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help with alpha on GLSL filter


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I'm writing a game and since the map will be quite big, I'm running the game logic in a GLSL shader.

the pipeline works, I see stuff getting updated etc, my only problem is when I try to create a political overlay of the calculated results. In the map (attached screen) the yellow area is colonized.

 

the problem is, no matter what alpha I return in my fragment, it's this almost but not quite solid yellow.

 

filter is super simple; if colonized (blue channel of the texture) then emit that player color (fixed yellow for now to simplify):

 vec4 oc = texture2D(uSampler, vTextureCoord);

 vec4 c = vec4(0.);
 //b channel holds colony value
 if (oc.b> 0. ) {
    c = vec4(1.,1.,0.,0.);
    c.a=0.1;
 }
 gl_FragColor = c;

 

I tried whatever value for c.a, but it's always the same result.

 

the filter is not applied to the galaxy map itself tho: it's another sprite, built on the render texture I use to hold the data, added as child:

 

    game.colonize= new Phaser.Filter(game,undefined, game.cache.getShader('colonize'));  //game logic
    game.colonize.setResolution(2048,2048);

    game.mapper= new Phaser.Filter(game,undefined, game.cache.getShader('mapper')); //color yellow colonized area, the one above
    game.mapper.setResolution(2048,2048);


    game.politicalRT = game.make.renderTexture(2048,2048);
    game.politicalRT.render(game.make.sprite(0, 0, 'mas')); //mas hold the mass density of the galaxy



    game.politicalSP = game.make.sprite(0, 0, game.politicalRT); //sp is redrawn on the render texture every update
    game.politicalOL = game.make.sprite(0, 0, game.politicalRT);
	

    game.politicalSP.filters = [game.colonize ];
    game.politicalOL.filters = [game.mapper ];


    game.galaxymap.inputEnabled = true;
    game.galaxymap.input.enableDrag(false);

    game.galaxymap.addChild(game.politicalOL); //politicalOL is that yellow blob that doesn't appear properly transparent

 

the mapper should picture a light, transparent yellow, but it isn't working. is there some magic in blending child filtered sprites?

 

 

 

XkyF1ev.png

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found out the issue, needed to add

game.politicalOL.blendMode = PIXI.blendModes.ADD;

to the child

but I don't understand why NORMAL does a SCREEN, beside, ADD seems correct but what I wanted was the kind of layer mixing paint programs call 'default', this one will saturate color instead of masking it with the topmost.

 

corr.PNG

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There is no magic, but you really have to very carefully examine your code for possible problems. As far as I see it, it plasters 100% alpha all over the surface. I'm gonna need a more complete source of your shader. I had similar issue when I tried using "vColor" - unless you use shader directly, it's not defined and results in glitches. I've noticed that shaders only work 100% "properly" if you attach them directly to renderable objects using their "shader" property.

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