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Merge pull request #1073 from TomHarte/AmigaSprites
Improve Amiga sprite emulation.
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commit
b67790df7d
@ -21,6 +21,8 @@
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using namespace Amiga;
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// TODO: I don't think the nonsense below, which was intended to allow a typed enum but also
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// clean combination, really works. Rethink.
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namespace {
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template <typename EnumT, EnumT... T> struct Mask {
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@ -34,6 +36,18 @@ template <typename EnumT, EnumT F, EnumT... T> struct Mask<EnumT, F, T...> {
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template <InterruptFlag... Flags> struct InterruptMask: Mask<InterruptFlag, Flags...> {};
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template <DMAFlag... Flags> struct DMAMask: Mask<DMAFlag, Flags...> {};
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constexpr uint16_t AudioFlags[] = {
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DMAMask<DMAFlag::AudioChannel0, DMAFlag::AllBelow>::value,
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DMAMask<DMAFlag::AudioChannel1, DMAFlag::AllBelow>::value,
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DMAMask<DMAFlag::AudioChannel2, DMAFlag::AllBelow>::value,
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DMAMask<DMAFlag::AudioChannel3, DMAFlag::AllBelow>::value,
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};
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constexpr auto BlitterFlag = DMAMask<DMAFlag::Blitter, DMAFlag::AllBelow>::value;
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constexpr auto BitplaneFlag = DMAMask<DMAFlag::Bitplane, DMAFlag::AllBelow>::value;
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constexpr auto CopperFlag = DMAMask<DMAFlag::Copper, DMAFlag::AllBelow>::value;
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constexpr auto DiskFlag = DMAMask<DMAFlag::Disk, DMAFlag::AllBelow>::value;
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constexpr auto SpritesFlag = DMAMask<DMAFlag::Sprites, DMAFlag::AllBelow>::value;
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}
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#define DMA_CONSTRUCT *this, reinterpret_cast<uint16_t *>(map.chip_ram.data()), map.chip_ram.size() >> 1
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@ -488,17 +502,6 @@ void Chipset::flush_output() {
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/// @returns @c true if this was a CPU slot; @c false otherwise.
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template <int cycle, bool stop_if_cpu> bool Chipset::perform_cycle() {
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constexpr uint16_t AudioFlags[] = {
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DMAMask<DMAFlag::AudioChannel0, DMAFlag::AllBelow>::value,
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DMAMask<DMAFlag::AudioChannel1, DMAFlag::AllBelow>::value,
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DMAMask<DMAFlag::AudioChannel2, DMAFlag::AllBelow>::value,
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DMAMask<DMAFlag::AudioChannel3, DMAFlag::AllBelow>::value,
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};
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constexpr auto BlitterFlag = DMAMask<DMAFlag::Blitter, DMAFlag::AllBelow>::value;
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constexpr auto BitplaneFlag = DMAMask<DMAFlag::Bitplane, DMAFlag::AllBelow>::value;
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constexpr auto CopperFlag = DMAMask<DMAFlag::Copper, DMAFlag::AllBelow>::value;
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constexpr auto DiskFlag = DMAMask<DMAFlag::Disk, DMAFlag::AllBelow>::value;
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constexpr auto SpritesFlag = DMAMask<DMAFlag::Sprites, DMAFlag::AllBelow>::value;
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// Update state as to whether bitplane fetching should happen now.
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//
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@ -607,11 +610,11 @@ template <int cycle, bool stop_if_cpu> bool Chipset::perform_cycle() {
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}
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if constexpr (cycle >= 0x16 && cycle < 0x36) {
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if((dma_control_ & SpritesFlag) == SpritesFlag && y_ >= vertical_blank_height_) {
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if((dma_control_ & SpritesFlag) == SpritesFlag) {
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constexpr auto sprite_id = (cycle - 0x16) >> 2;
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static_assert(sprite_id >= 0 && sprite_id < std::tuple_size<decltype(sprites_)>::value);
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if(sprites_[sprite_id].advance_dma(!(cycle&2))) {
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if(sprites_[sprite_id].advance_dma((~cycle&2) >> 1, y_, y_ == vertical_blank_height_)) {
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return false;
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}
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}
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@ -741,10 +744,6 @@ template <bool stop_on_cpu> Chipset::Changes Chipset::run(HalfCycles length) {
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is_long_field_ ^= interlace_;
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}
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for(auto &sprite: sprites_) {
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sprite.advance_line(y_, y_ == vertical_blank_height_);
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}
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fetch_vertical_ |= y_ == display_window_start_[1];
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fetch_vertical_ &= y_ != display_window_stop_[1];
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}
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@ -8,6 +8,8 @@
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#include "Sprites.hpp"
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#include <cassert>
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using namespace Amiga;
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namespace {
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@ -33,61 +35,69 @@ static_assert(expand_sprite_word(0x0000) == 0x00'00'00'00'00'00'00'00);
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// MARK: - Sprites.
