From c182b89694ea4e612fd2c76aea4e3234b43c9116 Mon Sep 17 00:00:00 2001
From: chai <chaifix@163.com>
Date: Thu, 6 Sep 2018 21:26:07 +0800
Subject: *update

---
 shader/metaball.shader | 240 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 226 insertions(+), 14 deletions(-)

(limited to 'shader/metaball.shader')

diff --git a/shader/metaball.shader b/shader/metaball.shader
index e7e344e..631ed93 100644
--- a/shader/metaball.shader
+++ b/shader/metaball.shader
@@ -1,15 +1,227 @@
-extern vec2 distortionFactor;
-extern vec2 scaleFactor;
-extern number feather;
-vec4 effect(vec4 color, Texture tex, vec2 uv, vec2 px) {
-  // to barrel coordinates
-  uv = uv * 2.0 - vec2(1.0);
-  // distort
-  uv *= scaleFactor;
-  uv += (uv.yx*uv.yx) * uv * (distortionFactor - 1.0);
-  number mask = (1.0 - smoothstep(1.0-feather,1.0,abs(uv.x)))
-              * (1.0 - smoothstep(1.0-feather,1.0,abs(uv.y)));
-  // to cartesian coordinates
-  uv = (uv + vec2(1.0)) / 2.0;
-  return color * Texel(tex, uv) * mask;
+extern vec3 iResolution;
+extern number iGlobalTime;
+extern vec4 iMouse;
+
+/*by mu6k, Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
+ I have no idea how I ended up here, but it demosceneish enough to publish.
+ You can use the mouse to rotate the camera around the 'object'.
+ If you can't see the shadows, increase occlusion_quality.
+ If it doesn't compile anymore decrease object_count and render_steps.
+ 15/06/2013:
+ - published
+ 16/06/2013:
+ - modified for better performance and compatibility
+ muuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuusk!*/
+
+#define occlusion_enabled
+#define occlusion_quality 4
+//#define occlusion_preview
+
+#define noise_use_smoothstep
+
+#define light_color vec3(0.1,0.4,0.6)
+#define light_direction normalize(vec3(.2,1.0,-0.2))
+#define light_speed_modifier 1.0
+
+#define object_color vec3(0.9,0.1,0.1)
+#define object_count 9
+#define object_speed_modifier 1.0
+
+#define render_steps 33
+
+number hash(number x)
+{
+    return fract(sin(x*.0127863)*17143.321);
+}
+
+number hash(vec2 x)
+{
+    return fract(cos(dot(x.xy,vec2(2.31,53.21))*124.123)*412.0);
+}
+
+vec3 cc(vec3 color, number factor,number factor2) //a wierd color modifier
+{
+    number w = color.x+color.y+color.z;
+    return mix(color,vec3(w)*factor,w*factor2);
+}
+
+number hashmix(number x0, number x1, number interp)
+{
+    x0 = hash(x0);
+    x1 = hash(x1);
+    #ifdef noise_use_smoothstep
+    interp = smoothstep(0.0,1.0,interp);
+    #endif
+    return mix(x0,x1,interp);
+}
+
+number noise(number p) // 1D noise
+{
+    number pm = mod(p,1.0);
+    number pd = p-pm;
+    return hashmix(pd,pd+1.0,pm);
+}
+
+vec3 rotate_y(vec3 v, number angle)
+{
+    number ca = cos(angle); number sa = sin(angle);
+    return v*mat3(
+        +ca, +.0, -sa,
+        +.0,+1.0, +.0,
+        +sa, +.0, +ca);
+}
+
+vec3 rotate_x(vec3 v, number angle)
+{
+    number ca = cos(angle); number sa = sin(angle);
+    return v*mat3(
+        +1.0, +.0, +.0,
+        +.0, +ca, -sa,
+        +.0, +sa, +ca);
+}
+
+number max3(number a, number b, number c)//returns the maximum of 3 values
+{
+    return max(a,max(b,c));
+}
+
+vec3 bpos[object_count];//position for each metaball
+
+number dist(vec3 p)//distance function
+{
+    number d=1024.0;
+    number nd;
+    for (int i=0 ;i<object_count; i++)
+    {
+        vec3 np = p+bpos[i];
+        number shape0 = max3(abs(np.x),abs(np.y),abs(np.z))-1.0;
+        number shape1 = length(np)-1.0;
+        nd = shape0+(shape1-shape0)*2.0;
