title: Skew an image using openGL shaders
body: <p>To lighten the work-load on my artist, I'm working on making a bare-bones skeletal animation system for images. I've conceptualized how all the parts work. But to make it animate how I want to, I need to be able to skew an image in real time. (If I can't do that, I still know how to make it work, but it'd be a lot prettier if I could skew images to add perspective)</p>
  
  <p>I'm using SFML, which doesn't support image skewing. I've been told I'd need to use OpenGL shaders on the image, but all the advice I got on that was "learn GLSL". So I figured maybe someone over here could help me out a bit.</p>
  
  <p>Does anyone know where I should start with this? Or how to do it?</p>
  
  <p>Basically, I want to be able to deforem an image to give it perspective (as shown in the following mockup)</p>
  
  <p><img src="https://i.stack.imgur.com/ZG5Az.png" alt="enter image description here">
  The images on the left are being skewed at the top and bottom. The images on the right are being skewed at the left and right.</p>