CODEWITHSUNDEEP
openglsfml
newprogrammer
newprogrammer

Reputation: 2604

OpenGL: Renderbuffer, depth buffer

I've been switching from freeglut to SFML for OpenGL 3.3 context/window creation. Now when I use freeglut and initialize the display mode with

unsigned int displayMode = GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH | GLUT_STENCIL;
glutInitDisplayMode (displayMode);

I can simply then type

glEnable(GL_DEPTH_TEST);
glDepthMask(GL_TRUE);
glDepthFunc(GL_LEQUAL);
glDepthRange(0.0f, 1.0f);

and then depth testing will be enabled. However, in SFML, it's a little more complicated. I won't go into the SFML code, but basically SFML creates a context/window for you. You can specify the number of depth bits and stencil bits, but it seems SFML does not actually allocate the depth buffer and attach it to the default framebuffer.

So how do I actually do this? I'm guessing you have to do something like glGenRenderbuffers, then glBindRenderbuffer then glRenderbufferStorage then glFramebufferRenderbuffer. The documentation is a little confusing. glRenderbufferStorage takes an internalformat parameter, and I'm not really sure how to indicate that I want a 24 bit depth buffer. Also, I'm not really sure how to access the default framebuffer (or are there two default framebuffers, because there's double buffering?).

Upvotes: 1

Views: 1943

Answers (2)

Jobin
Jobin

Reputation: 6984

In SFML depth can be enabled by ContextSettings. 

//Configuring SFML window
sf::ContextSettings window_settings;
window_settings.depthBits         = 24; // Request a 24-bit depth buffer
window_settings.stencilBits       = 8;  // Request a 8 bits stencil buffer
window_settings.antialiasingLevel = 2;  // Request 2 levels of antialiasing

// Opening SFML window
sf::Window window(sf::VideoMode(800, 600), "Title", sf::Style::Resize | sf::Style::Close, window_settings);
glewExperimental = GL_TRUE;

// Initializing glew and openGL
glewInit();
glViewport(0, 0, 800, 600);

// Enabling Depth
glEnable(GL_DEPTH_TEST);

Upvotes: 0

Robinson
Robinson

Reputation: 10122

When you create your window, you specify context settings that allow you to define the depth/stencil buffer formats. Something like this:

 sf::Window window(sf::VideoMode(1024, 768, 32), "SFML Window", sf::Style::Default, sf::ContextSettings(24, 8, 0, 3, 3));

The above would specify a 24 bit depth buffer with 8 bits of stencil. I'm assuming you're using SFML 2.0 here. Not sure if it's still in beta or is a final release of course.

Upvotes: 3

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