cessen/lut_extractor
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Arrange the output Rust code a little nicer.

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This commit is contained in:
Nathan Vegdahl 2022-04-22 14:56:56 -07:00
parent f37658a010
commit 2117c0179c
2 changed files with 23 additions and 44 deletions
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62
src/linear_log.rs
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@ -67,68 +67,48 @@ pub fn transition_point(line_offset: f64, slope: f64, log_offset: f64, base: f64
//------------------------------------------------------------- //-------------------------------------------------------------
/// Generates Rust code for a linear-to-log transfer function with the /// Generates Rust code for a both linear-to-log and log-to-linear
/// given parameters. /// functions with the given parameters.
pub fn generate_linear_to_log(line_offset: f64, slope: f64, log_offset: f64, base: f64) -> String { pub fn generate_code(line_offset: f64, slope: f64, log_offset: f64, base: f64) -> String {
let transition = 1.0 / (slope * base.ln()); let transition = 1.0 / (slope * base.ln());
let k = transition + log_offset; let k1 = transition + log_offset;
let k2 = (transition - line_offset + log_offset) * slope;
let l = (transition - line_offset + log_offset) * slope - transition.log(base); let l = (transition - line_offset + log_offset) * slope - transition.log(base);
format!( format!(
r#" r#"
const A: f32 = {};
const B: f32 = {};
const C: f32 = {};
const D: f32 = {};
const E: f32 = {};
pub fn linear_to_log(x: f32) -> f32 {{ pub fn linear_to_log(x: f32) -> f32 {{
const A: f32 = {}; const P: f32 = {};
const B: f32 = {};
const C: f32 = {};
const D: f32 = {};
const E: f32 = {};
const F: f32 = {};
if x <= A {{ if x <= P {{
(x - B) * C (x - A) * B
}} else {{ }} else {{
(x - D).log2() * (1.0 / E) + F ((x - C).log2() / D) + E
}} }}
}} }}
"#,
k,
line_offset,
slope,
log_offset,
base.log2(),
l,
)
}
/// Generates Rust code for a log-to-linear transfer function with the
/// given parameters.
pub fn generate_log_to_linear(line_offset: f64, slope: f64, log_offset: f64, base: f64) -> String {
let transition = 1.0 / (slope * base.ln());
let k = (transition - line_offset + log_offset) * slope;
let l = (transition - line_offset + log_offset) * slope - transition.log(base);
format!(
r#"
pub fn log_to_linear(x: f32) -> f32 {{ pub fn log_to_linear(x: f32) -> f32 {{
const A: f32 = {}; const P: f32 = {};
const B: f32 = {};
const C: f32 = {};
const D: f32 = {};
const E: f32 = {};
const F: f32 = {};
if x <= A {{ if x <= P {{
(x * (1.0 / C)) + B (x / B) + A
}} else {{ }} else {{
((x - F) * E).exp2() + D ((x - E) * D).exp2() + C
}} }}
}} }}
"#, "#,
k,
line_offset, line_offset,
slope, slope,
log_offset, log_offset,
base.log2(), base.log2(),
l, l,
k1,
k2,
) )
} }

5
src/optimize_log.rs
View File

@ -63,9 +63,8 @@ pub fn find_parameters(lut: &[f32]) {
// dbg!(offset, log_offset, slope, base, end); // dbg!(offset, log_offset, slope, base, end);
println!( println!(
"{}{}", "{}",
crate::linear_log::generate_linear_to_log(offset, slope, log_offset, base), crate::linear_log::generate_code(offset, slope, log_offset, base),
crate::linear_log::generate_log_to_linear(offset, slope, log_offset, base),
); );
} }