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Hi, I was trying to make an OpenGL/SDL program with 3D graphics, but the code I've written doesn't work. I made an OpenGL/SDL program that displays in 2D with no problems, so I think my OpenGL code is the problem and not my SDL code (I'm not entirely sure though).

The program runs and displays a black window, and closes when I click the window's close button.

Attached is my C source, which is linked against SDL, SDLmain, OpenGL, and GLU.

#include <SDL/SDL.h>
#include <SDL/SDL_opengl.h>

#include <math.h>

#define WIDTH 640
#define HEIGHT 480
#define BPP 32

#define CUBE_SIZE 6.0
#define CUBE_DEFAULT_SPEED 2.0

typedef struct {
    double x, y; // center point?
    double dx, dy;
    double angle;
    double d_angle;
} cube_t;

cube_t cube;

int running = 1;
SDL_Event event;



int init_GL() {
    glViewport(0, 0, WIDTH, HEIGHT);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    gluPerspective(45.0f, (WIDTH/HEIGHT), 1.0f, 1000.0f);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    gluLookAt(cube.x + 20, cube.y + 20, 20, cube.x, cube.y, 0, 0.0f, 1.0f, 0.0f);

    glEnable(GL_DEPTH_TEST);

    if (glGetError() != GL_NO_ERROR) {
        return 0;
    }

    return 1;
}

void init_objects() {
    cube.x = 20;
    cube.y = 20;
    cube.dx = 0;
    cube.dy = 0;
    cube.angle = 0;
    cube.d_angle = 0;
}

void handle_events() {
    if (SDL_PollEvent(&event)) {
        if (event.type == SDL_KEYDOWN) {
            switch (event.key.keysym.sym) { // stuff will be added here later
            }
        }
        else if (event.type == SDL_KEYUP) {
            switch (event.key.keysym.sym) {}
        }
        else if (event.type == SDL_QUIT) {
            running = 0;
        }
    }
}

void handle_movement() {
    cube.x += cube.dx;
    cube.y += cube.dy;
    cube.angle += cube.d_angle;
}

void handle_collisions() {
}

void render() {
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();

    glTranslatef(cube.x, cube.y, 0);
    glBegin(GL_QUADS);
        // bottom face
        glColor3f(1.0, 1.0, 1.0);
        glVertex3f(0.0, CUBE_SIZE, 0.0); // left back bottom
        glVertex3f(CUBE_SIZE, CUBE_SIZE, 0.0); // right back bottom
        glVertex3f(CUBE_SIZE, 0.0, 0.0); // right front bottom
        glVertex3f(0.0, CUBE_SIZE, 0.0); // left front bottom

        // front face
        glColor3f(0.0, 0.0, 1.0);
        glVertex3f(0.0, 0.0, 0.0); // left front bottom
        glVertex3f(0.0, 0.0, CUBE_SIZE); // left front top
        glVertex3f(CUBE_SIZE, 0.0, CUBE_SIZE); // right front top
        glVertex3f(CUBE_SIZE, 0.0, 0.0); // right front bottom

        // right face
        glColor3f(0.0, 1.0, 0.0);
        glVertex3f(CUBE_SIZE, 0.0, 0.0); // right front bottom
        glVertex3f(CUBE_SIZE, 0.0, CUBE_SIZE); // right front top
        glVertex3f(CUBE_SIZE, CUBE_SIZE, CUBE_SIZE); // right rear top
        glVertex3f(CUBE_SIZE, CUBE_SIZE, 0.0); // right rear bottom

        // left face
        glColor3f(1.0, 1.0, 0.0);
        glVertex3f(0.0, 0.0, 0.0); // left front bottom
        glVertex3f(0.0, 0.0, CUBE_SIZE); // left front top
        glVertex3f(0.0, CUBE_SIZE, CUBE_SIZE); // left rear top
        glVertex3f(0.0, CUBE_SIZE, 0.0); // left rear bottom

        // rear face
        glColor3f(0.0, 1.0, 1.0);
        glVertex3f(0.0, 0.0, 0.0); // left rear bottom
        glVertex3f(0.0, 0.0, CUBE_SIZE); // left rear top
        glVertex3f(CUBE_SIZE, 0.0, CUBE_SIZE); // right rear top
        glVertex3f(CUBE_SIZE, 0.0, 0.0); // right rear bottom

        // top face
        glColor3f(1.0, 0.0, 0.0);
        glVertex3f(0.0, 0.0, CUBE_SIZE); // left front top
        glVertex3f(0.0, CUBE_SIZE, CUBE_SIZE); // left rear top
        glVertex3f(CUBE_SIZE, CUBE_SIZE, CUBE_SIZE); // right rear top
        glVertex3f(CUBE_SIZE, 0.0, CUBE_SIZE); // right front top
    glEnd();

    SDL_GL_SwapBuffers();
}

int main(int argc, char **argv) {
    if (SDL_Init(SDL_INIT_EVERYTHING < 0)) return 1;
    if (SDL_SetVideoMode(WIDTH, HEIGHT, BPP, SDL_OPENGL) == NULL) return 1;
    SDL_WM_SetCaption("Moving Cube", NULL);
    if (init_GL() == 0) return 2;
    
    init_objects();
    
    while (running) {
        handle_events();
        handle_movement();

        render();

        SDL_Delay(1000/60);
    }

    SDL_Quit();
    
    return 0;
}
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Member Avatar for Bluefox815

Fixed the problem, turns out all I had to do was add Z values.

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