Fixes for pdf generation on macos

* Fixes first shader not automatically closing by adding `u_time` (see patriciogonzalezvivo/glslViewer#142).
* Use glslviewer's headless mode for generating images.
* Update to latest Pandoc CLI arguments to fix Pandoc CLI errors.
* Re-encode `12/accretion.jpg` and `13/holdsworth.jpg` to fix Pandoc jpg errors.
* Update appendix 2 README for generating the book as a pdf.

02/hello_world.frag

@@ -2,6 +2,8 @@
 precision mediump float;
 #endif
 
+uniform float u_time;
+
 void main() {
 	gl_FragColor = vec4(1.0,0.0,1.0,1.0);
 }

appendix/02/README.md

@@ -35,10 +35,16 @@ For parsing the Markdown chapters into Latex and then into a PDF file we will us
 
 In **MacOSX**:
 
-Download and Install [basictex & MacTeX-Additions](http://www.tug.org/mactex/morepackages.html) and then install [Pandoc](http://johnmacfarlane.net/pandoc/) and Python by:
+Download and Install [basictex & MacTeX-Additions] by:
 
 ```bash
-brew install pandoc python2.7
+brew cask install mactex-no-gui
+```
+
+and then install [Pandoc](http://johnmacfarlane.net/pandoc/), Python 2 & glslViewer by:
+
+```bash
+brew install pandoc python@2 glslviewer
 ```
 
 On **Raspberry Pi** (Raspbian):

src/parseBook.py

@@ -42,7 +42,7 @@ def injectShaderBlocks(_folder, _text):
             shaderImage = folder + "/tmp-" + shaderName + ".png"
             shaderCommand = "glslViewer " + shaderPath + " " + \
                             " ".join(shaderTexturePaths) + \
-                            " -s 0.5 -o " + shaderImage
+                            " -s 0.5 --headless -o " + shaderImage
             print shaderCommand
             returnCode = subprocess.call(shaderCommand, shell=True)
             rta += "![](" + shaderImage + ")\n"
@@ -83,9 +83,9 @@ for folder in folders:
 
 # Set up the appropriate options for the pandoc command
 inputOptions = chapters
-generalOptions = ["-N", "--smart", "--no-tex-ligatures", "--toc", "--standalone",
-                  "--preserve-tabs", "-V documentclass=scrbook", "-V papersize=a4", "-V links-as-note", "-S"]
-latexOptions = ["--latex-engine=" + latexEngine]
+generalOptions = ["-N", "--toc", "--standalone",
+                  "--preserve-tabs", "-V documentclass=scrbook", "-V papersize=a4", "-V links-as-note"]
+latexOptions = ["--pdf-engine=" + latexEngine]
 outputOptions = ["--output={0}".format(pdfBookPath)]
 pandocCommand = ["pandoc"] + outputOptions + \
     inputOptions + generalOptions + latexOptions