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◆ main openmsx / src / video / CharacterConverter.hh
2.6 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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#ifndef CHARACTERCONVERTER_HH
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#define CHARACTERCONVERTER_HH
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#include <cstdint>
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#include <span>
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namespace openmsx {
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class VDP;
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class VDPVRAM;
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class DisplayMode;
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/** Utility class for converting VRAM contents to host pixels.
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  */
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class CharacterConverter
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{
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public:
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	using Pixel = uint32_t;
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	/** Create a new bitmap scanline converter.
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	  * @param vdp The VDP of which the VRAM will be converted.
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	  * @param palFg Pointer to 16-entries array that specifies
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	  *   VDP foreground color index to host pixel mapping.
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	  *   This is kept as a pointer, so any changes to the palette
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	  *   are immediately picked up by convertLine.
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	  * @param palBg Pointer to 16-entries array that specifies
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	  *   VDP background color index to host pixel mapping.
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	  *   This is kept as a pointer, so any changes to the palette
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	  *   are immediately picked up by convertLine.
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	  */
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	CharacterConverter(VDP& vdp, std::span<const Pixel, 16> palFg, std::span<const Pixel, 16> palBg);
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	/** Convert a line of V9938 VRAM to 256 or 512 host pixels.
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	  * Call this method in non-planar display modes (Graphic4 and Graphic5).
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	  * @param buf Buffer where host pixels will be written to.
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	  *            Depending on the screen mode, the buffer must contain at
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	  *            least 256 or 512 pixels, but more is allowed (the extra
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	  *            pixels aren't touched).
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	  * @param line Display line number [0..255].
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	  */
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	void convertLine(std::span<Pixel> buf, int line) const;
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	/** Select the display mode to use for scanline conversion.
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	  * @param mode The new display mode.
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	  */
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	void setDisplayMode(DisplayMode mode);
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private:
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	inline void renderText1   (std::span<Pixel, 256> buf, int line) const;
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	inline void renderText1Q  (std::span<Pixel, 256> buf, int line) const;
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	inline void renderText2   (std::span<Pixel, 512> buf, int line) const;
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	inline void renderGraphic1(std::span<Pixel, 256> buf, int line) const;
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	inline void renderGraphic2(std::span<Pixel, 256> buf, int line) const;
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	inline void renderMulti   (std::span<Pixel, 256> buf, int line) const;
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	inline void renderMultiQ  (std::span<Pixel, 256> buf, int line) const;
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	inline void renderBogus   (std::span<Pixel, 256> buf) const;
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	inline void renderBlank   (std::span<Pixel, 256> buf) const;
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	inline void renderMultiHelper(Pixel* pixelPtr, int line,
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	                       unsigned mask, unsigned patternQuarter) const;
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	[[nodiscard]] std::span<const uint8_t, 32> getNamePtr(int line, int scroll) const;
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private:
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	VDP& vdp;
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	VDPVRAM& vram;
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	std::span<const Pixel, 16> palFg;
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	std::span<const Pixel, 16> palBg;
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	unsigned modeBase = 0; // not strictly needed, but avoids Coverity warning
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};
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} // namespace openmsx
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#endif