mirror of
https://github.com/drewcassidy/quicktex.git
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174 lines
6.7 KiB
C++
174 lines
6.7 KiB
C++
/* Python-rgbcx Texture Compression Library
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Copyright (C) 2021 Andrew Cassidy <drewcassidy@me.com>
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Partially derived from rgbcx.h written by Richard Geldreich <richgel99@gmail.com>
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and licenced under the public domain
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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 Lesser 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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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 Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser 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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#pragma once
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#include <array> // for array
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#include <cstdint> // for uint8_t, uint16_t
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#include <memory> // for unique_ptr
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#include "Color.h" // for Color
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namespace rgbcx {
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class Interpolator {
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public:
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enum class Type { Ideal, IdealRound, Nvidia, AMD };
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static std::unique_ptr<Interpolator> MakeInterpolator(Type type = Type::Ideal);
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virtual ~Interpolator() noexcept = default;
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/**
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* Performs a 2/3 interpolation of a pair of 5-bit values to produce an 8-bit value
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* Output is approximately (2v0 + v1)/3, with v0 and v1 first extended to 8 bits.
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* @param v0 The first 5-bit value
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* @param v1 The second 5-bit value
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* @return The interpolated value
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*/
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virtual uint8_t Interpolate5(uint8_t v0, uint8_t v1) const;
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/**
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* Performs a 2/3 interpolation of a pair of 5-bit values to produce an 8-bit value
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* Output is approximately (2v0 + v1)/3, with v0 and v1 first extended to 8 bits.
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* @param v0 The first 5-bit value
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* @param v1 The second 5-bit value
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* @return The interpolated value
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*/
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virtual uint8_t Interpolate6(uint8_t v0, uint8_t v1) const;
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/**
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* Performs a 2/3 interpolation of a pair of 8-bit values to produce an 8-bit value
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* Output is approximately (2v0 + v1)/3.
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* Output is not guranteed to be accurate for the given interpolator if CanInterpolate8Bit() is false
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* @param v0 The first 8-bit value
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* @param v1 The second 8-bit value
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* @return The interpolated value
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*/
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virtual uint8_t Interpolate8(uint8_t v0, uint8_t v1) const;
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/**
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* Performs a 1/2 interpolation of a pair of 5-bit values to produce an 8-bit value
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* Output is approximately (v0 + v1)/2, with v0 and v1 first extended to 8 bits.
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* @param v0 The first 5-bit value
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* @param v1 The second 5-bit value
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* @return The interpolated value
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*/
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virtual uint8_t InterpolateHalf5(uint8_t v0, uint8_t v1) const;
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/**
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* Performs a 1/2 interpolation of a pair of 6-bit values to produce an 8-bit value
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* Output is approximately (v0 + v1)/2, with v0 and v1 first extended to 8 bits.
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* @param v0 The first 6-bit value
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* @param v1 The second 6-bit value
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* @return The interpolated value
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*/
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virtual uint8_t InterpolateHalf6(uint8_t v0, uint8_t v1) const;
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/**
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* Performs a 1/2 interpolation of a pair of 8-bit values to produce an 8-bit value
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* Output is approximately (v0 + v1)/2.
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* Output is not guranteed to be accurate for the given interpolator if CanInterpolate8Bit() is false
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* @param v0 The first 8-bit value
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* @param v1 The second 8-bit value
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* @return The interpolated value
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*/
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virtual uint8_t InterpolateHalf8(uint8_t v0, uint8_t v1) const;
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/**
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* Generates the 4 colors for a BC1 block from the given 5:6:5-packed colors
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* @param low first 5:6:5 color for the block
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* @param high second 5:6:5 color for the block
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* @return and array of 4 Color values, with indices matching BC1 selectors
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*/
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virtual std::array<Color, 4> InterpolateBC1(uint16_t low, uint16_t high) const;
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virtual std::array<Color, 4> InterpolateBC1(Color low, Color high, bool use_3color) const;
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/**
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* Gets the type of an interpolator
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* @return The interpolator type
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*/
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virtual Type GetType() const noexcept { return Type::Ideal; }
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virtual bool CanInterpolate8Bit() const noexcept { return true; }
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/**
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* Checks if the interpolator uses an ideal algorithm
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* @return true if the interpolator is ideal, false otherwise.
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*/
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virtual bool IsIdeal() const noexcept {
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auto type = GetType();
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return (type == Type::Ideal || type == Type::IdealRound);
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}
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private:
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Color InterpolateColor24(const Color &c0, const Color &c1) const {
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return Color(Interpolate8(c0.r, c1.r), Interpolate8(c0.g, c1.g), Interpolate8(c0.b, c1.b));
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}
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Color InterpolateHalfColor24(const Color &c0, const Color &c1) const {
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return Color(InterpolateHalf8(c0.r, c1.r), InterpolateHalf8(c0.g, c1.g), InterpolateHalf8(c0.b, c1.b));
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}
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};
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class InterpolatorRound : public Interpolator {
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public:
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uint8_t Interpolate5(uint8_t v0, uint8_t v1) const override;
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uint8_t Interpolate6(uint8_t v0, uint8_t v1) const override;
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uint8_t Interpolate8(uint8_t v0, uint8_t v1) const override;
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Type GetType() const noexcept override { return Type::IdealRound; }
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};
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class InterpolatorNvidia : public Interpolator {
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public:
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uint8_t Interpolate5(uint8_t v0, uint8_t v1) const override;
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uint8_t Interpolate6(uint8_t v0, uint8_t v1) const override;
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uint8_t InterpolateHalf5(uint8_t v0, uint8_t v1) const override;
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uint8_t InterpolateHalf6(uint8_t v0, uint8_t v1) const override;
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std::array<Color, 4> InterpolateBC1(Color low, Color high, bool use_3color) const override;
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Type GetType() const noexcept override { return Type::Nvidia; }
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bool CanInterpolate8Bit() const noexcept override { return false; }
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private:
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Color InterpolateColor565(const Color &c0, const Color &c1) const {
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return Color(Interpolate5(c0.r, c1.r), Interpolate6(c0.g, c1.g), Interpolate5(c0.b, c1.b));
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}
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Color InterpolateHalfColor565(const Color &c0, const Color &c1) const {
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return Color(InterpolateHalf5(c0.r, c1.r), InterpolateHalf6(c0.g, c1.g), InterpolateHalf5(c0.b, c1.b));
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}
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};
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class InterpolatorAMD : public Interpolator {
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public:
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uint8_t Interpolate5(uint8_t v0, uint8_t v1) const override;
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uint8_t Interpolate6(uint8_t v0, uint8_t v1) const override;
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uint8_t Interpolate8(uint8_t v0, uint8_t v1) const override;
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uint8_t InterpolateHalf5(uint8_t v0, uint8_t v1) const override;
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uint8_t InterpolateHalf6(uint8_t v0, uint8_t v1) const override;
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uint8_t InterpolateHalf8(uint8_t v0, uint8_t v1) const override;
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Type GetType() const noexcept override { return Type::AMD; }
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};
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} // namespace rgbcx
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