bool MFCollision_RaySphereTest(const MFVector& rayPos, const MFVector& rayDir, const MFVector& spherePos, float radius, MFRayIntersectionResult *pResult) { MFVector diff = rayPos - spherePos; // calcuate the coefficients float a = rayDir.MagSquared3(); float b = (2.0f*rayDir).Dot3(diff); float c = diff.MagSquared3() - radius*radius; // calculate the stuff under the root sign, if it's negative no (real) solutions exist float d = b*b - 4.0f*a*c; if(d < 0.0f) // this means ray misses cylinder return false; float root = MFSqrt(d); float rcp2a = MFRcp(2.0f*a); float t1 = (-b - root)*rcp2a; float t2 = (-b + root)*rcp2a; if(t2 < 0.0f || t1 > 1.0f) return false; if(pResult) { pResult->time = MFMax(t1, 0.0f); pResult->surfaceNormal.Mad3(rayDir, pResult->time, diff); pResult->surfaceNormal.Normalise3(); } return true; }
bool MFCollision_SphereSphereTest(const MFVector &pos1, float radius1, const MFVector &pos2, float radius2, MFCollisionResult *pResult) { MFVector diff = pos2 - pos1; if(!pResult) { return diff.MagSquared3() < radius1*radius1 + radius2*radius2; } else { float length = diff.Magnitude3(); float totalRadius = radius1 + radius2; pResult->bCollide = length < totalRadius; if(pResult->bCollide) { pResult->depth = totalRadius - length; pResult->normal = -diff.Normalise3(); pResult->intersectionPoint = diff * ((length / totalRadius) * (radius1 / radius2)); } return pResult->bCollide; } }
void MFCollision_CalculateDynamicBoundingVolume(MFCollisionItem *pItem) { switch(pItem->pTemplate->type) { case MFCT_Mesh: { MFCollisionMesh *pMesh = (MFCollisionMesh*)pItem->pTemplate->pCollisionTemplateData; MFBoundingVolume &vol = pItem->pTemplate->boundingVolume; vol.min = vol.max = vol.boundingSphere = MakeVector(pMesh->pTriangles[0].verts[0], 0.0f); for(int a=0; a<pMesh->numTris; a++) { MFCollisionTriangle &tri = pMesh->pTriangles[a]; for(int b=0; b<3; b++) { vol.min = MFMin(vol.min, tri.verts[b]); vol.max = MFMin(vol.max, tri.verts[b]); vol.min.w = vol.max.w = 0.0f; // if point is outside bounding sphere MFVector diff = tri.verts[b] - vol.boundingSphere; float mag = diff.MagSquared3(); if(mag > vol.boundingSphere.w*vol.boundingSphere.w) { // fit sphere to include point mag = MFSqrt(mag) - vol.boundingSphere.w; mag *= 0.5f; diff.Normalise3(); vol.boundingSphere.Mad3(diff, mag, vol.boundingSphere); vol.boundingSphere.w += mag; } } } break; } default: MFDebug_Assert(false, "Invalid item type"); } }
bool MFCollision_RayCylinderTest(const MFVector& rayPos, const MFVector& rayDir, const MFVector& cylinderPos, const MFVector& cylinderDir, float cylinderRadius, bool capped, MFRayIntersectionResult *pResult, float *pCylinderTime) { MFVector local = rayPos - cylinderPos; float rayD = rayDir.Dot3(cylinderDir); float T0 = local.Dot3(cylinderDir); // bring T0 into 0.0-1.0 range float invMagSq = MFRcp(cylinderDir.MagSquared3()); rayD *= invMagSq; T0 *= invMagSq; // calculate some intermediate vectors MFVector v1 = rayDir - rayD*cylinderDir; MFVector v2 = local - T0*cylinderDir; // calculate coeff in quadratic formula float a = v1.MagSquared3(); float b = (2.0f*v1).Dot3(v2); float c = v2.MagSquared3() - cylinderRadius*cylinderRadius; // calculate the stuff under the root sign, if it's negative no (real) solutions exist float d = b*b - 4.0f*a*c; if(d < 0.0f) // this means ray misses cylinder