Tom Dalling

Modern OpenGL 08 – Even More Lighting: Directional Lights, Spotlights, & Multiple Lights

Sat, 01 Nov 2014 00:00:00 -0000

In this article, we will be adding directional lights, spotlights, and allowing for multiple lights instead of just one. This is the final article on lighting – at least for a while.

OpenGL in 2014

Sun, 21 Sep 2014 00:00:00 -0000

Valve is investing in OpenGL to hedge themselves against Microsoft. Some well-known developers have written about the deficiencies in the API. A few competing, proprietary APIs have popped up. In an effort to remain competitive, Khronos announces glnext: a ground-up rethinking of the OpenGL and OpenGL ES APIs. This post will look at developments in the OpenGL ecosystem over the last couple of years.

Explaining Homogeneous Coordinates & Projective Geometry

Mon, 24 Feb 2014 00:00:00 -0000

In this article I’m going to explain homogeneous coordinates (a.k.a. 4D coordinates) as simply as I can. In previous articles, we’ve used 4D vectors for matrix multiplication, but I’ve never really defined what the fourth dimension actually is. Now it’s time to take a closer look at projective geometry.

Also, welcome back! It has been a while since my last post. Hopefully I will find some time in the next couple of months to finish up the Modern OpenGL Series of articles. The code for article 08 is done, but writing the article will take some time.

Modern OpenGL 07 – More Lighting: Ambient, Specular, Attenuation, Gamma

Thu, 18 Apr 2013 00:00:00 -0000

In this article we will continue to implement lighting. We will implement the ambient and specular components of the Phong reflection model, attenuation, and gamma correction.

Modern OpenGL 06 – Diffuse Point Lighting

Sat, 23 Mar 2013 00:00:00 -0000

This is the first article covering lighting. We will begin our lighting adventure by implementing per-pixel, diffuse lighting with a single point light. In later articles we will implement ambient and specular reflection, directional lights, spotlights, attenuation, and using multiple lights.

Modern OpenGL 05 – Model Assets & Instances

Fri, 08 Feb 2013 00:00:00 -0000

In this article, we will be refactoring the code to be more like a 3D engine/framework. Specifically, we will be replacing some of the globals with structs that represent “assets” and “instances.” At the end, we will have a single wooden crate asset, and five instances of that asset arranged to spell out “Hi” in 3D.

Modern OpenGL 04 - Cameras, Vectors & Input

Mon, 21 Jan 2013 00:00:00 -0000

In this article, we will be consolidating the matrix and camera knowledge from the previous article into the new tdogl::Camera class, which will be a first-person shooter type of camera. Then, we will connect the camera to keyboard and mouse input, so we can move within the 3D scene and look around. This will involve learning a bit of vector math. We will also learn about inverting matrices, which was not mentioned in the previous article.

Modern OpenGL 03 - Matrices, Depth Buffering, Animation

Sun, 16 Dec 2012 00:00:00 -0000

In this article, we will replace our immobile 2D triangle with a spinning 3D cube. The end result will look like this:

Now that we’re finally getting something interesting on the screen, I can include more pictures! An album of animated gifs is available here: http://imgur.com/a/x8q7R

In order to make this spinning cube, we will learn a bit about matrix math, and how it is used to create perspective projections, rotation, translation, and the concept of a “camera.” We will also learn about depth buffering, and why it is necessary. We will also see how a typical 3D application implements changes over time, such as animation.

Modern OpenGL 02 - Textures

Sun, 02 Dec 2012 00:00:00 -0000

In this article, we will be adding a texture to the triangle. This will involve adding new variables to the vertex and fragment shaders, creating and using texture objects, and learning a bit about texture units and texture coordinates.

This article introduces two new classes to the tdogl namespace: tdogl::Bitmap and tdogl::Texture. These will allow us to load an image from a jpg, png, or bmp file into video memory, for use in the shaders. Also, the tdogl::Program class has some new methods for setting shader variables.

Modern OpenGL 01 - Getting Started in Xcode, Visual C++, and Linux

Sat, 24 Nov 2012 00:00:00 -0000

Welcome to the first of a series of articles about modern OpenGL. All the code will be open source, and downloadable from github: https://github.com/tomdalling/opengl-series.

By the end of this article, you will have a working OpenGL 3.2 project in Visual Studio 2013 on Windows, and Xcode on OSX. The app will have a vertex shader, a fragment shader, and will display a single triangle using a VAO and a VBO. The project will use GLEW to access the OpenGL API, GLFW to handle window creation and input, and GLM for matrix/vector math.

Yes, it is a little bit boring, but just getting a project set up correctly can be difficult, especially for beginners. Once this is out of the way we will get into the more interesting stuff.