Pygame update display

Question

I am writing a program where sensors(the white circles) are moving on the map to cover things. I counted the number of covered things(the small white dots), it's the right number. But the old covered things and sensor(white circles) are still on the screen. How can I update the display so that only newest objects are on the screen(no red dots should be in the circle path, and the circle path history should not be displayed).

Here is my display code. It gets called every frame.

    def _drawMap(self,ticks):
    # draw the map
    # draw the boundary
    boundary = self._polygonCoordinationTransformation(self.data.boundary_polygon_list)
    pygame.draw.polygon(self.screen, BLUE, boundary, LINEWIDTH)

    # draw obstacles
    for polygon in self.data.obstacles_list:
        polygon = self._polygonCoordinationTransformation(polygon)
        pygame.draw.polygon(self.screen, BLUE, polygon, LINEWIDTH)

    # draw agents
    self._executeSegment(self.agentsGroup.sprites()[0],(5,10),ticks)
    for agent in self.agentsGroup:
        pygame.draw.circle(self.screen, WHITE, agent.rect.center, self.data.sensor_range * self.scaleForMap,LINEWIDTH)

    # draw items
    self.updateUnseenItems()
    for itemObj in self.unseenItemGroup:
        pygame.draw.rect(self.screen, RED, itemObj, LINEWIDTH)

score 3 · Accepted Answer · edited May 23 '17 at 11:53

3

In pygame you can't clear the screen - instead you re-blit the background back over the top of what is currently there.

There's an excellent answer to the same question here.

Edit: In your case you probably want to fill the screen in with black:

screen.fill( (0,0,0) )

edited May 23 '17 at 11:53

Community

1
1

answered Mar 11 '17 at 23:28

Ari Cooper-Davis

3,374
3
26
43

2

Thank you! I added this as the first line of function in the qustion, and now it's working properly. – Bowen Kuang Mar 11 '17 at 23:33

Pygame update display

1 Answers1