CODEWITHSUNDEEP
c++opengl
GroniumArgor
GroniumArgor

Reputation: 113

moving camera using glOrtho

I'm having a problem with moving my camera with glOrtho. I have a small quad in the center and i want to try to move the camera using glOrtho, but it just doesn't seem to be working. The quad doesn't move at all, so the camera isn't moving too i guess. maybe i miss understand how glOrtho works? here is my code so far. 

void Camera::updateCamera(float x, float y, float zoom)
{
    camX = x;
    camY = y;
    this->zoom = zoom;
    viewWidth = 320;
    viewHeight = 240;
    //viewWidth = tan(60) * this->zoom;
    //viewHeight = tan(45) * this->zoom;    
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(camX - viewWidth,
        camX + viewWidth,
        camY - viewHeight,
        camY + viewHeight,
        -1,
        1);
    glMatrixMode(GL_MODELVIEW);
}

and here is where i apply it. i tried to move it along the x axis for 25 points.

void Engine::renderAll()
{
    x += 25;
    glClear(GL_COLOR_BUFFER_BIT);
    shader->use();
    camera.updateCamera(x, y, 1.0);
    //shader->setUniform4fv("view", camera.getView());
    batchManager->renderBatches();
    SDL_GL_SwapWindow(window);
}

Upvotes: 0

Views: 975

Answers (1)

Amadeus
Amadeus

Reputation: 10655

Yes, I guess you misundertood how glOrtho works. The role of glOrtho is transform a 3D view in a 2D view, using an orthographic projection.

If you want to work with positioning camera in a 3D space, the correct function is normally called LookAt. Once, it seems me that you are using old OpenGL, you can try the glu function gluLookAt

PS. In moderm openGL, this functions is now deprecated. I suggest you to try to learn the modern way.

Upvotes: 0

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