Programming

GLSL Core Tutorial Update – Playing with Texture Coordinates

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Based only on texture coordinates some interesting shaders can be built. In this new section of the GLSL Core Tutorial, a few common shaders, namely the stripes and grid shaders, will be explored. Basic antialising and GLSL functions mix and smoothstep will also be discussed. Source code and a VS2010 solution are also provided.

Multisampling – Hacking FreeGLUT’s default sample count

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Both FreeGLUT and GLUT allow us to define an OpenGL context with multisampling. However the number of samples is fixed (4) and I’ve not found a way to change it using the API.

In here we’re going to see how to hack FreeGLUT so that we can change the default number of samples. This can be achieved either by changing the default value, or by adding a new function to set this value.

Note: This hack should be used only for testing purposes, not for redistribution, as FreeGLUT has a large base of users which already have the official version installed.

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OpenGL Framebuffer Objects Tutorial

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OpenGL renders to framebuffers. By default OpenGL renders to screen, the default framebuffer that commonly contains a color and a depth buffer. This is great for many purposes where a pipeline consists of a single pass, a pass being a sequence of shaders. For instance a simple pass can have only a vertex and a … Read more

Update on GLSL Core Tutorial

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The Lighthouse3D GLSL Core Tutorial has been updated with a few sections, namely how to check the result of the compilation and linking operations, freeing up resources, and how do shaders communicate between themselves on modern OpenGL. The shader interfaces are presented and discussed, with examples and a comparison between the several mechanisms OpenGL provides.

Working with Core OpenGL in WX Wigets

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I’ve been working for some time with wxWidgets. The only thing I’ve missed, regarding OpenGL, is the ability to define my own OpenGL context, in particular Core profile and Debug contexts.

To be able to set a context we, or the toolkit we’re using, must use the wglCreateContextAttribsARB function, as defined in the WGL_ARB_create_context extension. As it happens, wxWidgets uses wglCreateContext, hence no OpenGL context can be explicitly defined using the provided source code for the current release (2.9.4).

As OpenGL context setting is not yet in the roadmap for future releases of wxWidgets, nor is it in its Todo List, I’m sharing a solution for this issue.

The solution is for the Windows platform, but other platforms should be as easy to change as well.

Note: I make no claim regarding the quality of the solution, it worked for me, and that’s all I claim. If anyone knows of a better way of doing this comments are most welcome, as they may prove useful for other readers (and me as well 🙂 ).

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Setting up Dev C++ for OpenGL

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Bloodshed Dev-C++ is a full-featured Integrated Development Environment (IDE) for the C/C++ programming language. It uses Mingw port of GCC (GNU Compiler Collection) as it’s compiler. Dev-C++ can also be used in combination with Cygwin or any other GCC based compiler. Here is a short tutorial that was pointed to me to setup Dev C++ … Read more