X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=examples%2Fbassteroids%2Fsource%2Fphysics.cpp;h=67cdf6fe596bbf29199b7af96174c92eecaefc92;hb=e7223a520b12663127b21afe8a68965898f34ded;hp=2453fd90ec82be2ed213eaec91da41c642b1b21f;hpb=9ce882cbb6bb7628d7c9883c43491a75c10625d7;p=libs%2Fgame.git

diff --git a/examples/bassteroids/source/physics.cpp b/examples/bassteroids/source/physics.cpp
index 2453fd9..67cdf6f 100644
--- a/examples/bassteroids/source/physics.cpp
+++ b/examples/bassteroids/source/physics.cpp
@@ -186,15 +186,17 @@ void Physics::apply_impulses()
 		LinAl::Vector<float, 2> v_p1 = entity1.velocity+LinAl::Vector<float, 2>(-r1.y, r1.x)*entity1.angular_velocity.radians();
 		LinAl::Vector<float, 2> v_p2 = entity2.velocity+LinAl::Vector<float, 2>(-r2.y, r2.x)*entity2.angular_velocity.radians();
 		LinAl::Vector<float, 2> v_rel = v_p2-v_p1;
-		LinAl::Vector<float, 2> tangent = normalize(v_rel-c.normal*inner_product(v_rel, c.normal));
+		LinAl::Vector<float, 2> tangent = v_rel-c.normal*inner_product(v_rel, c.normal);
+		float v_tan = tangent.norm();
+		tangent = (v_tan>1e-5 ? normalize(tangent) : LinAl::Vector<float, 2>(-c.normal.y, c.normal.x));
 		float restitution = 1.0f;
 		float friction_coeff = 0.1f;
 		float inv_mass_sum = entity1.inverse_mass+entity2.inverse_mass;
 		float reaction = (1+restitution)*inner_product(v_rel, c.normal)/inv_mass_sum;
-		float friction = reaction*friction_coeff;
+		float friction = min(reaction*friction_coeff, v_tan/inv_mass_sum);
 		LinAl::Vector<float, 2> impulse = c.normal*reaction+tangent*friction;
 		entity1.velocity += impulse*entity1.inverse_mass;
-		entity2.velocity -= impulse*entity2.inverse_momi;
+		entity2.velocity -= impulse*entity2.inverse_mass;
 		entity1.angular_velocity += Geometry::Angle<float>::from_radians(entity1.inverse_momi*(r1.x*impulse.y-r1.y*impulse.x));
 		entity2.angular_velocity -= Geometry::Angle<float>::from_radians(entity2.inverse_momi*(r2.x*impulse.y-r2.y*impulse.x));
 	}
@@ -249,11 +251,29 @@ void Physics::collide_circle_box(unsigned i, unsigned j)
 	LinAl::Vector<float, 2> local_closest(clamp(local_delta.x, -half_size.x, half_size.x), clamp(local_delta.y, -half_size.y, half_size.y));
 	LinAl::Vector<float, 2> local_cdelta = local_delta-local_closest;
 	float d_sq = inner_product(local_cdelta, local_cdelta);
+
 	if(d_sq<radius*radius)
 	{
 		Collision &collision = get_collision(i, j);
-		collision.normal = normalize(LinAl::Vector<float, 2>(c*local_cdelta.x-s*local_cdelta.y, c*local_cdelta.y+s*local_cdelta.x));
-		collision.depth = radius-sqrt(d_sq);
+		if(d_sq>1e-10)
+		{
+			collision.normal = normalize(LinAl::Vector<float, 2>(c*local_cdelta.x-s*local_cdelta.y, c*local_cdelta.y+s*local_cdelta.x));
+			collision.depth = radius-sqrt(d_sq);
+		}
+		else
+		{
+			LinAl::Vector<float, 2> inside_dist(half_size.x-abs(local_delta.x), half_size.y-abs(local_delta.y));
+			if(inside_dist.x<inside_dist.y)
+			{
+				collision.normal = LinAl::Vector<float, 2>(c, s) * (local_delta.x<0 ? -1.0f : 1.0f);
+				collision.depth = radius+inside_dist.x;
+			}
+			else
+			{
+				collision.normal = LinAl::Vector<float, 2>(-s, c) * (local_delta.y<0 ? -1.0f : 1.0f);
+				collision.depth = radius+inside_dist.y;
+			}
+		}
 		collision.point = pos1-collision.normal*(radius-collision.depth/2);
 		if(collision.body1!=i)
 			collision.normal = -collision.normal;