From ef5545f5bd5079483bf34faeaf1fc3bb17294d02 Mon Sep 17 00:00:00 2001
From: Kevin Poretti <kevinporetti@gmail.com>
Date: Sat, 11 Feb 2023 17:37:37 -0500
Subject: [PATCH] Conversions, assignment, and addition/subtraction

---
 README.md                                 |  9 ++++
 Source/UnrealFixedPoint/Private/Fixed.cpp |  3 ++
 Source/UnrealFixedPoint/Public/Fixed.h    | 57 +++++++++++++++++++++++
 3 files changed, 69 insertions(+)
 create mode 100644 Source/UnrealFixedPoint/Private/Fixed.cpp
 create mode 100644 Source/UnrealFixedPoint/Public/Fixed.h

diff --git a/README.md b/README.md
index 00ae41f..a7a4c09 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,15 @@ This library aims to closely match the interface and functionality of the existi
 - [ ] Fixed point version of FRotator
 	- [ ] FFixedRotator class implementation
 	- [ ] Corresponding FMath and UKismetMathLibrary utility functions
+- [ ] Blueprints
+	- [ ] Expose fixed arithmatic as pure Blueprint nodes
+	- [ ] Ability to edit fixed nums with float sliders/input fields
+		- [ ] Automatically do float <> fixed conversion when tweaking fixed point numbers in the editor
+- [ ] Plugin config
+	- [ ] Configure how fixed nums are shown in editor when exposed as UPROPERTY (as floats only, as float and underlying int, as underlying int only)
+- [ ] Handling errors and edge cases
+	- [ ] Overflow
+	- [ ] Infinity
 
 ### What is fixed point math?
 
diff --git a/Source/UnrealFixedPoint/Private/Fixed.cpp b/Source/UnrealFixedPoint/Private/Fixed.cpp
new file mode 100644
index 0000000..a29bbf0
--- /dev/null
+++ b/Source/UnrealFixedPoint/Private/Fixed.cpp
@@ -0,0 +1,3 @@
+// UnrealFixedPoint Copyright Kevin Poretti
+
+#include "Fixed.h"
diff --git a/Source/UnrealFixedPoint/Public/Fixed.h b/Source/UnrealFixedPoint/Public/Fixed.h
new file mode 100644
index 0000000..299eb86
--- /dev/null
+++ b/Source/UnrealFixedPoint/Public/Fixed.h
@@ -0,0 +1,57 @@
+// UnrealFixedPoint Copyright Kevin Poretti
+
+#pragma once
+
+#include "CoreMinimal.h"
+#include "Fixed.generated.h"
+
+/**
+ * 
+ */
+USTRUCT(BlueprintType)
+struct UNREALFIXEDPOINT_API FFixed
+{
+    GENERATED_BODY()
+
+public:
+    // 48 bits for the whole portion, 16 bits for the fractional portion
+    static constexpr uint8 DecimalBitPosition = 16;
+
+	FFixed() : Data(0) { }
+
+    // int types <> FFixed conversions
+    FORCEINLINE FFixed(int64 A) { Data = A << DecimalBitPosition; }
+    FORCEINLINE operator int64() const { return Data >> DecimalBitPosition; }
+
+    /*
+    int8
+    int16
+    FORCEINLINE operator uint8()
+    */
+
+    // floating point types <> FFixed conversions
+    FORCEINLINE FFixed(float A) { Data = static_cast<int64>(A * (1 << DecimalBitPosition) + (A >= 0 ? 0.5 : -0.5)); }
+    FORCEINLINE operator float() const { return static_cast<float>(Data) / (1 << DecimalBitPosition); }
+
+    FORCEINLINE FFixed(double A) { Data = static_cast<int64>(A * (1 << DecimalBitPosition) + (A >= 0 ? 0.5 : -0.5)); }
+    FORCEINLINE operator double() const { return static_cast<double>(Data) / (1 << DecimalBitPosition); }
+
+    // Arithmetic
+    FFixed operator+(const FFixed& Other) const { return Data + Other.Data; }
+    FFixed operator+=(const FFixed& Other) { Data += Other.Data; return Data; }
+
+    FFixed operator-(const FFixed& Other) const { return Data - Other.Data; }
+    FFixed operator-=(const FFixed& Other) { Data -= Other.Data; return Data; }
+
+    // Other overloads
+    FFixed operator=(const FFixed& Other) { Data = Other.Data; return Data; }
+    FFixed operator-() const { return -Data; }
+
+private:
+    int64 Data;
+};
+
+namespace FFixedMath
+{
+    
+}