User Interfaces - Game Programming Algorithms and Techniques - page 266

float range
// (x,y) center of radar on screen
Vector2 position
// Radius of radar on screen
float radius
// Radar background image
ImageFile radarImage
// List of all active RadarBlips
List blips
// Initialize function sets range, center, radi-
us, and image
...
function Update( float deltaTime )
// Clear out the List of blips from last
frame
blips .Clear()
// Get the player's position
...
// Convert playerPosition to a 2D coordinate.
// The below assumes a y-up world.
Vector2 playerPos2D = Vector2 ( playerPosi-
tion . x , playerPosition . z )
// Calculate the rotation that may need to be
applied to the blip
// Get the players normalized facing vector
...
// Convert playerFacing to 2D
Vector2 playerFacing2D = Vector2 ( playerFa-
cing . x , playerFacing . z )
// Angle between the player's 2D facing and
radar "forward"
float angle = acos(DotProduct( playerFacing2D ,
Vector2 (0,1)))
// Convert 3D vector so we can perform a
cross product