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  • Making a perfect map (not tile-based)

    - by Sri Harsha Chilakapati
    I would like to make a map system as in the GameMaker and the latest code is here. I've searched a lot in google and all of them resulted in tutorials about tile-maps. As tile maps do not fit for every type of game and GameMaker uses tiles for a different purpose, I want to make a "Sprite Based" map. The major problem I had experienced was collision detection being slow for large maps. So I wrote a QuadTree class here and the collision detection is fine upto 50000 objects in the map without PixelPerfect collision detection and 30000 objects with PixelPerferct collisions enabled. Now I need to implement the method "isObjectCollisionFree(float x, float y, boolean solid, GObject obj)". The existing implementation is becoming slow in Platformer games and I need suggestions on improvement. The current Implementation: /** * Checks if a specific position is collision free in the map. * * @param x The x-position of the object * @param y The y-position of the object * @param solid Whether to check only for solid object * @param object The object ( used for width and height ) * @return True if no-collision and false if it collides. */ public static boolean isObjectCollisionFree(float x, float y, boolean solid, GObject object){ boolean bool = true; Rectangle bounds = new Rectangle(Math.round(x), Math.round(y), object.getWidth(), object.getHeight()); ArrayList<GObject> collidables = quad.retrieve(bounds); for (int i=0; i<collidables.size(); i++){ GObject obj = collidables.get(i); if (obj.isSolid()==solid && obj != object){ if (obj.isAlive()){ if (bounds.intersects(obj.getBounds())){ bool = false; if (Global.USE_PIXELPERFECT_COLLISION){ bool = !GUtil.isPixelPerfectCollision(x, y, object.getAnimation().getBufferedImage(), obj.getX(), obj.getY(), obj.getAnimation().getBufferedImage()); } break; } } } } return bool; } Thanks.

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  • Bounding volume hierarchy - linked nodes (linear model)

    - by teodron
    The scenario A chain of points: (Pi)i=0,N where Pi is linked to its direct neighbours (Pi-1 and Pi+1). The goal: perform efficient collision detection between any two, non-adjacent links: (PiPi+1) vs. (PjPj+1). The question: it's highly recommended in all works treating this subject of collision detection to use a broad phase and to implement it via a bounding volume hierarchy. For a chain made out of Pi nodes, it can look like this: I imagine the big blue sphere to contain all links, the green half of them, the reds a quarter and so on (the picture is not accurate, but it's there to help understand the question). What I do not understand is: How can such a hierarchy speed up computations between segments collision pairs if one has to update it for a deformable linear object such as a chain/wire/etc. each frame? More clearly, what is the actual principle of collision detection broad phases in this particular case/ how can it work when the actual computation of bounding spheres is in itself a time consuming task and has to be done (since the geometry changes) in each frame update? I think I am missing a key point - if we look at the picture where the chain is in a spiral pose, we see that most spheres are already contained within half of others or do intersect them.. it's odd if this is the way it should work.

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  • 5 Free Intrusion Detection Softwares (IDS)

    Tools and Utilities to Monitor Your Network For Suspicious or Malicious Activity Snort for Windows Snort is an open source network intrusion detection system, capable of performing real-time traffi... [Author: Alam Je - Computers and Internet - March 24, 2010]

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  • Temporary Post Used For Theme Detection (407391ef-2a52-4f66-86ce-ae972978f67d – 3bfe001a-32de-4114-a6b4-4005b770f6d7)

    - by Kavitha
    This is a temporary post that was not deleted. Please delete this manually. (de29367c-6ce5-4b1f-8b4a-a859ecde27a9 – 3bfe001a-32de-4114-a6b4-4005b770f6d7) This article titled,Temporary Post Used For Theme Detection (407391ef-2a52-4f66-86ce-ae972978f67d – 3bfe001a-32de-4114-a6b4-4005b770f6d7), was originally published at Tech Dreams. Grab our rss feed or fan us on Facebook to get updates from us.

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  • Temporary Post Used For Theme Detection (be923fa6-3c12-49cc-ae55-c5fc02e681cb – 3bfe001a-32de-4114-a6b4-4005b770f6d7)

    - by Kavitha
    This is a temporary post that was not deleted. Please delete this manually. (19a474df-a007-467b-96e1-46716e6fae03 – 3bfe001a-32de-4114-a6b4-4005b770f6d7) This article titled,Temporary Post Used For Theme Detection (be923fa6-3c12-49cc-ae55-c5fc02e681cb – 3bfe001a-32de-4114-a6b4-4005b770f6d7), was originally published at Tech Dreams. Grab our rss feed or fan us on Facebook to get updates from us.

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  • Collision Detection for 2D

    - by Bhaskar
    I am working on a simple game, where I need to do a collision detection of two Texture2D. The code I have written is: bool perPixelCollission = false; Texture2D texture1 = sprite1.Texture; Texture2D texture2 = sprite1.Texture; Vector2 position1 = new Vector2(sprite1.CurrentScope.X, sprite1.CurrentScope.Y); Vector2 position2 = new Vector2(sprite2.CurrentScope.X, sprite2.CurrentScope.Y); uint[] bitsA = new uint[texture1.Width * texture1.Height]; uint[] bitsB = new uint[texture2.Width * texture2.Height]; Rectangle texture1Rectangle = new Rectangle(Convert.ToInt32(position1.X), Convert.ToInt32(position1.Y), texture1.Width, texture1.Height); Rectangle texture2Rectangle = new Rectangle(Convert.ToInt32(position2.X), Convert.ToInt32(position2.Y), texture2.Width, texture2.Height); texture1.GetData<uint>(bitsA); texture2.GetData<uint>(bitsB); int x1 = Math.Max(texture1Rectangle.X, texture2Rectangle.X); int x2 = Math.Min(texture1Rectangle.X + texture1Rectangle.Width, texture2Rectangle.X + texture2Rectangle.Width); int y1 = Math.Max(texture1Rectangle.Y, texture2Rectangle.Y); int y2 = Math.Min(texture1Rectangle.Y + texture1Rectangle.Height, texture2Rectangle.Y + texture2Rectangle.Height); for (int y = y1; y < y2; ++y) { for (int x = x1; x < x2; ++x) { if (((bitsA[(x - texture1Rectangle.X) + (y - texture1Rectangle.Y) * texture1Rectangle.Width] & 0xFF000000) >> 24) > 20 && ((bitsB[(x - texture2Rectangle.X) + (y - texture2Rectangle.Y) * texture2Rectangle.Width] & 0xFF000000) >> 24) > 20) { perPixelCollission = true; break; } } // Reduce amount of looping by breaking out of this. if (perPixelCollission) { break; } } return perPixelCollission; But this code is really making the game slow. Where can I get some very good collision detection tutorial and code? What is wrong in this code?

