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/*
* Simple trackball-like motion adapted (ripped off) from projtex.c
* (written by David Yu and David Blythe). See the SIGGRAPH '96
* Advanced OpenGL course notes.
*/
/* includes */
#include <math.h>
#include <assert.h>
#ifdef __APPLE_CC__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
#include "tb.h"
#include "trackball.h"
/* globals */
static GLuint tb_lasttime;
float curquat[4];
float lastquat[4];
int beginx, beginy;
static GLuint tb_width;
static GLuint tb_height;
static GLint tb_button = -1;
static GLboolean tb_tracking = GL_FALSE;
static GLboolean tb_animate = GL_TRUE;
static void
_tbAnimate(void)
{
add_quats(lastquat, curquat, curquat);
glutPostRedisplay();
}
void
_tbStartMotion(int x, int y, int time)
{
assert(tb_button != -1);
glutIdleFunc(0);
tb_tracking = GL_TRUE;
tb_lasttime = time;
beginx = x;
beginy = y;
}
void
_tbStopMotion(unsigned time)
{
assert(tb_button != -1);
tb_tracking = GL_FALSE;
if (time == tb_lasttime && tb_animate) {
glutIdleFunc(_tbAnimate);
} else {
if (tb_animate) {
glutIdleFunc(0);
}
}
}
void
tbAnimate(GLboolean animate)
{
tb_animate = animate;
}
void
tbInit(GLuint button)
{
tb_button = button;
trackball(curquat, 0.0, 0.0, 0.0, 0.0);
}
void
tbMatrix(void)
{
GLfloat m[4][4];
assert(tb_button != -1);
build_rotmatrix(m, curquat);
glMultMatrixf(&m[0][0]);
}
void
tbReshape(int width, int height)
{
assert(tb_button != -1);
tb_width = width;
tb_height = height;
}
void
tbMouse(int button, int state, int x, int y)
{
assert(tb_button != -1);
if (state == GLUT_DOWN && button == tb_button)
_tbStartMotion(x, y, glutGet(GLUT_ELAPSED_TIME));
else if (state == GLUT_UP && button == tb_button)
_tbStopMotion(glutGet(GLUT_ELAPSED_TIME));
}
void
tbMotion(int x, int y)
{
if (tb_tracking) {
trackball(lastquat,
(2.0 * beginx - tb_width) / tb_width,
(tb_height - 2.0 * beginy) / tb_height,
(2.0 * x - tb_width) / tb_width,
(tb_height - 2.0 * y) / tb_height
);
beginx = x;
beginy = y;
tb_animate = 1;
tb_lasttime = glutGet(GLUT_ELAPSED_TIME);
_tbAnimate();
}
}
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