From 9840b6fdee26aca36771e8576d2cc88cbbb87a9f Mon Sep 17 00:00:00 2001
From: Gary Talent <gary@drinkingtea.net>
Date: Wed, 20 Dec 2023 19:00:23 -0600
Subject: [PATCH] [nostalgia/core] Add a background priority option

---
 .../core/include/nostalgia/core/gfx.hpp       |  2 ++
 src/nostalgia/modules/core/src/gba/gfx.cpp    | 28 +++++++++----------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/src/nostalgia/modules/core/include/nostalgia/core/gfx.hpp b/src/nostalgia/modules/core/include/nostalgia/core/gfx.hpp
index d47763cd..6191cc7d 100644
--- a/src/nostalgia/modules/core/include/nostalgia/core/gfx.hpp
+++ b/src/nostalgia/modules/core/include/nostalgia/core/gfx.hpp
@@ -52,6 +52,8 @@ void setBgStatus(Context &ctx, unsigned bg, bool status) noexcept;
 
 void setBgCbb(Context &ctx, unsigned bgIdx, unsigned cbb) noexcept;
 
+void setBgPriority(Context &ctx, uint_t bgIdx, uint_t priority) noexcept;
+
 /**
  * @param section describes which section of the selected TileSheetSpace to use (e.g. MEM_PALLETE_BG[section])
  */
diff --git a/src/nostalgia/modules/core/src/gba/gfx.cpp b/src/nostalgia/modules/core/src/gba/gfx.cpp
index 2968dc28..ca0352c3 100644
--- a/src/nostalgia/modules/core/src/gba/gfx.cpp
+++ b/src/nostalgia/modules/core/src/gba/gfx.cpp
@@ -97,15 +97,16 @@ void setBgStatus(Context&, unsigned bg, bool status) noexcept {
 	REG_DISPCTL = REG_DISPCTL | ((REG_DISPCTL & ~mask) | mask);
 }
 
-static void setBgCbb(Context*, unsigned bgIdx, unsigned cbb) noexcept {
+void setBgCbb(Context&, unsigned bgIdx, unsigned cbb) noexcept {
 	auto &bgCtl = regBgCtl(bgIdx);
 	const auto &cbbData = g_cbbData[cbb];
 	teagba::bgSetBpp(&bgCtl, cbbData.bpp);
 	teagba::bgSetCbb(&bgCtl, cbb);
 }
 
-void setBgCbb(Context&, unsigned bgIdx, unsigned cbb) noexcept {
-	setBgCbb(nullptr, bgIdx, cbb);
+void setBgPriority(Context&, uint_t bgIdx, uint_t priority) noexcept {
+	auto &bgCtl = regBgCtl(bgIdx);
+	bgCtl = (bgCtl & 0b1111'1111'1111'1100u) | (priority & 0b11);
 }
 
 static ox::Error loadBgTileSheet(
@@ -215,24 +216,24 @@ void clearTileLayer(Context&, unsigned bgIdx) noexcept {
 [[maybe_unused]]
 void hideSprite(Context&, unsigned idx) noexcept {
 	//oxAssert(g_spriteUpdates < config::GbaSpriteBufferLen, "Sprite update buffer overflow");
-	teagba::GbaSpriteAttrUpdate oa;
-	oa.attr0 = uint16_t{0b11 << 8};
-	oa.idx = static_cast<uint16_t>(idx);
-	teagba::addSpriteUpdate(oa);
+	teagba::addSpriteUpdate({
+		.attr0 = uint16_t{0b11 << 8},
+		.idx = static_cast<uint16_t>(idx),
+	});
 }
 
 [[maybe_unused]]
 void showSprite(Context&, unsigned idx) noexcept {
 	//oxAssert(g_spriteUpdates < config::GbaSpriteBufferLen, "Sprite update buffer overflow");
-	teagba::GbaSpriteAttrUpdate oa;
-	oa.attr0 &= uint16_t{0b1111'1100'1111'1111};
-	oa.idx = static_cast<uint16_t>(idx);
-	teagba::addSpriteUpdate(oa);
+	teagba::addSpriteUpdate({
+		.attr0 = 0,
+		.idx = static_cast<uint16_t>(idx),
+	});
 }
 
 void setSprite(Context&, uint_t idx, Sprite const&s) noexcept {
 	//oxAssert(g_spriteUpdates < config::GbaSpriteBufferLen, "Sprite update buffer overflow");
-	teagba::GbaSpriteAttrUpdate const oa{
+	teagba::addSpriteUpdate({
 		.attr0 = static_cast<uint16_t>(
 			  (static_cast<uint16_t>(s.y & ox::onMask<uint8_t>(0b111'1111)))
 			| (static_cast<uint16_t>(1) << 10) // enable alpha
@@ -245,8 +246,7 @@ void setSprite(Context&, uint_t idx, Sprite const&s) noexcept {
 			  (static_cast<uint16_t>(s.tileIdx & ox::onMask<uint16_t>(8)))
 			| (static_cast<uint16_t>(s.priority & 0b11) << 10)),
 		.idx = static_cast<uint16_t>(idx),
-	};
-	teagba::addSpriteUpdate(oa);
+	});
 }
 
 }