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;
}
MFQuaternion MFMatrix::GetRotationQ() const
{
MFQuaternion q;
float trace = m[0] + m[5] + m[10] + 1.0f;
if(trace > 0.0f)
{
float s = MFRSqrt(trace) * 0.5f;
q.w = 0.25f / s;
q.x = (m[9] - m[6]) * s;
q.y = (m[2] - m[8]) * s;
q.z = (m[4] - m[1]) * s;
}
else
{
if(m[0] > m[5] && m[0] > m[10])
{
float s = 2.0f * MFSqrt(1.0f + m[0] - m[5] - m[10]);
float invS = 1.0f / s;
q.x = 0.25f * s;
q.y = (m[1] + m[4]) * invS;
q.z = (m[2] + m[8]) * invS;
q.w = (m[6] - m[9]) * invS;
}
else if(m[5] > m[10])
{
float s = 2.0f * MFSqrt(1.0f + m[5] - m[0] - m[10]);
float invS = 1.0f / s;
q.x = (m[1] + m[4]) * invS;
q.y = 0.25f * s;
q.z = (m[6] + m[9]) * invS;
q.w = (m[2] - m[8]) * invS;
}
else
{
float s = 2.0f * MFSqrt(1.0f + m[10] - m[0] - m[5]);
float invS = 1.0f / s;
q.x = (m[2] + m[8] ) * invS;
q.y = (m[6] + m[9] ) * invS;
q.z = 0.25f * s;
q.w = (m[1] - m[4] ) * invS;
}
}
return q;
}
void MFParticleSystem_DrawRotating(MFParticleSystem *pParticleSystem, const MFMatrix <v)
{
int numParticles = pParticleSystem->particles.GetLength();
if(!numParticles)
return;
float fadeStart = pParticleSystem->params.life - pParticleSystem->params.fadeDelay;
MFMaterial_SetMaterial(pParticleSystem->pMaterial);
MFPrimitive(PT_TriList, 0);
MFBegin(numParticles * 6);
MFParticle **ppI = pParticleSystem->particles.Begin();
while(*ppI)
{
MFParticle *pParticle = *ppI;
float dt = MFSystem_TimeDelta();
pParticle->rot += pParticleSystem->params.rotationRate * dt;
pParticle->size += pParticleSystem->params.scaleRate * dt;
pParticle->velocity += pParticleSystem->params.force * dt;
pParticle->pos += pParticle->velocity * dt;
float t = pParticle->size * 0.5f;
float rad = MFSqrt(t*t*2);
float xoff = MFCos(-pParticle->rot + 0.7853981f)*rad;
float yoff = MFSin(-pParticle->rot + 0.7853981f)*rad;
float alpha = MFMin(pParticle->life / fadeStart, 1.0f);
MFVector pos = ApplyMatrixH(pParticle->pos, ltv);
MFSetColourV(MakeVector(pParticle->colour, pParticle->colour.w * alpha));
MFSetTexCoord1(1, 0);
MFSetPosition(pos.x + xoff, pos.y + yoff, pos.z);
MFSetTexCoord1(0, 1);
MFSetPosition(pos.x - xoff, pos.y - yoff, pos.z);
MFSetTexCoord1(0, 0);
MFSetPosition(pos.x - yoff, pos.y + xoff, pos.z);
MFSetTexCoord1(1, 0);
MFSetPosition(pos.x + xoff, pos.y + yoff, pos.z);
MFSetTexCoord1(1, 1);
MFSetPosition(pos.x + yoff, pos.y - xoff, pos.z);
MFSetTexCoord1(0, 1);
MFSetPosition(pos.x - xoff, pos.y - yoff, pos.z);
pParticle->life -= dt;
if(pParticle->life < 0.0f)
pParticleSystem->particles.Destroy(ppI);
ppI++;
}
MFEnd();
}
void MFInputInternal_ApplySphericalDeadZone(float *pX, float *pY)
{
float length = *pX**pX + *pY**pY;
if(length)
{
length = MFSqrt(length);
float scale = 1.0f / length * MFClamp(0.0f, (length - gGamepadDeadZone) / (1.0f - gGamepadDeadZone), 1.0f);
*pX *= scale;
*pY *= scale;
}
}
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;
}
