projects/openmelee: ai/steer.d comparison

comparison ai/steer.d @ 19:08ddf9e71b88

steer to avoid

author	zzzzrrr <mason.green@gmail.com>
date	Wed, 25 Mar 2009 14:44:47 -0400
parents	7f74e064dad5
children	6efd0830715b

comparison

equal deleted inserted replaced

-:7f74e064dad5
+:08ddf9e71b88
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 module openmelee.ai.steer;
+import tango.io.Stdout : Stdout;
 import blaze.common.bzMath: bzDot, bzClamp, bzVec2;
+import blaze.collision.shapes.bzShape : bzShape;
+import tango.math.Math : sqrt;
 import blaze.dynamics.bzBody: bzBody;
 import openmelee.ships.ship : Ship, State;
 import openmelee.ai.utilities;
 {
 // Constructor: initializes state
 this (Ship ship)
 {
 m_ship = ship;
+m_body = ship.rBody;
+m_radius = 0.0f;
+// Find radius of body
+for (bzShape s = m_body.shapeList; s; s = s.next) {
+if(s.sweepRadius > m_radius) {
+m_radius = s.sweepRadius;
+}
+}
 }
 	struct PathIntersection
 {
 bool intersect;
 bzVec2 steerToAvoidObstacles (float minTimeToCollision, bzBody obstacles) {
 bzVec2 avoidance;
 PathIntersection nearest, next;
 float minDistanceToCollision = minTimeToCollision * m_speed;
 next.intersect = false;
 nearest.intersect = false;
 // test all obstacles for intersection with my forward axis,
 // select the one whose point of intersection is nearest
-for (bzBody o; o; o = o.next) {
+for (bzBody o = obstacles; o; o = o.next) {
+if(o is m_body) continue;
 // This code which presumes the obstacle is spherical
-//findNextIntersectionWithSphere (o, next);
+findNextIntersectionWithSphere(o, next);
 if (!nearest.intersect || (next.intersect && next.distance < nearest.distance)) {
 					nearest = next;
 }
 }
 // when a nearest intersection was found
 if (nearest.intersect && (nearest.distance < minDistanceToCollision)) {
+Stdout("Distance: ")(nearest.distance).newline;
 // compute avoidance steering force: take offset from obstacle to me,
 // take the component of that which is lateral (perpendicular to my
 // forward direction), set length to maxForce, add a bit of forward
 // component (in capture the flag, we never want to slow down)
 bzVec2 offset = m_position - nearest.obstacle.position;
-//avoidance = Vector3Helpers.PerpendicularComponent(offset, this.Forward);
+avoidance = perpendicularComponent(offset, m_forward);
 avoidance.normalize;
-avoidance *= m_maxForce;
+//avoidance *= m_maxForce;
-avoidance += m_forward * m_maxForce * 0.75f;
+//avoidance += m_forward * m_maxForce * 0.75f;
 }
 return avoidance;
 }
+		void findNextIntersectionWithSphere(bzBody obs,
+inout PathIntersection intersection) {
+			// This routine is based on the Paul Bourke's derivation in:
+			//   Intersection of a Line and a Sphere (or circle)
+			//   http://www.swin.edu.au/astronomy/pbourke/geometry/sphereline/
+			float b, c, d, p, q, s;
+			bzVec2 lc;
+			// initialize pathIntersection object
+			intersection.intersect = false;
+			intersection.obstacle = obs;
+			// find "local center" (lc) of sphere in boid's coordinate space
+			lc = m_body.localPoint(obs.position);
+			// computer line-sphere intersection parameters
+			b = 0;
+// Find radius of obstacle
+float obsRadius = 0;
+for (bzShape shape = obs.shapeList; shape; shape = shape.next) {
+if(shape.sweepRadius > obsRadius) {
+obsRadius = shape.sweepRadius;
+}
+}
+			c = square(lc.x) + square(lc.y) - square(obsRadius + m_radius);
+			d = (b * b) - (4 * c);
+			// when the path does not intersect the sphere
+			if (d < 0) return;
+			// otherwise, the path intersects the sphere in two points with
+			// parametric coordinates of "p" and "q".
+			// (If "d" is zero the two points are coincident, the path is tangent)
+			s = sqrt(d);
+			p = (-b + s) * 0.5f;
+			q = (-b - s) * 0.5f;
+			// both intersections are behind us, so no potential collisions
+			if ((p < 0) && (q < 0)) return;
+			// at least one intersection is in front of us
+			intersection.intersect = true;
+			intersection.distance =
+				((p > 0) && (q > 0)) ?
+				// both intersections are in front of us, find nearest one
+				((p < q) ? p : q) :
+				// otherwise only one intersections is in front, select it
+				((p > 0) ? p : q);
+		}
 /*
 // ------------------------------------------------------------------------
 // Unaligned collision avoidance behavior: avoid colliding with other
 // nearby vehicles moving in unconstrained directions.  Determine which
 bzVec2 m_position;
 bzVec2 m_velocity;
 bzVec2 m_up;
 bzVec2 m_side;
 bzVec2 m_forward;
+float m_radius;
+bzBody m_body;
 	float m_speed = 0;
 	float m_maxForce = 0;
 // Wander behavior

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comparison ai/steer.d @ 19:08ddf9e71b88