main.cpp 8.4 KB

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  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
  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. // Bind texture
  29. glBindTexture(GL_TEXTURE_2D, fontTex);
  30. glEnable(GL_TEXTURE_2D);
  31. // Setup matrices
  32. glMatrixMode(GL_PROJECTION);
  33. glLoadIdentity();
  34. glOrtho(0.0f, ImGui::GetIO().DisplaySize.x, ImGui::GetIO().DisplaySize.y, 0.0f, -1.0f, +1.0f);
  35. glMatrixMode(GL_MODELVIEW);
  36. glLoadIdentity();
  37. // Render command lists
  38. for (int n = 0; n < cmd_lists_count; n++)
  39. {
  40. const ImDrawList* cmd_list = cmd_lists[n];
  41. const unsigned char* vtx_buffer = (const unsigned char*)cmd_list->vtx_buffer.begin();
  42. glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer));
  43. glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer+8));
  44. glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (void*)(vtx_buffer+16));
  45. int vtx_offset = 0;
  46. const ImDrawCmd* pcmd_end = cmd_list->commands.end();
  47. for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++)
  48. {
  49. glScissor((int)pcmd->clip_rect.x, (int)pcmd->clip_rect.y, (int)(pcmd->clip_rect.z - pcmd->clip_rect.x), (int)(pcmd->clip_rect.w - pcmd->clip_rect.y));
  50. glDrawArrays(GL_TRIANGLES, vtx_offset, pcmd->vtx_count);
  51. vtx_offset += pcmd->vtx_count;
  52. }
  53. }
  54. glDisable(GL_SCISSOR_TEST);
  55. }
  56. static const char* ImImpl_GetClipboardTextFn()
  57. {
  58. return glfwGetClipboardString(window);
  59. }
  60. static void ImImpl_SetClipboardTextFn(const char* text, const char* text_end)
  61. {
  62. if (!text_end)
  63. text_end = text + strlen(text);
  64. // Add a zero-terminator because glfw function doesn't take a size
  65. char* buf = (char*)malloc(text_end - text + 1);
  66. memcpy(buf, text, text_end-text);
  67. buf[text_end-text] = '\0';
  68. glfwSetClipboardString(window, buf);
  69. free(buf);
  70. }
  71. // GLFW callbacks to get events
  72. static void glfw_error_callback(int error, const char* description)
  73. {
  74. fputs(description, stderr);
  75. }
  76. static float mouse_wheel = 0.0f;
  77. static void glfw_scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
  78. {
  79. mouse_wheel = (float)yoffset;
  80. }
  81. static void glfw_key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
  82. {
  83. ImGuiIO& io = ImGui::GetIO();
  84. if (action == GLFW_PRESS)
  85. io.KeysDown[key] = true;
  86. if (action == GLFW_RELEASE)
  87. io.KeysDown[key] = false;
  88. io.KeyCtrl = (mods & GLFW_MOD_CONTROL) != 0;
  89. io.KeyShift = (mods & GLFW_MOD_SHIFT) != 0;
  90. }
  91. static void glfw_char_callback(GLFWwindow* window, unsigned int c)
  92. {
  93. if (c > 0 && c <= 255)
  94. ImGui::GetIO().AddInputCharacter((char)c);
  95. }
  96. // OpenGL code based on http://open.gl tutorials
  97. void InitGL()
  98. {
  99. glfwSetErrorCallback(glfw_error_callback);
  100. if (!glfwInit())
  101. exit(1);
  102. glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
  103. window = glfwCreateWindow(1280, 720, "ImGui OpenGL example", NULL, NULL);
  104. glfwMakeContextCurrent(window);
  105. glfwSetKeyCallback(window, glfw_key_callback);
  106. glfwSetScrollCallback(window, glfw_scroll_callback);
  107. glfwSetCharCallback(window, glfw_char_callback);
  108. glewInit();
  109. }
  110. void InitImGui()
  111. {
  112. int w, h;
  113. glfwGetWindowSize(window, &w, &h);
  114. ImGuiIO& io = ImGui::GetIO();
  115. io.DisplaySize = ImVec2((float)w, (float)h); // Display size, in pixels. For clamping windows positions.
  116. 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)
  117. io.PixelCenterOffset = 0.5f; // Align OpenGL texels
  118. io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array.
