Learn opengl-with me first triangle

The previous article described the basic concepts of OpenGL, and the following describes the use of OpenGL as an example.

Triangle.cpp 1 #include <GL/glew.h> 2 #include <g  L/freeglut.h> 3 #include <iostream> 4 5 #define BUFFER_OFFSET (x) ((const void*) (x)) 6 7 enum Vao_ids
  {triangles, Numvaos};
  8 enum Buffer_ids {ArrayBuffer, numbuffers};
 9 enum Attrib_ids {vposition = 0};
 Ten Gluint Vaos[numvaos];
 Gluint Buffers[numbuffers];
 Gluint program;
 0 Const glchar* Vertex_shader = "#version 430 core \ n" Layout (location =) \ n "                                 + "in Vec4 vposition;\n" "void main () \ n" 19                                 "{\ n" gl_position = vposition;\n "21
 "}\n"; glchar* Fragment_shader = "#version 430 core\ n "Uniform vec4 color;\n" out Vec4 fcolor;\n "                                 "Void main () \ n" "{\ n" 28
 "Fcolor = color;\n" "}\n"; void Init_shader () +//vertex shader Gluint vertexshader = Glcreateshader (gl_vertex_shader
 );
 Glshadersource (vertexshader, 1, &vertex_shader, NULL);
 Glcompileshader (vertexshader);
 //check vertex shader compiling status PNs Glint compiled;
 Glchar log[256];
 Glgetshaderiv (VertexShader, Gl_compile_status, &compiled);
 if (!compiled), Glgetshaderinfolog (VertexShader, N, NULL, log);
 Std::cerr << "Vertex shader compile failed" << log << Std::endl; Fragment ShadeR Gluint fragmentshader = Glcreateshader (Gl_fragment_shader);
 Glshadersource (Fragmentshader, 1, &fragment_shader, NULL);
 Glcompileshader (Fragmentshader); //Check fragment shader compiling status Glgetshaderiv (Fragmentshader, Gl_compile_status, &com
 piled);
 if (!compiled) Glgetshaderinfolog (Fragmentshader, N, NULL, log);
 Std::cerr << "Fragment shader compile failed" << log << Std::endl;
 +//Link Shaders program = Glcreateprogram ();
 Glattachshader (program, vertexshader);
 Glattachshader (program, Fragmentshader);
 Gllinkprogram (program);
 //check link status glint linked;
 GLGETPROGRAMIV (program, Gl_link_status, &linked);
if (!linked) glgetprograminfolog (program, N, NULL, log); Std::cerr << "shader linking failed" << log << Std::endl;
 +//Delete shader Gldeleteshader (vertexshader);
 Gldeleteshader (Fragmentshader);
 Init_data () Glclearcolor (1, 1, 1, 0);                                                                                                                                                                    
 Glclear (Gl_color_buffer_bit); Bayi Glgenvertexar
 Rays (Numvaos, Vaos);
 Glbindvertexarray (Vaos[triangles]);  Glfloat Vertices[3][2] = {85 {-0.8,-0.9}, 86 {0.8,-0.9}, 87 {0,
 0.9}, 88};
 Glgenbuffers (numbuffers, buffers);
 Glbindbuffer (Gl_array_buffer, Buffers[arraybuffer]);
 Glbufferdata (Gl_array_buffer, sizeof (vertices), vertices, gl_static_draw); 94 GluseprograM (program);
 /Control fragment color Glint loc = glgetuniformlocation (program, "Color");
 gluniform4f (Loc, 1.0f, 0.0f, 0.0f, 1.0f);
 98 Glvertexattribpointer (vposition, 2, Gl_float, Gl_false, 0, Buffer_offset (0));
Glenablevertexattribarray (vposition); 101} 102 103 void display () 104 {glclear (gl_color_buffer_bit); 106 107 Glbindvertexar
Ray (Vaos[triangles]);
108 Gldrawarrays (gl_triangles, 0, 3);
109 Glflush (); 111 (int argc, char* argv[]) 113 {glutinit (&AMP;ARGC, argv); Glutinitdisplaymo
De (GLUT_RGBA);
Glutinitwindowsize (300, 300);
117 glutinitwindowposition (100, 100);
118 Glutcreatewindow ("Learn Opengl:first triangle");
119 Glewexperimental = Gl_true; 
121 if (Glewinit ()) 122 {123 Std::cout << "Unable to Initialize" << Std::endl;             124    Exit (1);
Init_shader} 126 ();
127 init_data ();
Glutdisplayfunc (display);
129 Glutmainloop ();                                                                                            130}

Running on Ubuntu: g++ Triangle.cpp-lgl-lglu-lglut-lglew

You can get the triangles shown in the following image: