forked from 0ad/0ad
janwas
5bf9bca9ef
there are too many W4 and "potentially uninitialized", so those are disabled by 0ad_warning_disable.h. the silly "int x = strlen" and very dangerous "int x = (void*)p" (and vice versa) problems are fixed. This was SVN commit r5526.
88 lines
2.5 KiB
C++
88 lines
2.5 KiB
C++
#include "precompiled.h"
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#include "0ad_warning_disable.h"
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# include <math.h>
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# include "sr_trackball.h"
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# include "sr_mat.h"
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//# define SR_USE_TRACE1
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# include "sr_trace.h"
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//=================================== SrTrackball ===================================
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SrTrackball::SrTrackball ()
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{
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init ();
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}
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SrTrackball::SrTrackball ( const SrTrackball& t )
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:rotation(t.rotation), last_spin(t.last_spin)
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{
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}
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void SrTrackball::init ()
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{
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rotation = SrQuat::null;
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}
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SrMat& SrTrackball::get_mat ( SrMat &m ) const
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{
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rotation.get_mat ( m );
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return m;
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}
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/* Project an x,y pair onto a sphere of radius r OR a hyperbolic sheet
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if we are away from the center of the sphere. */
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static float tb_project_to_sphere ( float r, float x, float y )
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{
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float d, t, z;
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d = sqrtf(x*x + y*y);
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if ( d < r*srsqrt2/2.0f ) z=sqrtf(r*r-d*d); // Inside sphere
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else { t=r/srsqrt2; z=t*t/d; } // On hyperbola
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return z;
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}
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void SrTrackball::get_spin_from_mouse_motion ( float p1x, float p1y, float p2x, float p2y, SrQuat& spin )
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{
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SrVec p1, p2, d, a; // a==Axes of rotation
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const float size=0.8f;
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float t;
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if ( p1x==p2x && p1y==p2y ) { spin=SrQuat::null; return; }
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// figure out z-coordinates for projection of P1 and P2 to deformed sphere
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p1.set ( p1x, p1y, tb_project_to_sphere(size,p1x,p1y) );
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p2.set ( p2x, p2y, tb_project_to_sphere(size,p2x,p2y) );
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a = cross ( p1, p2 ); // axis
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d = p1-p2; // how much to rotate around that axis.
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t = d.norm() / (2.0f*size);
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t = SR_BOUND ( t, -1.0f, 1.0f ); // avoid problems with out-of-control values...
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float ang = 2.0f * asinf(t);
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spin.set ( a, ang ); // a is normalized inside rot() :
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}
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void SrTrackball::increment_from_mouse_motion ( float lwinx, float lwiny, float winx, float winy )
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{
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get_spin_from_mouse_motion ( lwinx, lwiny, winx, winy, last_spin );
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rotation = last_spin * rotation;
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}
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void SrTrackball::increment_rotation ( const SrQuat& spin )
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{
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last_spin = spin;
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rotation = last_spin * rotation;
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}
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//=============================== friends ==========================================
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SrOutput& operator<< ( SrOutput& out, const SrTrackball& tb )
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{
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out << "rotat: " << tb.rotation << srnl <<
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"spin: " << tb.last_spin << srnl;
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return out;
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}
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//================================ End of File =========================================
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