Some OpenGL notes

some libraries:
	GLFW - window and GL context creation
	GLEW - GL extension loading
	SOIL - image loading
	GLM  - vector and matrix math


Window and context creation:
	Initialize GLFW (glfwInit)
	Set window hints to enable 3.3 core profile context (glfwWindowHint)
	Create window with glfwCreateWindow
	Make window context current with glfwMakeContextCurrent
	Set glewExperimental to true
	Initialize GLEW with glewInit


Vertex Buffer Objects (VBO's):
	VBO's store vertex data
	First load or define the vertex data in your main program
	Generate a buffer on the GPU with glGenBuffers
	Bind it with glBindBuffer
	Upload the data with glBufferData
	A buffer on the GPU must be binded as the active buffer before it can be used,
	for example, to GL_ARRAY_BUFFER for VBO's

Shaders:
	Load vertex and fragment shaders with glCreateShader, glShaderSource, and glCompileShader
	Check for compile errors with glGetShaderiv and glGetShaderInfoLog
	Create a GL program with glCreateProgram
	Attach the vertex and fragment shaders to the program with glAttachShader
	Set the output buffer number for the color output of the fragment shader with glBindFragDataLocation
	Link the program with glLinkProgram
	Bind the program with glUseProgram
	Generate a VAO using glGenVertexArrays
	Bind it using glBindVertexArray
	Binding a VAO will allow opengl to store shader attributes and the binded VBO so that you don't have to
	reset the attributes each time you use the shader. Note that this step is required.
	Set attributes with glGetAttribLocation, glVertexAttribPointer, and glEnableVertexAttribArray

Uniforms:
	Uniforms are kind of like global variables that always have the same value
	Get location of uniform variable with glGetUniformLocation
	Set it's value with glUniform**

Alpha blending:
	Enable with glEnable(GL_BLEND)
	set blending function with glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)

Element Buffer Objects (EBO's):
	Element buffers specify indexes into the VBO when rendering vertices
	This allows you to combine identical vertices
	Generate one with glGenBuffers
	Bind it to GL_ELEMENT_ARRAY_BUFFER
	Upload the data

Drawing:
	Draw triangles in currently bounded VBO with glDrawArrays
	Or if using an EBO, use glDrawElements

Textures:
	Load or define the pixel data in the main program
	Generate a texture buffer with glGenTextures
	Make a texture unit active with glActiveTexture (0 is active by default)
	Bind it with glBindTexture to GL_TEXTURE_2D
	Upload pixel data with glTexImage2D
	Set texture parameters with glTexParameteri/f
	Generate mipmaps with glGenerateMipmap
	Remember to supply the texture coordinates in the VBO
	In the fragment shader, sample the texture with a uniform of type sampler2D using the texture function
	Update the uniform sampler2D with the correct texture unit.

Uniform Buffer Objects (UBO's)
	Used for uploading data in bulk to the GPU
	Get the index of an interface block in GLSL with glGetUniformBlockIndex (optional, unless you have more than 1 blocks)
	Bind the block to a bind point with glUniformBlockBinding (binded to 0 by default. optional)
	Bind a buffer object to GL_UNIFORM_BUFFER and an index with glBindBufferBase
	Upload your data to the buffer object
	(watch out for padding and make sure to specify the right layout in your interface block in GLSL)
	In order to use variable length arrays, you must specify a static upper bound in the interface block,
	and indicate the actual length using a uniform