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  • Temporary Post Used For Theme Detection (2c152d1d-b299-442d-8586-f901f2ae7155 – 3bfe001a-32de-4114-a6b4-4005b770f6d7)

    - by Gopinath
    This is a temporary post that was not deleted. Please delete this manually. (095f0c04-8773-4c8c-8925-410f694fb4f4 – 3bfe001a-32de-4114-a6b4-4005b770f6d7) This article titled,Temporary Post Used For Theme Detection (2c152d1d-b299-442d-8586-f901f2ae7155 – 3bfe001a-32de-4114-a6b4-4005b770f6d7), was originally published at Tech Dreams. Grab our rss feed or fan us on Facebook to get updates from us.

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  • Browser Detection, do's and don'ts. Is this ok?

    - by JCOC611
    So, I understand that browser detection (ie. navigator.userAgent) shouldn't be used to decide which object method/property to use; yet, I want to set some simple CSS with JavaScript depending on the browser. However, it's not enough to justify a completely new StyleSheet. So is it OK if I use Browser Detection to decide what CSS to apply to an element? EDIT Ok, let's be SPECIFIC. I'm talking about a text-shadow inside a button (<input type="button"/>) The text inside the button isn't vertically centered in all browsers, so I tweak this with JS depending on the browser.

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  • Add collison detection to enemy sprites?

