libblur 0.24.0

// Copyright (c) Radzivon Bartoshyk. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// 1.  Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
//
// 2.  Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// 3.  Neither the name of the copyright holder nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

use crate::EdgeMode;
use crate::avx::fast_gaussian_next_f32::AvxSseF32x8;
use crate::avx::utils::_mm256_opt_fnmlaf_ps;
use crate::edge_mode::clamp_edge;
use crate::sse::{_mm_opt_fnmlaf_ps, load_f32, store_f32};
use crate::unsafe_slice::UnsafeSlice;
use crate::util::ScratchBuffer;
#[cfg(target_arch = "x86")]
use std::arch::x86::*;
#[cfg(target_arch = "x86_64")]
use std::arch::x86_64::*;

pub(crate) fn fg_horizontal_pass_avx_f32<const CN: usize>(
    slice: &UnsafeSlice<f32>,
    stride: u32,
    width: u32,
    height: u32,
    radius: u32,
    start: u32,
    end: u32,
    edge_mode: EdgeMode,
) {
    unsafe {
        if std::arch::is_x86_feature_detected!("fma") {
            fg_horizontal_pass_avx_f32_fma::<CN>(
                slice, stride, width, height, radius, start, end, edge_mode,
            );
        } else {
            fg_horizontal_pass_avx_f32_def::<CN>(
                slice, stride, width, height, radius, start, end, edge_mode,
            );
        }
    }
}

#[target_feature(enable = "avx2")]
fn fg_horizontal_pass_avx_f32_def<const CN: usize>(
    bytes: &UnsafeSlice<f32>,
    stride: u32,
    width: u32,
    height: u32,
    radius: u32,
    start: u32,
    end: u32,
    edge_mode: EdgeMode,
) {
    let unit = HorizontalExecutionUnit::<CN, false>::default();
    unit.pass(bytes, stride, width, height, radius, start, end, edge_mode);
}

#[target_feature(enable = "avx2", enable = "fma")]
fn fg_horizontal_pass_avx_f32_fma<const CN: usize>(
    bytes: &UnsafeSlice<f32>,
    stride: u32,
    width: u32,
    height: u32,
    radius: u32,
    start: u32,
    end: u32,
    edge_mode: EdgeMode,
) {
    let unit = HorizontalExecutionUnit::<CN, true>::default();
    unit.pass(bytes, stride, width, height, radius, start, end, edge_mode);
}

#[derive(Copy, Clone, Default)]
struct HorizontalExecutionUnit<const CN: usize, const FMA: bool> {}

impl<const CN: usize, const FMA: bool> HorizontalExecutionUnit<CN, FMA> {
    #[inline(always)]
    fn pass(
        &self,
        bytes: &UnsafeSlice<f32>,
        stride: u32,
        width: u32,
        height: u32,
        radius: u32,
        start: u32,
        end: u32,
        edge_mode: EdgeMode,
    ) {
        unsafe {
            let mut full_buffer = ScratchBuffer::<[AvxSseF32x8; 3], 1024>::new(1024);
            let buffer = full_buffer.as_mut_slice();

            let radius_64 = radius as i64;
            let width_wide = width as i64;

            let v_double = _mm256_set1_ps(2.);
            let v_weight = _mm256_set1_ps(1f32 / (radius as f32 * radius as f32));

            let mut yy = start as usize;

            while yy + 6 <= height.min(end) as usize {
                let mut diffs0 = _mm256_setzero_ps();
                let mut diffs1 = _mm256_setzero_ps();
                let mut diffs2 = _mm256_setzero_ps();

                let mut sums0 = _mm256_setzero_ps();
                let mut sums1 = _mm256_setzero_ps();
                let mut sums2 = _mm256_setzero_ps();

                let current_y0 = ((yy as i64) * (stride as i64)) as usize;
                let current_y1 = ((yy as i64 + 1) * (stride as i64)) as usize;
                let current_y2 = ((yy as i64 + 2) * (stride as i64)) as usize;
                let current_y3 = ((yy as i64 + 3) * (stride as i64)) as usize;
                let current_y4 = ((yy as i64 + 4) * (stride as i64)) as usize;
                let current_y5 = ((yy as i64 + 5) * (stride as i64)) as usize;

                let start_x = 0 - 2 * radius_64;
                for x in start_x..(width as i64) {
                    if x >= 0 {
                        let current_px = x as usize * CN;

