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// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
use rust_gtest_interop::prelude::*;
use std::simd::prelude::*;
chromium::import! {
"//ui/android:texture_compressor";
}
use texture_compressor::quant::{fast_div_255_round, prepare_averages, quantize_averages};
#[gtest(TextureCompressorTest, FastDiv255)]
fn test_fast_div_255() {
let multipliers = [15, 31];
for m in multipliers {
for i in 0..255 {
let expected = (m * i + 128) / 255;
expect_eq!(fast_div_255_round(Simd::splat(m * i)), Simd::splat(expected));
}
}
}
#[gtest(TextureCompressorTest, Averages)]
fn test_average() {
let values = [[0, 255, 0, 255]; 4].map(|row| row.map(|x| [Simd::splat(x); 3]));
let result = prepare_averages(&values);
for i in 0..4 {
// NB: Each subblock is 8 pixels.
expect_eq!(result[i].sum, [Simd::splat(255 * 2 * 2); 3]);
expect_eq!(result[i].avg, [Simd::splat(128); 3]);
}
}
#[gtest(TextureCompressorTest, AveragesMax)]
// Check that the maximum value doesn't overflow.
fn test_average_max() {
let values = [[255; 4]; 4].map(|row| row.map(|x| [Simd::splat(x); 3]));
let result = prepare_averages(&values);
for i in 0..4 {
// NB: Each subblock is 8 pixels.
expect_eq!(result[i].sum, [Simd::splat(255 * 4 * 2); 3]);
expect_eq!(result[i].avg, [Simd::splat(255); 3]);
}
}
#[gtest(TextureCompressorTest, QuantDiff)]
fn test_quant_diff() {
// Test input colors that are perfectly quantizable in diff mode.
// We don't strictly require diff mode to be selected however, because it is
// possible for a value to be perfectly quantizable in both modes.
for c_quantized in 0..31 {
let c_scaled = (c_quantized << 3) | (c_quantized >> 2);
let values = [[c_scaled; 4]; 4].map(|row| row.map(|x| [Simd::splat(x); 3]));
let result = quantize_averages(&values);
expect_eq!(result.scaled0, [Simd::splat(c_scaled); 3]);
expect_eq!(result.scaled1, [Simd::splat(c_scaled); 3]);
}
}
#[gtest(TextureCompressorTest, QuantIndiv)]
fn test_quant_indiv() {
let c1 = [0, 0, 0].map(|x| Simd::splat(x));
let c2 = [255, 255, 255].map(|x| Simd::splat(x));
let values = [[c1, c1, c2, c2]; 4];
let result = quantize_averages(&values);
expect_eq!(result.scaled0, [Simd::splat(0); 3]);
expect_eq!(result.scaled1, [Simd::splat(255); 3]);
let flip = (result.lo & Simd::splat(0x1)).simd_eq(Simd::splat(0x1));
expect_false!(flip.any());
}
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