TSA: Map POV/D-pad inputs to the X/Y axes. (Non-DirectInput mode) [V]

Essentially allowing D-pad controls for all games. The WinMM version
also covers controls in the resolution dialogs of TH14 and later.

Funded by an anonymous person.

thcrap_tsa/src/input.c

@@ -0,0 +1,123 @@
+/**
+  * Touhou Community Reliant Automatic Patcher
+  * Team Shanghai Alice support plugin
+  *
+  * ----
+  *
+  * Input detours. Currently providing POV hat → X/Y axis mapping.
+  */
+
+#include <thcrap.h>
+#include <stdbool.h>
+#include <math.h>
+
+// 180° / PI
+#define DEG_TO_RAD(x) ((x) * 0.0174532925199432957692369076848f)
+
+/// WinMM joystick API
+/// ------------------
+/*
+ * Thankfully, the joystick IDs are consistent and always refer to the same
+ * model of joystick, even across hot-swaps if you temporarily plug a
+ * different model into the same USB port. Even better for our purposes of
+ * remapping POV hats to the X/Y axes, the API also treats separate but
+ * identical controllers as matching the same ID.
+ *
+ * The "Preferred device" for older applications that can be set in the
+ * control panel will always be assigned to ID 0, even if it was unplugged in
+ * the meantime. Setting the Preferred device to (none) will not automatically
+ * re-assign another controller to ID 0.
+ *
+ * Also, IDs are always bound to the same USB port for the lifetime of a
+ * process, and controllers won't be recognized at all if they are hot-swapped
+ * into a different port than the one they were in before.
+ */
+
+typedef MMRESULT __stdcall joyGetPosEx_type(
+	UINT uJoyID,
+	JOYINFOEX *pji
+);
+
+DETOUR_CHAIN_DEF(joyGetPosEx);
+
+ typedef struct
+{
+	uint32_t min;
+	uint32_t max;
+} range_t;
+
+// joyGetDevCaps() will necessarily be slower
+typedef struct
+{
+	// joyGetPosEx() will return bogus values on joysticks without a POV, so
+	// we must check if we even have one.
+	bool initialized;
+	bool has_pov;
+	range_t range_x;
+	range_t range_y;
+} winmm_joy_caps_t;
+
+winmm_joy_caps_t *joy_info = NULL;
+
+MMRESULT __stdcall my_joyGetPosEx(UINT uJoyID, JOYINFOEX *pji)
+{
+	if(!pji) {
+		return MMSYSERR_INVALPARAM;
+	}
+	pji->dwFlags |= JOY_RETURNPOV;
+
+	MMRESULT ret_pos = chain_joyGetPosEx(uJoyID, pji);
+	if(ret_pos != JOYERR_NOERROR) {
+		return ret_pos;
+	}
+
+	winmm_joy_caps_t *jc = &joy_info[uJoyID];
+	if(!jc->initialized) {
+		JOYCAPSW caps;
+		MMRESULT ret_caps = joyGetDevCapsW(uJoyID, &caps, sizeof(caps));
+		assert(ret_caps == JOYERR_NOERROR);
+
+		jc->initialized = true;
+		jc->has_pov = caps.wCaps & JOYCAPS_HASPOV;
+		jc->range_x.min = caps.wXmin;
+		jc->range_x.max = caps.wXmax;
+		jc->range_y.min = caps.wYmin;
+		jc->range_y.max = caps.wYmax;
+	} else if(!jc->has_pov) {
+		return ret_pos;
+	}
+
+	if(pji->dwPOV != JOY_POVCENTERED) {
+		uint32_t x_center = (jc->range_x.max - jc->range_x.min) / 2;
+		uint32_t y_center = (jc->range_y.max - jc->range_y.min) / 2;
+
+		float angle_deg = pji->dwPOV / 100.0f;
+		float angle_rad = DEG_TO_RAD(angle_deg);
+		// POV values ≠ unit circle angles, so...
+		float angle_sin = 1.0f - cosf(angle_rad);
+		float angle_cos = sinf(angle_rad) + 1.0f;
+		pji->dwXpos = (DWORD)(jc->range_x.min + (angle_cos * x_center));
+		pji->dwYpos = (DWORD)(jc->range_y.min + (angle_sin * y_center));
+	}
+	return ret_pos;
+}
+/// ------------------
+
+__declspec(dllexport) void input_mod_detour(void)
+{
+	// This conveniently returns the number of *possible* joysticks, *not* the
+	// number of joysticks currently connected.
+	UINT num_devs = joyGetNumDevs();
+	if(num_devs == 0) {
+		return;
+	}
+	joy_info = (winmm_joy_caps_t*)calloc(sizeof(winmm_joy_caps_t), num_devs);
+	if(!joy_info) {
+		return;
+	}
+
+	detour_chain("winmm.dll", 1,
+		"joyGetPosEx", my_joyGetPosEx, &chain_joyGetPosEx,
+		NULL
+	);
+}

thcrap_tsa/thcrap_tsa.vcxproj

@@ -27,7 +27,7 @@
     <Link>
       <SubSystem>Windows</SubSystem>
       <ModuleDefinitionFile>thcrap_tsa.def</ModuleDefinitionFile>
-      <AdditionalDependencies>comctl32.lib;shlwapi.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <AdditionalDependencies>comctl32.lib;shlwapi.lib;winmm.lib;%(AdditionalDependencies)</AdditionalDependencies>
       <AdditionalDependencies Condition="$(UseDebugLibraries)==true">thcrap_d.lib;libpng16_d.lib;%(AdditionalDependencies)</AdditionalDependencies>
       <AdditionalDependencies Condition="$(UseDebugLibraries)!=true">thcrap.lib;libpng16.lib;%(AdditionalDependencies)</AdditionalDependencies>
     </Link>
@@ -42,6 +42,7 @@
     <ClCompile Include="src\gentext.cpp">
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
     </ClCompile>
+    <ClCompile Include="src\input.c" />
     <ClCompile Include="src\layout.c" />
     <ClCompile Include="src\music.c" />
     <ClCompile Include="src\png_ex.c" />