From 0f383adcdc02cad8dfb435ce73c1fe1c0c4b5bd6 Mon Sep 17 00:00:00 2001
From: Daniel Hader <dhader96@gmail.com>
Date: Fri, 28 Aug 2026 21:27:29 -0500
Subject: sprite proof of concept and improved display control bit flagging

---
 source/util.hpp | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 116 insertions(+), 11 deletions(-)

(limited to 'source/util.hpp')

diff --git a/source/util.hpp b/source/util.hpp
index 88a29ca..c034fe5 100644
--- a/source/util.hpp
+++ b/source/util.hpp
@@ -24,18 +24,40 @@ enum DisplayControlLayer : u16 {
 	BG1 = 0x0200,
 	BG2 = 0x0400,
 	BG3 = 0x0800,
-	BG4 = 0x1000,
+	Obj = 0x1000,
 };
 
-typedef u16 DisplayControlFlags;
+struct DisplayControlFlags {
+	u16 data;
 
-constexpr DisplayControlFlags operator|(DisplayControlMode mode, DisplayControlLayer layer) {
-	return static_cast<DisplayControlFlags>(static_cast<u16>(mode) | static_cast<u16>(layer));
-}
+	enum Layer : u16 {
+		BG0 = 0x0100,
+		BG1 = 0x0200,
+		BG2 = 0x0400,
+		BG3 = 0x0800,
+		Obj = 0x1000,
+	};
+
+	constexpr DisplayControlFlags() : data(0) {}
+	constexpr DisplayControlFlags &set_mode(u16 mode) {
+		assert(mode < 6);
+		this->data = (this->data & ~0x0007) | mode;
+		return *this;
+	}
+	constexpr DisplayControlFlags &enable_layer(u16 layer) {
+		this->data |= layer;
+		return *this;
+	}
+	constexpr DisplayControlFlags &set_1d_object_mapping(u16 enabled) {
+		this->data = (this->data & ~0x0040) | ((!!enabled) << 6);
+		return *this;
+	}
+	constexpr operator u16() const { return data; }
+};
 
-static inline void set_display_control(DisplayControlMode mode, DisplayControlLayer layer) {
-	static volatile DisplayControlFlags* const display_control = reinterpret_cast<DisplayControlFlags*>(0x04000000);
-	*display_control = mode | layer;
+static inline void set_display_control(const DisplayControlFlags &flags) {
+	static volatile u16* const display_control = reinterpret_cast<volatile u16*>(0x04000000);
+	*display_control = flags;
 }
 
 enum BGControlColorMode : u16 {
@@ -134,9 +156,9 @@ struct ScreenEntry {
 
 	constexpr ScreenEntry() : data(0) {}
 
-	constexpr ScreenEntry &set_tile_index(u16 tid) {
-		assert(tid < 1024);
-		this->data = (this->data & ~0x03ff) | tid;
+	constexpr ScreenEntry &set_tile_index(u16 index) {
+		assert(index < 1024);
+		this->data = (this->data & ~0x03ff) | index;
 		return *this;
 	}
 
@@ -161,6 +183,80 @@ struct ScreenEntry {
 
 typedef ScreenEntry ScreenBlock[1024];
 
+struct ObjectAttributes {
+	u16 attr0, attr1, attr2, _fill;
+
+	enum ObjectMode : u16 {
+		ModeDefault = 0x0000,
+		ModeHidden  = 0x0020,
+		ModeAffine  = 0x0010,
+		ModeDouble  = 0x0030,
+	};
+
+	enum GraphicsMode : u16 {
+		GraphicsDefault = 0x0000,
+		GraphicsBlend   = 0x0400,
+		GraphicsWindow  = 0x0800,
+	};
+
+	enum Size : u16 {
+		Size_8x8   = 0x0000,
+		Size_16x16 = 0x0001,
+		Size_32x32 = 0x0002,
+		Size_64x64 = 0x0003,
+		Size_16x8  = 0x0100,
+		Size_32x8  = 0x0101,
+		Size_32x16 = 0x0102,
+		Size_32x64 = 0x0103,
+		Size_8x16  = 0x0200,
+		Size_8x32  = 0x0201,
+		Size_16x32 = 0x0202,
+		Size_64x32 = 0x0203,
+	};
+
+	constexpr ObjectAttributes() : attr0(0), attr1(0), attr2(0), _fill(0) {}
+
+	constexpr ObjectAttributes &set_x(u16 x) {
+		assert(x < 256);
+		this->attr1 = (this->attr1 & ~0x000f) | x;
+		return *this;
+	}
+
+	constexpr ObjectAttributes &set_y(u16 y) {
+		assert(y < 256);
+		this->attr0 = (this->attr0 & ~0x000f) | y;
+		return *this;
+	}
+
+	constexpr ObjectAttributes &set_object_mode(ObjectMode mode) {
+		this->attr0 = (this->attr0 & ~0x0030) | mode;
+		return *this;
+	}
+
+	constexpr ObjectAttributes &set_graphics_mode(GraphicsMode mode) {
+		this->attr0 = (this->attr0 & ~0x00c0) | mode;
+		return *this;
+	}
+
+	constexpr ObjectAttributes &set_size(Size size) {
+		this->attr0 = (this->attr0 & ~0xc000) | ((size & 0x0300) << 6);
+		this->attr1 = (this->attr1 & ~0xc000) | ((size & 0x0003) << 14);
+		return *this;
+	}
+
+	constexpr ObjectAttributes &set_tile_index(u16 index) {
+		assert(index < 1024);
+		this->attr2 = (this->attr2 & ~0x003f) | index;
+		return *this;
+	}
+
+	constexpr ObjectAttributes &set_palette_bank(u16 bank) {
+		assert(bank < 16);
+		this->attr2 = (this->attr2 & ~0xf000) | (bank << 12);
+		return *this;
+	}
+};
+
 template <typename T>
 static inline void volatile_copy(volatile T* dst, const T* src) {
 	using U = std::conditional_t<(sizeof(T) % sizeof(u32) == 0) && (alignof(T) % alignof(u32) == 0), u32, u16>;
@@ -184,10 +280,19 @@ static inline void set_bg_palette(u32 bank, u32 index, const Color &color) {
 	volatile_copy(&banks[bank][index], &color);
 }
 
+static inline void set_obj_palette(u32 bank, u32 index, const Color &color) {
+	volatile PaletteBank *const banks = reinterpret_cast<volatile PaletteBank*>(0x05000200);
+	volatile_copy(&banks[bank][index], &color);
+}
 
 static inline void set_screen_entry(u32 block, u32 index, const ScreenEntry &entry) {
 	volatile ScreenBlock *const blocks = reinterpret_cast<volatile ScreenBlock*>(0x06000000);
 	volatile_copy(&blocks[block][index], &entry);
 }
 
+static inline void set_obj_attributes(u32 index, const ObjectAttributes &attr) {
+	volatile ObjectAttributes *const attrs = reinterpret_cast<volatile ObjectAttributes*>(0x07000000);
+	volatile_copy(&attrs[index], &attr);
+}
+
 #endif
-- 
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