From 3a59d9cb833bcfa41f5eaa222143e763d0bd0ed3 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Tue, 25 Apr 2023 03:24:03 -0700
Subject: [PATCH] Res: Add script for doing fake analog input by PWM-ing the
 d-pad

---
 res/scripts/analog-interpolate.lua | 77 ++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 res/scripts/analog-interpolate.lua

diff --git a/res/scripts/analog-interpolate.lua b/res/scripts/analog-interpolate.lua
new file mode 100644
index 000000000..d9d985a20
--- /dev/null
+++ b/res/scripts/analog-interpolate.lua
@@ -0,0 +1,77 @@
+local state = {}
+state.period = 4
+state.phase = 0
+state.x = 0
+state.y = 0
+
+function state.update()
+	state.phase = state.phase + 1
+	if state.phase == state.period then
+		state.phase = 0
+	end
+	if state.phase == 0 then
+		if input.activeGamepad then
+			local x = input.activeGamepad.axes[1] / 30000
+			local y = input.activeGamepad.axes[2] / 30000
+			-- Map the circle onto a square, since we don't
+			-- want to have a duty of 1/sqrt(2) on the angles
+			local theta = math.atan(y, x)
+			local r = math.sqrt(x * x + y * y)
+			if theta < math.pi * -3 / 4 then
+				r = -r / math.cos(theta)
+			elseif theta < math.pi * -1 / 4 then
+				r = -r / math.sin(theta)
+			elseif theta < math.pi * 1 / 4 then
+				r = r / math.cos(theta)
+			elseif theta < math.pi * 3 / 4 then
+				r = r / math.sin(theta)
+			elseif theta < math.pi * 5 / 4 then
+				r = -r / math.cos(theta)
+			end
+			state.x = math.cos(theta) * r
+			state.y = math.sin(theta) * r
+		else
+			state.x = 0
+			state.y = 0
+		end
+	end
+end
+
+function state.read()
+	emu:clearKeys(0xF0)
+	if math.floor(math.abs(state.x) * state.period) > state.phase then
+		if state.x > 0 then
+			emu:addKey(C.GB_KEY.RIGHT)
+		else
+			emu:addKey(C.GB_KEY.LEFT)
+		end
+	end
+	if math.floor(math.abs(state.y) * state.period) > state.phase then
+		if state.y > 0 then
+			emu:addKey(C.GB_KEY.DOWN)
+		else
+			emu:addKey(C.GB_KEY.UP)
+		end
+	end
+
+	-- The duty cycle approach can confuse menus and the like,
+	-- so the POV hat setting should force a direction on
+	if input.activeGamepad and #input.activeGamepad.hats > 0 then
+		local hat = input.activeGamepad.hats[1]
+		if hat & C.INPUT_DIR.UP ~= 0 then
+			emu:addKey(C.GB_KEY.UP)
+		end
+		if hat & C.INPUT_DIR.DOWN ~= 0 then
+			emu:addKey(C.GB_KEY.DOWN)
+		end
+		if hat & C.INPUT_DIR.LEFT ~= 0 then
+			emu:addKey(C.GB_KEY.LEFT)
+		end
+		if hat & C.INPUT_DIR.RIGHT ~= 0 then
+			emu:addKey(C.GB_KEY.RIGHT)
+		end
+	end
+end
+
+callbacks:add("frame", state.update)
+callbacks:add("keysRead", state.read)