From 4d3d6acd2857fe77434951503c1d59e7125bd856 Mon Sep 17 00:00:00 2001
From: nmlgc <nmlgc@nmlgc.net>
Date: Sun, 1 Dec 2019 17:22:06 +0100
Subject: [PATCH] [Decompilation] Templatize subpixels to offer both 16-bit and
 8-bit variants

Yup, TH03 actually uses a 4.4 fixed-point format.

Part of P0061, funded by Touhou Patch Center.
---
 th03/math/subpixel.hpp | 21 ++++++++++++++-------
 th03/math/subpixel.inc |  4 ++++
 2 files changed, 18 insertions(+), 7 deletions(-)
 create mode 100644 th03/math/subpixel.inc

diff --git a/th03/math/subpixel.hpp b/th03/math/subpixel.hpp
index 3e0b5d1e..f9b3f527 100644
--- a/th03/math/subpixel.hpp
+++ b/th03/math/subpixel.hpp
@@ -7,30 +7,37 @@ inline subpixel_t to_sp(float screen_v) {
 	return static_cast<subpixel_t>(screen_v * 16.0f);
 }
 
-class Subpixel {
+template <class T> class SubpixelBase {
 public:
 	// Code generation will require direct access to v, if performing
 	// arithmetic with a local variable...
-	subpixel_t v;
+	T v;
 
 	void operator +=(float screen_v) {
-		this->v += to_sp(screen_v);
+		this->v += static_cast<T>(to_sp(screen_v));
 	}
 
 	void operator -=(float screen_v) {
-		this->v -= to_sp(screen_v);
+		this->v -= static_cast<T>(to_sp(screen_v));
 	}
 
 	void operator =(float screen_v) {
-		v = to_sp(screen_v);
+		v = static_cast<T>(to_sp(screen_v));
 	}
 };
 
-struct SPPoint {
-	Subpixel x, y;
+template <class T> struct SPPointBase {
+	T x, y;
 
 	void set(float screen_x, float screen_y) {
 		x = screen_x;
 		y = screen_y;
 	}
 };
+
+// 16-bit (Q12.4)
+typedef SubpixelBase<subpixel_t> Subpixel;
+typedef SPPointBase<Subpixel> SPPoint;
+// 8-bit (Q4.4)
+typedef SubpixelBase<char> Subpixel8;
+typedef SPPointBase<Subpixel8> SPPoint8;
diff --git a/th03/math/subpixel.inc b/th03/math/subpixel.inc
new file mode 100644
index 00000000..2c46e5ef
--- /dev/null
+++ b/th03/math/subpixel.inc
@@ -0,0 +1,4 @@
+SPPoint8 struc
+	db ?	; x
+	db ?	; y
+SPPoint8 ends