コード例 #1
0
ファイル: Transform.c プロジェクト: chunkyguy/EWOGL
Transform Subtract(const Transform one, const Transform two){
 assert(one.parent == two.parent);
 return Transform_Create(GLKVector3Subtract(one.position, two.position),
                         GLKQuaternionSubtract(one.orientation, two.orientation),
                         //                         GLKVector4Subtract(one.rotation, two.rotation),
                         GLKVector3Subtract(one.scale, two.scale),
                         0);
}
コード例 #2
0
ファイル: RAGeographicUtils.c プロジェクト: KrisFu/EarthView
bool IntersectWithEllipsoid( GLKVector3 start, GLKVector3 end, GLKVector3* hit )
{
    // transform endpoints into unit sphere basis
    start = GLKMatrix4MultiplyAndProjectVector3(kEllipsoidToUnitSphere, start);
    end = GLKMatrix4MultiplyAndProjectVector3(kEllipsoidToUnitSphere, end);
    
    // use unit sphere
    const double r = 1.;
    
    GLKVector3 diff = GLKVector3Subtract(end, start);
    
    // calculate quadratic components
    double a = GLKVector3DotProduct( diff, diff );
    double b = GLKVector3DotProduct( GLKVector3MultiplyScalar(diff, 2.0), start );
    double c = GLKVector3DotProduct( start, start ) - ( r * r );
        
    // calculate discriminant
    double disc = ( b * b ) - ( 4.0 * a * c );
    
    // consider intersection for positive disc only (discard edge cases)
    if ( disc > 0.0 ) {
        // calculate two solutions
        double t1 = ( -b - sqrt(disc) ) / ( 2.0 * a );
        double t2 = ( -b + sqrt(disc) ) / ( 2.0 * a );
        
        // calculate points of intersection and normals
        if ( t1 > 0.0 && t1 < 1.0 ) {
            if ( hit ) {
                *hit = GLKVector3Add( start, GLKVector3MultiplyScalar(diff, t1));
                *hit = GLKMatrix4MultiplyAndProjectVector3(kUnitSphereToEllipsoid, *hit);
            }
            
            return true;
        }
        
        if ( t2 > 0.0 && t2 < 1.0 ) {
            if ( hit ) {
                *hit = GLKVector3Add( start, GLKVector3MultiplyScalar(diff, t2));
                *hit = GLKMatrix4MultiplyAndProjectVector3(kUnitSphereToEllipsoid, *hit);
            }
            
            return true;
        }
    }
    
    return false;
}