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Je dois écrire une fonction qui détecte l'intersection et retourne vrai ou faux. J'ai le fichier Shape.cpp, et les fichiers rectangle.cpp, circle.cpp héritent de celui-ci. J'ai essayé de le calculer, mais j'ai échoué. Il n'y a pas d'erreur, mais quand mon programme démarre, il plante. Ma question est pourquoi il se bloque? est mon chemin? Voici le fichier circle.cpp.Comment écrire une fonction d'intersection pour n'importe quel type de formes
bool Circ::intersects(Shape* pshape)
{
Rect *p1 = dynamic_cast<Rect*>(pshape);
Circ *p2 = dynamic_cast<Circ*>(pshape);
if(p1)
{
float circleDistance_x = abs(p2->getPos().x - p1->getPos().x);
float circleDistance_y = abs(p2->getPos().y - p1->getPos().y);
if(circleDistance_x > (p1->getSize().x/2 + p2->getRad()))
return false;
if(circleDistance_y > (p1->getSize().y/2 + p2->getRad()))
return false;
if(circleDistance_x <= (p1->getSize().x/2))
return true;
if(circleDistance_y <= (p1->getSize().y/2))
return true;
float cornerDistance_sq = (circleDistance_x - (p1->getSize().x/2)) + (circleDistance_y - (p1->getSize().y/2))*(circleDistance_y - (p1->getSize().y/2));
return (cornerDistance_sq <= p2->getRad()^2);
}
return false;
}
Ce n'est pas le code tout ce que je veux écrire. Mais quand ça échoue, je me suis arrêté pour écrire.
et mon fichier Shapes.h
#ifndef _SHAPES_H
#define _SHAPES_H
struct Point2d
{
float x, y;
};
struct Point3d
{
float r, g, b;
};
class Shape
{
protected:
bool m_bMarked;
Point3d m_col;
Point2d m_veldir;
Point2d m_pos;
float m_vel;
public:
Shape(Point2d& pos, Point2d& veldir, float vel, Point3d& col)
:m_pos(pos),m_veldir(veldir),m_vel(vel),m_col(col)
{
m_bMarked = false;
}
virtual ~Shape() {}
virtual void draw() = 0;
virtual bool intersects(Shape*) = 0;
inline void move() { m_pos.x += m_veldir.x*m_vel; m_pos.y += m_veldir.y*m_vel; }
inline void invert_xdir() { m_veldir.x *= -1; }
inline void invert_ydir() { m_veldir.y *= -1; }
inline void MarkShape() { m_bMarked = true; }
inline void UnMarkShape() { m_bMarked = false; }
inline bool isMarked() { return m_bMarked; }
inline void increase_vel() { m_vel += 0.01f; }
inline void decrease_vel() { m_vel -= 0.01f; }
};
#endif
Et enfin mon fichier ShapesMain.cpp
#include <time.h>
#include <GL/glut.h>
#include <cmath>
#include "Rectangle.h"
#include "Circle.h"
// YOU CAN CHANGE THE NUMBER OF SHAPES
#define SHAPE_COUNT 20
// YOU CAN MODIFY WINDOW SIZE BY CHANGING THESE
// YOU MAY ALSO VIEW WINDOW IN FULL SCREEN
#define WINDOWX 500
#define WINDOWY 500
// UNCOMMENT THE LINE BELOW TO STOP MOVING SHAPES
//#define NO_MOTION
// CHANGE THESE DIMENSIONS HOWEVER YOU LIKE
#define MAX_SHAPE_DIM 70
#define MIN_SHAPE_DIM 10
float g_windowWidth = WINDOWX;
float g_windowHeight = WINDOWY;
Shape* g_shapeList[SHAPE_COUNT];
int g_numShapes = 0;
bool g_bShowIntersection = true;
//------------------------------------
void Initialize()
{
srand (time(NULL));
// delete previous shapes, if there is any
if (g_numShapes > 0)
{
for (int i = 0; i < g_numShapes; i++)
delete g_shapeList[i];
}
// create a new shape repository
do {
g_numShapes = rand() % SHAPE_COUNT; // number of shapes are randomly determined
} while (g_numShapes < 5); // we dont want to have less than 5 shapes
int rect_count = g_numShapes * (rand() % 10/10.0f);
int circle_count = g_numShapes - rect_count;
int half_wind_x = 3* g_windowWidth/4;
int half_wind_y = 3* g_windowHeight/4;
int max_dim = MAX_SHAPE_DIM; // max dim. of any shape
int min_dim = MIN_SHAPE_DIM; // min dim. of any shape
int quad_wind = g_windowWidth/4;
for (int i= 0; i<g_numShapes; i++)
{
float x, y;
float v1, v2;
// set positions
do {
x = rand() % half_wind_x;
} while (x <= quad_wind);
do {
y = rand() % half_wind_y;
} while (y <= quad_wind);
Point2d pos = { x,y };
// set velocity directions
do{
v1 = rand() % 10/10.0f;
v2 = rand() % 10/10.0f;
} while (v1 == 0 || v2 == 0);
v1 *= (rand() % 2) ? -1 : 1;
v2 *= (rand() % 2) ? -1 : 1;
float vnorm = sqrt(v1*v1 + v2*v2);
Point2d veldir = { v1/vnorm, v2/vnorm };
// set velocity
float vel;
do {
vel = rand() % 2/10.0f;
} while (vel == 0);
#ifdef NO_MOTION
vel = 0.0f;
#endif
//set color
float R = rand()%100/100.0f;
float G = rand()%100/100.0f;
float B = rand()%100/100.0f;
Point3d color = { R,G,B };
// construct objects
if (i < rect_count)
{
float wx;
float wy;
do {
wx = rand() % quad_wind;
} while (wx < min_dim || wx>max_dim);
do {
wy = rand() % quad_wind;
} while (wy < min_dim || wy>max_dim);
Point2d size = { wx, wy };
Rect* pRect = new Rect(pos, size, veldir, vel, color);
g_shapeList[i] = pRect;
}
else
{
float rad;
do {
rad = rand() % quad_wind;
} while (rad < min_dim || rad>max_dim);
Circ* pCirc = new Circ(pos, rad, veldir, vel, color);
g_shapeList[i] = pCirc;
}
}
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
}
//-------------------------------------
// This function handles the intersections of shapes.
