Learning GL

Huge shoutout to Scott Greenup! Inspirational person who has unparallelled ability at coding! Check out his github.

Chapters:

Setups and basic concepts
Shapes
Triangle
Square
Circles

Last Update: 14/05/2015

1. Setups and basics

Setting up requires glfw package, makes things easier for starting. Language used is c++ which means that the #include <GLFW/glfw3.h> is needed to perform.

Basic Concepts:

Model View Projection
Very important
Handles how the objects are then displayed onto the screen
Basic concepts:

Model << local -> camera
View << camera -> world
Projection << world -> screen

Ratio is important especially when working with perspective/orthogonal, ensures that everything is displayed correctly

2. Shapes

Notes on working with shapes

Very important: When you draw a shape, make sure the points you put are in a adjacent in order!!
Shapes points are determined from the centre of the shape.
Protip: draw out the shape and work the points on paper prior to constructing the code.

Triangles

#include <GLFW/glfw3.h>

glBegin(GL_TRIANGLES);
glColor3f(1.f, 0.f, 0.f); //colours (R,G,B) [1.0 = max]
glVertex3f(-0.6f, -0.4f, 0.f); //First point, (x,y,z) coordinate from center

glColor3f(0.f, 1.f, 0.f); 
glVertex3f(0.6f, -0.4f, 0.f);

glColor3f(0.f, 0.f, 1.f);
glVertex3f(0.f, 0.6f, 0.f);

glEnd();

Squares

glBegin(GL_QUADS);
glColor3f(1.f, 1.f, 1.f); //colours in RGB
glVertex3f(0.2, 0.2, 0.f); //points in (x,y,z);

glColor3f(0.f, 1.f, 0.f);
glVertex3f(0.2, -0.2, 0.f);

glColor3f(1.f, 0.f, 0.f);
glVertex3f(-0.2, -0.2, 0.f);

glColor3f(0.f, 0.f, 1.f);
glVertex3f(-0.2, 0.2, 0.f);
glEnd();

Circles

Circles are a bit of a play around, you're going to have to #include <math.h>

float rad = 0.2f;
glBegin(GL_POLYGON);
for(float angle = 0; angle < 2*PI; angle += 0.01){
    glColor3f(0.f, 1.f, 1.f);
    glVertex3f(rad*cos(angle), rad*sin(angle), 0);
}
glEnd();

NatoliChris/learningGL