Other noise proposal for LIC

src/libRender/RadiumNBR/Shaders/ImageProcessingPass/ImageProcess.frag.glsl

@@ -6,49 +6,69 @@ in vec2 varTexcoord;
 
 vec2 imgSize          = vec2( textureSize( image_sampler, 0 ) );
 const int halfsize    = 40;
-const float dirFactor = 1.;
+const float dirFactor = 0.5;
 const float randCeil  = 0.3;
 
+#if 1
 float rand( vec2 co ) {
     return fract( sin( dot( co.xy, vec2( 12.9898, 78.233 ) ) ) * 43758.5453 );
 }
 float whiteNoise( in vec2 at ) {
     return ( rand( floor( at * randCeil ) / imgSize ) );
 }
+#else
+// noise (hash) functions : taken from https://www.shadertoy.com/view/4djSRW
+float hash12(vec2 p)
+{
+    vec3 p3  = fract(vec3(p.xyx) * .1031);
+    p3 += dot(p3, p3.yzx + 33.33);
+    return fract((p3.x + p3.y) * p3.z);
+}
+
+#define ITERATIONS 1
+float whiteNoise( in vec2 at ) {
+    float a = 0.0;
+    for (int t = 0; t < ITERATIONS; t++) {
+        float v = float(t+1)*.152;
+        vec2 pos = (at * v + 1517.01);
+        a += hash12(pos);
+    }
+    return a/float(ITERATIONS);
+}
+#undef ITERATIONS
+#endif
 
 // desc : texture that contains direction to convolve
 // invertdir invert (i.e. perpendicular) direction
 vec4 lic( in sampler2D desc, in bool invertdir ) {
 
-    vec2 coord;
-
     vec2 dir = texelFetch( desc, ivec2( gl_FragCoord.xy ), 0 ).xy;
+    if (length(dir) == 0) {return vec4 (0);}
+
     if ( invertdir ) dir = vec2( dir.y, -dir.x );
 
     vec4 res = vec4( whiteNoise( gl_FragCoord.xy ) );
-    vec2 currentdir;
-    vec2 tmpdir;
-    coord      = gl_FragCoord.xy;
-    currentdir = dir;
-    for ( int i = 1; i <= halfsize; i++ )
+    vec2 currentdir = dir;
+    vec2 coord      = gl_FragCoord.xy;
+
+    for ( int i = 0; i < halfsize; i++ )
     {
-        coord = coord + dirFactor * vec2( currentdir.x, currentdir.y );
+        coord = coord + dirFactor * currentdir;
         res += vec4( whiteNoise( coord ) );
-        tmpdir = texelFetch( desc, ivec2( coord ), 0 ).xy;
-        if ( invertdir ) tmpdir = vec2( tmpdir.y, -tmpdir.x );
-        currentdir = tmpdir;
+        currentdir = texelFetch( desc, ivec2( coord ), 0 ).xy;
+        if ( invertdir ) currentdir = vec2( currentdir.y, -currentdir.x );
     }
 
     coord      = gl_FragCoord.xy;
     currentdir = dir;
-    for ( int i = 1; i <= halfsize; i++ )
+    for ( int i = 0; i < halfsize; i++ )
     {
-        coord = coord - dirFactor * vec2( currentdir.x, currentdir.y );
+        coord = coord - dirFactor * currentdir;
         res += vec4( whiteNoise( coord ) );
-        tmpdir = texelFetch( desc, ivec2( coord ), 0 ).xy;
-        if ( invertdir ) tmpdir = vec2( tmpdir.y, -tmpdir.x );
-        currentdir = tmpdir;
+        currentdir = texelFetch( desc, ivec2( coord ), 0 ).xy;
+        if ( invertdir ) currentdir = vec2( currentdir.y, -currentdir.x );
     }
+
     res = res / ( 2.0f * float( halfsize ) + 1.0f );
     return smoothstep( 0.1, 0.9, res );
 }
@@ -70,5 +90,5 @@ void main() {
     out_color = vec4(result / (4 * half_width * half_width), 1);
     */
 
-    out_color = lic( image_sampler, true );
+    out_color = lic( image_sampler, false );
 }