Animating text – text as a mask for a movie

In this recipe, we will learn how we can use text as a mask for a movie using a simple shader program.

Getting ready

In this example, we are using one of the amazing videos provided by NASA taken by an ISS crew that you can find at http://eol.jsc.nasa.gov/. Please download oneand save it as video.mov inside the assets folder.

How to do it…

We will create a sample Cinder application to illustrate the mechanism. Perform the following steps to do so:

1. Include the necessary header files.

   #include "cinder/gl/Texture.h"
   #include "cinder/Text.h"
   #include "cinder/Font.h"
   #include "cinder/qtime/QuickTime.h"
   #include "cinder/gl/GlslProg.h"

2. Declare the member variables.

   qtime::MovieGl mMovie;
   gl::Texture     mFrameTexture, mTextTexture;
   gl::GlslProg  mMaskingShader;

3. Implement the setup method, as follows:

   setWindowSize(854, 480);
   
   TextLayout layout;
   layout.clear( ColorA(0.f,0.f,0.f, 0.f) );
   layout.setFont( Font("Arial Black", 96 ) );
   layout.setColor( Color( 1, 1, 1...