cessen/lut_extractor
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Arrange the output Rust code a little nicer.

Browse Source
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
src/linear_log.rs
View File

@ -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
/// given parameters.
pub fn generate_linear_to_log(line_offset: f64, slope: f64, log_offset: f64, base: f64) -> String {
/// Generates Rust code for a both linear-to-log and log-to-linear
/// functions with the given parameters.
pub fn generate_code(line_offset: f64, slope: f64, log_offset: f64, base: f64) -> String {
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);
format!(
r#"
const A: f32 = {};
const B: f32 = {};
const C: f32 = {};
const D: f32 = {};
const E: f32 = {};
pub fn linear_to_log(x: f32) -> f32 {{
const A: f32 = {};
const B: f32 = {};
const C: f32 = {};
const D: f32 = {};
const E: f32 = {};
const F: f32 = {};
const P: f32 = {};
if x <= A {{
(x - B) * C
if x <= P {{
(x - A) * B
}} 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 {{
const A: f32 = {};
const B: f32 = {};
const C: f32 = {};
const D: f32 = {};
const E: f32 = {};
const F: f32 = {};
const P: f32 = {};
if x <= A {{
(x * (1.0 / C)) + B
if x <= P {{
(x / B) + A
}} else {{
((x - F) * E).exp2() + D
((x - E) * D).exp2() + C
}}
}}
"#,
k,
line_offset,
slope,
log_offset,
base.log2(),
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);
println!(
"{}{}",
crate::linear_log::generate_linear_to_log(offset, slope, log_offset, base),
crate::linear_log::generate_log_to_linear(offset, slope, log_offset, base),
"{}",
crate::linear_log::generate_code(offset, slope, log_offset, base),
);
}