// if the user is not interested in marking intersections
// s/he can set bMarkIntersections to false..in this case
// no intersection test is performed
void MarkObjects(bool bMarkIntersections)
{
if (bMarkIntersections == false)
{
for (int i = 0; i < g_numShapes; i++)
g_shapeList[i]->UnMarkShape();
}
else
{
// reset the states of all shapes as unmarked
for (int i = 0; i < g_numShapes; i++)
g_shapeList[i]->UnMarkShape();
for (int i = 0; i < g_numShapes; i++)
{
for (int j = i+1; j < g_numShapes; j++)
{
if (g_shapeList[i]->intersects(g_shapeList[j]))
{
g_shapeList[i]->MarkShape();
g_shapeList[j]->MarkShape();
}
}
}
}
}
//------------------------------------
void UpdateData()
{
// create viewport bounding rectangles to keep the shapes within the viewport
Point2d Winpos = { -1.0,0.0 };
Point2d Winsize = { 1.0 , g_windowHeight };
Point2d Winveldir = { 0,0 }; // dummy veldir
float Winvel = 0.0f; //not moving
Point3d Wincol = { 0,0,0 }; // dummy color
Rect WindowRectLeft(Winpos, Winsize, Winveldir, Winvel, Wincol);
Winpos.x = 0.0; Winpos.y = -1.0;
Winsize.x = g_windowWidth; Winsize.y = 1.0;
Rect WindowRectBottom(Winpos, Winsize, Winveldir, Winvel, Wincol);
Winpos.x = g_windowWidth; Winpos.y = 0.0;
Winsize.x = 1; Winsize.y = g_windowHeight;
Rect WindowRectRight(Winpos, Winsize, Winveldir, Winvel, Wincol);
Winpos.x = 0.0; Winpos.y = g_windowHeight;
Winsize.x = g_windowWidth; Winsize.y = 1.0f;
Rect WindowRectUp(Winpos, Winsize, Winveldir, Winvel, Wincol);
for (int i = 0; i < g_numShapes; i++)
{
// move the shape
g_shapeList[i]->move();
// if it bounces to the window walls, invert its veldir
if (g_shapeList[i]->intersects(&WindowRectLeft) ||
g_shapeList[i]->intersects(&WindowRectRight))
g_shapeList[i]->invert_xdir();
if (g_shapeList[i]->intersects(&WindowRectBottom) ||
g_shapeList[i]->intersects(&WindowRectUp))
g_shapeList[i]->invert_ydir();
}
}
//------------------------------------
void ChangeSize(GLsizei w, GLsizei h)
{
if(h == 0)
h = 1;
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
g_windowHeight = h;
g_windowWidth = w;
glOrtho(0, g_windowWidth, 0, g_windowHeight , 1.0f, -1.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
//------------------------------------
void processNormalKeys(unsigned char key, int x, int y)
{
if (key == 'q') // PRESS 'q' to terminate the application
exit(0);
if(key=='r') // PRESS 'r' ket to reset the shapes
Initialize();
if (key == 's') // toggle between showing the intersections or not
g_bShowIntersection = g_bShowIntersection ? false: true;
}
//------------------------------------
void processSpecialKeys(int key, int x, int y)
{
switch(key) {
case GLUT_KEY_LEFT :
break;
case GLUT_KEY_RIGHT :
break;
case GLUT_KEY_UP:
// PRESSING UP ARROW KEY INCREASES THE SHAPE VELOCITIES
for (int i = 0; i < g_numShapes; i++)
g_shapeList[i]->increase_vel();
break;
case GLUT_KEY_DOWN:
// PRESSING DOWN ARROW KEY DECREASES THE SHAPE VELOCITIES
for (int i = 0; i < g_numShapes; i++)
g_shapeList[i]->decrease_vel();
break;
}
}
//-------------------------------------
void display() {
glClear(GL_COLOR_BUFFER_BIT); // Clear the color buffer
glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
UpdateData();
MarkObjects(g_bShowIntersection);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
for (int i= 0; i<g_numShapes; i++)
g_shapeList[i]->draw();
glutSwapBuffers();
}
//------------------------------------
int main(int argc, char* argv[])
{
glutInit(&argc, argv); // Initialize GLUT
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
glutInitWindowPosition(100,100);
glutInitWindowSize(WINDOWX, WINDOWY);
glutCreateWindow("COM102B - PA4");
// Register callback handler for window re-paint
glutDisplayFunc(display);
glutReshapeFunc(ChangeSize);
glutIdleFunc(display);
glutKeyboardFunc(processNormalKeys);
glutSpecialFunc(processSpecialKeys);
Initialize();
glutMainLoop(); // Enter infinitely event-processing loop
return 0;
}
Les formes se déplacent dans la fenêtre et vous voulez savoir quand elles se chevauchent? Si c'est le cas, vous devez suivre la zone dans laquelle se trouve la forme, puis comparer si cette zone est occupée par une autre forme. Vous pouvez définir une "grille" dans la fenêtre et calculer où est chaque forme si deux ou plusieurs formes occupent la même coordonnée de grille, eh bien, elles se croisent. Eh bien, c'est comme ça que j'attaquerais le problème ... –