[Maintenance] Templatize RGB and palette types for 4- and 8-bit components

Right, PC-98 hardware only supports 4 bits per RGB component, for a
total of 4,096 possible colors. The 8-bit RGB color values we've been
seeing throughout the later games are a master.lib extension, to allow
for more toning precision. Which TH01, with all its NIH syndrome,
doesn't use.

And yup, that means templates in the most basic header files… Since
that would have meant renaming *everything* to compile as C++, I simply
made these types exclusive to C++ code, thcrap style.

Part of P0066, funded by Keyblade Wiedling Neko and Splashman.

ReC98.h

@@ -14,17 +14,12 @@
 	palette_entry_rgb(fn); \
 	palette_show();
 
-// RGB color triple, used for the Palettes structure
-typedef union {
-	struct {
-		unsigned char r, g, b;
-	} c;
-	unsigned char v[3];
-} rgb_t;
-
-typedef struct {
-	rgb_t colors[16];
-} palette_t;
+#ifdef __cplusplus
+	// master.lib palettes use twice the bits per RGB component for more
+	// toning precision
+	typedef RGB<uint8_t> RGB8;
+	typedef Palette<RGB8> Palette8;
+#endif
 // ---------------------
 
 // Macros

pc98.h

@@ -15,6 +15,32 @@
 #define RES_Y 400
 #define ROW_SIZE (RES_X / 8)
 #define PLANE_SIZE (ROW_SIZE * RES_Y)
+
+#define COLOR_COUNT 16
+
+#pragma option -a1
+
+#ifdef __cplusplus
+	template <class ComponentType> union RGB {
+		struct {
+			ComponentType r, g, b;
+		} c;
+		ComponentType v[3];
+	};
+
+	template <class RGBType> struct Palette {
+		RGBType colors[COLOR_COUNT];
+	};
+
+	// The 16-color mode supports 4 bits per RGB component, for a total of
+	// 4,096 colors
+	typedef int8_t uint4_t;
+
+	typedef RGB<uint4_t> RGB4;
+	typedef Palette<RGB4> Palette4;
+#endif
+
+#pragma option -a.
 /// --------
 
 /// Keyboard

pc98.inc

@@ -16,4 +16,5 @@ RES_Y = 400
 ROW_SIZE = (RES_X / 8)
 ; Collides with master.lib's bfnt_entry_pat.asm
 ; PLANE_SIZE = (ROW_SIZE * RES_Y)
+COLOR_COUNT = 16
 ; ========

th03/main_01.cpp

@@ -5,6 +5,7 @@
 
 extern "C"
 {
+#include "platform.h"
 #include "pc98.h"
 #include "th03/sprite16.hpp"
 #include "th03/playfld.hpp"

th04/zunsoft.h

@@ -1,7 +1,7 @@
 // Copy of the palette used during the logo, to allow non-blocking fades in
 // contrast to master.lib's blocking palette_black_in() and palette_black_out()
 // functions. (Then again, master.lib has the PaletteTone global for that...)
-extern rgb_t zunsoft_palette[16];
+extern Palette8 zunsoft_palette;
 
 // Spawns [n] new explosions at the given screen-coordinate [origin] position.
 void pascal zunsoft_pyro_new(Point screen_origin, int n, char patnum_base);