins);
     app.add_plugins((ImagePlugin, GraphicsPlugin, SurfacePlugin));
     app.add_systems(First, (clear_transient_meshes, activate_cameras))
@@ -258,13 +270,13 @@ fn set_app(app: App) {
 /// Initialize the app, if not already initialized. Must be called from the main thread and cannot
 /// be called concurrently from multiple threads.
 #[cfg(not(target_arch = "wasm32"))]
-pub fn init() -> error::Result<()> {
+pub fn init(config: Config) -> error::Result<()> {
     setup_tracing()?;
     if is_already_init()? {
         return Ok(());
     }
 
-    let mut app = create_app();
+    let mut app = create_app(config);
     app.finish();
     app.cleanup();
     set_app(app);

examples/background_image.rs

@@ -19,7 +19,7 @@ fn main() {
 
 fn sketch() -> error::Result<()> {
     let mut glfw_ctx = GlfwContext::new(400, 400)?;
-    init()?;
+    init(Config::default())?;
 
     let width = 400;
     let height = 400;

examples/rectangle.rs

@@ -19,7 +19,7 @@ fn main() {
 
 fn sketch() -> error::Result<()> {
     let mut glfw_ctx = GlfwContext::new(400, 400)?;
-    init()?;
+    init(Config::default())?;
 
     let width = 400;
     let height = 400;