fix friction

[blobs.git] / src / creature / creature.cpp

diff --git a/src/creature/creature.cpp b/src/creature/creature.cpp
index 085d70f000554bec57537f0b419b62f474ccb3eb..9b85eff73a81d68d98bc308d3bbc3b146f257d04 100644 (file)
--- a/src/creature/creature.cpp
+++ b/src/creature/creature.cpp
@@ -463,27 +463,31 @@ void Creature::TickState(double dt) {
        }
        situation.SetState(state);
        // work is force times distance
-       DoWork(glm::length(f.acc) * Mass() * glm::length(f.vel) * dt);
+       // exclude gravity for no apparent reason
+       // actually, this should solely be based on steering force
+       DoWork(glm::length(f.acc - situation.GetPlanet().GravityAt(state.pos)) * Mass() * glm::length(f.vel) * dt);
 }
 
 Situation::Derivative Creature::Step(const Situation::Derivative &ds, double dt) const noexcept {
        Situation::State s = situation.GetState();
        s.pos += ds.vel * dt;
        s.vel += ds.acc * dt;
+       situation.EnforceConstraints(s);
        glm::dvec3 force(steering.Force(s));
        // gravity = antinormal * mass * Gm / r²
        glm::dvec3 normal(situation.GetPlanet().NormalAt(s.pos));
        force += glm::dvec3(
                -normal
-               * Mass() * situation.GetPlanet().GravitationalParameter()
-               / glm::length2(s.pos));
+               * (Mass() * situation.GetPlanet().GravitationalParameter()
+               / glm::length2(s.pos)));
        // if net force is applied and in contact with surface
-       if (!allzero(force) && glm::length2(s.pos) < (situation.GetPlanet().Radius() + 0.01) * (situation.GetPlanet().Radius() + 0.01)) {
-               // apply friction = -|normal force| * tangential force * coefficient
+       if (!allzero(force) && !allzero(s.vel) && glm::length2(s.pos) < (situation.GetPlanet().Radius() + 0.01) * (situation.GetPlanet().Radius() + 0.01)) {
+               // apply friction
                glm::dvec3 fn(normal * glm::dot(force, normal));
+               // TODO: friction somehow bigger than force?
                glm::dvec3 ft(force - fn);
                double u = 0.4;
-               glm::dvec3 friction(-glm::length(fn) * ft * u);
+               glm::dvec3 friction(-glm::clamp(glm::length(ft), 0.0, glm::length(fn) * u) * glm::normalize(s.vel));
                force += friction;
        }
        return {
@@ -847,7 +851,7 @@ bool Memory::RememberLocation(const Composition &accept, glm::dvec3 &pos) const
                        c.GetSimulation().Assets().random.SNorm(),
                        c.GetSimulation().Assets().random.SNorm(),
                        c.GetSimulation().Assets().random.SNorm());
-               pos += error * (2.0 * (1.0 - c.IntelligenceFactor()));
+               pos += error * (4.0 * (1.0 - c.IntelligenceFactor()));
                pos = glm::normalize(pos) * c.GetSituation().GetPlanet().Radius();
                return true;
        } else {
@@ -952,11 +956,13 @@ void Situation::Accelerate(const glm::dvec3 &dv) noexcept {
        EnforceConstraints(state);
 }
 
-void Situation::EnforceConstraints(State &s) noexcept {
+void Situation::EnforceConstraints(State &s) const noexcept {
        if (OnSurface()) {
                double r = GetPlanet().Radius();
                if (glm::length2(s.pos) < r * r) {
-                       s.pos = glm::normalize(s.pos) * r;
+                       const glm::dvec3 normal(GetPlanet().NormalAt(s.pos));
+                       s.pos = normal * r;
+                       s.vel -= normal * glm::dot(normal, s.vel);
                }
        }
 }
@@ -1064,7 +1070,7 @@ glm::dvec3 Steering::Force(const Situation::State &s) const noexcept {
        }
        // remove vertical component, if any
        const glm::dvec3 normal(c.GetSituation().GetPlanet().NormalAt(s.pos));
-       result += normal * glm::dot(normal, result);
+       result -= normal * glm::dot(normal, result);
        // clamp to max
        if (glm::length2(result) > max_force * max_force) {
                result = glm::normalize(result) * max_force;