Add "some links for learning shaders"

tex/forest.bib

@@ -514,3 +514,29 @@ @article{singh2009real
   year={2009},
   publisher={IEEE}
 }
+
+@book{glassner1989introduction,
+  title={An introduction to ray tracing},
+  author={Glassner, Andrew S},
+  year={1989},
+  publisher={Morgan Kaufmann}
+}
+
+@book{pharr2023physically,
+  title={Physically based rendering: From theory to implementation},
+  author={Pharr, Matt and Jakob, Wenzel and Humphreys, Greg},
+  year={2023},
+  publisher={MIT Press}
+}
+
+@article{keeter2020massively,
+  title={Massively parallel rendering of complex closed-form implicit surfaces},
+  author={Keeter, Matthew J},
+  journal={ACM Transactions on Graphics (TOG)},
+  volume={39},
+  number={4},
+  pages={141--1},
+  year={2020},
+  publisher={ACM New York, NY, USA}
+}
+

trees/math-000H.tree

@@ -0,0 +1,28 @@
+\import{tt-macros}
+% clifford hopf spin tt math draft
+\tag{math}
+\tag{draft}
+
+% definition theorem lemma construction observation
+% convention corollary axiom example exercise proof
+% discussion remark notation
+% \taxon{}
+% \refcardt{lemma}{}{}{}{
+
+% kostecki2011introduction leinster2016basic nakahira2023diagrammatic rosiak2022sheaf
+
+\note{some links for learning shaders}{
+  \ul{
+    \li{\citek{glassner1989introduction} is a classic book on ray tracing, now free to download [here](https://www.realtimerendering.com/blog/an-introduction-to-ray-tracing-is-now-free-for-download/).}
+    \li{\citek{pharr2023physically} is a complete, illustrative, and physically based ray-tracing renderer book, free to read [on line](https://pbr-book.org/).
+    }
+    \li{[Ray tracing weekend series](https://raytracing.github.io/) is a mini book series on ray tracing.}
+    \li{[Autodesk Standard Surface](https://autodesk.github.io/standard-surface/) contains references to many concepts and formulas for surface shaders.}
+    \li{[MPR](https://github.com/mkeeter/mpr) implements \citek{keeter2020massively} on GPU, while [Fidget](https://github.com/mkeeter/fidget) implements it on CPU.}
+    \li{[ShaderMania](https://github.com/markusmoenig/ShaderMania) seems to be a good tool to play with shaders. Similarly there are [Shadertoy](https://www.shadertoy.com/), which has a [VS Code extension](https://github.com/stevensona/shader-toy) and [a ThreeJS port](https://threejs.org/manual/#en/shadertoy).}
+    \li{[stackgl](https://stack.gl/) provides many packages for using in GLSL, [LYGIA](https://lygia.xyz/) is a similar effort, targeting a wider range of languages: GLSL/HLSL/MSL/WGSL/CUDA.}
+    \li{[The Book of Shaders](https://thebookofshaders.com/) is a good starting point. One could use [GlslCanvas](https://github.com/patriciogonzalezvivo/glslCanvas) or [glslViewer](https://github.com/patriciogonzalezvivo/glslViewer) to play with the shaders.
+    }
+    \li{For GA, there are [miniPGA.glsl](https://github.com/enkimute/LookMaNoMatrices/blob/main/src/miniPGA.glsl), [slerp optimization](https://www.shadertoy.com/view/DlGfRK), [Spinor 2d](https://www.shadertoy.com/view/mdjSWD), and [G2 Multivector-Valued Functions](https://www.shadertoy.com/view/wlf3RX). }
+  }
+}

trees/refs/glassner1989introduction.tree

@@ -0,0 +1,14 @@
+% ["forest"]
+\title{An introduction to ray tracing}
+\date{1989}
+\author{Andrew S Glassner}
+\taxon{reference}
+
+\meta{bibtex}{\startverb
+@book{glassner1989introduction,
+ title = {An introduction to ray tracing},
+ author = {Glassner, Andrew S},
+ year = {1989},
+ publisher = {Morgan Kaufmann}
+}
+\stopverb}

trees/refs/keeter2020massively.tree

@@ -0,0 +1,18 @@
+% ["forest"]
+\title{Massively parallel rendering of complex closed-form implicit surfaces}
+\date{2020}
+\author{Matthew J Keeter}
+\taxon{reference}
+
+\meta{bibtex}{\startverb
+@article{keeter2020massively,
+ title = {Massively parallel rendering of complex closed-form implicit surfaces},
+ author = {Keeter, Matthew J},
+ year = {2020},
+ journal = {ACM Transactions on Graphics (TOG)},
+ volume = {39},
+ number = {4},
+ pages = {141--1},
+ publisher = {ACM New York, NY, USA}
+}
+\stopverb}

trees/refs/pharr2023physically.tree

@@ -0,0 +1,14 @@
+% ["forest"]
+\title{Physically based rendering: From theory to implementation}
+\date{2023}
+\author{Matt Pharr}\author{Wenzel Jakob}\author{Greg Humphreys}
+\taxon{reference}
+
+\meta{bibtex}{\startverb
+@book{pharr2023physically,
+ title = {Physically based rendering: From theory to implementation},
+ author = {Pharr, Matt and Jakob, Wenzel and Humphreys, Greg},
+ year = {2023},
+ publisher = {MIT Press}
+}
+\stopverb}