Chapter 12: 3D Collision Detection and Shooting
Quiz Answers
When firing a shot in a 3D (or 2D, for that matter) game, how do you determine the direction of the shot?
Typically, the thing that's firing a shot (a camera, a gun, etc.) has a direction of its own. When firing a shot, you give the bullet or projectile the same direction vector as the item from which it emanates.
Fact or fiction: every model has a
BoundingSphereobject that surrounds the entire model and can be used for collision detection.Fiction. The
BoundingSphereobject belongs to aModelMeshobject. EveryModelhas one or moreModelMeshobjects. TheBoundingSpheretherefore may cover the entire model, but aModelmay also have several meshes, and in that case, theModelwill have multipleBoundingSphereobjects that each surround portions of theModel.
When using
BoundingSpheres associated with a moving model for collision detection, what must be done to theBoundingSpherein order to accurately detect collisions?BoundingSpheres do not automatically move, rotate, and scale with the model that owns them. You need to apply the movement, rotation, and scale matrices to theBoundingSpherebefore using them for collision detection.
What is the difference between drawing 2D images on screen in a 3D game and drawing 2D images on the screen in a 2D game?
Nothing. Drawing in 2D is the same regardless of whether there are also 3D graphics in the game.
How much does the tongue of a blue whale weigh?
As much as an average-sized elephant! ...