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, 0.0f,
  11          1.0f, -1.0f, 0.0f,
  12          0.0f,  1.0f, 0.0f,
  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 , model()
  29 , vtx_buf(0)
  30 , mvp_handle(0)
  31 , running(false) {
  32         GLContext::EnableVSync();
  33         program.LoadShader(
  34                 GL_VERTEX_SHADER,
  35                 "#version 330 core\n"
  36                 "layout(location = 0) in vec3 vertexPosition_modelspace;\n"
  37                 "uniform mat4 MVP;\n"
  38                 "void main() {\n"
  39                         "vec4 v = vec4(vertexPosition_modelspace, 1);\n"
  40                         "gl_Position = MVP * v;\n"
  41                 "}\n"
  42         );
  43         program.LoadShader(
  44                 GL_FRAGMENT_SHADER,
  45                 "#version 330 core\n"
  46                 "out vec3 color;\n"
  47                 "void main() {\n"
  48                         "color = vec3(1, 1, 1);\n"
  49                 "}\n"
  50         );
  51         program.Link();
  52         if (!program.Linked()) {
  53                 program.Log(std::cerr);
  54                 throw std::runtime_error("link program");
  55         }
  56
  57         GLuint VertexArrayID;
  58         glGenVertexArrays(1, &VertexArrayID);
  59         glBindVertexArray(VertexArrayID);
  60
  61         glGenBuffers(1, &vtx_buf);
  62         glBindBuffer(GL_ARRAY_BUFFER, vtx_buf);
  63         glBufferData(GL_ARRAY_BUFFER, sizeof(vtx_coords), vtx_coords, GL_STATIC_DRAW);
  64
  65         model.Position(glm::vec3(0, 0, -4));
  66
  67         mvp_handle = program.UniformLocation("MVP");
  68
  69         glClearColor(0.0, 0.0, 0.0, 1.0);
  70 }
  71
  72 Application::~Application() {
  73
  74 }
  75
  76
  77 void Application::Run() {
  78         running = true;
  79         Uint32 last = SDL_GetTicks();
  80         while (running) {
  81                 Uint32 now = SDL_GetTicks();
  82                 int delta = now - last;
  83                 Loop(delta);
  84                 last = now;
  85         }
  86 }
  87
  88 void Application::Loop(int dt) {
  89         HandleEvents();
  90         Render();
  91 }
  92
  93
  94 void Application::HandleEvents() {
  95         SDL_Event event;
  96         while (SDL_PollEvent(&event)) {
  97                 switch (event.type) {
  98                         case SDL_QUIT:
  99                                 running = false;
 100                                 break;
 101                         case SDL_WINDOWEVENT:
 102                                 switch (event.window.event) {
 103                                         case SDL_WINDOWEVENT_RESIZED:
 104                                                 cam.Viewport(event.window.data1, event.window.data2);
 105                                                 break;
 106                                         default:
 107                                                 break;
 108                                 }
 109                                 break;
 110                         default:
 111                                 break;
 112                 }
 113         }
 114 }
 115
 116 void Application::Render() {
 117         glClear(GL_COLOR_BUFFER_BIT);
 118
 119         program.Use();
 120
 121         glm::mat4 mvp(cam.MakeMVP(model.Transform()));
 122         glUniformMatrix4fv(mvp_handle, 1, GL_FALSE, &mvp[0][0]);
 123
 124         glEnableVertexAttribArray(0);
 125         glBindBuffer(GL_ARRAY_BUFFER, vtx_buf);
 126         glVertexAttribPointer(
 127                 0,        // attribute 0 (for shader)
 128                 3,        // size
 129                 GL_FLOAT, // type
 130                 GL_FALSE, // normalized
 131                 0,        // stride
 132                 nullptr   // offset
 133         );
 134         glDrawArrays(
 135                 GL_TRIANGLES, // how
 136                 0,            // start
 137                 3             // len
 138         );
 139         glDisableVertexAttribArray(0);
 140
 141         window.Flip();
 142 }
 143
 144 }