mirror of
https://github.com/Drezil/imgui.git
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312 lines
12 KiB
C++
312 lines
12 KiB
C++
// ImGui - standalone example application for OpenGL 2, using fixed pipeline
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#ifdef _MSC_VER
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#pragma warning (disable: 4996) // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen
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#endif
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#include "../../imgui.h"
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#define STB_IMAGE_IMPLEMENTATION
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#include "../shared/stb_image.h" // stb_image.h for PNG loading
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// Glfw/Glew
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#define GLEW_STATIC
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#include <GL/glew.h>
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#include <GLFW/glfw3.h>
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static GLFWwindow* window;
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static GLuint fontTex;
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static bool mousePressed[2] = { false, false };
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static ImVec2 mousePosScale(1.0f, 1.0f);
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// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
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// If text or lines are blurry when integrating ImGui in your engine:
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// - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
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// - try adjusting ImGui::GetIO().PixelCenterOffset to 0.5f or 0.375f
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static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
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{
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if (cmd_lists_count == 0)
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return;
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// We are using the OpenGL fixed pipeline to make the example code simpler to read!
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// A probable faster way to render would be to collate all vertices from all cmd_lists into a single vertex buffer.
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// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers.
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glPushAttrib(GL_ENABLE_BIT | GL_COLOR_BUFFER_BIT | GL_TRANSFORM_BIT);
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glEnable(GL_BLEND);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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glDisable(GL_CULL_FACE);
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glDisable(GL_DEPTH_TEST);
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glEnable(GL_SCISSOR_TEST);
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glEnableClientState(GL_VERTEX_ARRAY);
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glEnableClientState(GL_TEXTURE_COORD_ARRAY);
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glEnableClientState(GL_COLOR_ARRAY);
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// Setup texture
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glBindTexture(GL_TEXTURE_2D, fontTex);
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glEnable(GL_TEXTURE_2D);
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// Setup orthographic projection matrix
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const float width = ImGui::GetIO().DisplaySize.x;
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const float height = ImGui::GetIO().DisplaySize.y;
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glMatrixMode(GL_PROJECTION);
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glPushMatrix();
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glLoadIdentity();
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glOrtho(0.0f, width, height, 0.0f, -1.0f, +1.0f);
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glMatrixMode(GL_MODELVIEW);
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glPushMatrix();
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glLoadIdentity();
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// Render command lists
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for (int n = 0; n < cmd_lists_count; n++)
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{
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const ImDrawList* cmd_list = cmd_lists[n];
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const unsigned char* vtx_buffer = (const unsigned char*)&cmd_list->vtx_buffer.front();
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glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer + offsetof(ImDrawVert, pos)));
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glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer + offsetof(ImDrawVert, uv)));
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glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (void*)(vtx_buffer + offsetof(ImDrawVert, col)));
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int vtx_offset = 0;
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for (size_t cmd_i = 0; cmd_i < cmd_list->commands.size(); cmd_i++)
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{
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const ImDrawCmd* pcmd = &cmd_list->commands[cmd_i];
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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));
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glDrawArrays(GL_TRIANGLES, vtx_offset, pcmd->vtx_count);
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vtx_offset += pcmd->vtx_count;
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}
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}
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// Restore modified state
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glDisableClientState(GL_COLOR_ARRAY);
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glDisableClientState(GL_TEXTURE_COORD_ARRAY);
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glDisableClientState(GL_VERTEX_ARRAY);
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glMatrixMode(GL_MODELVIEW);
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glPopMatrix();
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glMatrixMode(GL_PROJECTION);
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glPopMatrix();
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glPopAttrib();
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}
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// NB: ImGui already provide OS clipboard support for Windows so this isn't needed if you are using Windows only.
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static const char* ImImpl_GetClipboardTextFn()
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{
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return glfwGetClipboardString(window);
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}
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static void ImImpl_SetClipboardTextFn(const char* text)
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{
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glfwSetClipboardString(window, text);
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}
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// GLFW callbacks to get events
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static void glfw_error_callback(int error, const char* description)
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{
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fputs(description, stderr);
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}
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static void glfw_mouse_button_callback(GLFWwindow* window, int button, int action, int mods)
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{
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if (action == GLFW_PRESS && button >= 0 && button < 2)
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mousePressed[button] = true;
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}
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static void glfw_scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
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{
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ImGuiIO& io = ImGui::GetIO();
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io.MouseWheel += (float)yoffset; // Use fractional mouse wheel, 1.0 unit 5 lines.
