Exemplo n.º 1
0
/* http://www.opengl.org/documentation/specs/man_pages/hardcopy/GL/html/glu/lookat.html
   http://msdn.microsoft.com/en-us/library/bb205343.aspx
*/
void
RMtx4LookAtRH( RMtx4* out, const RVec3* eye, const RVec3* at, const RVec3* up )
{
#define AX(i) RVec3GetElement( &axis_x, i )
#define AY(i) RVec3GetElement( &axis_y, i )
#define AZ(i) RVec3GetElement( &axis_z, i )

    RVec3 axis_x, axis_y, axis_z;

    RMtx4Identity( out );

    RVec3Sub( &axis_z, eye, at );
    RVec3Normalize( &axis_z, &axis_z );

    RVec3Cross( &axis_x, up, &axis_z );
    RVec3Normalize( &axis_x, &axis_x );

    RVec3Cross( &axis_y, &axis_z, &axis_x );

    SET_ELEMENT( out, 0, 0,  AX(0) );
    SET_ELEMENT( out, 0, 1,  AX(1) );
    SET_ELEMENT( out, 0, 2,  AX(2) );
    SET_ELEMENT( out, 0, 3,  -RVec3Dot(&axis_x, eye) );

    SET_ELEMENT( out, 1, 0,  AY(0) );
    SET_ELEMENT( out, 1, 1,  AY(1) );
    SET_ELEMENT( out, 1, 2,  AY(2) );
    SET_ELEMENT( out, 1, 3,  -RVec3Dot(&axis_y, eye) );

    SET_ELEMENT( out, 2, 0,  AZ(0) );
    SET_ELEMENT( out, 2, 1,  AZ(1) );
    SET_ELEMENT( out, 2, 2,  AZ(2) );
    SET_ELEMENT( out, 2, 3,  -RVec3Dot(&axis_z, eye) );

#undef AX
#undef AY
#undef AZ
}
Exemplo n.º 2
0
void
RQuatToAxisAngle( const RQuat* in, struct RVec3* axis, rmReal* radian )
{
    if ( axis )
    {
        RVec3 a;
        RVec3SetElements( &a, in->x, in->y, in->z );
        RVec3Normalize( axis, &a );
    }

    if ( radian )
    {
        *radian = 2.0f * rmAcos( in->w );
    }
}