Ocean simulation part one: using the discrete Fourier transform

In this post we will implement the statistical wave model from the equations in Tessendorf's paper[1] on simulating ocean water. We will implement this model using a discrete Fourier transform. In part two we will begin with the same equations but provide a deeper analysis in order to implement our own fast Fourier transform. Using the fast Fourier transform, we will be able to achieve interactive frame rates. Below are two screen captures. The first is a rendering of the surface using some Read more [...]

Tangent space normal mapping with GLSL

In the previous post we discussed lighting and environment mapping, and our evaluation of the lighting contribution was performed in view space. Here we will discuss lighting in tangent space and extend our lighting model to include a normal map. If we apply a texture to a surface, then for every point in the texture we can define a set of vectors that are tangent to that point. Once we transform our light vector, halfway vector, and normal vector into tangent space, we can use the normal map Read more [...]

Lighting and environment mapping with GLSL

In this post we will expand on our skybox project by adding an object to our scene for which we will evaluate lighting contributions and environment mapping. We will first make a quick edit to our Wavefront OBJ loader to utilize OpenGL's Vertex Buffer Object. Once we can render an object we will create a shader program to evaluate the lighting and reflections. Below are a couple of screen grabs of the final result. A couple of video captures are below. Read more [...]

Rendering a skybox using a cube map with OpenGL and GLSL

I realized in my previous posts the use of OpenGL wasn't up to spec. This post will attempt to implement skybox functionality using the more recent specifications. We'll use GLSL to implement a couple simple shaders. We will create an OpenGL program object to which we will bind our vertex and fragment shaders. A Vertex Buffer Object will be used to store our cube vertices and another to store the indices for the faces. Using a cube map texture will allow our vertices to double as texture coordinates. Read more [...]

A preliminary Wavefront OBJ loader in C++

This post will examine the Wavefront OBJ file format and present a preliminary loader in C++. We will overlook the format's support for materials and focus purely on the geometry. Once our model has been loaded, an OpenGL Display List will be used to render the model. Below is a rendering of a dragon model available at The Stanford 3D Scanning Repository. In the OBJ file used for this render the vertex normals were not present. At run time, normals were evaluated at each face for lighting calculations Read more [...]

A keyboard handler and timer in C++ for the Linux platform

In this post we will construct a simple timer for evaluating the duration of a frame in addition to a keyboard handler. We will use these objects in conjunction to update our position relative to a cube. SDL and OpenGL will be used for rendering. Below is a frame captured from our application. We will query an instance of our timer once for each pass through our application loop. It should yield the duration of the previous frame. The position of objects in the current frame can then Read more [...]

A Linux C++ joystick object

In this post we will implement an object in C++ for accessing the state of an attached joystick. Below is a rendering using SDL and OpenGL of a joystick state. In "/usr/include/linux/joystick.h" we find the following event structure: Once we have opened a device node for reading we will populate this event structure with the data read from the device. We define a structure for holding the state of the joystick. As we parse the event data, the joystick state structure is updated Read more [...]