+        d = mix(d,nd,smoothstep(-1.0,+1.0,d-nd));
+    }
+    return d;
+}
+
+vec3 normal(vec3 p,number e) //returns the normal, uses the distance function
+{
+    number d=dist(p);
+    return normalize(vec3(dist(p+vec3(e,0,0))-d,dist(p+vec3(0,e,0))-d,dist(p+vec3(0,0,e))-d));
+}
+
+vec3 light = light_direction; //global variable that holds light direction
+
+vec3 background(vec3 d)//render background
+{
+    number t=iGlobalTime*0.5*light_speed_modifier;
+    number qq = dot(d,light)*.5+.5;
+    number bgl = qq;
+    number q = (bgl+noise(bgl*6.0+t)*.85+noise(bgl*12.0+t)*.85);
+    q+= pow(qq,32.0)*2.0;
+    vec3 sky = vec3(0.1,0.4,0.6)*q;
+    return sky;
+}
+
+number occlusion(vec3 p, vec3 d)//returns how much a point is visible from a given direction
+{
+    number occ = 1.0;
+    p=p+d;
+    for (int i=0; i<occlusion_quality; i++)
+    {
+        number dd = dist(p);
+        p+=d*dd;
+        occ = min(occ,dd);
+    }
+    return max(.0,occ);
+}
+
+vec3 object_material(vec3 p, vec3 d)
+{
+    vec3 color = normalize(object_color*light_color);
+    vec3 n = normal(p,0.1);
+    vec3 r = reflect(d,n);
+
+    number reflectance = dot(d,r)*.5+.5;reflectance=pow(reflectance,2.0);
+    number diffuse = dot(light,n)*.5+.5; diffuse = max(.0,diffuse);
+
+    #ifdef occlusion_enabled
+        number oa = occlusion(p,n)*.4+.6;
+        number od = occlusion(p,light)*.95+.05;
+        number os = occlusion(p,r)*.95+.05;
+    #else
+        number oa=1.0;
+        number ob=1.0;
+        number oc=1.0;
+    #endif
+
+    #ifndef occlusion_preview
+        color =
+        color*oa*.2 + //ambient
+        color*diffuse*od*.7 + //diffuse
+        background(r)*os*reflectance*.7; //reflection
+    #else
+        color=vec3((oa+od+os)*.3);
+    #endif
+
+    return color;
+}
+
+#define offset1 4.7
+#define offset2 4.6
+
+void mainImage( out vec4 fragColor, in vec2 fragCoord )
+{
+    vec2 uv = fragCoord.xy / iResolution.xy - 0.5;
+    uv.x *= iResolution.x/iResolution.y; //fix aspect ratio
+    vec3 mouse = vec3(iMouse.xy/iResolution.xy - 0.5,iMouse.z-.5);
+
+    number t = iGlobalTime*.5*object_speed_modifier + 2.0;
+
+    for (int i=0 ;i<object_count; i++) //position for each metaball
+    {
+        bpos[i] = 1.3*vec3(
+            sin(t*0.967+number(i)*42.0),
+            sin(t*.423+number(i)*152.0),
+            sin(t*.76321+number(i)));
+    }
+
+    //setup the camera
+    vec3 p = vec3(.0,0.0,-4.0);
+    p = rotate_x(p,mouse.y*9.0+offset1);
+    p = rotate_y(p,mouse.x*9.0+offset2);
+    vec3 d = vec3(uv,1.0);
+    d.z -= length(d)*.5; //lens distort
+    d = normalize(d);
+    d = rotate_x(d,mouse.y*9.0+offset1);
+    d = rotate_y(d,mouse.x*9.0+offset2);
+
+    //and action!
+    number dd;
+    vec3 color;
+    for (int i=0; i<render_steps; i++) //raymarch
+    {
+        dd = dist(p);
+        p+=d*dd*.7;
+        if (dd<.04 || dd>4.0) break;
+    }
+
+    if (dd<0.5) //close enough
+        color = object_material(p,d);
+    else
+        color = background(d);
+
+    //post procesing
+    color *=.85;
+    color = mix(color,color*color,0.3);
+    color -= hash(color.xy+uv.xy)*.015;
+    color -= length(uv)*.1;
+    color =cc(color,.5,.6);
+    fragColor = vec4(color,1.0);
+}
+
+
+
+vec4 effect(vec4 color, Texture texture, vec2 texture_coords, vec2 pixel_coords){
+    vec2 fragCoord = texture_coords * iResolution.xy;
+    mainImage( color, fragCoord );
+    return color;
 }
\ No newline at end of file
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