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_img()
  22 , init_gl()
  23 , window()
  24 , ctx(window.CreateContext())
  25 , init_glew()
  26 , program()
  27 , cam()
  28 , vtx_buf(0)
  29 , mvp_handle(0)
  30 , running(false) {
  31         GLContext::EnableVSync();
  32         program.LoadShader(
  33                 GL_VERTEX_SHADER,
  34                 "#version 330 core\n"
  35                 "layout(location = 0) in vec3 vertexPosition_modelspace;\n"
  36                 "uniform mat4 MVP;\n"
  37                 "void main() {\n"
  38                         "vec4 v = vec4(vertexPosition_modelspace, 1);\n"
  39                         "gl_Position = MVP * v;\n"
  40                 "}\n"
  41         );
  42         program.LoadShader(
  43                 GL_FRAGMENT_SHADER,
  44                 "#version 330 core\n"
  45                 "out vec3 color;\n"
  46                 "void main() {\n"
  47                         "color = vec3(1, 1, 1);\n"
  48                 "}\n"
  49         );
  50         program.Link();
  51         if (!program.Linked()) {
  52                 program.Log(std::cerr);
  53                 throw std::runtime_error("link program");
  54         }
  55
  56         GLuint VertexArrayID;
  57         glGenVertexArrays(1, &VertexArrayID);
  58         glBindVertexArray(VertexArrayID);
  59
  60         glGenBuffers(1, &vtx_buf);
  61         glBindBuffer(GL_ARRAY_BUFFER, vtx_buf);
  62         glBufferData(GL_ARRAY_BUFFER, sizeof(vtx_coords), vtx_coords, GL_STATIC_DRAW);
  63
  64         mvp_handle = program.UniformLocation("MVP");
  65
  66         glClearColor(0.0, 0.0, 0.0, 1.0);
  67 }
  68
  69 Application::~Application() {
  70
  71 }
  72
  73
  74 void Application::Run() {
  75         running = true;
  76         Uint32 last = SDL_GetTicks();
  77         while (running) {
  78                 Uint32 now = SDL_GetTicks();
  79                 int delta = now - last;
  80                 Loop(delta);
  81                 last = now;
  82         }
  83 }
  84
  85 void Application::Loop(int dt) {
  86         HandleEvents();
  87         Render();
  88 }
  89
  90
  91 void Application::HandleEvents() {
  92         SDL_Event event;
  93         while (SDL_PollEvent(&event)) {
  94                 switch (event.type) {
  95                         case SDL_QUIT:
  96                                 running = false;
  97                                 break;
  98                         case SDL_WINDOWEVENT:
  99                                 switch (event.window.event) {
 100                                         case SDL_WINDOWEVENT_RESIZED:
 101                                                 cam.Viewport(event.window.data1, event.window.data2);
 102                                                 break;
 103                                         default:
 104                                                 break;
 105                                 }
 106                                 break;
 107                         default:
 108                                 break;
 109                 }
 110         }
 111 }
 112
 113 void Application::Render() {
 114         glClear(GL_COLOR_BUFFER_BIT);
 115
 116         program.Use();
 117
 118         glm::mat4 model(1.0f); // identity: no transformation
 119         glm::mat4 mvp(cam.MakeMVP(model));
 120         glUniformMatrix4fv(mvp_handle, 1, GL_FALSE, &mvp[0][0]);
 121
 122         glEnableVertexAttribArray(0);
 123         glBindBuffer(GL_ARRAY_BUFFER, vtx_buf);
 124         glVertexAttribPointer(
 125                 0,        // attribute 0 (for shader)
 126                 3,        // size
 127                 GL_FLOAT, // type
 128                 GL_FALSE, // normalized
 129                 0,        // stride
 130                 nullptr   // offset
 131         );
 132         glDrawArrays(
 133                 GL_TRIANGLES, // how
 134                 0,            // start
 135                 3             // len
 136         );
 137         glDisableVertexAttribArray(0);
 138
 139         window.Flip();
 140 }
 141
 142 }