                        let prepared_px0 = _mm256_mul_ps(sums0, v_weight);
                        let prepared_px1 = _mm256_mul_ps(sums1, v_weight);
                        let prepared_px2 = _mm256_mul_ps(sums2, v_weight);

                        let dst_ptr0 = bytes.get_ptr(current_y0 + current_px);
                        let dst_ptr1 = bytes.get_ptr(current_y1 + current_px);
                        let dst_ptr2 = bytes.get_ptr(current_y2 + current_px);
                        let dst_ptr3 = bytes.get_ptr(current_y3 + current_px);
                        let dst_ptr4 = bytes.get_ptr(current_y4 + current_px);
                        let dst_ptr5 = bytes.get_ptr(current_y5 + current_px);

                        store_f32::<CN>(dst_ptr0, _mm256_castps256_ps128(prepared_px0));
                        store_f32::<CN>(dst_ptr1, _mm256_extractf128_ps::<1>(prepared_px0));
                        store_f32::<CN>(dst_ptr2, _mm256_castps256_ps128(prepared_px1));
                        store_f32::<CN>(dst_ptr3, _mm256_extractf128_ps::<1>(prepared_px1));
                        store_f32::<CN>(dst_ptr4, _mm256_castps256_ps128(prepared_px2));
                        store_f32::<CN>(dst_ptr5, _mm256_extractf128_ps::<1>(prepared_px2));

                        let arr_index = ((x - radius_64) & 1023) as usize;
                        let d_arr_index = (x & 1023) as usize;

                        let da_b = buffer.get_unchecked(d_arr_index);
                        let da = buffer.get_unchecked(arr_index);

                        let d_s0 = _mm256_load_ps(da.as_ptr().cast());
                        let d_s1 = _mm256_load_ps(da[1..].as_ptr().cast());
                        let d_s2 = _mm256_load_ps(da[2..].as_ptr().cast());

                        let a_s0 = _mm256_load_ps(da_b.as_ptr().cast());
                        let a_s1 = _mm256_load_ps(da_b[1..].as_ptr().cast());
                        let a_s2 = _mm256_load_ps(da_b[2..].as_ptr().cast());

                        diffs0 = _mm256_add_ps(
                            diffs0,
                            _mm256_opt_fnmlaf_ps::<FMA>(a_s0, d_s0, v_double),
                        );
                        diffs1 = _mm256_add_ps(
                            diffs1,
                            _mm256_opt_fnmlaf_ps::<FMA>(a_s1, d_s1, v_double),
                        );
                        diffs2 = _mm256_add_ps(
                            diffs2,
                            _mm256_opt_fnmlaf_ps::<FMA>(a_s2, d_s2, v_double),
                        );
                    } else if x + radius_64 >= 0 {
                        let arr_index = (x & 1023) as usize;
                        let da_b = buffer.get_unchecked(arr_index);
                        let s0 = _mm256_load_ps(da_b.as_ptr().cast());
                        let s1 = _mm256_load_ps(da_b[1..].as_ptr().cast());
                        let s2 = _mm256_load_ps(da_b[2..].as_ptr().cast());

