main.cpp 9.8 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268
  1. #define GLEW_STATIC
  2. #include <GL/glew.h>
  3. #include <GLFW/glfw3.h>
  4. #define STB_IMAGE_IMPLEMENTATION
  5. #include "stb_image.h" // for .png loading
  6. #include "../../imgui.h"
  7. #ifdef _MSC_VER
  8. #pragma warning (disable: 4996) // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen
  9. #endif
  10. static GLFWwindow* window;
  11. static GLuint fontTex;
  12. // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structuer)
  13. // We are using the fixed pipeline.
  14. // A faster way would be to collate all vertices from all cmd_lists into a single vertex buffer
  15. static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
  16. {
  17. if (cmd_lists_count == 0)
  18. return;
  19. // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers.
  20. glEnable(GL_BLEND);
  21. glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  22. glDisable(GL_CULL_FACE);
  23. glDisable(GL_DEPTH_TEST);
  24. glEnable(GL_SCISSOR_TEST);
  25. glEnableClientState(GL_VERTEX_ARRAY);
  26. glEnableClientState(GL_TEXTURE_COORD_ARRAY);
  27. glEnableClientState(GL_COLOR_ARRAY);
  28. // Setup texture
  29. glBindTexture(GL_TEXTURE_2D, fontTex);
  30. glEnable(GL_TEXTURE_2D);
  31. // Setup orthographic projection matrix
  32. const float width = ImGui::GetIO().DisplaySize.x;
  33. const float height = ImGui::GetIO().DisplaySize.y;
  34. glMatrixMode(GL_PROJECTION);
  35. glLoadIdentity();
  36. glOrtho(0.0f, width, height, 0.0f, -1.0f, +1.0f);
  37. glMatrixMode(GL_MODELVIEW);
  38. glLoadIdentity();
  39. // Render command lists
  40. for (int n = 0; n < cmd_lists_count; n++)
  41. {
  42. const ImDrawList* cmd_list = cmd_lists[n];
  43. const unsigned char* vtx_buffer = (const unsigned char*)cmd_list->vtx_buffer.begin();
  44. glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer));
  45. glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer+8));
  46. glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (void*)(vtx_buffer+16));
  47. int vtx_offset = 0;
  48. const ImDrawCmd* pcmd_end = cmd_list->commands.end();
  49. for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++)
  50. {
  51. glScissor((int)pcmd->clip_rect.x, (int)(height - pcmd->clip_rect.w), (int)(pcmd->clip_rect.z - pcmd->clip_rect.x), (int)(pcmd->clip_rect.w - pcmd->clip_rect.y));
  52. glDrawArrays(GL_TRIANGLES, vtx_offset, pcmd->vtx_count);
  53. vtx_offset += pcmd->vtx_count;
  54. }
  55. }
  56. glDisable(GL_SCISSOR_TEST);
  57. }
  58. static const char* ImImpl_GetClipboardTextFn()
  59. {
  60. return glfwGetClipboardString(window);
  61. }
  62. static void ImImpl_SetClipboardTextFn(const char* text, const char* text_end)
  63. {
  64. if (!text_end)
  65. text_end = text + strlen(text);
  66. if (*text_end == 0)
  67. {
  68. // Already got a zero-terminator at 'text_end', we don't need to add one
  69. glfwSetClipboardString(window, text);
  70. }
  71. else
  72. {
  73. // Add a zero-terminator because glfw function doesn't take a size
  74. char* buf = (char*)malloc(text_end - text + 1);
  75. memcpy(buf, text, text_end-text);
  76. buf[text_end-text] = '\0';
  77. glfwSetClipboardString(window, buf);
  78. free(buf);
  79. }
  80. }
  81. // GLFW callbacks to get events
  82. static void glfw_error_callback(int error, const char* description)
  83. {
  84. fputs(description, stderr);
  85. }
  86. static void glfw_scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
  87. {
  88. ImGuiIO& io = ImGui::GetIO();
  89. io.MouseWheel = (yoffset != 0.0f) ? yoffset > 0.0f ? 1 : - 1 : 0; // Mouse wheel: -1,0,+1
  90. }
  91. static void glfw_key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
  92. {
  93. ImGuiIO& io = ImGui::GetIO();
  94. if (action == GLFW_PRESS)
  95. io.KeysDown[key] = true;
  96. if (action == GLFW_RELEASE)
  97. io.KeysDown[key] = false;
  98. io.KeyCtrl = (mods & GLFW_MOD_CONTROL) != 0;
  99. io.KeyShift = (mods & GLFW_MOD_SHIFT) != 0;
  100. }
  101. static void glfw_char_callback(GLFWwindow* window, unsigned int c)
  102. {
  103. if (c > 0 && c <= 255)
  104. ImGui::GetIO().AddInputCharacter((char)c);
  105. }
  106. // OpenGL code based on http://open.gl tutorials
  107. void InitGL()
  108. {
  109. glfwSetErrorCallback(glfw_error_callback);
  110. if (!glfwInit())
  111. exit(1);
  112. glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
  113. window = glfwCreateWindow(1280, 720, "ImGui OpenGL example", NULL, NULL);
  114. glfwMakeContextCurrent(window);
  115. glfwSetKeyCallback(window, glfw_key_callback);
  116. glfwSetScrollCallback(window, glfw_scroll_callback);
  117. glfwSetCharCallback(window, glfw_char_callback);
  118. glewInit();
  119. }
  120. void InitImGui()
  121. {
  122. int w, h;
  123. glfwGetWindowSize(window, &w, &h);
  124. ImGuiIO& io = ImGui::GetIO();
  125. io.DisplaySize = ImVec2((float)w, (float)h); // Display size, in pixels. For clamping windows positions.