    - by xBroak
    i'd like to add the same collision detection used by the player sprite to the enemy sprites or 'creeps' ive added all the relevant code I can see yet collisons are still not being detected and handled, please find below the class, I have no idea what is wrong currently, the list of walls to collide with is 'wall_list' import pygame import pauseScreen as dm import re from pygame.sprite import Sprite from pygame import Rect, Color from random import randint, choice from vec2d import vec2d from simpleanimation import SimpleAnimation import displattxt black = (0,0,0) white = (255,255,255) blue = (0,0,255) green = (101,194,151) global currentEditTool currentEditTool = "Tree" global editMap editMap = False open('MapMaker.txt', 'w').close() def draw_background(screen, tile_img): screen.fill(black) img_rect = tile_img.get_rect() global rect rect = img_rect nrows = int(screen.get_height() / img_rect.height) + 1 ncols = int(screen.get_width() / img_rect.width) + 1 for y in range(nrows): for x in range(ncols): img_rect.topleft = (x * img_rect.width, y * img_rect.height) screen.blit(tile_img, img_rect) def changeTool(): if currentEditTool == "Tree": None elif currentEditTool == "Rock": None def pauseGame(): red = 255, 0, 0 green = 0,255, 0 blue = 0, 0,255 screen.fill(black) pygame.display.update() if editMap == False: choose = dm.dumbmenu(screen, [ 'Resume', 'Enable Map Editor', 'Quit Game'], 64,64,None,32,1.4,green,red) if choose == 0: print("hi") elif choose ==1: global editMap editMap = True elif choose ==2: print("bob") elif choose ==3: print("bob") elif choose ==4: print("bob") else: None else: choose = dm.dumbmenu(screen, [ 'Resume', 'Disable Map Editor', 'Quit Game'], 64,64,None,32,1.4,green,red) if choose == 0: print("Resume") elif choose ==1: print("Dis ME") global editMap editMap = False elif choose ==2: print("bob") elif choose ==3: print("bob") elif choose ==4: print("bob") else: None class Wall(pygame.sprite.Sprite): # Constructor function def __init__(self,x,y,width,height): pygame.sprite.Sprite.__init__(self) self.image = pygame.Surface([width, height]) self.image.fill(green) self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x class insertTree(pygame.sprite.Sprite): def __init__(self,x,y,width,height, typ): pygame.sprite.Sprite.__init__(self) self.image = pygame.image.load("images/map/tree.png").convert() self.image.set_colorkey(white) self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x class insertRock(pygame.sprite.Sprite): def __init__(self,x,y,width,height, typ): pygame.sprite.Sprite.__init__(self) self.image = pygame.image.load("images/map/rock.png").convert() self.image.set_colorkey(white) self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x class Creep(pygame.sprite.Sprite): """ A creep sprite that bounces off walls and changes its direction from time to time. """ change_x=0 change_y=0 def __init__( self, screen, creep_image, explosion_images, field, init_position, init_direction, speed): """ Create a new Creep. screen: The screen on which the creep lives (must be a pygame Surface object, such as pygame.display) creep_image: Image (surface) object for the creep explosion_images: A list of image objects for the explosion animation. field: A Rect specifying the 'playing field' boundaries. The Creep will bounce off the 'walls' of this field. init_position: A vec2d or a pair specifying the initial position of the creep on the screen. init_direction: A vec2d or a pair specifying the initial direction of the creep. Must have an angle that is a multiple of 45 degres. speed: Creep speed, in pixels/millisecond (px/ms) """ Sprite.__init__(self) self.screen = screen self.speed = speed self.field = field self.rect = creep_image.get_rect() # base_image holds the original image, positioned to # angle 0. # image will be rotated. # self.base_image = creep_image self.image = self.base_image self.explosion_images = explosion_images # A vector specifying the creep's position on the screen # self.pos = vec2d(init_position) # The direction is a normalized vector # self.direction = vec2d(init_direction).normalized() self.state = Creep.ALIVE self.health = 15 def is_alive(self): return self.state in (Creep.ALIVE, Creep.EXPLODING) def changespeed(self,x,y): self.change_x+=x self.change_y+=y def update(self, time_passed, walls): """ Update the creep. time_passed: The time passed (in ms) since the previous update. """ if self.state == Creep.ALIVE: # Maybe it's time to change the direction ? # self._change_direction(time_passed) # Make the creep point in the correct direction. # Since our direction vector is in screen coordinates # (i.e. right bottom is 1, 1), and rotate() rotates # counter-clockwise, the angle must be inverted to # work correctly. # self.image = pygame.transform.rotate( self.base_image, -self.direction.angle) # Compute and apply the displacement to the position # vector. The displacement is a vector, having the angle # of self.direction (which is normalized to not affect # the magnitude of the displacement) # displacement = vec2d( self.direction.x * self.speed * time_passed, self.direction.y * self.speed * time_passed) self.pos += displacement # When the image is rotated, its size is changed. # We must take the size into account for detecting # collisions with the walls. # self.image_w, self.image_h = self.image.get_size() bounds_rect = self.field.inflate( -self.image_w, -self.image_h) if self.pos.x < bounds_rect.left: self.pos.x = bounds_rect.left self.direction.x *= -1 elif self.pos.x > bounds_rect.right: self.pos.x = bounds_rect.right self.direction.x *= -1 elif self.pos.y < bounds_rect.top: self.pos.y = bounds_rect.top self.direction.y *= -1 elif self.pos.y > bounds_rect.bottom: self.pos.y = bounds_rect.bottom self.direction.y *= -1 # collision detection old_x=bounds_rect.left new_x=old_x+self.direction.x bounds_rect.left = new_x # hit a wall? collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes bounds_rect.left=old_x old_y=self.pos.y new_y=old_y+self.direction.y self.pos.y = new_y collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes self.pos.y=old_y elif self.state == Creep.EXPLODING: if self.explode_animation.active: self.explode_animation.update(time_passed) else: self.state = Creep.DEAD self.kill() elif self.state == Creep.DEAD: pass #------------------ PRIVATE PARTS ------------------# # States the creep can be in. # # ALIVE: The creep is roaming around the screen # EXPLODING: # The creep is now exploding, just a moment before dying. # DEAD: The creep is dead and inactive # (ALIVE, EXPLODING, DEAD) = range(3) _counter = 0 def _change_direction(self, time_passed): """ Turn by 45 degrees in a random direction once per 0.4 to 0.5 seconds. """ self._counter += time_passed if self._counter > randint(400, 500): self.direction.rotate(45 * randint(-1, 1)) self._counter = 0 def _point_is_inside(self, point): """ Is the point (given as a vec2d) inside our creep's body? """ img_point = point - vec2d( int(self.pos.x - self.image_w / 2), int(self.pos.y - self.image_h / 2)) try: pix = self.image.get_at(img_point) return pix[3] > 0 except IndexError: return False def _decrease_health(self, n): """ Decrease my health by n (or to 0, if it's currently less than n) """ self.health = max(0, self.health - n) if self.health == 0: self._explode() def _explode(self): """ Starts the explosion animation that ends the Creep's life. """ self.state = Creep.EXPLODING pos = ( self.pos.x - self.explosion_images[0].get_width() / 2, self.pos.y - self.explosion_images[0].get_height() / 2) self.explode_animation = SimpleAnimation( self.screen, pos, self.explosion_images, 100, 300) global remainingCreeps remainingCreeps-=1 if remainingCreeps == 0: print("all dead") def draw(self): """ Blit the creep onto the screen that was provided in the constructor. """ if self.state == Creep.ALIVE: # The creep image is placed at self.pos. To allow for # smooth movement even when the creep rotates and the # image size changes, its placement is always # centered. # self.draw_rect = self.image.get_rect().move( self.pos.x - self.image_w / 2, self.pos.y - self.image_h / 2) self.screen.blit(self.image, self.draw_rect) # The health bar is 15x4 px. # health_bar_x = self.pos.x - 7 health_bar_y = self.pos.y - self.image_h / 2 - 6 self.screen.fill( Color('red'), (health_bar_x, health_bar_y, 15, 4)) self.screen.fill( Color('green'), ( health_bar_x, health_bar_y, self.health, 4)) elif self.state == Creep.EXPLODING: self.explode_animation.draw() elif self.state == Creep.DEAD: pass def mouse_click_event(self, pos): """ The mouse was clicked in pos. """ if self._point_is_inside(vec2d(pos)): self._decrease_health(3) #begin new player class Player(pygame.sprite.Sprite): change_x=0 change_y=0 frame = 0 def __init__(self,x,y): pygame.sprite.Sprite.