The sphere could a shader done around a spherical object http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter16.html

edit: i dont think it would need to be as complex as the one in the link though as you aren't trying to simulate light scattering.
if you can use the shaders you may be able to set it so fragments at right angles to the camera are less transparent than those facing it.

This is just thought i haven't had a chance to try yet.

But i have multiple floats being sent to a shader, at the moment i do them one at a time.
Would it make more sense to simply add all these floats to an array and send them in one setUniform command?

So instead of using

setUniform(String name, float val) ;
setUniform(String name, float val) ;
setUniform(String name, float val) ;
setUniform(String name, float val) ;


I would use setUniform(String name, float[] val) ;

I'm taking in the offsets and advance floats that are usually numbers like 48.0 , 52.1 etc
I think i may need to modify to work with "clip space" which seems to be -1.0 to 1.0 (not sure how though)

If you're wondering what it's for im attempting to implement signed distance field fonts. I actually managed to get it working with multiple overlays, one per each character but im trying to do it with a single one now. The repeat rendering sort of works in that it will draw each character in a string, however they all end up in single spot.

The uniforms bottomleftx and bottomlefty are finding where in the texture a character is before it's rendered(this works) though some characters end up being skewed
as the overlay dimensions don't match the character.

   @Override
   public boolean repeatRendering() {
      renderingIndex++;
     
      if(renderingIndex < charactersList.length && renderingIndex > 0)
      {
         
      advances = advances + charactersList[renderingIndex].advanceX;
   
     
      Overlayshader_.setUniform("a_colour",new SimpleVector(1,(renderingIndex*0.1f),0));
      Overlayshader_.setUniform("bottomLeftx",charactersList[renderingIndex].bottomLeftx);
      Overlayshader_.setUniform("bottomLefty", charactersList[renderingIndex].bottomLefty);   
      Overlayshader_.setUniform("width",charactersList[renderingIndex].width);
      Overlayshader_.setUniform("height",charactersList[renderingIndex].height);
     
      Overlayshader_.setUniform("offestx",renderingIndex);
      Overlayshader_.setUniform("offesty",0);
     
     
      return true;
      }
     
     
     
      setUpOverlayStart();
      renderingIndex=0;
      advances=0;
      return false;
   }


This is an example show three different strings i've added, the bottom one demonstrates a single character string a skewed zero.





And my vertex shader code



precision highp float;
// VERTEX SHADER


uniform mat4 modelViewMatrix;
uniform mat4 projectionMatrix;

uniform float bottomLeftx;
uniform float bottomLefty;

uniform float width;
uniform float height;
uniform vec3 a_colour;

uniform float offsetx;
uniform float offsety;

attribute vec2 texture0;
attribute vec4 position;



varying vec4 v_color;
varying vec2 v_texCoord;

void main()
{
v_color = vec4(a_colour.x,a_colour.y,a_colour.z,1.0);

v_texCoord.x = bottomLeftx + (texture0.x/width);
v_texCoord.y = bottomLefty + (texture0.y/height);


vec4 newpos = vec4(offsetx,offsety,0,0);

gl_Position = projectionMatrix*((modelViewMatrix  * position) +newpos);

}


I'll give that a shot, would gl_FragCoord work too? maybe if i altered that instead of naively thinking i could alter gl_position.

What is it doing?

I should specify why i want to know this. I'm curious is Signed Distance field fonts could be used to help build a UI.


Some links explaining how this works.

https://code.google.com/p/libgdx/wiki/DistanceFieldFonts

http://http.developer.nvidia.com/GPUGems3/gpugems3_ch34.html

https://forum.libcinder.org/#Topic/23286000001127007

https://code.google.com/p/glyphy/

http://www.valvesoftware.com/publications/2007/SIGGRAPH2007_AlphaTestedMagnification.pdf


fonts

http://openfontlibrary.org/en/catalogue?view=&page=7

oh yes 

For some silly reason i thought IrenderHook could only be implemented with via a shader object.

It works perfectly now with the IrenderHook implemented by entities themselves. (hopefully this wont bite in the ass later but it seems to work  )

Is there a way to quickly copy or share GLSLShader objects. I incorrectly assumed that using one shader among many objects would be ok but ive only just copped it that you need a shader for every instance, otherwise the uniforms will be set to those of the very last item updated before rendering.