From 834bbea25096d642e4666aecd0a1c4a412052a68 Mon Sep 17 00:00:00 2001
From: bill <b@i.ll>
Date: Wed, 24 Feb 2021 01:12:18 +0800
Subject: [PATCH] Milestone 2: Recursive Ray Tracing Completed. TODO:  - Bug
 fixes  - Optimizations  - Simple Interactions

---
 index.html  |  17 +++----
 shader.frag | 134 +++++++++++++++++++++++++++++++++++++++-------------
 2 files changed, 109 insertions(+), 42 deletions(-)

diff --git a/index.html b/index.html
index 57083b6..5285f86 100644
--- a/index.html
+++ b/index.html
@@ -39,23 +39,23 @@
 
 
 <!!-------- FRAGMENT SHADER: THIS IS WHERE YOU WILL DO YOUR WORK -------->
-
-<script src="shader.frag" id='my_fragment_shader' type='x-shader/x-fragment'> </script>
+<!!-------- FRAGMENT SHADER: MOVED TO ./shader.frag LOADED IN lib2.js -------->
+<!--script src="shader.frag" id='my_fragment_shader' type='x-shader/x-fragment'> </script>
 
 
 <!!-------- CREATE A PROPERLY DESCRIPTIVE TITLE BELOW -------->
 
 <script id='my_title' type='text/html'>
-The Bouncing Earth
+Solar RTX
 </script>
 
 
 <!!-------- HERE IS WHERE YOU CAN PROVIDE A LONGER TEXT DESCRIPTION -------->
 
 <script id='my_instructions' type='text/html'><font color=#909090>
-<p style="font-size:30px; ">This is a description 
-of my cool homework 
-that you are seeing now.</p>
+<p style="font-size:30px; ">I am implementing ray tracing<br>
+   to multiple spheres with a single<br>
+   light source and Phong shading.
 <p>
 <i style="font-size:25px;">Here is how it works:</i>
 <ul>
@@ -86,18 +86,19 @@ that you are seeing now.</p>
 </script>
 
 
-<!!-------- YOU PROBABLY DON'T WANT TO CHANGE ANYTHING BELOW FOR NOW -------->
+<!!-------- YOU PROBABLY WANT TO CHANGE ANYTHING BELOW RIGHT NOW -------->
    
 <script>
 
 // CREATE THE HTML DOCUMENT
 let flags = 0x0;
 let vs = my_vertex_shader.innerHTML;
+    //* LOADING FRAGMENT SHADER
     var client = new XMLHttpRequest();
     client.open('GET', './shader.frag');
     client.onloadend = function() {
       fs = (client.responseText);
-      // START EVERYTHING.
+      //* START EVERYTHING AFTER FRAGMENT SHADER IS DOWNLOADED.
       gl_start(canvas1, vs, fs);
       editor.getSession().setValue(fs);
       editor.session.on('change', function(delta) {
diff --git a/shader.frag b/shader.frag
index caecb87..cceeea0 100644
--- a/shader.frag
+++ b/shader.frag
@@ -1,4 +1,7 @@
 
+vec3 foregroundColor = vec3(.0841, .5329, .9604);
+vec3 groundColor = vec3(.2, .3, .5);
+vec4 groundSpecular = vec4(.71, .71, .71, 10.);
 uniform float uTime;// TIME, IN SECONDS
 uniform int flags;
 //FLAGS 0-RT, 1-TEX, 2-
@@ -8,13 +11,19 @@ varying vec3 vPos;// -1 < vPos.x < +1
 
 float fl=3.;
 const float pi=3.14159265359;
-const int n_ref=10;
+const int n_ref=1;
 const int ns=2;
 vec4 Sph[ns];
 uniform sampler2D uSampler[ns];
 vec3 Ambient[ns];
 vec3 Diffuse[ns];
 vec4 Specular[ns];
+struct RT{
+   vec3 color;
+   float ks;
+   // vec3 ptr;
+   // vec3 normal;
+} stack[n_ref];
 