__init__(self) # LOAD PLATER IMAGES # Set height, width self.images = [] for i in range(1,17): img = pygame.image.load("images/player/" + str(i)+".png").convert() #player images img.set_colorkey(white) self.images.append(img) self.image = self.images[0] self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x self.health = 15 self.image_w, self.image_h = self.image.get_size() health_bar_x = self.rect.x - 7 health_bar_y = self.rect.y - self.image_h / 2 - 6 screen.fill( Color('red'), (health_bar_x, health_bar_y, 15, 4)) screen.fill( Color('green'), ( health_bar_x, health_bar_y, self.health, 4)) def changespeed(self,x,y): self.change_x+=x self.change_y+=y def _decrease_health(self, n): """ Decrease my health by n (or to 0, if it's currently less than n) """ self.health = max(0, self.health - n) if self.health == 0: self._explode() def update(self,walls): # collision detection old_x=self.rect.x new_x=old_x+self.change_x self.rect.x = new_x # hit a wall? collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes self.rect.x=old_x old_y=self.rect.y new_y=old_y+self.change_y self.rect.y = new_y collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes self.rect.y=old_y # right to left if self.change_x < 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 # Grab the image, divide by 4 # every 4 frames. self.image = self.images[self.frame//4] # Move left to right. # images 4...7 instead of 0...3. if self.change_x > 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 self.image = self.images[self.frame//4+4] if self.change_y > 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 self.image = self.images[self.frame//4+4+4] if self.change_y < 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 self.image = self.images[self.frame//4+4+4+4] score = 0 # initialize pyGame pygame.init() # 800x600 sized screen global screen screen = pygame.display.set_mode([800, 600]) screen.fill(black) #bg_tile_img = pygame.image.load('images/map/grass.png').convert_alpha() #draw_background(screen, bg_tile_img) #pygame.display.flip() # Set title pygame.display.set_caption('Test') #background = pygame.Surface(screen.get_size()) #background = background.convert() #background.fill(black) # Create the player player = Player( 50,50 ) player.rect.x=50 player.rect.y=50 movingsprites = pygame.sprite.RenderPlain() movingsprites.add(player) # Make the walls. (x_pos, y_pos, width, height) global wall_list wall_list=pygame.sprite.RenderPlain() wall=Wall(0,0,10,600) # left wall wall_list.add(wall) wall=Wall(10,0,790,10) # top wall wall_list.add(wall) #wall=Wall(10,200,100,10) # poke wall wall_list.add(wall) wall=Wall(790,0,10,600) #(x,y,thickness, height) wall_list.add(wall) wall=Wall(10,590,790,10) #(x,y,thickness, height) wall_list.add(wall) f = open('MapMaker.txt') num_lines = sum(1 for line in f) print(num_lines) lineCount = 0 with open("MapMaker.txt") as infile: for line in infile: f = open('MapMaker.txt') print(line) coords = line.split(',') #print(coords[0]) #print(coords[1]) #print(coords[2]) #print(coords[3]) #print(coords[4]) if "tree" in line: print("tree in") wall=insertTree(int(coords[0]),int(coords[1]), int(coords[2]),int(coords[3]),coords[4]) wall_list.add(wall) elif "rock" in line: print("rock in") wall=insertRock(int(coords[0]),int(coords[1]), int(coords[2]),int(coords[3]),coords[4] ) wall_list.add(wall) width = 20 height = 540 height = height - 48 for i in range(0,23): width = width + 32 name = insertTree(width,540,790,10,"tree") #wall_list.add(name) name = insertTree(width,height,690,10,"tree") #wall_list.add(name) CREEP_SPAWN_TIME = 200 # frames creep_spawn = CREEP_SPAWN_TIME clock = pygame.time.Clock() bg_tile_img = pygame.image.load('images/map/grass.png').convert() img_rect = bg_tile_img FIELD_RECT = Rect(50, 50, 700, 500) CREEP_FILENAMES = [ 'images/player/1.png', 'images/player/1.png', 'images/player/1.png'] N_CREEPS = 3 creep_images = [ pygame.image.load(filename).convert_alpha() for filename in CREEP_FILENAMES] explosion_img = pygame.image.load('images/map/tree.png').convert_alpha() explosion_images = [ explosion_img, pygame.transform.rotate(explosion_img, 90)] creeps = pygame.sprite.RenderPlain() done = False #bg_tile_img = pygame.image.load('images/map/grass.png').convert() #draw_background(screen, bg_tile_img) totalCreeps = 0 remainingCreeps = 3 while done == False: creep_images = pygame.image.load("images/player/1.png").convert() creep_images.set_colorkey(white) draw_background(screen, bg_tile_img) if len(creeps) != N_CREEPS: if totalCreeps < N_CREEPS: totalCreeps = totalCreeps + 1 print(totalCreeps) creeps.add( Creep( screen=screen, creep_image=creep_images, explosion_images=explosion_images, field=FIELD_RECT, init_position=( randint(FIELD_RECT.left, FIELD_RECT.right), randint(FIELD_RECT.top, FIELD_RECT.bottom)), init_direction=(choice([-1, 1]), choice([-1, 1])), speed=0.01)) for creep in creeps: creep.update(60,wall_list) creep.draw() for event in pygame.event.get(): if event.type == pygame.QUIT: done=True if event.type == pygame.KEYDOWN: if event.key == pygame.K_LEFT: player.changespeed(-2,0) creep.changespeed(-2,0) if event.key == pygame.K_RIGHT: player.changespeed(2,0) creep.changespeed(2,0) if event.key == pygame.K_UP: player.changespeed(0,-2) creep.changespeed(0,-2) if event.key == pygame.K_DOWN: player.changespeed(0,2) creep.changespeed(0,2) if event.key == pygame.K_ESCAPE: pauseGame() if event.key == pygame.K_1: global currentEditTool currentEditTool = "Tree" changeTool() if event.key == pygame.K_2: global currentEditTool currentEditTool = "Rock" changeTool() if event.type == pygame.KEYUP: if event.key == pygame.K_LEFT: player.changespeed(2,0) creep.changespeed(2,0) if event.key == pygame.K_RIGHT: player.changespeed(-2,0) creep.changespeed(-2,0) if event.key == pygame.K_UP: player.changespeed(0,2) creep.changespeed(0,2) if event.key == pygame.K_DOWN: player.changespeed(0,-2) creep.changespeed(0,-2) if event.type == pygame.MOUSEBUTTONDOWN and pygame.mouse.get_pressed()[0]: for creep in creeps: creep.mouse_click_event(pygame.mouse.get_pos()) if editMap == True: x,y = pygame.mouse.get_pos() if currentEditTool == "Tree": name = insertTree(x-10,y-25, 10 , 10, "tree") wall_list.add(name) wall_list.draw(screen) f = open('MapMaker.txt', "a+") image = pygame.image.load("images/map/tree.png").convert() screen.blit(image, (30,10)) pygame.display.flip() f.write(str(x) + "," + str(y) + ",790,10, tree\n") #f.write("wall=insertTree(" + str(x) + "," + str(y) + ",790,10)\nwall_list.add(wall)\n") elif currentEditTool == "Rock": name = insertRock(x-10,y-25, 10 , 10,"rock") wall_list.add(name) wall_list.draw(screen) f = open('MapMaker.txt', "a+") f.write(str(x) + "," + str(y) + ",790,10,rock\n") #f.write("wall=insertRock(" + str(x) + "," + str(y) + ",790,10)\nwall_list.add(wall)\n") else: None #pygame.display.flip() player.update(wall_list) movingsprites.draw(screen) wall_list.draw(screen) pygame.display.flip() clock.tick(60) pygame.quit()

