Course name:  It will (hopefully) change soon

Ok, let's recap a bit, and talk about 3D graphics
	OpenGL:  Open Graphics Library
		Started by an industry group including Silicone Graphics
		Presently maintained by the Khronos group
		Current version is 4.6
		Cross-platform, and supported everywhere I can think of
		"Red Book" is the standard guide, but the online version covers 1.x
			- If you order a print copy for money, it can cover more recent versions
		"Orange Book" is the GLSL guide, but again, the online version is old
			- Worth reading anyway though
		A major shift took place in OpenGL 2.0, and "shader" programming was added
	
Basics:  What is a transformation?
	https://www.tutorialspoint.com/computer_graphics/3d_transformation.htm
	Matrix Multiplication (review of whenever)
	Basic operations:
		Rotation
		Translation
		Scaling
	Shear isn't used all that much in graphics for games and such, but it works too...
	You can combine multiple transformations in a single matrix!
	Crafting a matrix is a fine way to accomplish any transformation

The fixed graphics pipeline and OpenGL 1.x
	Red book illustration
	Red book chapter 3 camera picture
	The red book:  https://www.glprogramming.com/red/
	This pipeline is flexible, easy to use, and efficient
	But, it is less direct than programming vertex and fragment operations directly!
	Bit of an aside:  Where does ray tracing fit in?
		Lighting calculations happen in the vertex operations in OpenGL 1.x
		So in our red book diagram, that's the box!
		How it works
		Must do collision detection on the GPU, generally computationally infeasible for games
		How else to do it?

Back to the point:  Manual operations in the real world, and my cousin
	Direct control in detail is good, but it's also a hassle
	Separates the pro from the novice
	So, roll up your sleeves and get ready for work!
	It's ok to be a novice at some things, but not at your profession
		I dislike being a novice so much, I'd rather drink bad lever espresso
	I can't strike an arc, but thanks to the easy way, I can arc weld

OpenGL 2.x and the shader programming revolution
	Game developers desired greater control over vertex and fragment operations
	Vulkan takes the control further
	
So, we will have a high-level shader programming language!
	There are a few out there.  We'll learn GLSL

Compiler is IN THE DRIVER
	Why?  Depends on the hardware!
	This is in contrast to Cg, HLSL, etc.
		Driver update can change compiler
		New compiler can be used for new hardware!
	The bad old days:  ARB_vertex_program and ARB_fragment_program
	Frontend is open source
	Back ends generally aren't
		I'm sure there's one out there
	
More about GLSL
	C basis, but matrix operations are built-in!
	Let's look at the shader programs from the first tutorial again
		Focus in on the programs, not what we had to do to run them
	We can unpack vectors with .x, .y, .z
	So, how about reshaping the triangle?
		Piece of cake
	Upside-down?  Sideways?
	You already changed the fragment shader program
		How about a fade?
		Built-in variables:  https://www.khronos.org/opengl/wiki/Built-in_Variable_(GLSL)
		Or, different colors on each side?  That could actually be hard with 1.x!

Question to think about:  Why is gl_Position NOT available in the fragment shader?
	Thinking period while I apply a fade in the other direction as well
	Discussion

If we have time:
	The vertex shader interprets the vertices however it wants
	That means we can actually hack these in the vertex shader, in 2D, without matrix operations
	Scale up and down?
	Translate?
	The hard one:  Rotation?

Next time:  Detail on communication between C code and shaders