app.cpp 3.2 KB

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  1. /*
  2. * 2D Physic Engine
  3. * app.cpp: basic application handling.
  4. * Based on pikuma.com Learn Game Physics Engine Programming course.
  5. * Copyright (c) 2022 986-Studio. All rights reserved.
  6. *
  7. * Created by Manoël Trapier on 07/06/2022.
  8. */
  9. #include <app.h>
  10. #include <graphics.h>
  11. #include <imgui.h>
  12. #include <imgui_sdl.h>
  13. #include <imgui_impl_sdl.h>
  14. #include <physics/constants.h>
  15. void application::parseParameters(int argc, char *argv[])
  16. {
  17. // Nothing to do for now
  18. }
  19. void application::setup()
  20. {
  21. this->running = graphics::openWindow();
  22. this->millisecsPreviousFrame = SDL_GetTicks();
  23. this->particles.push_back(new particle(50, 100, 1.0, 4));
  24. this->particles.push_back(new particle(50, 200, 3.0, 12));
  25. }
  26. void application::input()
  27. {
  28. SDL_Event event;
  29. while(SDL_PollEvent(&event))
  30. {
  31. //ImGui_ImplSDL2_ProcessEvent(&event);
  32. //ImGuiIO &io = ImGui::GetIO();
  33. switch(event.type)
  34. {
  35. case SDL_QUIT:
  36. this->running = false;
  37. break;
  38. case SDL_KEYDOWN:
  39. if (event.key.keysym.sym == SDLK_ESCAPE)
  40. {
  41. this->running = false;
  42. }
  43. break;
  44. }
  45. }
  46. }
  47. double application::syncAndDeltatime()
  48. {
  49. /* Let's make sure we are running at the expected framerate */
  50. uint32_t now = SDL_GetTicks();
  51. int32_t timeToWait = MILLISECS_PER_FRAME - (now - this->millisecsPreviousFrame);
  52. if ((timeToWait > 0) && (timeToWait <= MILLISECS_PER_FRAME))
  53. {
  54. SDL_Delay(timeToWait);
  55. }
  56. double deltaTime = (SDL_GetTicks() - this->millisecsPreviousFrame) / 1000.0;
  57. /* clamp maximum deltatime to avoid weird behaviours */
  58. if (deltaTime > 0.016)
  59. {
  60. deltaTime = 0.016;
  61. }
  62. this->millisecsPreviousFrame = SDL_GetTicks();
  63. return deltaTime;
  64. }
  65. void application::update()
  66. {
  67. vec2 wind = vec2(0.2 * PIXELS_PER_METER, 0);
  68. double deltaTime = this->syncAndDeltatime();
  69. this->part->addForce(wind);
  70. for (auto part:this->particles)
  71. {
  72. part->addForce(wind);
  73. part->integrate(deltaTime);
  74. // check the particles position and keep the particule in the window.
  75. if ( ((part->position.y - part->radius) <= 0) ||
  76. ((part->position.y + part->radius) >= graphics::height()))
  77. {
  78. part->velocity.y = -part->velocity.y;
  79. }
  80. if ( ((part->position.x - part->radius) <= 0) ||
  81. ((part->position.x + part->radius) >= graphics::width()))
  82. {
  83. part->velocity.x = -part->velocity.x;
  84. }
  85. }
  86. if ( ((this->part->position.x - this->part->radius) <= 0) ||
  87. ((this->part->position.x + this->part->radius) >= graphics::width()))
  88. {
  89. this->part->velocity.x = -this->part->velocity.x;
  90. }
  91. }
  92. void application::render()
  93. {
  94. graphics::clearScreen(0xFF056263);
  95. for (auto part:this->particles)
  96. {
  97. graphics::draw::fillCircle(part->position.x, part->position.y, part->radius, 0xFFFFFFFF);
  98. }
  99. graphics::draw::fillCircle(this->part->position.x, this->part->position.y, 4, 0xFFFFFFFF);
  100. graphics::renderFrame();
  101. }
  102. void application::destroy()
  103. {
  104. // Nothing for now.
  105. for (auto part:this->particles)
  106. {
  107. delete part;
  108. }
  109. graphics::closeWindow();
  110. }