Adding a blur effect

In this recipe, we will learn how we can apply a blur effect while drawing a texture.

Getting ready

In this recipe, we are going to use a Gaussian blur shader provided by Geeks3D at http://www.geeks3d.com/20100909/shader-library-gaussian-blur-post-processing-filter-in-glsl/.

How to do it…

We will implement a sample Cinder application to illustrate the mechanism. Perform the following steps:

1. Create a file inside the assets folder with the name passThru_vert.glsl and put the following code snippet inside it:

   void main()
   {
     gl_Position = ftransform();
     gl_TexCoord[0] = gl_MultiTexCoord0;
     gl_FrontColor = gl_Color; 
   }

2. Create a file inside the assets folder with the name gaussian_v_frag.glsland and put the following code snippet inside it:

   #version 120
   
   uniform sampler2D sceneTex; // 0
   
   uniform float rt_w; // render target width
   uniform float rt_h; // render target height
   uniform float vx_offset;
   
   float offset[3] = float[]( 0.0, 1.3846153846, 3.2307692308 );
   float weight[3] =...