Free camera script for Silent Hill in BizHawk

sh_freelook.lua

-- Free camera script for Silent Hill in BizHawk
-- Only tested with the North American version
--
-- L3+R3 to toggle on and off
--
-- Submit improvements at https://gist.github.com/samfromcadott/
-- Fell free to adapt this for other games
--
-- Copyright 2021 Sam Jackson
-----------------------------

-- Options
-----------------------------

lookSpeed = 15
moveSpeed = 200

-- Memory addresses
-----------------------------

harryAddress = {
	x = 0x0BA024,
	y = 0x0BA028,
	z = 0x0BA02C,
	yaw = 0x0BA032
}

camAddress = {
	pitch = 0x0B9D88,
	yaw = 0x0B9D8A,
	roll = 0x0B9D8C,
	x = 0x0B9D20,
	y = 0x0B9D24,
	z = 0x0B9D28
}


function radian(angle)
	-- Converts from Silent Hill's angles (4096 per rotation) to radians
	return angle * math.pi/2048

end

function initCam()
	return {
		pitch = memory.read_u16_le(camAddress.pitch),
		yaw = memory.read_u16_le(camAddress.yaw),
		roll = memory.read_u16_le(camAddress.roll),
		x = memory.read_s32_le(camAddress.x),
		y = memory.read_s32_le(camAddress.y),
		z = memory.read_s32_le(camAddress.z)
	}

end

function initHarry()
	return {
		x = memory.read_s32_le(harryAddress.x),
		y = memory.read_s32_le(harryAddress.y),
		z = memory.read_s32_le(harryAddress.z),
		yaw = memory.read_u16_le(harryAddress.yaw)
	}

end

function switchMode()
	-- Check if the player is trying to toggle free look
	if joypad.getimmediate()["P1 L3"] and joypad.getimmediate()["P1 R3"] then
		freeCam = not freeCam
		camera = initCam()
		if freeCam then
			harry = initHarry()
		end

	end

end

function lockHarry()
	-- Keep Harry's location and yaw constant so he doesn't screw up stuff
	memory.write_s32_le(harryAddress.x, harry.x)
	memory.write_s32_le(harryAddress.y, harry.y)
	memory.write_s32_le(harryAddress.z, harry.z)
	memory.write_u16_le(harryAddress.yaw, harry.yaw)

end

function move()
	-- Update the camera location using left joystick
	local front = {x = 0.0, y = 0.0, z = 0.0}
	local right = {x = 0.0, y = 0.0, z = 0.0}
	local up = {x = 0.0, y = 1.0, z = 0.0} -- Silent Hill uses y+ as the up direction

	-- Create the facing vector
	front.x = math.sin(radian(camera.yaw))*math.cos(radian(camera.pitch))
	front.y = math.sin(radian(camera.pitch))
	front.z = math.cos(radian(camera.yaw))*math.cos(radian(camera.pitch))

	-- The right vector should be the cross product of the front and the up vector
	right.x = front.y*up.z - front.z*up.y
	right.y = front.y*up.x - front.x*up.z
	right.z = front.x*up.y - front.y*up.x

	-- Move camera
	camera.x = camera.x + (front.x * moveSpeed) * getJoyStick('L').y
	camera.y = camera.y - (front.y * moveSpeed) * getJoyStick('L').y
	camera.z = camera.z + (front.z * moveSpeed) * getJoyStick('L').y

	camera.x = camera.x - (right.x * moveSpeed) * getJoyStick('L').x
	camera.y = camera.y + (right.y * moveSpeed) * getJoyStick('L').x
	camera.z = camera.z - (right.z * moveSpeed) * getJoyStick('L').x

	memory.write_s32_le(camAddress.x, camera.x)
	memory.write_s32_le(camAddress.y, camera.y)
	memory.write_s32_le(camAddress.z, camera.z)

end

function look()
	-- Update the camera rotation using right joystick
	camera.pitch = (camera.pitch + getJoyStick('R').y * lookSpeed)%4096
	camera.yaw = (camera.yaw + getJoyStick('R').x * lookSpeed)%4096
	camera.roll = 0

	memory.write_u16_le(camAddress.pitch, camera.pitch)
	memory.write_u16_le(camAddress.yaw, camera.yaw)
	memory.write_u16_le(camAddress.roll, camera.roll)

end

function getJoyStick(stick)
	-- Gets the direction the joystick is moved
	-- stick argument should be 'L' or 'R'
	local dir = {x = 0, y = 0}
	if input.get()["X1 "..stick.."StickUp"] then
		dir.y = 1
	elseif input.get()["X1 "..stick.."StickDown"] then
		dir.y = -1
	end

	if input.get()["X1 "..stick.."StickRight"] then
		dir.x = 1
	elseif input.get()["X1 "..stick.."StickLeft"] then
		dir.x = -1
	end

	return dir

end

-- Start up
-----------------------------

camera = initCam()
harry = initHarry()

freeCam = false

-- Main loop
-----------------------------

while true do
	switchMode()

	if freeCam then
		lockHarry()
		look()
		move()
	end

	emu.frameadvance()

end