CODEWITHSUNDEEP
c++opengl
gn66
gn66

Reputation: 853

How do I move an object in c++/opengl to a new place and erase the old object

I'm making Pacman game in opengl and I want to move my pacman in the game represented by a matrix.

The matrix have 16x16 and i put 4's when I whant to draw the walls, 3 for the small spheres and 2 for the pacman.

In the main class of my project I read a key from keyboard and i send the information to the class I defined the game. In that class I have this function:

void boardGame::refreshPacman(int n, int m)
{

    int x, y;


    (* pacman).movePacman(n, m); // This is working, it send information to class Pacman. In there I store the n (x axe) and m(y axe), and i get the next coordinates where pacman should translate.


    x = (* pacman).getPacX(); // get coordinate of the old pacman
    y = (* pacman).getPacY(); // get coordinate of the old pacman

    board[x][y] = 0; // delete old information of pacman in matrix 

    x += n; // set the coordinates of x axis for new pacman
    y += m; // set the coordinates of y axis for new pacman

    wall[x][y] = 2; // insert the information of new pacman in matrix

    pac->redraw (x, y, 0.5); // construct the new pacman
}

Pacman It's not beeing erased. Can you tell me what do I need to do next, and waht am I doing wrong?

Upvotes: 0

Views: 1259

Answers (2)

datenwolf
datenwolf

Reputation: 162164

Pacman It's not beeing erased. Can you tell me what do I need to do next, and waht am I doing wrong?

OpenGL is not a scenegraph (this is becomming the one statement I'm apparently make in almost every answer). It's a drawing API, which allows you to draw dancy points, lines and triangles. There's no concept of "geometric objects".

If you change something: Clear the old picture and draw a new one!

Upvotes: 4

ApprenticeHacker
ApprenticeHacker

Reputation: 22011

Use the -> operator with class pointers.

(* pacman).movePacman(n, m);

Should be:

pacman->movePacman(n,m);

To erase the earlier pacman, try redrawing the screen before adding the new one. Also, does the pacman destructor internally also end the rendering of the pacman image/sprite?

Upvotes: 2

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