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/* ----------------------------------------------------------------------- *
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 * This file is part of GEL, http://www.imm.dtu.dk/GEL
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 * Copyright (C) the authors and DTU Informatics
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 * For license and list of authors, see ../../doc/intro.pdf
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 * ----------------------------------------------------------------------- */
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#include "../GL/glew.h"
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#include "GLViewController.h"
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#include "SimpleTrackBall.h"
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using namespace std;
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using namespace CGLA;
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namespace GLGraphics
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{
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		void SimpleTrackBall::roll_x(float dx)
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		{
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				float mouse_sign = ((dx<0)?-1.0f:1.0f);
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				phi += mouse_sign * da;
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		}
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		void SimpleTrackBall::roll_y(float dy)
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		{
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				float sgn = (dy<0)?1.0f:-1.0f;
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				theta += sgn * da;
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				theta = min(float(M_PI)-0.001f, max(0.0001f, theta));
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		}
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		void SimpleTrackBall::up_axis(char up)
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		{
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				switch(up)
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				{
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						case 'x':
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						case 'X':
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								X=1;
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								Y=2;
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								Z=0;
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								break;
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						case 'y':
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						case 'Y':
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								X=0;
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								Y=1;
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								Z=2;
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								break;
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						case 'z':
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						case 'Z':
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								X=2;
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								Y=0;
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								Z=1;
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								break;
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				}
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				theta = static_cast<float>(M_PI_2);
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				phi = 0;
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		}
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/** Call this to set up OpenGL viewing matrix. It will also
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		clear the view matrix. */
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		void SimpleTrackBall::gl_view() const
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		{
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				const Vec3f up(0,1,0);
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				float x = r * sin(theta) * cos(phi);
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				float y = r * cos(theta);
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				float z = r * sin(theta) * sin(phi);
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				Vec3f dir(x,y,z);
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				Vec3f e = center + Vec3f(dir[X], dir[Y], dir[Z]);
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				glLoadIdentity();
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				gluLookAt(e[0],e[1],e[2],
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									center[0],center[1],center[2],
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									up[X], up[Y], up[Z]);
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		}
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/** Roll ball. Call with the x,y coordinates. This function is typically
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		called from GLUT's mouse motion callback. */
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		void SimpleTrackBall::roll(int x, int y)
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		{
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				if(firsttime)
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						firsttime=false;
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				else
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				{
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						float dx = x - oldx;
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						float dy = y - oldy;
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						if(dx*dx>dy*dy)
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								roll_x(dx);
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						else
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								roll_y(dy);
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				}
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				oldx = x;
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				oldy = y;
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		}
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}