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  • 2D SAT How to find collision center or point or area?

    - by Felipe Cypriano
    I've just implemented collision detection using SAT and this article as reference to my implementation. The detection is working as expected but I need to know where both rectangles are colliding. I need to find the center of the intersection, the black point on the image above. I've found some articles about this but they all involve avoiding the overlap or some kind of velocity, I don't need this. I just need to put a image on top of it. Like two cars crashed so I put an image on top of the collision. Any ideas? ## Update The information I've about the rectangles are the four points that represents them, the upper right, upper left, lower right and lower left coordinates. I'm trying to find an algorithm that can give me the intersection of these points.

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  • Which of VLC's dependencies causes sound device detection?

    - by Raphael
    I am setting up a headless music server based on the minimal Ubuntu image. After having installed the packages openssh-server,pulseaudio, libmad0,flac,liboff0,libid3tag0,libvorbis0a,ffmpeg, mpd,mpc,mpdscribble, paman,paprefs,pavumeter neither my internal soundcard nor the external DAC where detected by pulseaudio, that is pactl list did only list the dummy devices. Several reboots did not change that. The hardware devices are detected properly: ~$ lsusb | grep Texas Bus 002 Device 002: ID 08bb:2706 Texas Instruments Japan ~$ lspci | grep Audio 00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 02) Following a hunch, I installed vlc with all dependencies. After a reboot, both devices are detected! ~$ pactl list | grep "Sink: alsa_output" Monitor of Sink: alsa_output.pci-0000_00_1b.0.analog-stereo Monitor of Sink: alsa_output.usb-Burr-Brown_from_TI_USB_Audio_DAC-00-DAC.analog-stereo Now I would like to remove VLC again but keep the devices. The question is: which of the many dependencies of VLC enables proper device detection? And why on earth is it not a dependency of pulseaudio?

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  • What is the best approach to 2D collision detection on the iPhone?

    - by Magic Bullet Dave
    Been working on this problem of collision detection and there appears to be 3 main approaches I could take: Sprite and mask approach. (AND the overlap of the sprites and check for a non-zero number in the resulting sprite pixel data). Bounding circles, rectangles or polygons. (Create one or more shapes that enclose the sprites and do the basic maths to check for overlaps). Use an existing sprite library. The first approach, even though it would have been the way I would have done it in the old days of 16x16 sprite blocks, it appears that there just isn’t an easy way of getting at the individual image pixel data and/or alpha channel within Quartz (or OPENGL for that matter). Detecting the overlap of the bounding box is easy, but then creating a 3rd image from the overlap and then testing it for pixels is complicated and my gut feel is that even if we could get it to work would be slow. Am I missing something neat here? The second approach involves dividing up our sprites into several polygons and testing them for overlaps. The more polygons the more accurate the collision detection. The benefit is that it is fast, and can be accurate. The downside is it makes the sprite creation more complicated. i.e., we have to create the polygons for each sprite. For speed the best approach is to create a tree of polygons. The 3rd approach I’m not sure about as it involves buying code (or using an open source licence). I am not sure what the best library to use is or whether this would make life easier or give us a problem integrating this into our app. So in short I am favouring the polygon and tree approach and would appreciate you views on this before I go and write lots of code. Best regards Dave

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  • Setup MSSQL replication with peer to peer topology: problem setting up Conflict Detection