return false; float root = MFSqrt(d); float rcp2a = MFRcp(2.0f*a); float t1 = (-b - root)*rcp2a; float t2 = (-b + root)*rcp2a; if(t1 > 1.0f || t2 < 0.0f) return false; // the cylinder is beyond the ray.. if(capped || pCylinderTime || pResult) { float t = MFMax(t1, 0.0f); // get the t for the cylinders ray MFVector intersectedRay; intersectedRay.Mad3(rayDir, t, local); float ct = intersectedRay.Dot3(cylinderDir) * invMagSq; if(capped && (ct < 0.0f || ct > 1.0f)) { // we need to test the caps // TODO: this is REALLY slow!! can be majorly improved!! // generate a plane for the cap MFVector point, plane; if(rayD > 0.0f) { // the near one point = cylinderPos; plane = MFCollision_MakePlaneFromPointAndNormal(point, -cylinderDir); } else { // the far one point = cylinderPos + cylinderDir; plane = MFCollision_MakePlaneFromPointAndNormal(point, cylinderDir); } // test the ray against the plane bool collide = MFCollision_RayPlaneTest(rayPos, rayDir, plane, pResult); if(collide) { // calculate the intersection point intersectedRay.Mad3(rayDir, pResult->time, rayPos); intersectedRay.Sub3(intersectedRay, point); // and see if its within the cylinders radius if(intersectedRay.MagSquared3() <= cylinderRadius * cylinderRadius) { return true; } } return false; } if(pResult) { pResult->time = t; pResult->surfaceNormal.Mad3(cylinderDir, -ct, intersectedRay); pResult->surfaceNormal.Normalise3(); } if(pCylinderTime) { *pCylinderTime = ct; } } return true; }
MF_API void MFParticleSystem_AddParticle(MFParticleEmitter *pEmitter) { MFParticleEmitterParameters *pE = &pEmitter->params; MFParticleSystem *pParticleSystem = pE->pParticleSystem; MFParticle *pNew = NULL; if(pParticleSystem->particles.GetLength() < pParticleSystem->params.maxActiveParticles) pNew = pParticleSystem->particles.Create(); if(pNew) { MFParticleParameters *pP = &pParticleSystem->params; pNew->colour = pP->colour; pNew->life = pP->life; pNew->rot = 0.0f; pNew->size = pP->size; switch(pE->type) { case MFET_Point: pNew->pos = pE->position.GetTrans(); break; case MFET_Sphere: case MFET_Disc: { MFVector offset; do { offset = MakeVector(MFRand_Range(-pE->radius, pE->radius), MFRand_Range(-pE->radius, pE->radius), MFRand_Range(-pE->radius, pE->radius)); } while(offset.MagSquared3() > pE->radius*pE->radius); if(pE->type == MFET_Disc) { // flatten it on to the disc float dist = offset.Dot3(pE->position.GetYAxis()); offset -= pE->position.GetYAxis()*dist; } pNew->pos = pE->position.GetTrans() + offset; break; } } switch(pE->behaviour) { case MFEB_Direction: pNew->velocity.Normalise3(pE->startVector); break; case MFEB_TargetAttract: pNew->velocity.Normalise3(pE->startVector - pE->position.GetTrans()); break; case MFEB_TargetRepel: pNew->velocity.Normalise3(pE->position.GetTrans() - pE->startVector); break; } pNew->velocity *= pE->velocity + MFRand_Range(-pE->velocityScatter, pE->velocityScatter); if(pE->directionScatter) { MFVector scatter; do { scatter = MakeVector(MFRand_Range(-1, 1), MFRand_Range(-1, 1), MFRand_Range(-1, 1)); float dist = scatter.Dot3(pE->position.GetYAxis()); scatter -= pE->position.GetYAxis()*dist; } while(scatter.MagSquared3() < 0.000001f); scatter.Normalise3(); MFMatrix scatterMat; scatterMat.SetRotation(scatter, MFRand_Unit()*pE->directionScatter); pNew->velocity = ApplyMatrixH(pNew->velocity, scatterMat); } } }