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70 lines
2.0 KiB
C++
70 lines
2.0 KiB
C++
/*
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* \brief Texturizing function for polygon painting
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* \date 2015-06-29
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* \author Norman Feske
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*/
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/*
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* Copyright (C) 2015-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _INCLUDE__POLYGON_GFX__TEXTURIZE_RGBA_H_
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#define _INCLUDE__POLYGON_GFX__TEXTURIZE_RGBA_H_
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/* Genode includes */
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#include <util/color.h>
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#include <os/pixel_rgba.h>
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#include <util/geometry.h>
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namespace Polygon {
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template <typename PT>
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static inline void texturize_rgba(Genode::Point<>, Genode::Point<>, PT *,
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unsigned char *, unsigned, PT const *,
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unsigned char const *, unsigned);
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}
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/**
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* Texturize scanline
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*/
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template <typename PT>
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static inline void Polygon::texturize_rgba(Genode::Point<> start, Genode::Point<> end,
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PT *dst, unsigned char *dst_alpha,
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unsigned num_values,
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PT const *texture_base,
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unsigned char const *alpha_base,
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unsigned texture_width)
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{
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/* sanity check */
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if (num_values <= 0) return;
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/* use 16.16 fixpoint values for the calculation */
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int tx_ascent = ((end.x() - start.x())<<16)/(int)num_values,
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ty_ascent = ((end.y() - start.y())<<16)/(int)num_values;
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/* set start values for color components */
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int tx = start.x()<<16,
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ty = start.y()<<16;
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for ( ; num_values--; dst++, dst_alpha++) {
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/* blend pixel from texture with destination point on surface */
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unsigned long src_offset = (ty>>16)*texture_width + (tx>>16);
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int const a = alpha_base[src_offset];
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*dst = texture_base[src_offset];
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*dst_alpha += (unsigned char)(((255 - *dst_alpha)*a) >> 8);
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/* walk through texture */
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tx += tx_ascent;
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ty += ty_ascent;
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}
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}
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#endif /* _INCLUDE__POLYGON_GFX__TEXTURIZE_RGBA_H_ */
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