    - by Roel
    Hi, I'm setting up a SQL Replication strategy, using MSSQL2008 with peer-to-peer publications (2 servers, each one subscribes to the other). I followed this HOWTO from MSDN, and the setup seems to be working fine: add a record to one table on server A, query on server B shows the new record. So far, so good. So far I only have one table 'Templates': Id PK (calculated field) NodeId int default 1/2 (Server A = 1, Server B = 2) LocalId int autoid Name nvarchar(100) Now, I would like to enable 'Conflict detection', which should be enabled by default. But every time I try to save the 'Conflict Detection' feature in the Publication Properties I get the following error: Cannot save Peer conflict detection properties. An exception occurred while executing a Transact-SQL statement or batch.(Microsoft.SqlServer.ConnectionInfo) Program Location: at Microsoft.SqlServer.Management.Common.ServerConnection.ExecuteNonQuery(String sqlCommand, ExecutionTypes executionType) at Microsoft.SqlServer.Management.Common.ServerConnection.ExecuteNonQuery(String sqlCommand) at Microsoft.SqlServer.Replication.ReplicationObject.ExecCommand(String commandIn) at Microsoft.SqlServer.Replication.TransPublication.SetPeerConflictDetection(Boolean enablePeerConflictDetection, Int32 peerOriginatorID) at Microsoft.SqlServer.Management.UI.PubPropSubscriptionOptions.SaveP2PConflictDetection() at Microsoft.SqlServer.Management.UI.PubPropSubscriptionOptions.SaveProperties(ExecutionMode& executionResult) Column name 'Id' does not exist in the target table or view. Changed database context to 'TestDB'. (.Net SqlClient Data Provider) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=10.00.2531&EvtSrc=MSSQLServer&EvtID=1911&LinkId=20476 Server Name: SERVER_A Error Number: 1911 Severity: 16 State: 1 Line Number: 2 Program Location: at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) at System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async) at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe) at System.Data.SqlClient.SqlCommand.ExecuteNonQuery() at Microsoft.SqlServer.Management.Common.ServerConnection.ExecuteNonQuery(String sqlCommand, ExecutionTypes executionType) Now, I googled the hell out of this error, and nothing shows up. I also can't seem to find out what the exact target table of the error "Column name 'Id' does not exist..." is. Has anyone every done this successfully? Am I missing something? Having this setup without conflict detection feels pretty useless... EDIT OK, so after some more research and setting up with different databases etc, I found out that the calculated 'Id' column of the Templates table is the culprit. I don't know why, but the replication doesn't seem to allow calculated columns (which are also primary key). It works now too, without the 'Id' column, and using the NodeId and LocalId as a combined PK. So now the question is, why isn't it allowed to have a calculated column as PK for replication with conflict detection?

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  • Sliding collision response

    - by dbostream
    I have been reading plenty of tutorials about sliding collision responses yet I am not able to implement it properly in my project. What I want to do is make a puck slide along the rounded corner boards of a hockey rink. In my latest attempt the puck does slide along the boards but there are some strange velocity behaviors. First of all the puck slows down a lot pretty much right away and then it slides for awhile and stops before exiting the corner. Even if I double the speed I get a similar behavior and the puck does not make it out of the corner. I used some ideas from this document http://www.peroxide.dk/papers/collision/collision.pdf. This is what I have: Update method called from the game loop when it is time to update the puck (I removed some irrelevant parts). I use two states (current, previous) which are used to interpolate the position during rendering. public override void Update(double fixedTimeStep) { /* Acceleration is set to 0 for now. */ Acceleration.Zero(); PreviousState = CurrentState; _collisionRecursionDepth = 0; CurrentState.Position = SlidingCollision(CurrentState.Position, CurrentState.Velocity * fixedTimeStep + 0.5 * Acceleration * fixedTimeStep * fixedTimeStep); /* Should not this be affected by a sliding collision? and not only the position. */ CurrentState.Velocity = CurrentState.Velocity + Acceleration * fixedTimeStep; Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private Vector2 SlidingCollision(Vector2 position, Vector2 velocity) { if(_collisionRecursionDepth > 5) return position; bool collisionFound = false; Vector2 futurePosition = position + velocity; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ if(!collisionFound) return futurePosition; /* If no collision was detected it is safe to move to the future position. */ /* It is not exactly the intersection point, but slightly before. */ Vector2 newPosition = intersectionPoint; /* oldVelocity is set to the distance from the newPosition(intersection point) to the position it had moved to had it not collided. */ Vector2 oldVelocity = futurePosition - newPosition; /* Project the distance left to move along the intersection normal. */ Vector2 newVelocity = oldVelocity - intersectionPointNormal * oldVelocity.DotProduct(intersectionPointNormal); if(newVelocity.LengthSq() < 0.001) return newPosition; /* If almost no speed, no need to continue. */ _collisionRecursionDepth++; return SlidingCollision(newPosition, newVelocity); } What am I doing wrong with the velocity? I have been staring at this for very long so I have gone blind. I have tried different values of recursion depth but it does not seem to make it better. Let me know if you need more information. I appreciate any help. EDIT: A combination of Patrick Hughes' and teodron's answers solved the velocity problem (I think), thanks a lot! This is the new code: I decided to use a separate recursion method now too since I don't want to recalculate the acceleration in each recursion. public override void Update(double fixedTimeStep) { Acceleration.Zero();// = CalculateAcceleration(fixedTimeStep); PreviousState = new MovingEntityState(CurrentState.Position, CurrentState.Velocity); CurrentState = SlidingCollision(CurrentState, fixedTimeStep); Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private MovingEntityState SlidingCollision(MovingEntityState state, double timeStep) { bool collisionFound = false; /* Calculate the next position given no detected collision. */ Vector2 futurePosition = state.Position + state.Velocity * timeStep; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ /* If no collision was detected it is safe to move to the future position. */ if (!collisionFound) return new MovingEntityState(futurePosition, state.Velocity); /* Set new position to the intersection point (slightly before). */ Vector2 newPosition = intersectionPoint; /* Project the new velocity along the intersection normal. */ Vector2 newVelocity = state.Velocity - 1.90 * intersectionPointNormal * state.Velocity.DotProduct(intersectionPointNormal); /* Calculate the time of collision. */ double timeOfCollision = Math.Sqrt((newPosition - state.Position).LengthSq() / (futurePosition - state.Position).LengthSq()); /* Calculate new time step, remaining time of full step after the collision * current time step. */ double newTimeStep = timeStep * (1 - timeOfCollision); return SlidingCollision(new MovingEntityState(newPosition, newVelocity), newTimeStep); } Even though the code above seems to slide the puck correctly please have a look at it. I have a few questions, if I don't multiply by 1.90 in the newVelocity calculation it doesn't work (I get a stack overflow when the puck enters the corner because the timeStep decreases very slowly - a collision is found early in every recursion), why is that? what does 1.90 really do and why 1.90? Also I have a new problem, the puck does not move parallell to the short side after exiting the curve; to be more exact it moves outside the rink (I am not checking for any collisions with the short side at the moment). When I perform the collision detection I first check that the puck is in the correct quadrant. For example bottom-right corner is quadrant four i.e. circleCenter.X < puck.X && circleCenter.Y puck.Y is this a problem? or should the short side of the rink be the one to make the puck go parallell to it and not the last collision in the corner? EDIT2: This is the code I use for collision detection, maybe it has something to do with the fact that I can't make the puck slide (-1.0) but only reflect (-2.0): /* Point is the current position (not the predicted one) and quadrant is 4 for the bottom-right corner for example. */ if (GeometryHelper.PointInCircleQuadrant(circleCenter, circleRadius, state.Position, quadrant)) { /* The line is: from = state.Position, to = futurePosition. So a collision is detected when from is inside the circle and to is outside. */ if (GeometryHelper.LineCircleIntersection2d(state.Position, futurePosition, circleCenter, circleRadius, intersectionPoint, quadrant)) { collisionFound = true; /* Set the intersection point to slightly before the real intersection point (I read somewhere this was good to do because of floting point precision, not sure exactly how much though). */ intersectionPoint = intersectionPoint - Vector2.NormalizeRet(state.Velocity) * 0.001; /* Normal at the intersection point. */ intersectionPointNormal = Vector2.NormalizeRet(circleCenter - intersectionPoint) } } When I set the intersection point, if I for example use 0.1 instead of 0.001 the puck travels further before it gets stuck, but for all values I have tried (including 0 - the real intersection point) it gets stuck somewhere (but I necessarily not get a stack overflow). Can something in this part be the cause of my problem? I can see why I get the stack overflow when using -1.0 when calculating the new velocity vector; but not how to solve it. I traced the time steps used in the recursion (initial time step is always 1/60 ~ 0.01666): Recursion depth Time step next recursive call [Start recursion, time step ~ 0.016666] 0 0,000985806527246773 [No collision, stop recursion] [Start recursion, time step ~ 0.016666] 0 0,0149596704364629 1 0,0144883449376379 2 0,0143155612984837 3 0,014224925727213 4 0,0141673917461608 5 0,0141265435314026 6 0,0140953966184117 7 0,0140704653746625 ...and so on. As you can see the collision is detected early in every recursive call which means the next time step decreases very slowly thus the recursion depth gets very big - stack overflow.

