Open our game's project file if it's not already open.

Switch to the Ship.h file.

Add an instance variable called _quadHitpoints, which is a pointer to SPQuad, as shown in the following line of code:

SPQuad *_quadHitpoints;

Switch to the Ship.m file. Just after where we create the cannonball images in the initializer, we add a quad which should be the border for our hit point representation, as shown in the following code:

float hitpointsHeight = 5.0f;
SPQuad *hitpointsBorder = [SPQuad quadWithWidth:clipNorth.width height:hitpointsHeight color:SP_BLACK];

We add the background for the hit points box, as shown in the following code:

uint redColor = SP_COLOR(200, 0, 0);
SPQuad *quadMaxHitpoints = [SPQuad quadWithWidth:hitpointsBorder.width - 2.0f height:hitpointsHeight - 2.0f color:redColor];

We set the background for the hit points box to have a one point margin, which...