SHADER 学习日志

smoothstep 发光

vec2 fixUV(in vec2 c) {
    return (2. * c - iResolution.xy) / min(iResolution.x, iResolution.y);
}

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fixUV(fragCoord);
    vec3 col = vec3( 0.9 , 0.65 , 0.1   ) ;
    float d= length(uv);
    col = mix(col.rgb , vec3(0.  ) , smoothstep( 0.5 ,1. , d  ) );
    fragColor = vec4(col,1.0);
}

float remap01( float a , float b , float t ){

    return clamp( (t-a)/(b-a), 0.  , 1.   );
}


vec2 fixUV(in vec2 c) {
    return (2. * c - iResolution.xy) / min(iResolution.x, iResolution.y);
}

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 uv = fixUV(fragCoord);
    vec3 col = vec3( 0.9 , 0.65 , 0.1   ) ;
    float d= length(uv);
    
    
    float edgeShader =   remap01( 0.45 , 0.8, d );
    col *= edgeShader;
    
    
    col = mix( col , vec3( 0.)   , step(   0.8 , d ) )  ;
    fragColor = vec4(col,1.0);
}

映射

// t ∈ [a,b] 。 输出 0 ~ 1
float remap01( float a , float b , float t ){
    return clamp( (t-a)/(b-a), 0.  , 1.   );
}

//   t ∈ [a,b] 。 把[a,b] 区间的数值映射到 [c,d]区间 。   [a,b] →  [c,d]
float remap ( float a , float b , float c , float d , float t ){


    return  remap01( a , b , t ) * ( d - c ) + c;

}

float remap01( float a , float b , float t ){

    return clamp( (t-a)/(b-a), 0.  , 1.   );
}


vec2 fixUV(in vec2 c) {
    return (2. * c - iResolution.xy) / min(iResolution.x, iResolution.y);
}

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 uv = fixUV(fragCoord);
    vec3 col = vec3( 0.9 , 0.65 , 0.1   ) ;
    float d= length(uv);
    
    
    float edgeShader =   remap01( 0.45 , 0.8, d );
    col *= 1. - edgeShader;
    
    
   // col = mix( col , vec3( 0.)   , step(   0.8 , d ) )  ;
    fragColor = vec4(col,1.0);
}

float remap01( float a , float b , float t ){

    return clamp( (t-a)/(b-a), 0.  , 1.   );
}


float remap ( float a , float b , float c , float d , float t ){


    return  remap01( a , b , t ) * ( d - c ) + c;

}


vec2 fixUV(in vec2 c) {
    return (2. * c - iResolution.xy) / min(iResolution.x, iResolution.y);
}

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 uv = fixUV(fragCoord);
    vec3 col = vec3( 0.9 , 0.65 , 0.1   ) ;
    float d= length(uv);
    
    
    float highLight  =  remap ( -1. , 1. , 0. , 0.5 , uv.y );
    
    
 
    
    
   // col = mix( col , vec3( 0.)   , step(   0.8 , d ) )  ;
    fragColor = vec4(col * highLight,1.0);
}

局部坐标

vec2 within(vec2 uv , vec4 rect){
    return vec2(( uv - rect.xy ) / (  rect.zw  -   rect.xy ) );
}

vec2 within(vec2 uv , vec4 rect){

    return vec2(( uv - rect.xy ) / (  rect.zw  -   rect.xy ) );

}

vec2 fixUV(in vec2 c) {
    return (2. * c - iResolution.xy) / min(iResolution.x, iResolution.y);
}

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 uv = fixUV(fragCoord);
    vec3 col = vec3( 0.9 , 0.65 , 0.1   ) ;
    
    
    
    
    vec2 locUv = within(uv , vec4( 0.3 , 0.3 , 0.8 , 0.8 ));
    
    float d= length(locUv);

    col = mix( col , vec3( 0.)   , step(   0.8 , d ) )  ;
    fragColor = vec4(col ,1.0);
}