librashader/librashader-runtime/src/scaling.rs

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use crate::scaling;
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use librashader_common::Size;
use librashader_presets::{Scale2D, ScaleFactor, ScaleType, Scaling};
use num_traits::AsPrimitive;
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use std::ops::Mul;
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pub trait ViewportSize<T>
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where
T: Mul<ScaleFactor, Output = f32> + Copy + 'static,
f32: AsPrimitive<T>,
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{
/// Produce a `Size<T>` scaled with the input scaling options.
fn scale_viewport(self, scaling: Scale2D, viewport: Size<T>) -> Size<T>;
}
impl<T> ViewportSize<T> for Size<T>
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where
T: Mul<ScaleFactor, Output = f32> + Copy + 'static,
f32: AsPrimitive<T>,
{
fn scale_viewport(self, scaling: Scale2D, viewport: Size<T>) -> Size<T>
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where
T: Mul<ScaleFactor, Output = f32> + Copy + 'static,
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f32: AsPrimitive<T>,
{
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scaling::scale(scaling, self, viewport)
}
}
pub trait MipmapSize<T> {
/// Calculate the number of mipmap levels for a given size.
fn calculate_miplevels(self) -> T;
fn scale_mipmap(self, miplevel: T) -> Size<T>;
}
impl MipmapSize<u32> for Size<u32> {
fn calculate_miplevels(self) -> u32 {
let mut size = std::cmp::max(self.width, self.height);
let mut levels = 0;
while size != 0 {
levels += 1;
size >>= 1;
}
levels
}
fn scale_mipmap(self, miplevel: u32) -> Size<u32> {
let scaled_width = std::cmp::max(self.width >> miplevel, 1);
let scaled_height = std::cmp::max(self.height >> miplevel, 1);
Size::new(scaled_width, scaled_height)
}
}
fn scale<T>(scaling: Scale2D, source: Size<T>, viewport: Size<T>) -> Size<T>
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where
T: Mul<ScaleFactor, Output = f32> + Copy + 'static,
f32: AsPrimitive<T>,
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{
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let width = match scaling.x {
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Scaling {
scale_type: ScaleType::Input,
factor,
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} => source.width * factor,
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Scaling {
scale_type: ScaleType::Absolute,
factor,
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} => factor.into(),
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Scaling {
scale_type: ScaleType::Viewport,
factor,
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} => viewport.width * factor,
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};
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let height = match scaling.y {
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Scaling {
scale_type: ScaleType::Input,
factor,
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} => source.height * factor,
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Scaling {
scale_type: ScaleType::Absolute,
factor,
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} => factor.into(),
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Scaling {
scale_type: ScaleType::Viewport,
factor,
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} => viewport.height * factor,
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};
Size {
width: width.round().as_(),
height: height.round().as_(),
}
}