port from perforce

hgplus/ShaderMinifier/tests/real/quaternion.frag

@@ -0,0 +1,112 @@
+uniform vec2 resolution;
+uniform float time;
+uniform sampler2D tex0;
+uniform sampler2D tex1;
+uniform sampler2D tex2;
+uniform sampler2D tex3;
+
+float jinteresct(in vec3 rO, in vec3 rD, in vec4 c, out float ao)
+{
+    float mz2,md2,dist,t;
+    float res=1000.0;
+    vec4 z,nz;
+
+    ao = 0.0;
+    for(t=0.0;t<6.0;t+=dist)
+    {
+        ao += 1.0;
+        vec3 p=rO+t*rD;
+
+        // calc distance
+        z=vec4(p,(c.y+c.x)*.3);
+        md2=1.0;
+        mz2=dot(z,z);
+
+        for(int i=0;i<9;i++)
+        {
+             // |dz|^2 -> 4*|dz|^2
+             md2*=4.0*mz2;
+             // z -> z2 + c
+             nz.x=z.x*z.x-dot(z.yzw,z.yzw);
+             nz.yzw=2.0*z.x*z.yzw;
+             z=nz+c;
+
+             mz2=dot(z,z);
+             if(mz2>4.0)
+                 break;
+         }
+
+         dist=0.25*sqrt(mz2/md2)*log(mz2);
+
+         if(dist<0.0005)
+         {
+             res=t;
+             break;
+         }
+
+     }
+
+    return res;
+}
+
+
+vec3 calcNormal(in vec3 p, in vec4 c)
+{
+    vec4 nz,ndz,dz[4];
+
+    vec4 z=vec4(p,(c.y+c.x)*.3);
+
+    dz[0]=vec4(1.0,0.0,0.0,0.0);
+    dz[1]=vec4(0.0,1.0,0.0,0.0);
+    dz[2]=vec4(0.0,0.0,1.0,0.0);
+  //dz[3]=vec4(0.0,0.0,0.0,1.0);
+
+    for(int i=0;i<9;i++)
+    {
+        vec4 mz = vec4(z.x,-z.y,-z.z,-z.w);
+        // derivative
+        dz[0]=vec4(dot(mz,dz[0]),z.x*dz[0].yzw+dz[0].x*z.yzw);
+        dz[1]=vec4(dot(mz,dz[1]),z.x*dz[1].yzw+dz[1].x*z.yzw);
+        dz[2]=vec4(dot(mz,dz[2]),z.x*dz[2].yzw+dz[2].x*z.yzw);
+        //dz[3]=vec4(dot(mz,dz[3]),z.x*dz[3].yzw+dz[3].x*z.yzw);
+
+        // z = z2 + c
+        nz.x=dot(z, mz);
+        nz.yzw=2.0*z.x*z.yzw;
+        z=nz+c;
+
+        if(dot(z,z)>4.0)
+            break;
+        }
+
+    return normalize(vec3(dot(z,dz[0]),dot(z,dz[1]),dot(z,dz[2])));
+}
+
+
+void main(void)
+{
+    vec2 p = -1.0 + 2.0 * gl_FragCoord.xy / resolution.xy;
+    vec3 color = vec3(0.0);
+    vec4 cccc = vec4( .7*cos(.5*time), .7*sin(.3*time), .7*cos(1.0*time), 0.0 );
+    vec3 edir = normalize(vec3(p,1.0));
+    vec3 wori = vec3(0.0,0.0,-2.0);
+
+    float ao;
+    float t = jinteresct(wori,edir,cccc,ao);
+    if(t<100.0)
+    {
+        vec3 inter = wori + t*edir;
+        vec3 nor = calcNormal(inter,cccc);
+
+        float dif = .5 + .5*dot( nor, vec3(0.57703) );
+        ao = max( 1.0-ao*0.005, 0.0 );
+
+        color = vec3(1.0,.9,.5)*dif*ao +  .5*vec3(.6,.7,.8)*ao;
+    }
+    else
+    {
+        color = vec3(0.5,0.51,0.52)+vec3(0.5,0.47,0.45)*p.y;
+    }
+
+    gl_FragColor = vec4(color,1.0);
+}