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.

I think you want the invert function for Object3d?

http://www.jpct.net/doc/com/threed/jpct/Object3D.html#invert()