n64-emu/third_party/parallel-rdp-standalone/parallel-rdp/shaders/dither.h
2023-08-06 14:03:29 +09:00

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2.6 KiB
C

/* Copyright (c) 2020 Themaister
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef DITHER_H_
#define DITHER_H_
const u8 dither_matrices[2][16] = u8[][](
u8[](U8_C(0), U8_C(6), U8_C(1), U8_C(7), U8_C(4), U8_C(2), U8_C(5), U8_C(3), U8_C(3), U8_C(5), U8_C(2), U8_C(4), U8_C(7), U8_C(1), U8_C(6), U8_C(0)),
u8[](U8_C(0), U8_C(4), U8_C(1), U8_C(5), U8_C(4), U8_C(0), U8_C(5), U8_C(1), U8_C(3), U8_C(7), U8_C(2), U8_C(6), U8_C(7), U8_C(3), U8_C(6), U8_C(2)));
u8x3 rgb_dither(ivec3 orig_rgb, int dith)
{
ivec3 rgb_dith = (ivec3(dith) >> ivec3(0, 3, 6)) & 7;
ivec3 rgb = mix((orig_rgb & 0xf8) + 8, ivec3(255), greaterThan(orig_rgb, ivec3(247)));
ivec3 replace_sign = (rgb_dith - (orig_rgb & 7)) >> 31;
ivec3 dither_diff = rgb - orig_rgb;
rgb = orig_rgb + (dither_diff & replace_sign);
return u8x3(rgb & 0xff);
}
void dither_coefficients(int x, int y, int dither_mode_rgb, int dither_mode_alpha, out int rgb_dither, out int alpha_dither)
{
const int DITHER_SPLAT = (1 << 0) | (1 << 3) | (1 << 6);
if (dither_mode_rgb < 2)
rgb_dither = int(dither_matrices[dither_mode_rgb][(y & 3) * 4 + (x & 3)]) * DITHER_SPLAT;
else if (dither_mode_rgb == 2)
rgb_dither = noise_get_dither_color();
else
rgb_dither = 0;
if (dither_mode_alpha == 3)
alpha_dither = 0;
else
{
if (dither_mode_alpha == 2)
{
alpha_dither = noise_get_dither_alpha();
}
else
{
alpha_dither = dither_mode_rgb >= 2 ?
int(dither_matrices[dither_mode_rgb & 1][(y & 3) * 4 + (x & 3)]) : (rgb_dither & 7);
if (dither_mode_alpha == 1)
alpha_dither = ~alpha_dither & 7;
}
}
}
#endif