engine/src/core-data/Common/MatDefs/Misc/Particle.frag

#ifdef USE_TEXTURE
uniform sampler2D m_Texture;
varying vec4 texCoord;
#endif

varying vec4 color;

void main(){
    if (color.a <= 0.01)
        discard;

    #ifdef USE_TEXTURE
        #ifdef POINT_SPRITE
            vec2 uv = mix(texCoord.xy, texCoord.zw, gl_PointCoord.xy);
        #else
            vec2 uv = texCoord.xy;
        #endif
        gl_FragColor = texture2D(m_Texture, uv) * color;
    #else
        gl_FragColor = color;
    #endif
}