glsl opengl es shader 闪电特效，多条闪电交织

glsl opengl es shader 闪电特效，多条闪电交织

转载自  http://glslsandbox.com/

// Lightning
// By: Brandon Fogerty
// bfogerty at gmail dot com 
// xdpixel.com




// By: Brandon Fogerty
// bfogerty at gmail dot com 
// xdpixel.com
 
 
// EVEN MORE MODS BY 27
 
 
#ifdef GL_ES
precision lowp float;
#endif
// EVEN MORE MODS BY 27




#ifdef GL_ES
precision lowp float;
#endif


uniform float time;
uniform vec2 resolution;


const float count = 7.0;


float Hash( vec2 p, in float s)
{
    vec3 p2 = vec3(p.xy,27.0 * abs(sin(s)));
    return fract(sin(dot(p2,vec3(27.1,61.7, 12.4)))*273758.5453123);
}


float noise(in vec2 p, in float s)
{
    vec2 i = floor(p);
    vec2 f = fract(p);
    f *= f * (3.0-2.0*f);


    return mix(mix(Hash(i + vec2(0.,0.), s), Hash(i + vec2(1.,0.), s),f.x),
               mix(Hash(i + vec2(0.,1.), s), Hash(i + vec2(1.,1.), s),f.x),
               f.y) * s;
}


float fbm(vec2 p)
{
     float v = 0.0;
     v += noise(p*1., 0.35);
     v += noise(p*2., 0.25);
     v += noise(p*4., 0.125);
     v += noise(p*8., 0.0625);
     return v;
}


void main( void ) 
{


vec2 uv = ( gl_FragCoord.xy / resolution.xy ) * 2.0 - 1.0;
uv.x *= resolution.x/resolution.y;


vec3 finalColor = vec3( 0.0 );
for( float i=1.; i < count; ++i )
{
float t = abs(1.0 / ((uv.x + fbm( uv + time/i)) * (i*50.0)));
finalColor +=  t * vec3( i * 0.075 +0.1, 0.5, 2.0 );
}

gl_FragColor = vec4( finalColor, 1.0 );


}