topdown shooting help

[Seth144k]

theres this really weird bug that happens where when you shoot, the bullets are basically still tracking the mouse and its not really working correctly. if somebody could please take a look at this and help, it would be greatly appreciated!

[knorke]

Code: Select all

function player:update(dt)
....
for _,v in ipairs(self.bullets) do
        local e = 200
        local mx, my = love.mouse.getPosition()
        local w = math.atan2(my-self.body:getY(), mx-self.body:getX())
        v.body:setX(v.body:getX()+math.cos(w)*e*dt)
        v.body:setY(v.body:getY()+math.sin(w)*e*dt)
    end

Each frame you are re-setting the position of each bullet.
That position is the mouse-position plus some rotation but that makes no sense, think about it:
The mouse position only matters when aiming the gun. After the bullet is fired it should just continue on its path, the mouse position has become irrelevant.
Just for completeness, movement of object is usually something like this:

Code: Select all

newX=oldX+speedX*dt
newY=oldY+speedY*dt

But you use box2D physics, so it is not necessary to update positions by hand.
Instead, use setLinearVelocity() to set the bullet's X&Y speed when it is created.

[darkfrei]

theres this really weird bug that happens where when you shoot, the bullets are basically still tracking the mouse and its not really working correctly. if somebody could please take a look at this and help, it would be greatly appreciated!

Just fixed this two functions in src/player.lua:

Code: Select all

function player:shoot(dt)
	local px, py = self.body:getPosition()
	local w = math.atan2(love.mouse.getY()-px, love.mouse.getX()-py)
	local bullet = {}
	bullet.body = love.physics.newBody(world, self.body:getX()+math.cos(w), self.body:getY()+math.sin(w))
	bullet.shape = love.physics.newCircleShape(10)
	bullet.fixture = love.physics.newFixture(bullet.body, bullet.shape)

--	local e = 200
	local speed = 200
	local mx, my = love.mouse.getPosition()
	local angle = math.atan2(my-self.body:getY(), mx-self.body:getX())
	bullet.vx = speed * math.cos (angle)
	bullet.vy = speed * math.sin (angle)


	table.insert(self.bullets, bullet)
end

function player:mousepressed(button)
	if button == 1 and pistol.unlocked then
		self:shoot(love.timer.getDelta())
	end
end

function player:update(dt)
	local rot = math.atan2(love.mouse.getY()-self.body:getY(), love.mouse.getX()-self.body:getX())

	for _, bullet in ipairs(self.bullets) do
--        local e = 200
--        local mx, my = love.mouse.getPosition()
--        local w = math.atan2(my-self.body:getY(), mx-self.body:getX())
		local dx = dt*bullet.vx
		local dy = dt*bullet.vy
		bullet.body:setX(bullet.body:getX()+dx)
		bullet.body:setY(bullet.body:getY()+dy)
	end

	-- rotate player towards the mouse
	self.body:setAngle(rot)
	local vx = 0
	local vy = 0
	if love.keyboard.isDown("a") then
		vx = self.speed * -1
	end
	if love.keyboard.isDown("d") then
		vx = self.speed * 1
	end
	if love.keyboard.isDown("w") then
		vy = self.speed * -1
	end
	if love.keyboard.isDown("s") then
		vy = self.speed * 1
	end
	self.body:setLinearVelocity(vx, vy)
end