                        diffs0 = _mm256_opt_fnmlaf_ps::<FMA>(diffs0, s0, v_double);
                        diffs1 = _mm256_opt_fnmlaf_ps::<FMA>(diffs1, s1, v_double);
                        diffs2 = _mm256_opt_fnmlaf_ps::<FMA>(diffs2, s2, v_double);
                    }

                    let next_row_x = clamp_edge!(edge_mode, x + radius_64, 0, width_wide);
                    let next_row_px = next_row_x * CN;

                    let s_ptr0 = bytes.get_ptr(current_y0 + next_row_px);
                    let s_ptr1 = bytes.get_ptr(current_y1 + next_row_px);
                    let s_ptr2 = bytes.get_ptr(current_y2 + next_row_px);
                    let s_ptr3 = bytes.get_ptr(current_y3 + next_row_px);
                    let s_ptr4 = bytes.get_ptr(current_y4 + next_row_px);
                    let s_ptr5 = bytes.get_ptr(current_y5 + next_row_px);

                    let px0 = load_f32::<CN>(s_ptr0);
                    let px1 = load_f32::<CN>(s_ptr1);
                    let px2 = load_f32::<CN>(s_ptr2);
                    let px3 = load_f32::<CN>(s_ptr3);
                    let px4 = load_f32::<CN>(s_ptr4);
                    let px5 = load_f32::<CN>(s_ptr5);

                    let arr_index = ((x + radius_64) & 1023) as usize;

                    let px01 = _mm256_insertf128_ps::<1>(_mm256_castps128_ps256(px0), px1);
                    let px23 = _mm256_insertf128_ps::<1>(_mm256_castps128_ps256(px2), px3);
                    let px45 = _mm256_insertf128_ps::<1>(_mm256_castps128_ps256(px4), px5);

                    let da_b = buffer.get_unchecked_mut(arr_index);

                    _mm256_store_ps(da_b.as_mut_ptr().cast(), px01);
                    _mm256_store_ps(da_b[1..].as_mut_ptr().cast(), px23);
                    _mm256_store_ps(da_b[2..].as_mut_ptr().cast(), px45);

                    diffs0 = _mm256_add_ps(diffs0, px01);
                    diffs1 = _mm256_add_ps(diffs1, px23);
                    diffs2 = _mm256_add_ps(diffs2, px45);

                    sums0 = _mm256_add_ps(sums0, diffs0);
                    sums1 = _mm256_add_ps(sums1, diffs1);
                    sums2 = _mm256_add_ps(sums2, diffs2);
                }

                yy += 6;
            }

            for y in yy..height.min(end) as usize {
                let mut diffs = _mm_setzero_ps();
                let mut summs = _mm_setzero_ps();

                let current_y = ((y as i64) * (stride as i64)) as usize;

                let start_x = 0 - 2 * radius_64;
                for x in start_x..(width as i64) {
                    if x >= 0 {
                        let current_px = x as usize * CN;

                        let pixel = _mm_mul_ps(summs, _mm256_castps256_ps128(v_weight));

                        let bytes_offset = current_y + current_px;

                        let dst_ptr = bytes.get_ptr(bytes_offset);
                        store_f32::<CN>(dst_ptr, pixel);

                        let arr_index = ((x - radius_64) & 1023) as usize;
                        let d_arr_index = (x & 1023) as usize;

                        let d_buf_ptr = buffer.get_unchecked(d_arr_index).as_ptr();
                        let d_stored = _mm_load_ps(d_buf_ptr.cast());

                        let buf_ptr = buffer.get_unchecked(arr_index).as_ptr();
                        let a_stored = _mm_load_ps(buf_ptr.cast());

                        diffs = _mm_add_ps(
                            diffs,
                            _mm_opt_fnmlaf_ps::<FMA>(
                                a_stored,
                                d_stored,
                                _mm256_castps256_ps128(v_double),
                            ),
                        );
                    } else if x + radius_64 >= 0 {
                        let arr_index = (x & 1023) as usize;
                        let buf_ptr = buffer.get_unchecked(arr_index).as_ptr();
                        let stored = _mm_load_ps(buf_ptr.cast());
                        diffs = _mm_opt_fnmlaf_ps::<FMA>(
                            diffs,
                            stored,
                            _mm256_castps256_ps128(v_double),
                        );
                    }

                    let next_row_y = y * (stride as usize);
                    let next_row_x = clamp_edge!(edge_mode, x + radius_64, 0, width_wide);
                    let next_row_px = next_row_x * CN;