  119. io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
  120. io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
  121. io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
  122. io.KeyMap[ImGuiKey_DownArrow] = GLFW_KEY_DOWN;
  123. io.KeyMap[ImGuiKey_Home] = GLFW_KEY_HOME;
  124. io.KeyMap[ImGuiKey_End] = GLFW_KEY_END;
  125. io.KeyMap[ImGuiKey_Delete] = GLFW_KEY_DELETE;
  126. io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE;
  127. io.KeyMap[ImGuiKey_Enter] = GLFW_KEY_ENTER;
  128. io.KeyMap[ImGuiKey_Escape] = GLFW_KEY_ESCAPE;
  129. io.KeyMap[ImGuiKey_A] = GLFW_KEY_A;
  130. io.KeyMap[ImGuiKey_C] = GLFW_KEY_C;
  131. io.KeyMap[ImGuiKey_V] = GLFW_KEY_V;
  132. io.KeyMap[ImGuiKey_X] = GLFW_KEY_X;
  133. io.KeyMap[ImGuiKey_Y] = GLFW_KEY_Y;
  134. io.KeyMap[ImGuiKey_Z] = GLFW_KEY_Z;
  135. io.RenderDrawListsFn = ImImpl_RenderDrawLists;
  136. io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
  137. io.GetClipboardTextFn = ImImpl_GetClipboardTextFn;
  138. // Load font texture
  139. glGenTextures(1, &fontTex);
  140. glBindTexture(GL_TEXTURE_2D, fontTex);
  141. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  142. glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  143. const void* png_data;
  144. unsigned int png_size;
  145. ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size);
  146. int tex_x, tex_y, tex_comp;
  147. void* tex_data = stbi_load_from_memory((const unsigned char*)png_data, (int)png_size, &tex_x, &tex_y, &tex_comp, 0);
  148. glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tex_x, tex_y, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_data);
  149. stbi_image_free(tex_data);
  150. }
  151. void Shutdown()
  152. {
  153. ImGui::Shutdown();
  154. glfwTerminate();
  155. }
  156. int main(int argc, char** argv)
  157. {
  158. InitGL();
  159. InitImGui();
  160. double time = glfwGetTime();
  161. while (!glfwWindowShouldClose(window))
  162. {
  163. ImGuiIO& io = ImGui::GetIO();
  164. glfwPollEvents();
  165. // 1) ImGui start frame, setup time delta & inputs
  166. const double current_time = glfwGetTime();
  167. io.DeltaTime = (float)(current_time - time);
  168. time = current_time;
  169. double mouse_x, mouse_y;
  170. glfwGetCursorPos(window, &mouse_x, &mouse_y);
  171. io.MousePos = ImVec2((float)mouse_x, (float)mouse_y); // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
  172. io.MouseDown[0] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) != 0;
  173. io.MouseDown[1] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0;
  174. io.MouseWheel = (mouse_wheel != 0) ? mouse_wheel > 0.0f ? 1 : - 1 : 0; // Mouse wheel: -1,0,+1
  175. mouse_wheel = 0.0f;
  176. ImGui::NewFrame();
  177. // 2) ImGui usage
  178. static bool show_test_window = true;
  179. static bool show_another_window = false;
  180. static float f;
  181. ImGui::Text("Hello, world!");
  182. ImGui::SliderFloat("float", &f, 0.0f, 1.0f);
  183. show_test_window ^= ImGui::Button("Test Window");
  184. show_another_window ^= ImGui::Button("Another Window");
  185. // Calculate and show framerate
  186. static float ms_per_frame[120] = { 0 };
  187. static int ms_per_frame_idx = 0;
  188. static float ms_per_frame_accum = 0.0f;
  189. ms_per_frame_accum -= ms_per_frame[ms_per_frame_idx];
  190. ms_per_frame[ms_per_frame_idx] = io.DeltaTime * 1000.0f;
  191. ms_per_frame_accum += ms_per_frame[ms_per_frame_idx];
  192. ms_per_frame_idx = (ms_per_frame_idx + 1) % 120;
  193. const float ms_per_frame_avg = ms_per_frame_accum / 120;
  194. ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", ms_per_frame_avg, 1000.0f / ms_per_frame_avg);
  195. if (show_test_window)
  196. {
  197. // More example code in ShowTestWindow()
  198. 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!
  199. ImGui::ShowTestWindow(&show_test_window);
  200. }
  201. if (show_another_window)
  202. {
  203. ImGui::Begin("Another Window", &show_another_window, ImVec2(200,100));
  204. ImGui::Text("Hello");
  205. ImGui::End();
  206. }
  207. // 3) Rendering
  208. glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
  209. glClearColor(0.8f, 0.6f, 0.6f, 1.0f);
  210. glClear(GL_COLOR_BUFFER_BIT);
  211. ImGui::Render();
  212. glfwSwapBuffers(window);
  213. }
  214. Shutdown();
  215. return 0;
  216. }