You learned to set the properties of brushes in the map editor. These are the initial values for the properties, when a new game begins. Now you will see how you can change them during gameplay.

First, we have to bulid a small scene to work with. Start from the default template data and add Theo wizard as an action object (tile=202, id=1000, type=dynamic, class=action) and Poggie as a dynamic brush (tile=177, id=1001, type=dynamic, class=none). Place Theo at 592,216 and Poggie at 688,240. Save the map.

Here are the defines that can be used to access the properties of dynamic brushes. O_LAYER, O_X, O_Y, O_W, O_H, O_TILE, O_FRAME, O_MAP, O_FLIP, O_COLOR, O_SHADER, O_SCALE, O_ID, O_MATERIAL, O_DRAW, O_DISABLE, O_DELAY, O_ANIM, O_COLLIDER, O_CLASS, O_STATUS, O_TARGET, O_DEATH, O_COLLISION, O_USER

We're going to make Theo work some magic on little Poggie. Add the following ActionObject callback in the game.gs file, as usual. Run the game, press action on Theo and see the results.

func ActionObject_1000() { idx = ObjFind(1001); // poggie index y = ObjGet(idx,O_Y); // get vertical coordinate of poggie y-=16; // adjust it up, by 16 pixels ObjSet(idx,O_Y,y); // set it }

Now, upside down...

func ActionObject_1000() { idx = ObjFind(1001); // poggie index flip = ObjGet(idx,O_FLIP); flip ^= 2; // toggle vertical bit 1 (2 is 10 in binary) ObjSet(idx,O_FLIP,flip); }

A miraculous change...

func ActionObject_1000() { idx = ObjFind(1001); // poggie index ObjSet(idx,O_TILE,183); // set another tile of poggie ObjSet(idx,O_X,680); // adjust position ObjSet(idx,O_Y,232); // because this brush is bigger ObjSet(idx,O_W,26); // change the brush size ObjSet(idx,O_H,26); // to match the new tile // change mapping too (left and top are already 0) ObjSet(idx,O_MAP+2,26); // change the mapping right value ObjSet(idx,O_MAP+3,26); // change the mapping bottom value Message2(20,8,"MEHEE!"); MessagePop(); }

And a little coloring...

func ActionObject_1000() { idx = ObjFind(1001); // poggie index // set some random colors rand = gs_rand(4); if(rand==0) ObjSet(idx,O_COLOR,COLOR_YELLOW); else if(rand==1) ObjSet(idx,O_COLOR,COLOR_MAGENTA); else if(rand==2) ObjSet(idx,O_COLOR,COLOR_BLUE); else ObjSet(idx,O_COLOR,COLOR_RED); }

And finaly, a little growing...

func ActionObject_1000() { idx = ObjFind(1001); // poggie index x = ObjGet(idx,O_X); y = ObjGet(idx,O_Y); w = ObjGet(idx,O_W); h = ObjGet(idx,O_H); s = ObjGet(idx,O_SCALE); if(s>=400) return; // not too big x-=w; y-=h; w*=2; h*=2; s*=2; ObjSet(idx,O_X,x); ObjSet(idx,O_Y,y); ObjSet(idx,O_W,w); ObjSet(idx,O_H,h); ObjSet(idx,O_SCALE,s); }



To hide Poggie you can either set the O_DRAW property to 0, or even better, you can set the O_DISABLE to 1. If the draw property is used, Poggie will just be invisible, but you will be able to interact with him. If disabled, Poggie will be both invisible and inactive.

func ActionObject_1000() { idx = ObjFind(1001); // poggie index ObjSet(idx,O_DRAW,0); // make it invisible }

The animation delay can slow the things down.

func ActionObject_1000() { idx = ObjFind(1001); // poggie index ObjSet(idx,O_DELAY,12); // bigger delay, slower animation }

All properties of dynamic brushes are stored in the .sav file when the game is saved. They are set back when the game is loaded. So you can change them anytime and don't worry about them. The type and the id properties must not be altered, because they can mess some internal order in the engine. All other properties can be changed any time, if the given values are valid.

Play a little with these properties and make sure you understand them well.

To learn more details, see the reference chapters about objects.
Engine exported objects properties and functions.