                    let s_ptr = bytes.get_ptr(next_row_y + next_row_px);
                    let pixel_color = load_f32::<CN>(s_ptr);

                    let arr_index = ((x + radius_64) & 1023) as usize;
                    let buf_ptr = buffer.get_unchecked_mut(arr_index).as_mut_ptr();

                    diffs = _mm_add_ps(diffs, pixel_color);
                    summs = _mm_add_ps(summs, diffs);
                    _mm_store_ps(buf_ptr.cast(), pixel_color);
                }
            }
        }
    }
}

pub(crate) fn fg_vertical_pass_avx_f32<const CN: usize>(
    slice: &UnsafeSlice<f32>,
    stride: u32,
    width: u32,
    height: u32,
    radius: u32,
    start: u32,
    end: u32,
    edge_mode: EdgeMode,
) {
    unsafe {
        if std::arch::is_x86_feature_detected!("fma") {
            fg_vertical_pass_avx_f32_fma::<CN>(
                slice, stride, width, height, radius, start, end, edge_mode,
            );
        } else {
            fg_vertical_pass_avx_f32_def::<CN>(
                slice, stride, width, height, radius, start, end, edge_mode,
            );
        }
    }
}

#[target_feature(enable = "avx2")]
fn fg_vertical_pass_avx_f32_def<const CN: usize>(
    bytes: &UnsafeSlice<f32>,
    stride: u32,
    width: u32,
    height: u32,
    radius: u32,
    start: u32,
    end: u32,
    edge_mode: EdgeMode,
) {
    let unit = VerticalExecutionUnit::<CN, false>::default();
    unit.pass(bytes, stride, width, height, radius, start, end, edge_mode);
}

#[target_feature(enable = "avx2", enable = "fma")]
fn fg_vertical_pass_avx_f32_fma<const CN: usize>(
    bytes: &UnsafeSlice<f32>,
    stride: u32,
    width: u32,
    height: u32,
    radius: u32,
    start: u32,
    end: u32,
    edge_mode: EdgeMode,
) {
    let unit = VerticalExecutionUnit::<CN, true>::default();
    unit.pass(bytes, stride, width, height, radius, start, end, edge_mode);
}

#[derive(Copy, Clone, Default)]
struct VerticalExecutionUnit<const CN: usize, const FMA: bool> {}

impl<const CN: usize, const FMA: bool> VerticalExecutionUnit<CN, FMA> {
    #[inline(always)]
    fn pass(
        &self,
        bytes: &UnsafeSlice<f32>,
        stride: u32,
        width: u32,
        height: u32,
        radius: u32,
        start: u32,
        end: u32,
        edge_mode: EdgeMode,
    ) {
        unsafe {
            let mut full_buffer = ScratchBuffer::<[AvxSseF32x8; 3], 1024>::new(1024);
            let buffer = full_buffer.as_mut_slice();

            let v_double = _mm256_set1_ps(2.);
            let v_weight = _mm256_set1_ps(1f32 / (radius as f32 * radius as f32));

            let height_wide = height as i64;

            let radius_64 = radius as i64;

            let mut xx = start as usize;

            while xx + 6 <= width.min(end) as usize {
                let mut diffs0 = _mm256_setzero_ps();
                let mut diffs1 = _mm256_setzero_ps();
                let mut diffs2 = _mm256_setzero_ps();

                let mut sums0 = _mm256_setzero_ps();
                let mut sums1 = _mm256_setzero_ps();
                let mut sums2 = _mm256_setzero_ps();

                let current_px0 = xx * CN;
                let current_px1 = (xx + 1) * CN;
                let current_px2 = (xx + 2) * CN;
                let current_px3 = (xx + 3) * CN;
                let current_px4 = (xx + 3) * CN;
                let current_px5 = (xx + 3) * CN;

                let start_y = 0 - 2 * radius as i64;
                for y in start_y..height_wide {
                    if y >= 0 {
                        let current_y = (y * (stride as i64)) as usize;