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  • Simple collision detection for pong

    - by Dave Voyles
    I'm making a simple pong game, and things are great so far, but I have an odd bug which causes my ball (well, it's a box really) to get stuck on occasion when detecting collision against the ceiling or floor. It looks as though it is trying to update too frequently to get out of the collision check. Basically the box slides against the top or bottom of the screen from one paddle to the other, and quickly bounces on and off the wall while doing so, but only bounces a few pixels from the wall. What can I do to avoid this problem? It seems to occur at random. Below is my collision detection for the wall, as well as my update method for the ball. public void UpdatePosition() { size.X = (int)position.X; size.Y = (int)position.Y; position.X += speed * (float)Math.Cos(direction); position.Y += speed * (float)Math.Sin(direction); CheckWallHit(); } // Checks for collision with the ceiling or floor. // 2*Math.pi = 360 degrees // TODO: Change collision so that ball bounces from wall after getting caught private void CheckWallHit() { while (direction > 2 * Math.PI) { direction -= 2 * Math.PI; } while (direction < 0) { direction += 2 * Math.PI; } if (position.Y <= 0 || (position.Y > resetPos.Y * 2 - size.Height)) { direction = 2 * Math.PI - direction; } }

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  • Keyboard-shortcut key-press-detection sensitivity settings

    - by Juve
    last week I switched from Ubuntu 10.10 to 12.04 and after setting up my keyboard shortcuts, e.g., CTRL+ALT+E for my favorite editor and CTRL+ALT+X for the terminal, I noticed that the behavior when pressing the appropriate keys changed somehow. I know this is very subjective and I am not 100% percent sure if I am suddenly just too lazy when using my keyboard, but here is what I noticed: To run your shortcuts, you usually press the modifiers first and in addition press the alphanum key. Now, if I hold the modifiers down very consciously and press the alphanum key afterwards everything works fine. However, I noticed that I may often release the modifiers a bit too early. In Ubuntu 10.10 (metacity/compiz) my keyboard shortcuts would still execute and my tools would pop up. This does not work anymore in 12.04. Nevertheless, I still believe the old behavior to be more intuitive and would like to have it back. I a nutshell: Is there a parameter to control the shortcut-key-press detection behavior? I already searched the ubuntu keyboard options and searched for "keyboard" in gconf-editor but could not find any hints so far.

