mirror of
https://github.com/genodelabs/genode.git
synced 2024-12-19 05:37:54 +00:00
77 lines
2.2 KiB
C++
77 lines
2.2 KiB
C++
/*
|
|
* \brief RGB565-optimized interpolation functions for polygon painting
|
|
* \date 2015-06-19
|
|
* \author Norman Feske
|
|
*/
|
|
|
|
/*
|
|
* Copyright (C) 2015-2017 Genode Labs GmbH
|
|
*
|
|
* This file is part of the Genode OS framework, which is distributed
|
|
* under the terms of the GNU Affero General Public License version 3.
|
|
*/
|
|
|
|
#ifndef _INCLUDE__POLYGON_GFX__INTERPOLATE_RGB565_H_
|
|
#define _INCLUDE__POLYGON_GFX__INTERPOLATE_RGB565_H_
|
|
|
|
/* Genode includes */
|
|
#include <util/dither_matrix.h>
|
|
#include <os/pixel_rgb565.h>
|
|
#include <polygon_gfx/interpolate_rgba.h>
|
|
|
|
namespace Polygon {
|
|
|
|
using Genode::Pixel_rgb565;
|
|
|
|
template <>
|
|
inline void interpolate_rgba(Color, Color, Pixel_rgb565 *,
|
|
unsigned char *, unsigned, int, int);
|
|
}
|
|
|
|
|
|
/**
|
|
* Specialization that employs dithering
|
|
*/
|
|
template <>
|
|
inline void Polygon::interpolate_rgba(Color start, Color end, Pixel_rgb565 *dst,
|
|
unsigned char *dst_alpha,
|
|
unsigned num_values, int x, int y)
|
|
{
|
|
/* sanity check */
|
|
if (num_values <= 0) return;
|
|
|
|
/* use 16.16 fixpoint values for the calculation */
|
|
int r_ascent = ((end.r - start.r)<<16) / (int)num_values,
|
|
g_ascent = ((end.g - start.g)<<16) / (int)num_values,
|
|
b_ascent = ((end.b - start.b)<<16) / (int)num_values,
|
|
a_ascent = ((end.a - start.a)<<16) / (int)num_values;
|
|
|
|
/* set start values for color components */
|
|
int r = start.r<<16,
|
|
g = start.g<<16,
|
|
b = start.b<<16,
|
|
a = start.a<<16;
|
|
|
|
for ( ; num_values--; dst++, dst_alpha++, x++) {
|
|
|
|
int const dither_value = Genode::Dither_matrix::value(x, y) << 12;
|
|
|
|
/* combine current color value with existing pixel via alpha blending */
|
|
*dst = Pixel_rgb565::mix(*dst,
|
|
Pixel_rgb565((r + dither_value) >> 16,
|
|
(g + dither_value) >> 16,
|
|
(b + dither_value) >> 16),
|
|
(a + dither_value) >> 16);
|
|
|
|
*dst_alpha += ((255 - *dst_alpha)*(a + dither_value)) >> (16 + 8);
|
|
|
|
/* increment color-component values by ascent */
|
|
r += r_ascent;
|
|
g += g_ascent;
|
|
b += b_ascent;
|
|
a += a_ascent;
|
|
}
|
|
}
|
|
|
|
#endif /* _INCLUDE__POLYGON_GFX__INTERPOLATE_RGB565_H_ */
|