                        let prepared_px0 = _mm256_mul_ps(sums0, v_weight);
                        let prepared_px1 = _mm256_mul_ps(sums1, v_weight);
                        let prepared_px2 = _mm256_mul_ps(sums2, v_weight);

                        let dst_ptr0 = bytes.get_ptr(current_y + current_px0);
                        let dst_ptr1 = bytes.get_ptr(current_y + current_px1);
                        let dst_ptr2 = bytes.get_ptr(current_y + current_px2);
                        let dst_ptr3 = bytes.get_ptr(current_y + current_px3);
                        let dst_ptr4 = bytes.get_ptr(current_y + current_px4);
                        let dst_ptr5 = bytes.get_ptr(current_y + current_px5);

                        store_f32::<CN>(dst_ptr0, _mm256_castps256_ps128(prepared_px0));
                        store_f32::<CN>(dst_ptr1, _mm256_extractf128_ps::<1>(prepared_px0));
                        store_f32::<CN>(dst_ptr2, _mm256_castps256_ps128(prepared_px1));
                        store_f32::<CN>(dst_ptr3, _mm256_extractf128_ps::<1>(prepared_px1));
                        store_f32::<CN>(dst_ptr4, _mm256_castps256_ps128(prepared_px2));
                        store_f32::<CN>(dst_ptr5, _mm256_extractf128_ps::<1>(prepared_px2));

                        let arr_index = ((y - radius_64) & 1023) as usize;
                        let d_arr_index = (y & 1023) as usize;

                        let da_b = buffer.get_unchecked(d_arr_index);
                        let da = buffer.get_unchecked(arr_index);

                        let d_s0 = _mm256_load_ps(da.as_ptr().cast());
                        let d_s1 = _mm256_load_ps(da[1..].as_ptr().cast());
                        let d_s2 = _mm256_load_ps(da[2..].as_ptr().cast());

                        let a_s0 = _mm256_load_ps(da_b.as_ptr().cast());
                        let a_s1 = _mm256_load_ps(da_b[1..].as_ptr().cast());
                        let a_s2 = _mm256_load_ps(da_b[2..].as_ptr().cast());

                        diffs0 = _mm256_add_ps(
                            diffs0,
                            _mm256_opt_fnmlaf_ps::<FMA>(a_s0, d_s0, v_double),
                        );
                        diffs1 = _mm256_add_ps(
                            diffs1,
                            _mm256_opt_fnmlaf_ps::<FMA>(a_s1, d_s1, v_double),
                        );
                        diffs2 = _mm256_add_ps(
                            diffs2,
                            _mm256_opt_fnmlaf_ps::<FMA>(a_s2, d_s2, v_double),
                        );
                    } else if y + radius_64 >= 0 {
                        let arr_index = (y & 1023) as usize;
                        let da_b = buffer.get_unchecked(arr_index);
                        let s0 = _mm256_load_ps(da_b.as_ptr().cast());
                        let s1 = _mm256_load_ps(da_b[1..].as_ptr().cast());
                        let s2 = _mm256_load_ps(da_b[2..].as_ptr().cast());

                        diffs0 = _mm256_opt_fnmlaf_ps::<FMA>(diffs0, s0, v_double);
                        diffs1 = _mm256_opt_fnmlaf_ps::<FMA>(diffs1, s1, v_double);
                        diffs2 = _mm256_opt_fnmlaf_ps::<FMA>(diffs2, s2, v_double);
                    }

                    let next_row_y =
                        clamp_edge!(edge_mode, y + radius_64, 0, height_wide) * (stride as usize);

                    let s_ptr0 = bytes.get_ptr(next_row_y + current_px0);
                    let s_ptr1 = bytes.get_ptr(next_row_y + current_px1);
                    let s_ptr2 = bytes.get_ptr(next_row_y + current_px2);
                    let s_ptr3 = bytes.get_ptr(next_row_y + current_px3);
                    let s_ptr4 = bytes.get_ptr(next_row_y + current_px4);
                    let s_ptr5 = bytes.get_ptr(next_row_y + current_px5);