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  • C# XNA 2D Multiple boxes collision detection and movement

    - by zini
    Hi, I've been making simple game where you shoot boxes that are coming towards you. All game objects are simple rectangles. Now I have problem with collision detection; how to check where the collision comes so I can change the coordinates right? I have this kind of situation: http://imgur.com/8yjfW Imagine that all of those blocks are moving towards you (green box). If those orange boxes collide with each other, they should "avoid" themselves and not go through each other. I have class Enemy which has properties x, y and such. Now I'm doing the collision like this: // os.Count is an amount of other enemies colliding with this enemy if (os.Count == 0) { // If enemy doesn't collide with other enemy lasty = y; lastx = x; slope = (x - player.x) / (y - player.y); x += slope * l; // l is "movement speed" of enemy (float) if (y > player.y) { y = lasty; } else if (y < player.y) { y += l; } } else { foreach(Enemy b in os) { if (b.y > this.y) { // If some colliding enemy is closer player than this enemy, that closer one will be moved towards the player b.lasty = b.y; if (!BiggestY(os)) { // BiggestY returns true if this enemy has the biggest Y b.y += b.l; } b.x = b.lastx; } } } But this is very, very bad way to do this. I know it, but I just can't figure out other way. And as a matter in fact, this method doesn't even work pretty good; if multiple enemies are colliding same enemy they go through each other. I explained this pretty badly, but I hope that you understand this. And to sum up, as I said: How to check where the collision comes so I can change the coordinates right?

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  • Does any one know is there any collision detection API for HTML5 Canvas..?

    - by angos
    I have been experimenting HTML5 canvas by coding basic mind-mapping application. I have tried to find out if there is any javascript API used for managing object in canvas like collision detection between images or shapes. I think it is not a good idea to write my own since there might be some good API around. Anyone have clue or some information on this. I would very much appreciate.

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  • How do I detect and handle collisions using a tile property with Slick2D?

    - by oracleCreeper
    I am trying to set up collision detection in Slick2D based on a tilemap. I currently have two layers on the maps I'm using, a background layer, and a collision layer. The collision layer has a tile with a 'blocked' property, painted over the areas the player can't walk on. I have looked through the Slick documentation, but do not understand how to read a tile property and use it as a flag for collision detection. My method of 'moving' the player is somewhat different, and might affect how collisions are handled. Instead of updating the player's location on the window, the player always stays in the same spot, updating the x and y the map is rendered at. I am working on collisions with objects by restricting the player's movement when its hitbox intersects an object's hitbox. The code for the player hitting the right side of an object, for example, would look like this: if(Player.bounds.intersects(object.bounds)&&(Player.x<=(object.x+object.width+0.5))&&Player.isMovingLeft){ isInCollision=true; level.moveMapRight(); } else if(Player.bounds.intersects(object.bounds)&&(Player.x<=(object.x+object.width+0.5))&&Player.isMovingRight){ isInCollision=true; level.moveMapRight(); } else if(Player.bounds.intersects(object.bounds)&&(Player.x<=(object.x+object.width+0.5))&&Player.isMovingUp){ isInCollision=true; level.moveMapRight(); } else if(Player.bounds.intersects(object.bounds)&&(Player.x<=(object.x+object.width+0.5))&&Player.isMovingDown){ isInCollision=true; level.moveMapRight(); } and in the level's update code: if(!Player.isInCollision) Player.manageMovementInput(map, i); However, this method still has some errors. For example, when hitting the object from the right, the player will move up and to the left, clipping through the object and becoming stuck inside its hitbox. If there is a more effective way of handling this, any advice would be greatly appreciated.

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  • Integration error in high velocity

    - by Elektito
    I've implemented a simple simulation of two planets (simple 2D disks really) in which the only force is gravity and there is also collision detection/response (collisions are completely elastic). I can launch one planet into orbit of the other just fine. The collision detection code though does not work so well. I noticed that when one planet hits the other in a free fall it speeds backward and goes much higher than its original position. Some poking around convinced me that the simplistic Euler integration is causing the error. Consider this case. One object has a mass of 1kg and the other has a mass equal to earth. Say the object is 10 meters above ground. Assume that our dt (delta t) is 1 second. The object goes to the height of 9 meters at the end of the first iteration, 7 at the end of the second, 4 at the end of the third and 0 at the end of the fourth iteration. At this points it hits the ground and bounces back with the speed of 10 meters per second. The problem is with dt=1, on the first iteration it bounces back to a height of 10. It takes several more steps to make the object change its course. So my question is, what integration method can I use which fixes this problem. Should I split dt to smaller pieces when velocity is high? Or should I use another method altogether? What method do you suggest? EDIT: You can see the source code here at github:https://github.com/elektito/diskworld/

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  • How do i approach this collision model?

    - by PeeS
    this is the game level prototype i have already implemented. It has few objects per room to allow me to finally add some collision detection/response code into it. VIDEO As you can probably see, every object inside has it's own AABB, even the room itself has AABB. So a player is like 'inside the Room AABB'. My player will be exactly inside the room, so he would have to collide correctly with those AABBs, so that when he hits any of those objects inside he get's a proper collision response from those AABB's. Now i would like to hear from you what kind of collision approach should i choose in here? How do i approach this kind of stuff: AABB to AABB collision detection then when this is positive go with AABB - Tri to find proper plane normal and calculate response ? AABB to AABB then when positive go with AABB - AABB Side check to find proper proper plane normal and calculate response? Anything else? How do you do this ? Many thanks.

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  • Using 2d collision with 3d objects

    - by Lyise
    I'm planning to write a fairly basic scrolling shoot 'em up, however, I have run into a query with regards to checking for collision. I plan to have a fixed top down view, where the player and enemies are all 3d objects on a fixed plane, and when the enemy or player fires at the other, their shots will also be along this fixed plane. In order to handle the collision, I have read up a bit on collision detection in 3d, as it is not something I have looked into previously, but I'm not sure what would be ideal for this situation. My options appear to be: Sphere collision, however, this lacks the pixel precision I would like Detection using all vertexes and planes of each object, but this seems overly convoluted for a fixed plane of play Rendering the play screen in black and white (where white is an object, black is empty space), once for enemies and once for the player, and checking for collisions that way (if a pixel is white on both, there is a collision) Which of these would be the best approach, or is there another option that I am missing? I have done this previously using 2d sprites, however I can't use the same thinking here as I don't have the image to refer to.

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