Implement ddx, ddy, fwidth (#256)

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Ashley Hauck 2020-11-19 13:42:22 +01:00 committed by GitHub
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commit fcef9ba8de
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@ -1,5 +1,6 @@
#![no_std] #![no_std]
#![feature(register_attr, repr_simd, core_intrinsics)] #![feature(register_attr, repr_simd, core_intrinsics)]
#![cfg_attr(target_arch = "spirv", feature(asm))]
#![register_attr(spirv)] #![register_attr(spirv)]
// Our standard Clippy lints that we use in Embark projects, we opt out of a few that are not appropriate for the specific crate (yet) // Our standard Clippy lints that we use in Embark projects, we opt out of a few that are not appropriate for the specific crate (yet)
#![warn( #![warn(
@ -97,6 +98,68 @@ pointer_addrspace!(incoming_ray_payload_khr, IncomingRayPayloadKHR, true);
pointer_addrspace!(shader_record_buffer_khr, ShaderRecordBufferKHR, true); pointer_addrspace!(shader_record_buffer_khr, ShaderRecordBufferKHR, true);
pointer_addrspace!(physical_storage_buffer, PhysicalStorageBuffer, true); pointer_addrspace!(physical_storage_buffer, PhysicalStorageBuffer, true);
pub trait Derivative {
fn ddx(self) -> Self;
fn ddx_fine(self) -> Self;
fn ddx_coarse(self) -> Self;
fn ddy(self) -> Self;
fn ddy_fine(self) -> Self;
fn ddy_coarse(self) -> Self;
fn fwidth(self) -> Self;
fn fwidth_fine(self) -> Self;
fn fwidth_coarse(self) -> Self;
}
#[cfg(target_arch = "spirv")]
macro_rules! deriv_caps {
(true) => {
asm!("OpCapability DerivativeControl")
};
(false) => {};
}
macro_rules! deriv_fn {
($name:ident, $inst:ident, $needs_caps:tt) => {
fn $name(self) -> Self {
#[cfg(not(target_arch = "spirv"))]
panic!(concat!(stringify!($name), " is not supported on the CPU"));
#[cfg(target_arch = "spirv")]
unsafe {
let o;
deriv_caps!($needs_caps);
asm!(
concat!("{1} = ", stringify!($inst), " typeof{0} {0}"),
in(reg) self,
out(reg) o,
);
o
}
}
};
}
macro_rules! deriv_impl {
($ty:ty) => {
impl Derivative for $ty {
deriv_fn!(ddx, OpDPdx, false);
deriv_fn!(ddx_fine, OpDPdxFine, true);
deriv_fn!(ddx_coarse, OpDPdxCoarse, true);
deriv_fn!(ddy, OpDPdy, false);
deriv_fn!(ddy_fine, OpDPdyFine, true);
deriv_fn!(ddy_coarse, OpDPdyCoarse, true);
deriv_fn!(fwidth, OpFwidth, false);
deriv_fn!(fwidth_fine, OpFwidthFine, true);
deriv_fn!(fwidth_coarse, OpFwidthCoarse, true);
}
};
}
// "must be a scalar or vector of floating-point type. The component width must be 32 bits."
deriv_impl!(f32);
// TODO: Fix rustc to support these
// deriv_impl!(glam::Vec2);
// deriv_impl!(glam::Vec3);
// deriv_impl!(glam::Vec4);
/// libcore requires a few external symbols to be defined: /// libcore requires a few external symbols to be defined:
/// <https://github.com/rust-lang/rust/blob/c2bc344eb23d8c1d18e803b3f1e631cf99926fbb/library/core/src/lib.rs#L23-L27> /// <https://github.com/rust-lang/rust/blob/c2bc344eb23d8c1d18e803b3f1e631cf99926fbb/library/core/src/lib.rs#L23-L27>
/// TODO: This is copied from `compiler_builtins/mem.rs`. Can we use that one instead? The note in the above link says /// TODO: This is copied from `compiler_builtins/mem.rs`. Can we use that one instead? The note in the above link says