Platformer Progress Update 2

Another little update on the progress of the platformer. Its now up to build 0.75 and I’ve been doing lots of fiddling with little things here and there, because I have been busy.

Heres the main points of interest since the last update:

I’ve added a ram counter to the showFPS debug text. It reads high on the simulator because it counts more than it should.

The level select screen has a scrolling interface which takes 4 level buttons on each page. Each Page will represent a ‘Stage’ and I like to think that each stage will be of a different theme.

Credits menu has the same level scroller implemented, but will have a page for programming, art & music peoples, along with links for the respective people, and text (maybe a little quote).

Settings menu now has particle toggle and player motion streak toggles added, but don’t change anything yet.

Fundamentals of a splash-screen, which will come up automatically, play a little animation, then be dismissed to the main menu.

Experiments with the CCCamera classes (the cocos2d camera)

I’ve ran through 4 different techniques for camera control in cocos2d. Because I found little help on this on the net, I shall post some little snippets to guide anyone who needs them. I have my player referenced as player in these samples. This is mostly old code, I have cleaned it up and simplified… This all belongs in a tick/gameloop function to actually update the position

Option 1:

Scroll the layer on a lock onto the player. The PTM_RATIO and +90 account for position on screen, and box2d.

CGPoint cameraPosition = ccp(-1 * playerPosition.x * PTM_RATIO + 90, -1 * playerPosition.y *PTM_RATIO + 90); 
[self setPosition:cameraPosition];

Option 2:

Use CCFollow to do essentially the same things as Option 1. This will not show anything outside the worldBoundary area. Because Im using Tile tilemaps, I have added two points to the tilemap to define the max/min camera areas.

CCTMXObjectGroup *cameraobjects = [tileMap objectGroupNamed:@"Objects"];
    NSMutableDictionary *spointPoint = [cameraobjects objectNamed:@"start"];        
	int spointx = [[spointPoint valueForKey:@"x"] intValue];
    int spointy = [[spointPoint valueForKey:@"y"] intValue];
    NSMutableDictionary *epointPoint = [cameraobjects objectNamed:@"end"];        
	int epointx = [[epointPoint valueForKey:@"x"] intValue];
    int epointy = [[epointPoint valueForKey:@"y"] intValue];
    
    CGRect tilemapBounds = CGRectMake(0, 0, epointx - spointx, epointy - spointy);
    id cameraMove = [CCFollow actionWithTarget:player worldBoundary:tilemapBounds];
    [self runAction:cameraMove];

Option 3:

Use the CCCamera. I found a lot of websites recommend against using CCCamera, because it doesn’t scroll the layer, and can make co-ordinates a pain later with conversions. I actually needed it to work, but camera control isn’t high on my list right now. The values are all 0, because I haven’t tried it out properly yet.

[self.camera setCenterX:0 centerY:0 centerZ:0];<br />
[self.camera setEyeX:0 eyeY:0 eyeZ:0]; //[CCCamera getZEye] is often used in eyeZ here

Option 4:

Very similar to Option2, but a little different in form. It uses a function to get the position of the object we want to track, and the function takes into account the boundaries.

-(void)setViewpointCenter:(CGPoint) position {
   
     CGSize winSize = [[CCDirector sharedDirector] winSize];
 
//I store these values in a singleton when the map is loaded
     int mapWidth = someNumber;
     int mapHeight = someOtherNumber;

     int x = MAX(position.x, winSize.width / 2);
     int y = MAX(position.y, winSize.height / 2);
     x = MIN(x, (mapWidth * mapWidth) - winSize.width / 2);
     y = MIN(y, (mapHeight * mapHeight) - winSize.height/2);
     CGPoint actualPosition = ccp(x, y);
     
//figure out where the 'camera' will centre, and where the viewpoint is based on above calculations
     CGPoint centerOfView = ccp(winSize.width/2, winSize.height/2);
     CGPoint viewPoint = ccpSub(centerOfView, actualPosition);
     self.position = viewPoint;

which is used with

[self setViewpointCenter:player.position];

In the gameloop function

I really need to figure out the syntax highlighting plugin to make that read nicer… Hopefully more to come when I’m done with my final exams in two weeks.