CODEWITHSUNDEEP
opengl
Bob
Bob

Reputation: 93

How to draw multiple cubes in OpenGL

I want to draw several cubes using glutSolidCube in some points in space. The examples I have found just call glutSolidCube and it works, but the only way a cube gets drawn for me is if the line is enclosed in glBegin(GL_POLYGON), which isn't required in the examples I've seen, and I only get one cube instead of several. What I have is:

glColor3f(1, 0, 0);
glLoadIdentity();
glTranslatef(5,2,1);
glutSolidCube(1);


glLoadIdentity();
glTranslatef(10,8,0);
glutSolidCube(1);

glLoadIdentity();
glTranslatef(3,7,9);
glutSolidCube(1);

glLoadIdentity();
glTranslatef(1,4,6);
glutSolidCube(1);

When I run this nothing happens. I know there's not a problem with the points being outside my view because if I draw vertices at the same points, I can see them. As far as I can tell from the examples and documentation I've read, I'm not doing anything incorrect. Can someone tell me what I'm doing wrong or give me a snippet of code that draws multiple cubes?

Upvotes: 9

Views: 20037

Answers (2)

genpfault
genpfault

Reputation: 52084

#include <GL/glut.h>

void init()
{
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glEnable(GL_COLOR_MATERIAL);
}

void display()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    GLint viewport[4];
    glGetIntegerv(GL_VIEWPORT, viewport);
    double aspect = (double)viewport[2] / (double)viewport[3];
    gluPerspective(60, aspect, 1, 100);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    // move back a bit
    glTranslatef( 0, 0, -35 );

    static float angle = 0;
    angle += 1.0f;

    glPushMatrix();
        glTranslatef(0,0,0);
        glRotatef(angle, 0.1, 0.2, 0.5);
        glColor3ub(255,0,255);
        glutSolidCube(5);
    glPopMatrix();

    glPushMatrix();
        glTranslatef(10,-10,0);
        glRotatef(angle, 0.1, 0.2, 0.5);
        glColor3ub(255,0,0);
        glutSolidCube(5);
    glPopMatrix();

    glPushMatrix();
        glTranslatef(10,10,0);
        glRotatef(angle, 0.1, 0.2, 0.5);
        glColor3ub(0,255,0);
        glutSolidCube(5);
    glPopMatrix();

    glPushMatrix();
        glTranslatef(-10,10,0);
        glRotatef(angle, 0.1, 0.2, 0.5);
        glColor3ub(0,0,255);
        glutSolidCube(5);
    glPopMatrix();

    glPushMatrix();
        glTranslatef(-10,-10,0);
        glRotatef(angle, 0.1, 0.2, 0.5);
        glColor3ub(255,255,0);
        glutSolidCube(5);
    glPopMatrix();

    glutSwapBuffers();
}

void reshape(int w, int h)
{
    glViewport(0, 0, w, h);
}

void timer(int extra)
{
    glutPostRedisplay();
    glutTimerFunc(16, timer, 0);
}

int main(int argc, char **argv)
{
    glutInit(&argc, argv);
    glutInitWindowSize(640,480);
    glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE);
    glutCreateWindow("CUBES");

    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutTimerFunc(0, timer, 0);

    init();

    glutMainLoop();
    return 0;
}

Upvotes: 7

John Alexiou
John Alexiou

Reputation: 29244

Try this:

glColor3f(1, 0, 0);
glPushMatrix();
glTranslatef(5,2,1);
glutSolidCube(1);
glPopMatrix();

glPushMatrix();
glTranslatef(10,8,0);
glutSolidCube(1);
glPopMatrix();

glPushMatrix();
glTranslatef(3,7,9);
glutSolidCube(1);
glPopMatrix();

glPushMatrix();
glTranslatef(1,4,6);
glutSolidCube(1);
glPopMatrix();

Without re-setting the model view matrix with glLoadIdentity(). Note that to start with you need to call glOrtho() or glPerspective() to set the camera once.

Upvotes: 9

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