A project with some basic code to work with OpenGL. Nothing productive, just to understand how some things work. Code might be "overcommented" for easier understanding.
Requires GLEW.
/**
*
* OpenGL Pipeline
*
* CPU: Vertex data
* GPU:
* vertex processing (vertex shader): local, eye, clip, world
* primitive assembly: triangles, quads, lines, points
* rasterization: smoothing, multisampling
* fragment processing (fragment shader): alpha, depth, textures, stencil,
* Framebuffer: pixels
*/ -
OpenGL Coordinate System
-
right handed
-
X,Y and Z in the direction of the viewer
-
Matrices
-
Can rotate, scale and translate vertex positions
-
Map to a different coodinate system
-
Or use to project vertices onto the screen
-
Model transformations (with matrices)
-
Transforms from local space to world space
-
Common/recommended order: Scale, rotate, and translate
-
Order of the matrix multiplication is in the opposite order
-
E.g. final matrix = [translate matrix] * [rotate matrix] * [scale matrix]
-
View transformations
-
Transforms from world space to eye space
-
Required is position of the viewer, target point and vector for UP
-
Projection matrix
-
Transforms eye space coordinates to clip space (i.e. screen area)
GLEW:
- interface for OpenGL1.1 and above
- can check/load OpenGL extensions
GLFW:
- allows support for multiple windows
- for window creation and management
- can handle input devices (mouse, keyboard, joystick, gamepad)
SDL:
- can do more
- allows access to audio, fs,