Lua Masking

The next Step is adding an Interface-Object (technically it is categorized as a "Button", but you don't have to make it clickable, then it just is Interface-Decoration) and name it "PlayerHealthbar". My Test-Bar was a Texture with a Size of 512*24px, but any Size will automaticaly work.

Then you only have to add this as a Definition-Script:

eff = "PlayerHealth_Shader"

shader_effects[eff] = { shader = Shaders[eff].Compiled }

shaderAddEffect(eff)

shaderRemoveEffect(eff)

Buttons["PlayerHealthbar"].ShaderSet = shader_effects[eff].num.num

bind(eff, "Health", field("Values.PlayerHealth.Int * 0.01")) 

(The last Line in the Lua-Script, where it says "Values.PlayerHealth.Int * 0.01", that is where you can insert your Value-Name instead of "PlayerHealth" if you want.)

And eventually add a new Shader under the "Shader"-Tab (I am assuming you are using Visionaire 5, you mentioned having started to try it out) named "PlayerHealth_Shader", and paste this Code into it:

#ifdef GL_ES

precision lowp float;

precision lowp int;

#endif

uniform sampler2D texel;

varying vec2 uvVarying;

uniform float Health;

void main ()

{

  vec4 color = vec4(0.0);

  if (uvVarying.x < Health) {

    //color = vec4( mix( vec3(1.0,0.0,0.0), vec3(0.0,1.0,0.0), Health), 1.0);

    color = vec4( (

      vec3(pow(1.0-Health,0.33),0.0,0.0) + 

      vec3(0.0,pow(Health,0.67),0.0)

    ), 1.0);

  }

  gl_FragColor = (texture2D (texel, uvVarying) * color);

} 

There is one Line (#12) I have commented out -- that Line basically mixes the Colors with a dark Ocre in the Middle. I don't suggest you use that, because frankly, it is just an ugly Color, but I inserted it anyway (albeit outcommented) for you to freely choose.

Instead, Lines #14 and #15 (could be one Line, but I thought I'd split it into several so you can look at it more easily) use a slightly more complex Way of Mixing where I initially used Powers of Values between 0.25 to 0.5 to give the red and green Values more rounded Falloffs and thusly have a brighter Yellow in the Middle; however, I noticed that, other than with a fully visible and fully green Healthbar, the deep red Color of low Health would never be visible because by that Point the Bar is effectively gone -- so instead, I used Powers of one and two Thirds (0.33 and 0.67) to have an intentionally uneven Color-Falloff: Now, the low Healthbar will still have quite a nice Red-Value, but the Mid-Color is more of an Orange. You can change that if you want, but I think that is the best Way to go.