How to mask/clipping a sprite?

selimanac · March 30, 2019, 1:25pm

I guess I couldn’t explain myself correctly. What I’m trying to achieve/meant is the same with GUI Clipping but for sprites.
I’m looking for a shader based solution for build-in sprite.

Something like this:

github.com/tonybeltramelli/Cocos2D-Mask-Shader

src/MaskNegative.fsh

master

#ifdef GL_ES
precision mediump float;
#endif

varying vec2 v_texCoord;
uniform sampler2D u_texture;
uniform sampler2D u_overlayTexture;

void main()
{
    vec4 normalColor = texture2D(u_texture, v_texCoord).rgba;
    vec4 maskColor = texture2D(u_overlayTexture, v_texCoord).rgba;
    gl_FragColor = vec4(maskColor.r, maskColor.g, maskColor.b, normalColor.a);
    
}

or

Without using quads
Per sprite from an atlas(with multiple sprites in it)
Works with diffent OpenGL vesions, especially for mobile
Fast (minimum draw calls, batched (if possible))