void Physics::Forces(Vektor &velocity, float c, float aWeight, float dt)
{
Vektor Fg = Physics::Gravity(aWeight);
Vektor Fd = Physics::AirResistance(velocity, c);
if(velocity.z < 0)
Fd.z = -Fd.z;
if(velocity.x < 0)
Fd.x = -Fd.x;
Vektor Ft = Vektor(Fd.x + Fg.x, Fd.y + Fg.y, Fd.z + Fg.z);
Vektor acc = Vektor((Ft.x / aWeight), (Ft.y / aWeight), (Ft.z / aWeight));
Physics::VelocityChange(velocity, acc, dt);
}
Vektor Physics::Wind()
{
float wind_x = 0; float wind_y = 0;
wind_x = hge->Random_Float(-7.5f, 7.5f); // by removing half of what the maximum value can be,
wind_y = hge->Random_Float(-7.5f, 7.5f); // roughly 50% of the values will be negative
return Vektor(wind_x, wind_y, 0); // wind speed will be -7.5 < (x,y) < 7.5 => max speed = sqrt(2*7.49) ~= 10.6 m/s
}
Vektor Physics::AirResistance(Vektor &velocity, float c)
{
//F=c*v^2
float Fx = c * pow(velocity.x, 2);
float Fy = c * pow(velocity.y, 2);
float Fz = c * pow(velocity.z, 2);
return Vektor(Fx, Fy, Fz);
}
//Rendering functions.
void MAPGEN::set_light(float az, float alt){
az *= 0.034906585;
alt *= 0.0174532925;
float lx, ly, lz;
lx = 10*sin(az);
ly = -10*cos(az);
lz = 10*sin(alt);
lx *= cos(alt);
ly *= cos(alt);
ljus=Vektor(lx, ly, lz);
}
Vektor Physics::CrossProduct(Vektor first, Vektor second)
{
float x,y,z;
//Räknar ut vektorprodukt mellan två vektorer
x = first.y * second.z - first.z * second.y;
y = first.z * second.x - first.x * second.z;
z = first.x * second.y - first.y * second.x;
return Vektor(x, y, z);
}
Vektor Physics::ArrowInitialVelocity(Bow *bow, float aWeight, float angleUD, float angleSTS)
{
// Calculate initiate speed for the arrow.
float velocity = (sqrt(bow->GetEp() * 2 / (aWeight + bow->GetK() * bow->GetWeight())) * 100);
// Convert angle from degrees to radians.
float angleUDrad = M_PI / 2 - Physics::DegreeToRad(angleUD);
float angleSTSrad = M_PI / 2 - Physics::DegreeToRad(angleSTS);
// Using Spherical coordinate system to find out the velocity-vector using 2 angles.
float v_x = velocity * sin(angleUDrad) * cos(angleSTSrad);
float v_y = velocity * sin(angleUDrad) * sin(angleSTSrad);
float v_z = velocity * cos(angleUDrad);
return Vektor(v_x, v_y, v_z);
}
Vektor
bicubic_bezier_patch::normal ( float u,float v )
{
float h[4][4];
memcpy ( h,m_ps,16*sizeof ( float ) );
h[0][0]= ( 1-u ) * ( ( 1-v ) *h[0][0]+v*h[0][1] ) +u* ( ( 1-v ) *h[1][0]+v*h[1][1] );
h[0][1]= ( 1-u ) * ( ( 1-v ) *h[0][1]+v*h[0][2] ) +u* ( ( 1-v ) *h[1][1]+v*h[1][2] );
h[0][2]= ( 1-u ) * ( ( 1-v ) *h[0][2]+v*h[0][3] ) +u* ( ( 1-v ) *h[1][2]+v*h[1][3] );
h[1][0]= ( 1-u ) * ( ( 1-v ) *h[1][0]+v*h[1][1] ) +u* ( ( 1-v ) *h[2][0]+v*h[2][1] );
h[1][1]= ( 1-u ) * ( ( 1-v ) *h[1][1]+v*h[1][2] ) +u* ( ( 1-v ) *h[2][1]+v*h[2][2] );
h[1][2]= ( 1-u ) * ( ( 1-v ) *h[1][2]+v*h[1][3] ) +u* ( ( 1-v ) *h[2][2]+v*h[2][3] );
h[2][0]= ( 1-u ) * ( ( 1-v ) *h[2][0]+v*h[2][1] ) +u* ( ( 1-v ) *h[3][0]+v*h[3][1] );
h[2][1]= ( 1-u ) * ( ( 1-v ) *h[2][1]+v*h[2][2] ) +u* ( ( 1-v ) *h[3][1]+v*h[3][2] );
h[2][2]= ( 1-u ) * ( ( 1-v ) *h[2][2]+v*h[2][3] ) +u* ( ( 1-v ) *h[3][2]+v*h[3][3] );
h[0][0]= ( 1-u ) * ( ( 1-v ) *h[0][0]+v*h[0][1] ) +u* ( ( 1-v ) *h[1][0]+v*h[1][1] );
h[0][1]= ( 1-u ) * ( ( 1-v ) *h[0][1]+v*h[0][2] ) +u* ( ( 1-v ) *h[1][1]+v*h[1][2] );
h[1][0]= ( 1-u ) * ( ( 1-v ) *h[1][0]+v*h[1][1] ) +u* ( ( 1-v ) *h[2][0]+v*h[2][1] );
h[1][1]= ( 1-u ) * ( ( 1-v ) *h[1][1]+v*h[1][2] ) +u* ( ( 1-v ) *h[2][1]+v*h[2][2] );
return Vektor ( - ( ( ( ( 1-v ) *h[0][1]+v *h[1][1] )- ( ( 1-v ) *h[0][0]+v *h[1][0] ) ) / 1 ),
- ( ( ( ( 1-u ) *h[1][0]+u *h[1][1] )- ( ( 1-u ) *h[0][0]+u *h[0][1] ) ) / 1 ),
3 );
}
Vektor Physics::Gravity(float aWeight)
{
float Fz = GRAV * aWeight;
return Vektor(0, 0, Fz);
}
Vektor Vektor::operator*(double lhs)
{
return Vektor(v1*lhs, v2*lhs, v3*lhs);
}