From 9d94155128b0895dd6e8790c159df0b5fda0fd40 Mon Sep 17 00:00:00 2001
From: Patricio Gonzalez Vivo <patriciogonzalezvivo@gmail.com>
Date: Tue, 13 Dec 2016 16:20:19 -0500
Subject: [PATCH] adding glslviewer

---
 09/tmp/dots-texture.frag | 17 ++++++++++++-----
 appendix/00/README-de.md |  2 +-
 appendix/00/README-it.md |  2 +-
 appendix/00/README.md    |  2 +-
 appendix/01/README-de.md |  7 +------
 appendix/01/README-it.md |  7 +------
 appendix/01/README.md    |  7 +------
 7 files changed, 18 insertions(+), 26 deletions(-)

diff --git a/09/tmp/dots-texture.frag b/09/tmp/dots-texture.frag
index 73f58d0..58441bf 100644
--- a/09/tmp/dots-texture.frag
+++ b/09/tmp/dots-texture.frag
@@ -13,7 +13,7 @@ float rows = 100.0;
 
 vec2 brickTile(vec2 _st, float _zoom){
   _st *= _zoom;
-  if (fract(_st.y * 0.5) > 0.5){
+  if (fract(_st.y * 0.5) > 0.5) {
       _st.x += 0.5;
   }
   return fract(_st);
@@ -28,13 +28,20 @@ float circle(vec2 _st, float _radius){
 void main(){
 
   vec2 st = gl_FragCoord.xy/u_resolution.xy;
+  st = (st-.5)*1.02+.5;
   st.x *= u_resolution.x/u_resolution.y;
+
   vec2 pos = st;
+  float grid = 50.;
 
-  st = brickTile(st,500.);
+  st *= grid;
+  if (fract(st.y * 0.5) > 0.5){
+      st.x += 0.5;
+      pos.x += 0.5/grid;
+  }
   
-  float pattern = texture2D(u_tex0,pos).r;
-  pattern = circle(st, pattern);
+  float pattern = texture2D(u_tex0,clamp(floor(pos*grid)/grid+vec2(.5,.5)/grid,vec2(0.),vec2(1.))).r;
+  pattern = circle(fract(st), smoothstep(0.1,1.,pattern));
 
-  gl_FragColor = vec4(1.-vec3(pattern),1.0);
+  gl_FragColor = vec4(pattern,0.,0.,pattern);
 }
\ No newline at end of file
diff --git a/appendix/00/README-de.md b/appendix/00/README-de.md
index f4162ac..1039790 100644
--- a/appendix/00/README-de.md
+++ b/appendix/00/README-de.md
@@ -17,7 +17,7 @@ Auf einem **RaspberryPi** gibst Du folgendes ein:
 ```bash
 sudo apt-get update
 sudo apt-get upgrade
-sudo apt-get install git-core
+sudo apt-get install git-core glslviewer
 ```
 
 Hast Du alles beisammen, musst Du lediglich folgende Befehle aufrufen, um das *Book of Shaders* per GIT auf Deinen Rechner zu laden und den Server zur Anzeige des Inhalts zu starten:
diff --git a/appendix/00/README-it.md b/appendix/00/README-it.md
index 115166e..37f3e4a 100644
--- a/appendix/00/README-it.md
+++ b/appendix/00/README-it.md
@@ -17,7 +17,7 @@ Su **Raspberry Pi** è necessario fare:
 ```bash
 sudo apt-get update
 sudo apt-get upgrade
-sudo apt-get install git-core
+sudo apt-get install git-core glslviewer
 ```
 
 Una volta che avete installato tutto, non vi resta che fare:
diff --git a/appendix/00/README.md b/appendix/00/README.md
index 55fbb01..f8bfc2d 100644
--- a/appendix/00/README.md
+++ b/appendix/00/README.md
@@ -17,7 +17,7 @@ On **Raspberry Pi** you need to do:
 ```bash
 sudo apt-get update
 sudo apt-get upgrade
-sudo apt-get install git-core
+sudo apt-get install git-core glslviewer
 ```
 
 Once you have everything installed you just need to do:
diff --git a/appendix/01/README-de.md b/appendix/01/README-de.md
index 5156fd7..93824be 100644
--- a/appendix/01/README-de.md
+++ b/appendix/01/README-de.md
@@ -13,12 +13,7 @@ Um die angesprochenen Tools auf einem RaspberryPi zu installieren, rufe nach dem
 ```bash
 sudo apt-get update
 sudo apt-get upgrade
-sudo apt-get install git-core
-cd ~ 
-git clone http://github.com/patriciogonzalezvivo/glslViewer.git
-cd glslViewer
-make
-make install
+sudo apt-get install git-core glslviewer
 cd ~
 git clone https://github.com/patriciogonzalezvivo/thebookofshaders.git
 cd thebookofshaders
diff --git a/appendix/01/README-it.md b/appendix/01/README-it.md
index d104012..65eca12 100644
--- a/appendix/01/README-it.md
+++ b/appendix/01/README-it.md
@@ -11,12 +11,7 @@ Per installare e configurare tutto ciò sul Raspberry Pi, dopo l'installazione d
 ```bash
 sudo apt-get update
 sudo apt-get upgrade
-sudo apt-get install git-core
-cd ~ 
-git clone http://github.com/patriciogonzalezvivo/glslViewer.git
-cd glslViewer
-make
-make install
+sudo apt-get install git-core glslviewer
 cd ~
 git clone https://github.com/patriciogonzalezvivo/thebookofshaders.git
 cd thebookofshaders
diff --git a/appendix/01/README.md b/appendix/01/README.md
index de5a1e0..f05b7aa 100644
--- a/appendix/01/README.md
+++ b/appendix/01/README.md
@@ -11,12 +11,7 @@ To install and set this all up on the Raspberry Pi after installing the OS and l
 ```bash
 sudo apt-get update
 sudo apt-get upgrade
-sudo apt-get install git-core
-cd ~ 
-git clone http://github.com/patriciogonzalezvivo/glslViewer.git
-cd glslViewer
-make
-make install
+sudo apt-get install git-core glslviewer
 cd ~
 git clone https://github.com/patriciogonzalezvivo/thebookofshaders.git
 cd thebookofshaders