From 6de0e882e9da4de0622f44f7c18a05a29670b17b Mon Sep 17 00:00:00 2001
From: Gary Talent <gary@drinkingtea.net>
Date: Fri, 22 Dec 2023 01:02:24 -0600
Subject: [PATCH] [teagba] Change sprite buffer to fully update on every VSync

---
 deps/teagba/include/teagba/gfx.hpp | 11 ++++++-----
 deps/teagba/src/gfx.cpp            | 21 ++++++---------------
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/deps/teagba/include/teagba/gfx.hpp b/deps/teagba/include/teagba/gfx.hpp
index 8c2b6a03..530eeac7 100644
--- a/deps/teagba/include/teagba/gfx.hpp
+++ b/deps/teagba/include/teagba/gfx.hpp
@@ -29,13 +29,14 @@ enum DispCtl {
 };
 
 struct OX_ALIGN8 GbaSpriteAttrUpdate {
-		uint16_t attr0 = 0;
-		uint16_t attr1 = 0;
-		uint16_t attr2 = 0;
-		uint16_t idx = 0;
-
+	uint16_t attr0 = 0;
+	uint16_t attr1 = 0;
+	uint16_t attr2 = 0;
+	uint16_t idx = 0;
 };
 
+GbaSpriteAttrUpdate &spriteAttr(size_t i) noexcept;
+
 void addSpriteUpdate(const GbaSpriteAttrUpdate &upd) noexcept;
 
 void applySpriteUpdates() noexcept;
diff --git a/deps/teagba/src/gfx.cpp b/deps/teagba/src/gfx.cpp
index 0fb2bf49..3c89bbc2 100644
--- a/deps/teagba/src/gfx.cpp
+++ b/deps/teagba/src/gfx.cpp
@@ -10,32 +10,23 @@
 
 namespace teagba {
 
-static volatile uint16_t g_spriteUpdates = 0;
 static ox::Array<GbaSpriteAttrUpdate, 128> g_spriteBuffer;
 
+GbaSpriteAttrUpdate &spriteAttr(size_t i) noexcept {
+	return g_spriteBuffer[i];
+}
+
 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;
+	g_spriteBuffer[upd.idx] = upd;
 	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];
+	for (auto const&oa : g_spriteBuffer) {
 		MEM_OAM[oa.idx] = std::bit_cast<uint64_t>(oa);
 	}
-	g_spriteUpdates = 0;
 }
 
 }