Would You Like To Make A Game?

miamirb, 2/20/2017

Transcript

3. Making a Game • Who should make games, and why • Basics of Gosu • Making a character move
 • Game Design • Class Hierarchies • Developing Cat AI • Win Conditions
6. Gosu Basics
12. class Human < Sprite SPEED = 2 def update if window.button_down? Gosu::KbLeft self.x -= SPEED elsif window.button_down? Gosu::KbRight self.x += SPEED end if window.button_down? Gosu::KbUp self.y -= SPEED elsif window.button_down? Gosu::KbDown self.y += SPEED end end end Let’s get moving!
13. Little One Zedo Piper Autobiographical game
14. Autobiographical game Help Piper find his bowl
15. Autobiographical game Help Piper find his bowl Piper is easily spooked
16. Autobiographical game Help Piper find his bowl Piper is easily spooked Get near Piper to chase him
17. Win when Piper gets to food
22. Developing Cat AI • Start with “get near cat, cat runs somewhere randomly” • Cat doesn’t teleport, cat does have to travel through space between origin and destination • Break movement into discrete frames
23. Cat from a start point chooses a destination
24. We calculate delta x and delta y by subtracting each part of the coördinates from each other From there, we also calculate the angle theta by getting the arctangent of delta y over delta x
25. We also calculate the magnitude or total distance of the move with the pythagorean theorem
26. Since we have to split the movement into frames, we use the magnitude of the move and the cat speed to figure out how many frames the move should take. From that, we take the angle of the move, calculate the cosine and sine of the angle, and multiply those values by the speed to figure out how much we should move per frame in both axes
27. def distance_to(other) Math.sqrt((self.x - other.x)**2 + (self.y - other.y)**2) end
28. def update check_win case state when :waiting waiting_update when :running running_update end end
29. def waiting_update return if distance_to(human) > PROXIMITY take_off end
30. def take_off target_x = rand(window.width - image.width) target_y = rand(window.height - image.height) delta_x = x - target_x delta_y = y - target_y angle = Math.atan2(delta_y, delta_x) magnitude = Math.sqrt((delta_x ** 2) + (delta_y ** 2)) self.step_x = -SPEED * Math.cos(angle) self.step_y = -SPEED * Math.sin(angle) self.step_count = magnitude / SPEED self.state = :running end
31. def update check_win case state when :waiting waiting_update when :running running_update end end
32. def running_update if step_count <= 0 self.state = :waiting return end self.step_count -= 1 self.x += step_x self.y += step_y end
33. Win Conditions • Cat checks proximity to bowl • If close, win and quit (TODO: not that lol)
34. def check_win return if distance_to(bowl) > PROXIMITY puts "om nom nom nom you win" exit 0 end
35. live coding goes here • https://github.com/bkerley/catherder • https://github.com/jdiago/dodge_this