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https://github.com/libretro/scummvm.git
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154 lines
5.0 KiB
C++
154 lines
5.0 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#ifndef GRAPHICS_PALETTE_H
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#define GRAPHICS_PALETTE_H
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#include "common/scummsys.h"
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#include "common/hashmap.h"
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#include "common/noncopyable.h"
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/**
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* @defgroup graphics_palette PaletteManager
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* @ingroup graphics
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*
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* @brief The PaletteManager class.
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*
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* @{
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*/
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/**
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* The PaletteManager is part of the OSystem backend API and responsible
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* for handling the (possibly emulated) "hardware" palette needed for
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* many old games (e.g. in EGA and VGA mode).
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*
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* By itself it is a pure abstract class, i.e. an "interface"; you can
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* use the OSystem::getPaletteManager() method to obtain an instance
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* that you can use to perform actual palette modifications.
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*/
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class PaletteManager : Common::NonCopyable {
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public:
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virtual ~PaletteManager() {}
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/**
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* Replace the specified range of the palette with new colors.
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* The palette entries from 'start' till (start+num-1) will be replaced - so
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* a full palette update is accomplished via start=0, num=256.
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*
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* The palette data is specified in interleaved RGB format. That is, the
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* first byte of the memory block 'colors' points at is the red component
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* of the first new color; the second byte the green component of the first
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* new color; the third byte the blue component, the last byte to the alpha
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* (transparency) value. Then the second color starts, and so on. So memory
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* looks like this: R1-G1-B1-R2-G2-B2-R3-...
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*
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* @param colors the new palette data, in interleaved RGB format
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* @param start the first palette entry to be updated
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* @param num the number of palette entries to be updated
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*
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* @note It is an error if start+num exceeds 256, behavior is undefined
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* in that case (the backend may ignore it silently or assert).
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* @note It is an error if this function gets called when the pixel format
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* in use (the return value of getScreenFormat) has more than one
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* byte per pixel.
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*
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* @see getScreenFormat
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*/
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virtual void setPalette(const byte *colors, uint start, uint num) = 0;
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/**
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* Grabs a specified part of the currently active palette.
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* The format is the same as for setPalette.
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*
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* This should return exactly the same RGB data as was setup via previous
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* setPalette calls.
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*
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* For example, for every valid value of start and num of the following
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* code:
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*
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* byte origPal[num*3];
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* // Setup origPal's data however you like
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* g_system->setPalette(origPal, start, num);
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* byte obtainedPal[num*3];
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* g_system->grabPalette(obtainedPal, start, num);
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*
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* the following should be true:
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*
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* memcmp(origPal, obtainedPal, num*3) == 0
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*
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* @see setPalette
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* @param colors the palette data, in interleaved RGB format
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* @param start the first platte entry to be read
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* @param num the number of palette entries to be read
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*
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* @note It is an error if this function gets called when the pixel format
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* in use (the return value of getScreenFormat) has more than one
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* byte per pixel.
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*
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* @see getScreenFormat
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*/
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virtual void grabPalette(byte *colors, uint start, uint num) const = 0;
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};
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/** @} */
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namespace Graphics {
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class PaletteLookup {
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public:
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PaletteLookup();
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/**
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* @brief Construct a new Palette Lookup object
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*
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* @param palette the palette data, in interleaved RGB format
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* @param len the number of palette entries to be read
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*/
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PaletteLookup(const byte *palette, uint len);
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/**
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* @brief Pass palette to the look up. It also compares given palette
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* with the current one and resets cache only when their contents is different.
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*
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* @param palette the palette data, in interleaved RGB format
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* @param len the number of palette entries to be read
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*
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* @return true if palette was changed and false if it was the same
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*/
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bool setPalette(const byte *palette, uint len);
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/**
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* @brief This method returns closest color from the palette
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* and it uses cache for faster lookups
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*
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* @param useNaiveAlg if true, use a simpler algorithm (non-floating point calculations)
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*
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* @return the palette index
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*/
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byte findBestColor(byte r, byte g, byte b, bool useNaiveAlg = false);
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private:
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byte _palette[256 * 3];
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uint _paletteSize;
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Common::HashMap<int, byte> _colorHash;
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};
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} // // end of namespace Graphics
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#endif
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