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}
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static void glfw_key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
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{
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ImGuiIO& io = ImGui::GetIO();
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if (action == GLFW_PRESS)
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io.KeysDown[key] = true;
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if (action == GLFW_RELEASE)
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io.KeysDown[key] = false;
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io.KeyCtrl = (mods & GLFW_MOD_CONTROL) != 0;
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io.KeyShift = (mods & GLFW_MOD_SHIFT) != 0;
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}
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static void glfw_char_callback(GLFWwindow* window, unsigned int c)
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{
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if (c > 0 && c < 0x10000)
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ImGui::GetIO().AddInputCharacter((unsigned short)c);
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}
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// OpenGL code based on http://open.gl tutorials
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void InitGL()
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{
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glfwSetErrorCallback(glfw_error_callback);
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if (!glfwInit())
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exit(1);
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glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
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window = glfwCreateWindow(1280, 720, "ImGui OpenGL example", NULL, NULL);
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glfwMakeContextCurrent(window);
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glfwSetKeyCallback(window, glfw_key_callback);
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glfwSetMouseButtonCallback(window, glfw_mouse_button_callback);
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glfwSetScrollCallback(window, glfw_scroll_callback);
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glfwSetCharCallback(window, glfw_char_callback);
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glewInit();
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}
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void InitImGui()
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{
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int w, h;
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int display_w, display_h;
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glfwGetWindowSize(window, &w, &h);
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glfwGetFramebufferSize(window, &display_w, &display_h);
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mousePosScale.x = (float)display_w / w; // Some screens e.g. Retina display have framebuffer size != from window size, and mouse inputs are given in window/screen coordinates.
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mousePosScale.y = (float)display_h / h;
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ImGuiIO& io = ImGui::GetIO();
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io.DisplaySize = ImVec2((float)display_w, (float)display_h); // Display size, in pixels. For clamping windows positions.
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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 time step is variable)
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io.PixelCenterOffset = 0.0f; // Align OpenGL texels
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io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array.
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io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
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io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
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io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
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io.KeyMap[ImGuiKey_DownArrow] = GLFW_KEY_DOWN;
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io.KeyMap[ImGuiKey_Home] = GLFW_KEY_HOME;
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io.KeyMap[ImGuiKey_End] = GLFW_KEY_END;
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io.KeyMap[ImGuiKey_Delete] = GLFW_KEY_DELETE;
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io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE;
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io.KeyMap[ImGuiKey_Enter] = GLFW_KEY_ENTER;
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io.KeyMap[ImGuiKey_Escape] = GLFW_KEY_ESCAPE;
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io.KeyMap[ImGuiKey_A] = GLFW_KEY_A;
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io.KeyMap[ImGuiKey_C] = GLFW_KEY_C;
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io.KeyMap[ImGuiKey_V] = GLFW_KEY_V;
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io.KeyMap[ImGuiKey_X] = GLFW_KEY_X;
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io.KeyMap[ImGuiKey_Y] = GLFW_KEY_Y;
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io.KeyMap[ImGuiKey_Z] = GLFW_KEY_Z;
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io.RenderDrawListsFn = ImImpl_RenderDrawLists;
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io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
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io.GetClipboardTextFn = ImImpl_GetClipboardTextFn;
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// Load font texture
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glGenTextures(1, &fontTex);
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glBindTexture(GL_TEXTURE_2D, fontTex);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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#if 1
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// Default font (embedded in code)
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const void* png_data;
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unsigned int png_size;
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ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size);
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int tex_x, tex_y, tex_comp;
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void* tex_data = stbi_load_from_memory((const unsigned char*)png_data, (int)png_size, &tex_x, &tex_y, &tex_comp, 0);
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IM_ASSERT(tex_data != NULL);
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#else
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// Custom font from filesystem
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io.Font = new ImFont();
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io.Font->LoadFromFile("../../extra_fonts/mplus-2m-medium_18.fnt");
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IM_ASSERT(io.Font->IsLoaded());
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int tex_x, tex_y, tex_comp;
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void* tex_data = stbi_load("../../extra_fonts/mplus-2m-medium_18.png", &tex_x, &tex_y, &tex_comp, 0);
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IM_ASSERT(tex_data != NULL);
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// Automatically find white pixel from the texture we just loaded
