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vennt
Member
I'm trying to draw my chipmunk body/shape above my sprite, I'm not sure if its possible though.
Right now I'm using an atlas sprite manager to create my sprite and adding it with a negative z-index.
My shape/body primitive is rendering underneath the sprite though (if I unattach my sprite to the shape, I see the rendered primitive fall out from underneath the sprite).
Is it possible?
Steve Oldmeadow
Administrator
Yes, it is possible just make sure the primitives are drawn after the AtlasSpriteManager. The z position of the AtlasSprite is irrelevant - it only controls the draw order of that sprite relative to other AtlasSprites within the same AtlasSpriteManager.
vennt
Member
I've tried some things, but I'm lost. I'm not quite sure how to approach drawing after the Atlas Manager. Can you lead me in the right direction?
I'm using an eachShape function (from other examples) and the cpSpaceHashEach calls are inside the -draw method (in my Scene.m) I'm loading my AtlasSpriteManager from another class inside the Scene.m init after I've setup the chipmunk space. It seems like that is the correct order, but it won't render above the sprite.
Steve Oldmeadow
Administrator
It is a lot easier to explain if you post some code, and don't forget to wrap it with back ticks.
To render the shapes above the sprites you need a way to get a render call after the sprites have rendered. An easy way to do this is to create a new cocos layer/node that sits on top of everything else and it will render the shapes.
In .h file:
@interface ChipmunkLayer : CocosNode
{
cpSpace* space;
}
-(id) initWithSpace:(cpSpace*) pSpace;
@endin .m file
@implementation ChipmunkLayer
-(id) initWithSpace:(cpSpace*) pSpace
{
if( (self=[super init]) )
{
space = pSpace;
}
return self;
}
-(void) draw
{
cpSpaceHasEach( space->activeShapes, &drawEachShape, nil );
cpSpaceHasEach( space->staticShapes, &drawEachShape, nil );
}
@endAll you need to do is create a ChipmunkLayer and add it on top of your scene.
Of course you also need to supply the drawEachShape() function.
I'm having a spot of trouble with this. I've created a new CocosNode as describes above (fixing the cpSpacehas(h)Each) spelling mistake. But I don't quite get the "&drawEachShape" part.
I defined and implemented a method in the class, but I get a "drawEachShape undeclared (first use in this function)" error. Here' the code...
#import "ChipmunkDebug.h"
@implementation ChipmunkDebug
-(id) initWithSpace:(cpSpace *)pSpace
{
if((self == [super init])){
space = pSpace;
}
return self;
}
-(void) draw
{
//I'm only interested in Static Shapes at the moment
cpSpaceHashEach( space->staticShapes, &drawEachShape, nil );
}
-(void) drawEachShape:(cpShape *)thisShape
{
}
i also tried [self drawEachShape] and @selector(drawEachShape:) but still got nowhere. I'm blindly feeling my way through this.
I suspect it's got something to do with C and Objective C differences, but could someone point out what I need to do? Cheers.
Yep you're right, its the difference between c and obj-c. You need to define drawEachShape as a C function, and define it outside your implementation... like this:
#import "ChipmunkDebug.h"
void drawEachShape(void* shape, void *optionalData)
{
}
@implementation ChipmunkDebug
@endcpSpaceHashEach expects pointers to C-style functions, so it must be done this way. Also note that the signature of the function must take two (void*) args, the first being the shape (in this case) and the second being some arbitrary data you passed it (in this case you passed nil).
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