                    let px0 = load_f32::<CN>(s_ptr0);
                    let px1 = load_f32::<CN>(s_ptr1);
                    let px2 = load_f32::<CN>(s_ptr2);
                    let px3 = load_f32::<CN>(s_ptr3);
                    let px4 = load_f32::<CN>(s_ptr4);
                    let px5 = load_f32::<CN>(s_ptr5);

                    let arr_index = ((y + radius_64) & 1023) as usize;

                    let px01 = _mm256_insertf128_ps::<1>(_mm256_castps128_ps256(px0), px1);
                    let px23 = _mm256_insertf128_ps::<1>(_mm256_castps128_ps256(px2), px3);
                    let px45 = _mm256_insertf128_ps::<1>(_mm256_castps128_ps256(px4), px5);

                    let da_b = buffer.get_unchecked_mut(arr_index);

                    _mm256_store_ps(da_b.as_mut_ptr().cast(), px01);
                    _mm256_store_ps(da_b[1..].as_mut_ptr().cast(), px23);
                    _mm256_store_ps(da_b[2..].as_mut_ptr().cast(), px45);

                    diffs0 = _mm256_add_ps(diffs0, px01);
                    diffs1 = _mm256_add_ps(diffs1, px23);
                    diffs2 = _mm256_add_ps(diffs2, px45);

                    sums0 = _mm256_add_ps(sums0, diffs0);
                    sums1 = _mm256_add_ps(sums1, diffs1);
                    sums2 = _mm256_add_ps(sums2, diffs2);
                }

                xx += 6;
            }

            for x in xx..width.min(end) as usize {
                let mut diffs = _mm_setzero_ps();
                let mut summs = _mm_setzero_ps();

                let start_y = 0 - 2 * radius as i64;

                let current_px = x * CN;

                for y in start_y..height_wide {
                    let current_y = (y * (stride as i64)) as usize;

                    if y >= 0 {
                        let pixel = _mm_mul_ps(summs, _mm256_castps256_ps128(v_weight));

                        let bytes_offset = current_y + current_px;

                        let dst_ptr = bytes.get_ptr(bytes_offset);
                        store_f32::<CN>(dst_ptr, pixel);

                        let arr_index = ((y - radius_64) & 1023) as usize;
                        let d_arr_index = (y & 1023) as usize;

                        let d_buf_ptr = buffer.get_unchecked(d_arr_index).as_ptr();
                        let d_stored = _mm_load_ps(d_buf_ptr.cast());

                        let buf_ptr = buffer.get_unchecked(arr_index).as_ptr();
                        let a_stored = _mm_load_ps(buf_ptr.cast());

                        diffs = _mm_add_ps(
                            diffs,
                            _mm_opt_fnmlaf_ps::<FMA>(
                                a_stored,
                                d_stored,
                                _mm256_castps256_ps128(v_double),
                            ),
                        );
                    } else if y + radius_64 >= 0 {
                        let arr_index = (y & 1023) as usize;
                        let buf_ptr = buffer.get_unchecked(arr_index).as_ptr();
                        let stored = _mm_load_ps(buf_ptr.cast());
                        diffs = _mm_opt_fnmlaf_ps::<FMA>(
                            diffs,
                            stored,
                            _mm256_castps256_ps128(v_double),
                        );
                    }

                    let next_row_y =
                        clamp_edge!(edge_mode, y + radius_64, 0, height_wide) * (stride as usize);
                    let next_row_x = x * CN;

                    let s_ptr = bytes.get_ptr(next_row_y + next_row_x);
                    let pixel_color = load_f32::<CN>(s_ptr);

                    let arr_index = ((y + radius_64) & 1023) as usize;
                    let buf_ptr = buffer.get_unchecked_mut(arr_index).as_mut_ptr();

                    diffs = _mm_add_ps(diffs, pixel_color);
                    summs = _mm_add_ps(summs, diffs);
                    _mm_store_ps(buf_ptr.cast(), pixel_color);
                }
            }
        }
    }
}