src/app.cpp

   1 #include "app.hpp"
   2
   3 #include <iostream>
   4 #include <stdexcept>
   5
   6
   7 namespace {
   8
   9 constexpr GLfloat vtx_coords[] = {
  10         -1.0f, -1.0f, -5.0f,
  11          1.0f, -1.0f, -5.0f,
  12          0.0f,  1.0f, -5.0f,
  13 };
  14
  15 }
  16
  17 namespace blank {
  18
  19 Application::Application()
  20 : init_sdl()
  21 , init_gl()
  22 , window()
  23 , ctx(window.CreateContext())
  24 , init_glew()
  25 , program()
  26 , cam()
  27 , vtx_buf(0)
  28 , mvp_handle(0)
  29 , running(false) {
  30         GLContext::EnableVSync();
  31         program.LoadShader(
  32                 GL_VERTEX_SHADER,
  33                 "#version 330 core\n"
  34                 "layout(location = 0) in vec3 vertexPosition_modelspace;\n"
  35                 "uniform mat4 MVP;\n"
  36                 "void main() {\n"
  37                         "vec4 v = vec4(vertexPosition_modelspace, 1);\n"
  38                         "gl_Position = MVP * v;\n"
  39                 "}\n"
  40         );
  41         program.LoadShader(
  42                 GL_FRAGMENT_SHADER,
  43                 "#version 330 core\n"
  44                 "out vec3 color;\n"
  45                 "void main() {\n"
  46                         "color = vec3(1, 1, 1);\n"
  47                 "}\n"
  48         );
  49         program.Link();
  50         if (!program.Linked()) {
  51                 program.Log(std::cerr);
  52                 throw std::runtime_error("link program");
  53         }
  54
  55         GLuint VertexArrayID;
  56         glGenVertexArrays(1, &VertexArrayID);
  57         glBindVertexArray(VertexArrayID);
  58
  59         glGenBuffers(1, &vtx_buf);
  60         glBindBuffer(GL_ARRAY_BUFFER, vtx_buf);
  61         glBufferData(GL_ARRAY_BUFFER, sizeof(vtx_coords), vtx_coords, GL_STATIC_DRAW);
  62
  63         mvp_handle = program.UniformLocation("MVP");
  64
  65         glClearColor(0.0, 0.0, 0.0, 1.0);
  66 }
  67
  68 Application::~Application() {
  69
  70 }
  71
  72
  73 void Application::Run() {
  74         running = true;
  75         Uint32 last = SDL_GetTicks();
  76         while (running) {
  77                 Uint32 now = SDL_GetTicks();
  78                 int delta = now - last;
  79                 Loop(delta);
  80                 last = now;
  81         }
  82 }
  83
  84 void Application::Loop(int dt) {
  85         HandleEvents();
  86         Render();
  87 }
  88
  89
  90 void Application::HandleEvents() {
  91         SDL_Event event;
  92         while (SDL_PollEvent(&event)) {
  93                 switch (event.type) {
  94                         case SDL_QUIT:
  95                                 running = false;
  96                                 break;
  97                         case SDL_WINDOWEVENT:
  98                                 switch (event.window.event) {
  99                                         case SDL_WINDOWEVENT_RESIZED:
 100                                                 cam.Viewport(event.window.data1, event.window.data2);
 101                                                 break;
 102                                         default:
 103                                                 break;
 104                                 }
 105                                 break;
 106                         default:
 107                                 break;
 108                 }
 109         }
 110 }
 111
 112 void Application::Render() {
 113         glClear(GL_COLOR_BUFFER_BIT);
 114
 115         program.Use();
 116
 117         glm::mat4 model(1.0f); // identity: no transformation
 118         glm::mat4 mvp(cam.MakeMVP(model));
 119         glUniformMatrix4fv(mvp_handle, 1, GL_FALSE, &mvp[0][0]);
 120
 121         glEnableVertexAttribArray(0);
 122         glBindBuffer(GL_ARRAY_BUFFER, vtx_buf);
 123         glVertexAttribPointer(
 124                 0,        // attribute 0 (for shader)
 125                 3,        // size
 126                 GL_FLOAT, // type
 127                 GL_FALSE, // normalized
 128                 0,        // stride
 129                 nullptr   // offset
 130         );
 131         glDrawArrays(
 132                 GL_TRIANGLES, // how
 133                 0,            // start
 134                 3             // len
 135         );
 136         glDisableVertexAttribArray(0);
 137
 138         window.Flip();
 139 }
 140
 141 }