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void Sprite::set_start_position(uint16_t value) {
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// b8–b15: low 8 bits of VSTART;
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// b0–b7: high 8 bits of HSTART.
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v_start_ = (v_start_ & 0xff00) | (value >> 8);
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h_start = uint16_t((h_start & 0x0001) | ((value & 0xff) << 1));
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}
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void Sprite::set_stop_and_control(uint16_t value) {
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// b8–b15: low 8 bits of VSTOP;
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// b7: attachment flag;
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// b3–b6: unused;
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// b2: VSTART high bit;
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// b1: VSTOP high bit;
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// b0: HSTART low bit.
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h_start = uint16_t((h_start & 0x01fe) | (value & 0x01));
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v_stop_ = uint16_t((value >> 8) | ((value & 0x02) << 7));
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v_start_ = uint16_t((v_start_ & 0x00ff) | ((value & 0x04) << 6));
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attached = value & 0x80;
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// Disarm the sprite, but expect graphics next from DMA.
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// Disarm the sprite.
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visible = false;
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dma_state_ = DMAState::FetchImage;
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}
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void Sprite::set_image_data(int slot, uint16_t value) {
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// Store data; also mark sprite as visible (i.e. 'arm' it)
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// if data is being stored to slot 0.
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data[slot] = value;
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visible |= slot == 0;
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}
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void Sprite::advance_line(int y, bool is_end_of_blank) {
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if(dma_state_ == DMAState::FetchImage && y == v_start_) {
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visible = true;
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}
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if(is_end_of_blank || y == v_stop_) {
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dma_state_ = DMAState::FetchControl;
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visible = true;
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}
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}
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bool Sprite::advance_dma(int offset, int y, bool is_first_line) {
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assert(offset == 0 || offset == 1);
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bool Sprite::advance_dma(int offset) {
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if(!visible) return false;
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// Fetch another word.
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// Determine which word would be fetched, if DMA occurs.
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// A bit of a cheat.
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const uint16_t next_word = ram_[pointer_[0] & ram_mask_];
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++pointer_[0];
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// Put the fetched word somewhere appropriate and update the DMA state.
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switch(dma_state_) {
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// i.e. stopped.
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default: return false;
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// "When the vertical position of the beam counter is equal to the VSTOP
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// value in the sprite control words, the next two words fetched from the
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// sprite data structure are written into the sprite control registers
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// instead of being sent to the color registers"
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//
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// Guesswork, primarily from observing Spindizzy Worlds: the first line after
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// vertical blank also triggers a control reload. Seek to verify.
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if(y == v_stop_ || is_first_line) {
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if(offset) {
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// Second control word: stop position (mostly).
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set_stop_and_control(next_word);
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} else {
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// First control word: start position.
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set_start_position(next_word);
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}
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} else {
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visible |= y == v_start_;
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if(!visible) return false; // Act as if there wasn't a fetch.
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case DMAState::FetchControl:
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if(offset) {
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set_stop_and_control(next_word);
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} else {
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set_start_position(next_word);
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}
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return true;
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case DMAState::FetchImage:
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set_image_data(1 - bool(offset), next_word);
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return true;
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// Write colour word 1, then colour word 0; 0 is the word that 'arms'
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// the sprite (i.e. makes it visible).
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set_image_data(1 - offset, next_word);
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}
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return false;
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// Acknowledge the fetch.
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++pointer_[0];
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return true;
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}
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template <int sprite> void TwoSpriteShifter::load(
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@ -23,8 +23,7 @@ class Sprite: public DMADevice<1> {
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void set_stop_and_control(uint16_t value);
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void set_image_data(int slot, uint16_t value);
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void advance_line(int y, bool is_end_of_blank);
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bool advance_dma(int offset);
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bool advance_dma(int offset, int y, bool is_first_line);
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uint16_t data[2]{};
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bool attached = false;
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@ -33,11 +32,6 @@ class Sprite: public DMADevice<1> {
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private:
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uint16_t v_start_ = 0, v_stop_ = 0;
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enum class DMAState {
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FetchControl,
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FetchImage
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} dma_state_ = DMAState::FetchControl;
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};
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class TwoSpriteShifter {
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