OpenGL Super Treasure Study notes (1) First triangle

Execution effect
Code and parsing:

triangle.cpp//triangle////Created by Fengsser on 15/6/20.//Copyright (c) 2015 Fengsser. All rights reserved.//#include <gltools.h>//used to mask differences between different platforms, build forms, etc. # include <GLShaderManager.h> #ifdef __ Apple__#include <glut/glut.h> #else # define Freeglut_static#endifglbatch trianglebatch; Glshadermanager shadermanager;//the size of the form to accept the new width and height, the number of units is the image of void changesize (int w,int h) {//Finish mapping from the destination coordinate system to the screen coordinate system, glint X, Glint y is the coordinate of the viewport in the lower-left corner of the form.    Veiwport is the rendering area. Glviewport (0, 0, W, h);}    Set Render-contextvoid SETUPRC () {//Set back Color R,g,b,a glclearcolor (0.0f, 0.0f, 1.0f, 1.0f);    Initializes the shader manager shadermanager.initializestockshaders (); Sets the triangle. The array Vvert includes all 3 vertices of x, y, Z, Cartesian coordinates (the coordinate system of junior high school).
    Glfloat vverts[] = { -0.5f,0.0f,0.0f, 0.5f,0.0f,0.0f, 0.0f,0.5f,0.0f,};    Build a triangular batch of trianglebatch.begin (gl_triangles,3);    trianglebatch.copyvertexdata3f (Vverts); Trianglebatch.end ();} Start rendering void Renderscene (void) {//Clear buffer: Color | depth | template glclear (gl_color_buffer_bit | Gl_depth_buffer_bit |    Gl_stencil_buffer_bit);    Sets a set of floating-point numbers to represent red glfloat vred[] = {1.0f,0.0f,0.0f,1.0f}; Transmits the color to the storage shader, the glt_shader_identity shader, which simply renders the geometry on the screen using the specified color with the default Cartesian coordinates Shadermanager.usestockshader (glt_shader_    identity,vred);    Submit Geometry shader Trianglebatch.draw (); Renders in the back buffer. Then at the end of the exchange to the foreground glutswapbuffers ();} int main (int argc,char* argv[]) {gltsetworkingdirectory (argv[0]);//Set Current working folder. For Mac OS X glutinit (&AMP;ARGC, argv); Transfer command-line parameters and initialize the GLUT library//Tell the GLUT library which display mode to use when creating the form, Glut_double: double-buffered form. Glut_rgba:rgba color mode; Glut_depth: Deep test glut_stencil: Template Test Glutinitdisplaymode (glut_double | Glut_rgba | glut_depth |    GLUT_STENCIL); Glutinitwindowsize (+);//glut form size,Form Glutcreatewindow ("Triangle");//Create a form with a caption of Triangle//register to listen, events are emitted in the out loop, form size changes and OpenGL render Glutreshapefunc (changesize    );    Glutdisplayfunc (Renderscene);    Initialize the missing entry point Glewinit in the OpenGL driver and check for initialization failure.    Glenum err = Glewinit ();        if (GLEW_OK! = Err) {fprintf (stderr, "Glew error:%s\n", glewgeterrorstring (err));    return 1; } SETUPRC ();//rc-render context Glutmainloop ();//start main loop return 0;}

Key processes

about Viewports (viewPort) and forms:
viewport. Renders (draws) the area.

General and form and so on large. A viewport is used to map pixel coordinates from a logical Cartesian coordinate system to a physical screen.

OpenGL Super Treasure Study notes (1) First triangle