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// (io.Font->TexUvForWhite needs to contains UV coordinates pointing to a white pixel in order to render solid objects)
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for (int tex_data_off = 0; tex_data_off < tex_x*tex_y; tex_data_off++)
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if (((unsigned int*)tex_data)[tex_data_off] == 0xffffffff)
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{
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io.Font->TexUvForWhite = ImVec2((float)(tex_data_off % tex_x)/(tex_x), (float)(tex_data_off / tex_x)/(tex_y));
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break;
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}
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#endif
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tex_x, tex_y, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_data);
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stbi_image_free(tex_data);
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}
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void UpdateImGui()
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{
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ImGuiIO& io = ImGui::GetIO();
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// Setup time step
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static double time = 0.0f;
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const double current_time = glfwGetTime();
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io.DeltaTime = (float)(current_time - time);
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time = current_time;
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// Setup inputs
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// (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents())
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double mouse_x, mouse_y;
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glfwGetCursorPos(window, &mouse_x, &mouse_y);
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io.MousePos = ImVec2((float)mouse_x * mousePosScale.x, (float)mouse_y * mousePosScale.y); // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
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io.MouseDown[0] = mousePressed[0] || glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) != 0; // If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame.
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io.MouseDown[1] = mousePressed[1] || glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0;
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// Start the frame
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ImGui::NewFrame();
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}
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// Application code
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int main(int argc, char** argv)
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{
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InitGL();
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InitImGui();
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while (!glfwWindowShouldClose(window))
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{
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ImGuiIO& io = ImGui::GetIO();
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mousePressed[0] = mousePressed[1] = false;
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glfwPollEvents();
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UpdateImGui();
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static bool show_test_window = true;
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static bool show_another_window = false;
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// 1. Show a simple window
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// Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets appears in a window automatically called "Debug"
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{
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static float f;
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ImGui::Text("Hello, world!");
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ImGui::SliderFloat("float", &f, 0.0f, 1.0f);
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show_test_window ^= ImGui::Button("Test Window");
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show_another_window ^= ImGui::Button("Another Window");
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// Calculate and show frame rate
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static float ms_per_frame[120] = { 0 };
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static int ms_per_frame_idx = 0;
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static float ms_per_frame_accum = 0.0f;
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ms_per_frame_accum -= ms_per_frame[ms_per_frame_idx];
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ms_per_frame[ms_per_frame_idx] = ImGui::GetIO().DeltaTime * 1000.0f;
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ms_per_frame_accum += ms_per_frame[ms_per_frame_idx];
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ms_per_frame_idx = (ms_per_frame_idx + 1) % 120;
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const float ms_per_frame_avg = ms_per_frame_accum / 120;
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ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", ms_per_frame_avg, 1000.0f / ms_per_frame_avg);
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}
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// 2. Show another simple window, this time using an explicit Begin/End pair
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if (show_another_window)
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{
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ImGui::Begin("Another Window", &show_another_window, ImVec2(200,100));
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ImGui::Text("Hello");
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ImGui::End();
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}
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// 3. Show the ImGui test window. Most of the sample code is in ImGui::ShowTestWindow()
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if (show_test_window)
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{
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ImGui::SetNewWindowDefaultPos(ImVec2(650, 20)); // Normally user code doesn't need/want to call this, because positions are saved in .ini file. Here we just want to make the demo initial state a bit more friendly!
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ImGui::ShowTestWindow(&show_test_window);
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}
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// Rendering
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glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
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glClearColor(0.8f, 0.6f, 0.6f, 1.0f);
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glClear(GL_COLOR_BUFFER_BIT);
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ImGui::Render();
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glfwSwapBuffers(window);
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}
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ImGui::Shutdown();
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glfwTerminate();
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return 0;
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}
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