/*
Done each frame before collision testing, it updates the "on tile" states
and then applies acceleration and gravity to the sprite's velocity. Then it
initializes the swept shape for the sprite.
*/
void Physics::prepSpriteForCollisionTesting(World *world, CollidableObject *sprite)
{
// THIS GUY HAS ALL THE PHYSICS STUFF FOR THE SPRITE
PhysicalProperties *pp = sprite->getPhysicalProperties();
// APPLY ACCELERATION
pp->applyAcceleration();
// APPLY GRAVITY
pp->incVelocity(0.0f, gravity);
// NOW, IF THE SPRITE WAS ON A TILE LAST FRAME LOOK AHEAD
// TO SEE IF IT IS ON A TILE NOW. IF IT IS, UNDO GRAVITY.
// THIS HELPS US AVOID SOME PROBLEMS
if (sprite->wasOnTileLastFrame())
{
// FIRST MAKE SURE IT'S SWEPT SHAPE ACCOUNTS FOR GRAVITY
sprite->updateSweptShape(1.0f);
// WE'LL LOOK THROUGH THE COLLIDABLE LAYERS
vector<WorldLayer*> *layers = world->getLayers();
for (int i = 0; i < world->getNumLayers(); i++)
{
WorldLayer *layer = layers->at(i);
if (layer->hasCollidableTiles())
{
bool test = layer->willSpriteCollideOnTile(this, sprite);
if (test)
{
sprite->setOnTileThisFrame(true);
pp->setVelocity(pp->getVelocityX(), 0.0f);
sprite->updateSweptShape(1.0f);
return;
}
else
cout << "What Happened?";
}
}
}
// INIT THE SWEPT SHAPE USING THE NEWLY APPLIED
// VELOCITY. NOTE THAT 100% OF THE FRAME TIME
// IS LEFT, DENOTED BY 1.0f
sprite->updateSweptShape(1.0f);
}
