nostalgia/deps/teagba/src/gfx.cpp

41 lines
1.2 KiB
C++

/*
* Copyright 2016 - 2023 Gary Talent (gary@drinkingtea.net). All rights reserved.
*/
#include <teagba/addresses.hpp>
#include <teagba/bios.hpp>
#include <teagba/irq.hpp>
#include <teagba/gfx.hpp>
namespace teagba {
volatile uint16_t g_spriteUpdates = 0;
ox::Array<GbaSpriteAttrUpdate, 128> g_spriteBuffer;
void addSpriteUpdate(const GbaSpriteAttrUpdate &upd) noexcept {
// block until g_spriteUpdates is less than buffer len
if (g_spriteUpdates >= g_spriteBuffer.size()) [[unlikely]] {
teagba_vblankintrwait();
}
const auto ie = REG_IE; // disable vblank interrupt handler
REG_IE = REG_IE & static_cast<uint16_t>(~teagba::Int_vblank); // disable vblank interrupt handler
const auto updateCnt = g_spriteUpdates;
g_spriteBuffer[updateCnt] = upd;
g_spriteUpdates = updateCnt + 1;
REG_IE = ie; // enable vblank interrupt handler
}
void applySpriteUpdates() noexcept {
// copy g_spriteUpdates to allow it to use a register instead of reading
// from memory every iteration of the loop, needed because g_spriteUpdates
// is volatile
const unsigned updates = g_spriteUpdates;
for (unsigned i = 0; i < updates; ++i) {
const auto &oa = g_spriteBuffer[i];
MEM_OAM[oa.idx] = *reinterpret_cast<const uint64_t*>(&oa);
}
}
}