  126. io.DeltaTime = 1.0f/60.0f; // Time elapsed since last frame, in seconds (in this sample app we'll override this every frame because our timestep is variable)
  127. io.PixelCenterOffset = 0.5f; // Align OpenGL texels
  128. io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array.
  129. io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
  130. io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
  131. io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
  132. io.KeyMap[ImGuiKey_DownArrow] = GLFW_KEY_DOWN;
  133. io.KeyMap[ImGuiKey_Home] = GLFW_KEY_HOME;
  134. io.KeyMap[ImGuiKey_End] = GLFW_KEY_END;
  135. io.KeyMap[ImGuiKey_Delete] = GLFW_KEY_DELETE;
  136. io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE;
  137. io.KeyMap[ImGuiKey_Enter] = GLFW_KEY_ENTER;
  138. io.KeyMap[ImGuiKey_Escape] = GLFW_KEY_ESCAPE;
  139. io.KeyMap[ImGuiKey_A] = GLFW_KEY_A;
  140. io.KeyMap[ImGuiKey_C] = GLFW_KEY_C;
  141. io.KeyMap[ImGuiKey_V] = GLFW_KEY_V;
  142. io.KeyMap[ImGuiKey_X] = GLFW_KEY_X;
  143. io.KeyMap[ImGuiKey_Y] = GLFW_KEY_Y;
  144. io.KeyMap[ImGuiKey_Z] = GLFW_KEY_Z;
  145. io.RenderDrawListsFn = ImImpl_RenderDrawLists;
  146. io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
  147. io.GetClipboardTextFn = ImImpl_GetClipboardTextFn;
  148. // Load font texture
  149. glGenTextures(1, &fontTex);
  150. glBindTexture(GL_TEXTURE_2D, fontTex);
  151. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  152. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  153. const void* png_data;
  154. unsigned int png_size;
  155. ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size);
  156. int tex_x, tex_y, tex_comp;
  157. void* tex_data = stbi_load_from_memory((const unsigned char*)png_data, (int)png_size, &tex_x, &tex_y, &tex_comp, 0);
  158. glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tex_x, tex_y, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_data);
  159. stbi_image_free(tex_data);
  160. }
  161. void UpdateImGui()
  162. {
  163. ImGuiIO& io = ImGui::GetIO();
  164. // Setup timestep
  165. static double time = 0.0f;
  166. const double current_time = glfwGetTime();
  167. io.DeltaTime = (float)(current_time - time);
  168. time = current_time;
  169. // Setup inputs
  170. // (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents())
  171. double mouse_x, mouse_y;
  172. glfwGetCursorPos(window, &mouse_x, &mouse_y);
  173. io.MousePos = ImVec2((float)mouse_x, (float)mouse_y); // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
  174. io.MouseDown[0] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) != 0;
  175. io.MouseDown[1] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0;
  176. // Start the frame
  177. ImGui::NewFrame();
  178. }
  179. // Application code
  180. int main(int argc, char** argv)
  181. {
  182. InitGL();
  183. InitImGui();
  184. while (!glfwWindowShouldClose(window))
  185. {
  186. ImGuiIO& io = ImGui::GetIO();
  187. io.MouseWheel = 0;
  188. glfwPollEvents();
  189. UpdateImGui();
  190. // Create a simple window
  191. // Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets appears in a window automatically called "Debug"
  192. static bool show_test_window = true;
  193. static bool show_another_window = false;
  194. static float f;
  195. ImGui::Text("Hello, world!");
  196. ImGui::SliderFloat("float", &f, 0.0f, 1.0f);
  197. show_test_window ^= ImGui::Button("Test Window");
  198. show_another_window ^= ImGui::Button("Another Window");
  199. // Calculate and show framerate
  200. static float ms_per_frame[120] = { 0 };
  201. static int ms_per_frame_idx = 0;
  202. static float ms_per_frame_accum = 0.0f;
  203. ms_per_frame_accum -= ms_per_frame[ms_per_frame_idx];
  204. ms_per_frame[ms_per_frame_idx] = ImGui::GetIO().DeltaTime * 1000.0f;
  205. ms_per_frame_accum += ms_per_frame[ms_per_frame_idx];
  206. ms_per_frame_idx = (ms_per_frame_idx + 1) % 120;
  207. const float ms_per_frame_avg = ms_per_frame_accum / 120;
  208. ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", ms_per_frame_avg, 1000.0f / ms_per_frame_avg);
  209. // Show the ImGui test window
  210. // Most of user example code is in ImGui::ShowTestWindow()
  211. if (show_test_window)
  212. {
  213. ImGui::SetNewWindowDefaultPos(ImVec2(650, 20)); // Normally user code doesn't need/want to call it because positions are saved in .ini file anyway. Here we just want to make the demo initial state a bit more friendly!
  214. ImGui::ShowTestWindow(&show_test_window);
  215. }
  216. // Show another simple window
  217. if (show_another_window)
  218. {
  219. ImGui::Begin("Another Window", &show_another_window, ImVec2(200,100));
  220. ImGui::Text("Hello");
  221. ImGui::End();
  222. }
  223. // Rendering
  224. glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
  225. glClearColor(0.8f, 0.6f, 0.6f, 1.0f);
  226. glClear(GL_COLOR_BUFFER_BIT);
  227. ImGui::Render();
  228. glfwSwapBuffers(window);
  229. }
  230. ImGui::Shutdown();
  231. glfwTerminate();
  232. return 0;
  233. }