// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License in the LICENSE-APACHE file or at:
// https://www.apache.org/licenses/LICENSE-2.0
//! Options
use super::Error;
use log::warn;
use std::env::var;
use std::path::PathBuf;
pub use wgpu::{BackendBit, PowerPreference};
/// Config mode
///
/// See [`Options::from_env`] documentation.
#[derive(Clone, PartialEq, Hash)]
pub enum ConfigMode {
/// Read-only mode
Read,
/// Use default config and write out
WriteDefault,
}
/// Shell options
#[derive(Clone, PartialEq, Hash)]
pub struct Options {
/// Config file path. Default: empty. See `KAS_CONFIG` doc.
pub config_path: PathBuf,
/// Config mode. Default: Read.
pub config_mode: ConfigMode,
/// Adapter power preference. Default value: low power.
pub power_preference: PowerPreference,
/// Adapter backend. Default value: PRIMARY (Vulkan/Metal/DX12).
pub backends: BackendBit,
}
impl Default for Options {
fn default() -> Self {
Options {
config_path: PathBuf::new(),
config_mode: ConfigMode::Read,
power_preference: PowerPreference::LowPower,
backends: BackendBit::PRIMARY,
}
}
}
impl Options {
/// Construct a new instance, reading from environment variables
///
/// The following environment variables are read, in case-insensitive mode.
///
/// ### Config
///
/// The `KAS_CONFIG` variable, if given, provides a path to the KAS config
/// file, where configuration can be read and/or written.
///
/// WARNING: file formats are unstable!
///
/// If `KAS_CONFIG` is not set, platform-default configuration is used
/// without reading or writing. This may change to use a platform-specific
/// default path in future versions.
///
/// The `KAS_CONFIG_MODE` variable determines the read/write mode:
///
/// - `Read` (default): read-only
/// - `WriteDefault`: generate platform-default configuration, and write
/// it to the config path, overwriting any existing config
///
/// Note: in the future, the default will likely change to a read-write mode,
/// allowing changes to be written out.
///
/// ### Power preference
///
/// The `KAS_POWER_PREFERENCE` variable supports:
///
/// - `Default`
/// - `LowPower`
/// - `HighPerformance`
///
/// ### Backend
///
/// The `KAS_BACKENDS` variable supports:
///
/// - `Vulkan`
/// - `GL`
/// - `Metal`
/// - `DX11`
/// - `DX12`
/// - `PRIMARY`: any of Vulkan, Metal or DX12
/// - `SECONDARY`: any of GL or DX11
pub fn from_env() -> Self {
let mut options = Options::default();
if let Ok(v) = var("KAS_CONFIG") {
options.config_path = v.into();
}
if let Ok(mut v) = var("KAS_CONFIG_MODE") {
v.make_ascii_uppercase();
options.config_mode = match v.as_str() {
"READ" => ConfigMode::Read,
"WRITEDEFAULT" => ConfigMode::WriteDefault,
other => {
warn!("Unexpected environment value: KAS_CONFIG_MODE={}", other);
options.config_mode
}
};
}
if let Ok(mut v) = var("KAS_POWER_PREFERENCE") {
v.make_ascii_uppercase();
options.power_preference = match v.as_str() {
"DEFAULT" | "LOWPOWER" => PowerPreference::LowPower,
"HIGHPERFORMANCE" => PowerPreference::HighPerformance,
other => {
warn!(
"Unexpected environment value: KAS_POWER_PREFERENCE={}",
other
);
options.power_preference
}
}
}
if let Ok(mut v) = var("KAS_BACKENDS") {
v.make_ascii_uppercase();
options.backends = match v.as_str() {
"VULKAN" => BackendBit::VULKAN,
"GL" => BackendBit::GL,
"METAL" => BackendBit::METAL,
"DX11" => BackendBit::DX11,
"DX12" => BackendBit::DX12,
"PRIMARY" => BackendBit::PRIMARY,
"SECONDARY" => BackendBit::SECONDARY,
other => {
warn!("Unexpected environment value: KAS_BACKENDS={}", other);
options.backends
}
}
}
options
}
pub(crate) fn adapter_options(&self) -> wgpu::RequestAdapterOptions {
wgpu::RequestAdapterOptions {
power_preference: self.power_preference,
compatible_surface: None,
}
}
pub(crate) fn backend(&self) -> BackendBit {
self.backends
}
/// Load KAS config
pub fn config(&self) -> Result<kas::event::Config, Error> {
if !self.config_path.as_os_str().is_empty() {
match self.config_mode {
ConfigMode::Read => Ok(kas::event::Config::from_path(
&self.config_path,
Default::default(),
)?),
ConfigMode::WriteDefault => {
let config: kas::event::Config = Default::default();
config.write_path(&self.config_path, Default::default())?;
Ok(config)
}
}
} else {
Ok(Default::default())
}
}
}