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fa13611bbf
- Changes most `/* comments */` to `// comments` - Changes `/**` block comments consistently to `/*` - Adds consistent license comments to all files Also renames `T_POP_SET` to `T_Z80_SET`
68 lines
2.1 KiB
C++
68 lines
2.1 KiB
C++
/*
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* This file is part of RGBDS.
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*
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* Copyright (c) 2022, Eldred Habert and RGBDS contributors.
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*
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* SPDX-License-Identifier: MIT
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*/
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#ifndef RGBDS_GFX_RGBA_HPP
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#define RGBDS_GFX_RGBA_HPP
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#include <cstdint>
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#include <stdint.h>
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struct Rgba {
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uint8_t red;
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uint8_t green;
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uint8_t blue;
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uint8_t alpha;
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constexpr Rgba(uint8_t r, uint8_t g, uint8_t b, uint8_t a)
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: red(r), green(g), blue(b), alpha(a) {}
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/*
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* Constructs the color from a "packed" RGBA representation (0xRRGGBBAA)
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*/
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explicit constexpr Rgba(uint32_t rgba = 0)
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: red(rgba >> 24), green(rgba >> 16), blue(rgba >> 8), alpha(rgba) {}
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static constexpr Rgba fromCGBColor(uint16_t cgbColor) {
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constexpr auto _5to8 = [](uint8_t fiveBpp) -> uint8_t {
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fiveBpp &= 0b11111; // For caller's convenience
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return fiveBpp << 3 | fiveBpp >> 2;
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};
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return {_5to8(cgbColor), _5to8(cgbColor >> 5), _5to8(cgbColor >> 10),
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(uint8_t)(cgbColor & 0x8000 ? 0x00 : 0xFF)};
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}
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/*
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* Returns this RGBA as a 32-bit number that can be printed in hex (`%08x`) to yield its CSS
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* representation
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*/
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uint32_t toCSS() const {
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auto shl = [](uint8_t val, unsigned shift) { return static_cast<uint32_t>(val) << shift; };
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return shl(red, 24) | shl(green, 16) | shl(blue, 8) | shl(alpha, 0);
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}
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friend bool operator!=(Rgba const &lhs, Rgba const &rhs) { return lhs.toCSS() != rhs.toCSS(); }
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/*
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* CGB colors are RGB555, so we use bit 15 to signify that the color is transparent instead
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* Since the rest of the bits don't matter then, we return 0x8000 exactly.
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*/
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static constexpr uint16_t transparent = 0b1'00000'00000'00000;
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static constexpr uint8_t transparency_threshold = 0x10;
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bool isTransparent() const { return alpha < transparency_threshold; }
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static constexpr uint8_t opacity_threshold = 0xF0;
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bool isOpaque() const { return alpha >= opacity_threshold; }
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/*
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* Computes the equivalent CGB color, respects the color curve depending on options
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*/
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uint16_t cgbColor() const;
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bool isGray() const { return red == green && green == blue; }
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uint8_t grayIndex() const;
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};
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#endif // RGBDS_GFX_RGBA_HPP
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