andy-thomason/octet

A single module, header only C++ framework for learning OpenGL

octet

Octet is a framework for teaching OpenGL and the rudiments of game programming such as Geometry construction, Shaders, Matrices, Rigid body Physics and Fluid dynamics.

It has a number of examples in the src/examples directory.

To use with visual studio, fork this repository into your own account and then "Clone Into Desktop" using the GitHub tool and open one of the .sln files in src/examples.

There is a python script for generating your own projects from a template.

From the octet directory run:

packaging\make_example.py my_example

To create your own project in src/examples

Examples should also work with Xcode, although testing is a lot less thorough. If it does not work, send me a pull request with fixes, please...

Octet is a bit unusual in that it does not use external libraries such as libjpeg or zlib. These are implemented in source form in the framework so that you can understand the code. The source of most academic libraries is almost unreadble, so we aim to help your understanding of coding codecs such as GIF, JPEG, ZIP and so on.

octet's Issues

Translating after rotating gives wrong orientation to objects.

The following code draws the axis twice - the second time after rotating 30 degrees on the Y axis, and then translating along the (local) X axis.

mat4t mat;
mat.loadIdentity();
app_scene->add_shape(mat, new mesh_box(vec3(5.0f, 0.1f, 0.1f)), red, false);
app_scene->add_shape(mat, new mesh_box(vec3(0.1f, 5.0f, 0.1f)), green, false);
app_scene->add_shape(mat, new mesh_box(vec3(0.1f, 0.1f, 5.0f)), blue, false);

mat.rotateY(30);
mat.translate(1, 0, 0);
app_scene->add_shape(mat, new mesh_box(vec3(2.0f, 0.1f, 0.1f)), red, false);
app_scene->add_shape(mat, new mesh_box(vec3(0.1f, 2.0f, 0.1f)), green, false);
app_scene->add_shape(mat, new mesh_box(vec3(0.1f, 0.1f, 2.0f)), blue, false);

It looks like this:

When it should look like this:

The position of the object is correct, but its orientation is as if the rotation had been in the opposite direction.

bug in mesh::calc_aabb

Hi Andy,
Just spotted a bug in mesh::calc_aabb,
vmax = max(pos, vmin);
should be:
vmax = max(pos, vmax);
Cheers!
Daniel