This is love2d code, but it should help with the logic & math part.
-- Tutorial 1: Hamster Ball
-- Add an image to the game and move it around using
-- the arrow keys.
-- compatible with löve 0.6.0 and up
function love.load()
hamster = love.graphics.newImage("hamster.png")
x = 50
y = 50
speed = 100
end
function love.update(dt)
if love.keyboard.isDown("right") then
x = x + (speed * dt)
elseif love.keyboard.isDown("left") then
x = x - (speed * dt)
end
if love.keyboard.isDown("down") then
y = y + (speed * dt)
elseif love.keyboard.isDown("up") then
y = y - (speed * dt)
end
end
function love.draw()
love.graphics.draw(hamster, x, y)
end
That is basic code on how to move an image around with the WASD keys.