build.rs

  1use std::{
  2    env,
  3    path::{Path, PathBuf},
  4};
  5
  6use cbindgen::Config;
  7
  8fn main() {
  9    generate_dispatch_bindings();
 10    let header_path = generate_shader_bindings();
 11    #[cfg(feature = "runtime_shaders")]
 12    emit_stitched_shaders(&header_path);
 13    #[cfg(not(feature = "runtime_shaders"))]
 14    compile_metal_shaders(&header_path);
 15}
 16
 17fn generate_dispatch_bindings() {
 18    println!("cargo:rustc-link-lib=framework=System");
 19    println!("cargo:rerun-if-changed=src/platform/mac/dispatch.h");
 20
 21    let bindings = bindgen::Builder::default()
 22        .header("src/platform/mac/dispatch.h")
 23        .allowlist_var("_dispatch_main_q")
 24        .allowlist_var("DISPATCH_QUEUE_PRIORITY_DEFAULT")
 25        .allowlist_var("DISPATCH_TIME_NOW")
 26        .allowlist_function("dispatch_get_global_queue")
 27        .allowlist_function("dispatch_async_f")
 28        .allowlist_function("dispatch_after_f")
 29        .allowlist_function("dispatch_time")
 30        .parse_callbacks(Box::new(bindgen::CargoCallbacks))
 31        .layout_tests(false)
 32        .generate()
 33        .expect("unable to generate bindings");
 34
 35    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
 36    bindings
 37        .write_to_file(out_path.join("dispatch_sys.rs"))
 38        .expect("couldn't write dispatch bindings");
 39}
 40
 41fn generate_shader_bindings() -> PathBuf {
 42    let output_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("scene.h");
 43    let crate_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());
 44    let mut config = Config::default();
 45    config.include_guard = Some("SCENE_H".into());
 46    config.language = cbindgen::Language::C;
 47    config.export.include.extend([
 48        "Bounds".into(),
 49        "Corners".into(),
 50        "Edges".into(),
 51        "Size".into(),
 52        "Pixels".into(),
 53        "PointF".into(),
 54        "Hsla".into(),
 55        "ContentMask".into(),
 56        "Uniforms".into(),
 57        "AtlasTile".into(),
 58        "PathRasterizationInputIndex".into(),
 59        "PathVertex_ScaledPixels".into(),
 60        "ShadowInputIndex".into(),
 61        "Shadow".into(),
 62        "QuadInputIndex".into(),
 63        "Underline".into(),
 64        "UnderlineInputIndex".into(),
 65        "Quad".into(),
 66        "SpriteInputIndex".into(),
 67        "MonochromeSprite".into(),
 68        "PolychromeSprite".into(),
 69        "PathSprite".into(),
 70        "SurfaceInputIndex".into(),
 71        "SurfaceBounds".into(),
 72    ]);
 73    config.no_includes = true;
 74    config.enumeration.prefix_with_name = true;
 75
 76    let mut builder = cbindgen::Builder::new();
 77
 78    let src_paths = [
 79        crate_dir.join("src/scene.rs"),
 80        crate_dir.join("src/geometry.rs"),
 81        crate_dir.join("src/color.rs"),
 82        crate_dir.join("src/window.rs"),
 83        crate_dir.join("src/platform.rs"),
 84        crate_dir.join("src/platform/mac/metal_renderer.rs"),
 85    ];
 86    for src_path in src_paths {
 87        println!("cargo:rerun-if-changed={}", src_path.display());
 88        builder = builder.with_src(src_path);
 89    }
 90
 91    builder
 92        .with_config(config)
 93        .generate()
 94        .expect("Unable to generate bindings")
 95        .write_to_file(&output_path);
 96
 97    output_path
 98}
 99
100/// To enable runtime compilation, we need to "stitch" the shaders file with the generated header
101/// so that it is self-contained.
102#[cfg(feature = "runtime_shaders")]
103fn emit_stitched_shaders(header_path: &Path) {
104    use std::str::FromStr;
105    fn stitch_header(header: &Path, shader_path: &Path) -> std::io::Result<PathBuf> {
106        let header_contents = std::fs::read_to_string(header)?;
107        let shader_contents = std::fs::read_to_string(shader_path)?;
108        let stitched_contents = format!("{header_contents}\n{shader_contents}");
109        let out_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("stitched_shaders.metal");
110        let _ = std::fs::write(&out_path, stitched_contents)?;
111        Ok(out_path)
112    }
113    let shader_source_path = "./src/platform/mac/shaders.metal";
114    let shader_path = PathBuf::from_str(shader_source_path).unwrap();
115    stitch_header(header_path, &shader_path).unwrap();
116    println!("cargo:rerun-if-changed={}", &shader_source_path);
117}
118#[cfg(not(feature = "runtime_shaders"))]
119fn compile_metal_shaders(header_path: &Path) {
120    use std::process::{self, Command};
121    let shader_path = "./src/platform/mac/shaders.metal";
122    let air_output_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("shaders.air");
123    let metallib_output_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("shaders.metallib");
124    println!("cargo:rerun-if-changed={}", shader_path);
125
126    let output = Command::new("xcrun")
127        .args([
128            "-sdk",
129            "macosx",
130            "metal",
131            "-gline-tables-only",
132            "-mmacosx-version-min=10.15.7",
133            "-MO",
134            "-c",
135            shader_path,
136            "-include",
137            &header_path.to_str().unwrap(),
138            "-o",
139        ])
140        .arg(&air_output_path)
141        .output()
142        .unwrap();
143
144    if !output.status.success() {
145        eprintln!(
146            "metal shader compilation failed:\n{}",
147            String::from_utf8_lossy(&output.stderr)
148        );
149        process::exit(1);
150    }
151
152    let output = Command::new("xcrun")
153        .args(["-sdk", "macosx", "metallib"])
154        .arg(air_output_path)
155        .arg("-o")
156        .arg(metallib_output_path)
157        .output()
158        .unwrap();
159
160    if !output.status.success() {
161        eprintln!(
162            "metallib compilation failed:\n{}",
163            String::from_utf8_lossy(&output.stderr)
164        );
165        process::exit(1);
166    }
167}