Book Image

OpenGL Development Cookbook

By : Muhammad Mobeen Movania
Book Image

OpenGL Development Cookbook

By: Muhammad Mobeen Movania

Overview of this book

OpenGL is the leading cross-language, multi-platform API used by masses of modern games and applications in a vast array of different sectors. Developing graphics with OpenGL lets you harness the increasing power of GPUs and really take your visuals to the next level. OpenGL Development Cookbook is your guide to graphical programming techniques to implement 3D mesh formats and skeletal animation to learn and understand OpenGL. OpenGL Development Cookbook introduces you to the modern OpenGL. Beginning with vertex-based deformations, common mesh formats, and skeletal animation with GPU skinning, and going on to demonstrate different shader stages in the graphics pipeline. OpenGL Development Cookbook focuses on providing you with practical examples on complex topics, such as variance shadow mapping, GPU-based paths, and ray tracing. By the end you will be familiar with the latest advanced GPU-based volume rendering techniques.
Table of Contents (15 chapters)
OpenGL Development Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Implementing the twirl filter using the fragment shader


We will use a simple image manipulation operator in the fragment shader by implementing the twirl filter on the GPU.

Getting ready

This recipe builds up on the image loading recipe from Chapter 1, Introduction to Modern OpenGL. The code for this recipe is contained in the Chapter3/TwirlFilter directory.

How to do it…

Let us get started with the recipe as follows:

  1. Load the image as in the ImageLoader recipe from Chapter 1, Introduction to Modern OpenGL. Set the texture wrap mode to GL_CLAMP_TO_BORDER.

    int texture_width = 0, texture_height = 0, channels=0;
    GLubyte* pData = SOIL_load_image(filename.c_str(), &texture_width, &texture_height, &channels, SOIL_LOAD_AUTO);
    int i,j;
    for( j = 0; j*2 < texture_height; ++j )
    {
      int index1 = j * texture_width * channels;
      int index2 = (texture_height - 1 - j) * texture_width * channels;
      for( i = texture_width * channels; i > 0; --i )
      {
        GLubyte temp = pData[index1];
        pData...