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

Cleaned up floating point ulp code.

Browse Source 
The logic is much clearer now, and the code is more compact.
This commit is contained in:
Nathan Vegdahl 2019-10-30 21:05:01 +09:00
parent 1aeb3ed7ff
commit e586442a0a
1 changed files with 20 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
src/fp_utils.rs
View File

@ -13,36 +13,32 @@ pub fn fp_gamma(n: u32) -> f32 {
}
pub fn increment_ulp(v: f32) -> f32 {
// Handle special cases
if (v.is_infinite() && v > 0.0) || v.is_nan() {
return v;
}
// Handle zero
let v = if v == -0.0 { 0.0 } else { v };
// Increase ulp by 1
if v >= 0.0 {
bits_to_f32(f32_to_bits(v) + 1)
if v.is_finite() {
if v > 0.0 {
f32::from_bits(v.to_bits() + 1)
} else if v < -0.0 {
f32::from_bits(v.to_bits() - 1)
} else {
bits_to_f32(f32_to_bits(v) - 1)
f32::from_bits(0x00_00_00_01)
}
} else {
// Infinity or NaN.
v
}
}
pub fn decrement_ulp(v: f32) -> f32 {
// Handle special cases
if (v.is_infinite() && v < 0.0) || v.is_nan() {
return v;
}
// Handle zero
let v = if v == 0.0 { -0.0 } else { v };
// Decrease ulp by 1
if v <= -0.0 {
bits_to_f32(f32_to_bits(v) + 1)
if v.is_finite() {
if v > 0.0 {
f32::from_bits(v.to_bits() - 1)
} else if v < -0.0 {
f32::from_bits(v.to_bits() + 1)
} else {
bits_to_f32(f32_to_bits(v) - 1)
f32::from_bits(0x80_00_00_01)
}
} else {
// Infinity or NaN.
v
}
}
@ -85,18 +81,6 @@ pub fn robust_ray_origin(pos: Point, pos_err: f32, nor: Normal, ray_dir: Vector)
Point::new(x, y, z)
}
#[inline(always)]
fn f32_to_bits(v: f32) -> u32 {
use std::mem::transmute_copy;
unsafe { transmute_copy::<f32, u32>(&v) }
}
#[inline(always)]
fn bits_to_f32(bits: u32) -> f32 {
use std::mem::transmute_copy;
unsafe { transmute_copy::<u32, f32>(&bits) }
}
#[cfg(test)]
mod tests {
use super::*;