Game Physics Engine Development, 2nd Edition

6.3 S tiff Springs 101

Excerpt from file src/pfgen.cpp

void ParticleBuoyancy::updateForce(Particle* particle, real duration)

{

// Calculate the submersion depth.

real depth = particle->getPosition().y;

// Check if we’re out of the water.

if (depth >= waterHeight + maxDepth) return;

Vector3 force(0,0,0);

// Check if we’re at maximum depth.

if (depth <= waterHeight - maxDepth)

{

force.y = liquidDensity * volume;

particle->addForce(force);

return;

}

// Otherwise we are partly submerged.

force.y = liquidDensity * volume *

(depth - maxDepth - waterHeight) / 2 * maxDepth;

particle->addForce(force);

}

I have assumed in this code that the buoyancy is acting in the up