 bool getflag(int flag,int bit){
    float shifted = float(int(float(flag)/ pow(2.,float(bit))));
@@ -61,7 +70,8 @@ void main(){
    vec3 V=vec3(0.,0.,fl);
    vec3 W=normalize(vec3(x,y,-fl));
    // RAY TRACE TO ALL OBJECTS IN THE SCENE
-   
+   bool rtxoff = getflag(flags, 1);
+   int cnt_ref = n_ref;
    for(int j=0;j<n_ref;j++)
    {
       float tMin=10000.;
@@ -82,42 +92,98 @@ void main(){
          }
       }
       // IF RAY HITS SPHERE
-      float t = tMin;
-      vec3 S=V+t*W;
-      for(int i = 0; i < ns; ++ i)
-         if(i == iMin)
-         {
-            //*TEXTURE MAPPING
-            vec3 tex_sph=S-Sph[i].xyz;
-            float R=Sph[i].w;
-            float tex_x=acos(abs(tex_sph.x)/sqrt(R*R-tex_sph.y*tex_sph.y));
-            if(tex_sph.x>0.)
-               tex_x=pi-tex_x;
-            tex_x=R*tex_x;
-            tex_x*=1.5708;//*Correct aspect ratio of texture 2:1 -> 2pir:2r
-            tex_x=tex_x+float(uTime)*R;
-            float _2pir=2.*pi*R;
-            float quo=float(int(tex_x/_2pir));
-            tex_x=clampv((tex_x-quo*_2pir),0.,_2pir)/_2pir;
-            vec3 texture_color;
-            if(!getflag(flags,0))
-               texture_color=texture2D(uSampler[i],vec2(tex_x,((R-tex_sph.y)/(2.*R)))).xyz;
-            
-            vec3 N=normalize(S-Sph[i].xyz);
-            vec3 VDir=normalize(V-Sph[i].xyz);
-            //*DIRECTIONS ARE NORMALIZED TO GET THE CORRECT PHONG LIGHTING
-            vec3 realLDir=normalize(LDir-S);
-            color=(
-                  Ambient[i]
-                  +Diffuse[i]*max(0.,dot(N,realLDir))*LCol
-               )*texture_color
+      if(iMin >= 0){
+         float t = tMin;
+         vec3 S=V+t*W;
+         for(int i = 0; i < ns; ++ i)
+            if(i == iMin)
+            {
+               //*TEXTURE MAPPING
+               vec3 tex_sph=S-Sph[i].xyz;
+               float R=Sph[i].w;
+               float tex_x=acos(abs(tex_sph.x)/sqrt(R*R-tex_sph.y*tex_sph.y));
+               if(tex_sph.x>0.)
+                  tex_x=pi-tex_x;
+               tex_x=R*tex_x;
+               tex_x*=1.5708;//*Correct aspect ratio of texture 2:1 -> 2pir:2r
+               tex_x=tex_x+float(uTime)*R;
+               float _2pir=2.*pi*R;
+               float quo=float(int(tex_x/_2pir));
+               tex_x=clampv((tex_x-quo*_2pir),0.,_2pir)/_2pir;
+               vec3 texture_color;
+               if(!getflag(flags,0))
+                  texture_color=texture2D(uSampler[i],vec2(tex_x,((R-tex_sph.y)/(2.*R)))).xyz;
+               else texture_color = foregroundColor;
+               vec3 N=normalize(S-Sph[i].xyz);
+               //*DIRECTIONS ARE NORMALIZED TO GET THE CORRECT PHONG LIGHTING
+               vec3 realLDir=normalize(LDir-S);
+               color=(
+                     Ambient[i]
+                     +Diffuse[i]*max(0.,dot(N,realLDir))*LCol
+                  )*texture_color
+                  
+               ;
                // + SPECULAR COMPONENT GOES HERE
-               +Specular[i].xyz*pow(max(0.,dot(2.*dot(N,realLDir)*N-realLDir,VDir)),Specular[i].w)
+               if(rtxoff || j == n_ref - 1)
+                  color += Specular[i].xyz*pow(max(0.,dot(2.*dot(N,realLDir)*N-realLDir,-W)),Specular[i].w);
+               stack[j] = RT(color, 0.05);
+               V = S;
+               W = -normalize(2. * dot(N, W) * N - W);
+               break;
+            }
+      }
+      else {
+      // TO SIMIPIFY THINGS UP, I'LL ASSUME THAT EVERYTHING 
+      // IS INSIDE THE BOUNDING BOX [(-1,-1,-1), (1,1,1)]
+      // AND THERE'S A INFINITE FLOOR [y = -1]
+
+         float t = -(1.+V.y)/W.y;
+         if(t >= 0.)
+         {   
+            vec3 S = vec3(V.x + t*W.x, -1, V.z + t*W.z);
+            vec3 realLDir=normalize(LDir - S);
+            color=(
+                  0.5
+                  +0.5*max(0.,realLDir.y)*LCol
+               )*groundColor
             ;
+            // + SPECULAR COMPONENT GOES HERE
+            if(rtxoff || j == n_ref - 1)
+               color += groundSpecular.xyz*
+                  pow(max(0., dot(vec3(-realLDir.x, realLDir.y,-realLDir.z),-W)),groundSpecular.w);
+            stack[j] = RT(color, 0.1);
+            V = S;
+            W = vec3(-W.x, W.y, -W.z);
+         }
+         else{
+            if(j > 0)
+               stack[j] = RT(vec3(1.,1.,1.)*pow(max(0.,dot(-W, normalize(LDir - V))), 10.), 1.);
+            cnt_ref = j;// + 1;
             break;
-         }       
-         if(getflag(flags, 1))
+         }
+      }       
+      // RTX off
+      if(rtxoff)
+         break;
+   }
+   if(rtxoff)
+      color = stack[0].color;
+   else
+   {
+      color = vec3(0,0,0);
+      float currks = 1.;
+      for(int i = 0; i < n_ref; ++i)
+      {
+         if(i >= cnt_ref)
+         {
+            color += currks * stack[i - 1].color;
             break;
+         }
+         color += currks *(1.-stack[i].ks) * stack[i].color;
+         currks *= stack[i].ks;
+      }
+      if(n_ref == cnt_ref)
+         color += currks * stack[n_ref - 1].color;
    }
    // APPLY GAMMA CORRECTION AND SET THE PIXEL COLOR.
    gl_FragColor=vec4(sqrt(color),1.);