pixelbender: Implement pbasm, a PixelBender assembler

pbasm is a PixelBender assembler that can be used to craft kernels.

Author: kjarosh

Cargo.lock

@@ -19,6 +19,7 @@ members = [
     "render",
     "render/canvas",
     "render/naga-agal",
+    "render/pbasm",
     "render/wgpu",
     "render/webgl",
 

Cargo.toml

@@ -31,6 +31,9 @@ num-derive = { workspace = true }
 byteorder = { workspace = true }
 wgpu = { workspace = true, optional = true }
 indexmap = { workspace = true }
+pest = { version = "2.8.1", optional = true }
+pest_derive = { version = "2.8.1", optional = true }
+serde_json = { version = "1.0.140", optional = true }
 
 # This crate has a `compile_error!` on apple platforms
 [target.'cfg(not(target_vendor = "apple"))'.dependencies.renderdoc]
@@ -50,3 +53,4 @@ tessellator = ["lyon"]
 web = ["wasm-bindgen"]
 wgpu = ["dep:wgpu"]
 serde = ["dep:serde"]
+assembly = ["dep:pest", "dep:pest_derive", "dep:serde_json"]

render/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "pbasm"
+description = "pbasm: The Last PixelBender (Assembler)"
+authors = ["Kamil Jarosz <kjarosh256@gmail.com>"]
+version = "0.1.0"
+edition.workspace = true
+homepage.workspace = true
+license.workspace = true
+repository.workspace = true
+
+[lints]
+workspace = true
+
+[dependencies]
+clap = { workspace = true }
+anyhow = { workspace = true }
+ruffle_render = { path = "..", features = ["assembly"] }

render/pbasm/Cargo.toml

@@ -0,0 +1,27 @@
+# pbasm: The Last PixelBender (Assembler)
+
+`pbasm` is a PixelBender assembler with a custom syntax.
+
+## Usage
+
+In order to assemble a `.pbasm` file, run:
+
+```bash
+pbasm kernel.pbasm -o kernel.pbj
+```
+
+In order to disassemble a `.pbj` file, run:
+
+```bash
+pbasm -d kernel.pbj -o kernel.pbasm
+```
+
+## Syntax
+
+See [integration tests](./integration_tests/) for syntax examples.
+
+## Notes
+
+`pbasm` aims mainly to be useful for Ruffle developers, which means that it
+should be able to produce malformed shaders too, so that we can make sure they
+are handled properly.

render/pbasm/README.md

@@ -0,0 +1,56 @@
+use anyhow::{anyhow, Context, Result};
+use clap::Parser;
+use ruffle_render::pixel_bender::{
+    assembly::PixelBenderShaderAssembly, disassembly::PixelBenderShaderDisassembly, parse_shader,
+};
+use std::io::{IsTerminal, Write};
+
+#[derive(Parser, Debug)]
+#[clap(name = "pbasm", author, version)]
+pub struct Opt {
+    #[clap(name = "source")]
+    pub source: String,
+
+    #[clap(short = 'd', long = "disassemble")]
+    pub disassemble: bool,
+
+    #[clap(short = 'o', long = "output")]
+    pub output: Option<String>,
+}
+
+fn disassemble(opt: Opt, write: &mut dyn Write) -> Result<()> {
+    let data = std::fs::read(&opt.source).context("Failed to open source file")?;
+    let parsed =
+        parse_shader(&data, false).map_err(|e| anyhow!("Failed to parse the shader: {e}"))?;
+    write!(write, "{}", PixelBenderShaderDisassembly(&parsed))
+        .context("Failed to write disassembly")?;
+    Ok(())
+}
+
+fn assemble(opt: Opt, write: &mut dyn Write) -> Result<()> {
+    let input = std::fs::read_to_string(&opt.source).context("Failed to open source file")?;
+    let assembly = PixelBenderShaderAssembly::new(&input, write);
+    assembly.assemble()?;
+    Ok(())
+}
+
+pub fn run_main(opt: Opt) -> Result<()> {
+    let mut out: Box<dyn Write> = if let Some(output) = opt.output.as_ref().filter(|o| *o != "-") {
+        Box::new(std::fs::File::create(output).context("Failed to create the output file")?)
+    } else {
+        if !opt.disassemble && std::io::stdout().is_terminal() {
+            return Err(anyhow!(
+                "Cowardly refusing to output binary data to a terminal"
+            ));
+        }
+        Box::new(std::io::stdout())
+    };
+
+    if opt.disassemble {
+        disassemble(opt, &mut out)?;
+    } else {
+        assemble(opt, &mut out)?;
+    }
+
+    Ok(())
+}

render/pbasm/src/lib.rs

@@ -0,0 +1,8 @@
+use anyhow::Result;
+use clap::Parser;
+use pbasm::{run_main, Opt};
+
+fn main() -> Result<()> {
+    let opt: Opt = Opt::parse();
+    run_main(opt)
+}

render/pbasm/src/main.rs

@@ -4,6 +4,8 @@
 #[cfg(test)]
 mod tests;
 
+#[cfg(feature = "assembly")]
+pub mod assembly;
 pub mod disassembly;
 
 use byteorder::{BigEndian, LittleEndian, ReadBytesExt};
@@ -101,7 +103,7 @@ pixel_bender_type_with_opcode! {
     }
 }
 
-#[derive(Debug, PartialEq, Copy, Clone)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone, PartialOrd, Ord)]
 pub enum PixelBenderRegChannel {
     R = 0,
     G = 1,