My attempt to build modern tanks with old pygame.
After dealing with pygame, I consider myself overqualified for Google Maps.
DANGER: A LOT OF MATHS INVOLVING COS, SIN ANG TRIGONOMETRY FORMULAS
Most of the time working on this game was spent outside the laptop,
trying to remember trigonometry and geometry formulas from school
and correlating them to pygame coordinate system.
(which made my brain hurt,
still does)
- rotaing:
- rotating in pygame is happening not about center, but relative to top
left corner of the rectangle the image is in. While the image is rotating,
its rectangle is changing its size. To make it look like the image rotates about
its center you have to change the coordinates of the top left corner of the
image.
It's hard to read, it was even harder to code.
It was probably the most challenging part of the project.
- finding center of bottom image to put the tank top in
- tring to change the relative center of tank top -- the point the top is
rotating about
- finding exact spots where some of theimages should appear (like fire out
of the turret when the tank shoots)
- shooting shells involved rotating too. Despite already having code that
handled this kind of stuff quite good, the amount of small bugs accumulated
by that time and some inattention made this task increadibly hard.
It forced me to review my code a couple of hundred of times and do some major
refactoring
- time:
- creating time in the game, so that images (like explisions) can render
depending on that time
- collision:
- finding the tank area depending on its corners and checking if the point
lies inside that area. Pygame coordinate system made this task even harder.
def move_tank_bottom(self, list_of_objects):
radians = self.bottom_angle * math.pi / 180
add_x = math.cos(radians) * self.speed
add_y = math.sin(radians) * self.speed
new_bottom_angle = self.bottom_angle + self.turn_speed
new_x = self.x + add_x
new_y = self.y - add_y
if self.detect_collision(list_of_objects, self.find_corners(new_bottom_angle, new_x, new_y, self.width, self.height)):
new_x = self.x + add_x/2
new_y = self.y - add_y/2
new_bottom_angle = self.bottom_angle + self.turn_speed/2
if not self.detect_collision(list_of_objects, self.find_corners(new_bottom_angle, self.x, self.y, self.width, self.height) ):
self.bottom_angle = new_bottom_angle
if not self.detect_collision(list_of_objects, self.find_corners(self.bottom_angle, new_x, self.y, self.width, self.height) ):
self.x = new_x
if not self.detect_collision(list_of_objects, self.find_corners(self.bottom_angle, self.x, new_y, self.width, self.height) ):
self.y = new_y
def point_within_my_area(self, point_coordinates, corners_list):
#x1,y1###############x2,y2#
# #
# #
#x4,y4###############x3,y3#
## straight (line) formula => ax + bx + c = 0
## or (y1 -y2)x + (x2 - x1)y + (x1y2 - x2y1) = 0
x = point_coordinates[0]
y = point_coordinates[1]
for i in range(len(corners_list)):
x1 = corners_list[i][0]
y1 = corners_list[i][1]
next_i = (i + 1) % (len(corners_list))
x2 = corners_list[next_i][0]
y2 = corners_list[next_i][1]
a = y1 - y2
b = x2 - x1
c = x1 * y2 - x2 * y1
if a * x + b * y + c < 0: ## checking if the point lies on the right side
return False ## of every line, which would mean it's inside
return True ## the area
def detect_collision(self, list_of_objects, my_corners_list):
for obj in list_of_objects:
if obj != self:
if self.it_within_my_area(obj, my_corners_list) or self.me_within_its_area(obj, my_corners_list ):
return True
return FalseAll in all, even though there were probably thousands of libraries better suited for game developing at that point, I'm incredibly glad I encountered all of those challenges and were able to persevere.
Of course, I wouldn't be able to do this by myself, especially at the start, when this huge pile of problems seemed to be impossible to solve. For guidence and assistence, I'd like to thank all of my mentors and especially Jonathan Martin @nybblr.