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#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <time.h>
#ifdef WIN32
#include <windows.h>
#include <float.h>
#define isnan(x) _isnan(x)
#endif
#include <GL/gl.h>
#include <GL/glu.h>
#ifndef M_PI
#define M_PI 3.14159265358979323846264338327950288
#endif
#include "math/vector.h"
#include "exception.h"
#include "camerahandler.h"
#include "demolib_prefs.h"
#if DEMOLIB_MAINLOOP
CameraHandler::CameraHandler(MainLoop *ml, const char *title, const char *elem, Hashtable *attr) :
Event(ml, title, elem, attr, "x:y:z:lx:ly:lz:zrot")
{
this->gravity = attr->get_float("gravity");
this->layer = -60.0f;
}
CameraHandler::~CameraHandler()
{
}
void CameraHandler::start_effect() { }
#define DELTA 0.01f
#define MULTDELTA 100.0f
void CameraHandler::draw_scene(float progress)
{
/* get our position */
Vector pos(this->get_val("x", progress),
this->get_val("y", progress),
this->get_val("z", progress));
/* determine two speeds, and thus get the acceleration */
Vector pos1(this->get_val("x", progress + DELTA),
this->get_val("y", progress + DELTA),
this->get_val("z", progress + DELTA));
Vector sp1 = (pos1 - pos) * MULTDELTA;
Vector pos2(this->get_val("x", progress + DELTA * 2.0f),
this->get_val("y", progress + DELTA * 2.0f),
this->get_val("z", progress + DELTA * 2.0f));
Vector sp2 = (pos2 - pos1) * MULTDELTA;
Vector acc = (sp2 - sp1) * MULTDELTA;
/*
* find the "left" vector, relative to the absolute up position,
* and the forward component
*/
Vector up(0.0f, 1.0f, 0.0f);
Vector left = sp1.cross_product(up).normalize();
/*
* find the acceleration in the "left" direction
*/
float acc_proj = acc * left;
/*
* find the rotation by a/g
*/
float camrot = acos(acc_proj / this->gravity) - M_PI / 2.0f;
if (left.x < 0.0f) {
if (camrot < 0.0f) camrot = -camrot;
} else {
if (camrot > 0.0f) camrot = -camrot;
}
const float x = pos.x;
const float y = pos.y;
const float z = pos.z;
const float lx = this->get_val("lx", progress);
const float ly = this->get_val("ly", progress);
const float lz = this->get_val("lz", progress);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
if (camrot > -M_PI && camrot < M_PI && !isnan(camrot)) {
gluLookAt(x, y, z, lx, ly, lz, sin(camrot), cos(camrot), 0.0f);
} else {
gluLookAt(x, y, z, lx, ly, lz, 0.0f, 1.0f, 0.0f);
}
glTranslatef(x, y, z);
glRotatef(this->get_val("zrot", progress), lx - x, ly - y, lz - z);
glTranslatef(-x, -y, -z);
}
void CameraHandler::end_effect() {}
#endif
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