307 lines
13 KiB
C++
307 lines
13 KiB
C++
// ImGui GLFW binding with OpenGL (legacy, fixed pipeline)
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// (GLFW is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan graphics context creation, etc.)
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// Implemented features:
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// [X] User texture binding. Cast 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID in imgui.cpp.
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// **DO NOT USE THIS CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)**
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// **Prefer using the code in the opengl3_example/ folder**
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// This code is mostly provided as a reference to learn how ImGui integration works, because it is shorter to read.
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// If your code is using GL3+ context or any semi modern OpenGL calls, using this is likely to make everything more
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// complicated, will require your code to reset every single OpenGL attributes to their initial state, and might
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// confuse your GPU driver.
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// The GL2 code is unable to reset attributes or even call e.g. "glUseProgram(0)" because they don't exist in that API.
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// You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this.
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// If you use this binding you'll need to call 4 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXXX_NewFrame(), ImGui::Render() and ImGui_ImplXXXX_Shutdown().
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// If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp.
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// https://github.com/ocornut/imgui
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#include "imgui.h"
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#include "imgui_impl_glfw_gl2.h"
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// GLFW
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#include <GLFW/glfw3.h>
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#ifdef _WIN32
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#undef APIENTRY
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#define GLFW_EXPOSE_NATIVE_WIN32
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#define GLFW_EXPOSE_NATIVE_WGL
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#include <GLFW/glfw3native.h>
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#endif
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// Data
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static GLFWwindow* g_Window = NULL;
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static double g_Time = 0.0f;
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static bool g_MouseJustPressed[3] = { false, false, false };
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static GLuint g_FontTexture = 0;
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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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void ImGui_ImplGlfwGL2_RenderDrawLists(ImDrawData* draw_data)
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// Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so.
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// If text or lines are blurry when integrating ImGui in your engine: in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
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{
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// Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
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ImGuiIO& io = ImGui::GetIO();
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int fb_width = (int)(io.DisplaySize.x * io.DisplayFramebufferScale.x);
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int fb_height = (int)(io.DisplaySize.y * io.DisplayFramebufferScale.y);
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if (fb_width == 0 || fb_height == 0)
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return;
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draw_data->ScaleClipRects(io.DisplayFramebufferScale);
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// We are using the OpenGL fixed pipeline to make the example code simpler to read!
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// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers, polygon fill.
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GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
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GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
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GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
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GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
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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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glEnable(GL_TEXTURE_2D);
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glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
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//glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context where shaders may be bound
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// Setup viewport, orthographic projection matrix
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glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
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glMatrixMode(GL_PROJECTION);
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glPushMatrix();
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glLoadIdentity();
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glOrtho(0.0f, io.DisplaySize.x, io.DisplaySize.y, 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 < draw_data->CmdListsCount; n++)
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{
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const ImDrawList* cmd_list = draw_data->CmdLists[n];
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const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data;
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const ImDrawIdx* idx_buffer = cmd_list->IdxBuffer.Data;
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glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, pos)));
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glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, uv)));
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glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, col)));
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for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
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{
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const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
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if (pcmd->UserCallback)
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{
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pcmd->UserCallback(cmd_list, pcmd);
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}
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else
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{
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glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);
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glScissor((int)pcmd->ClipRect.x, (int)(fb_height - pcmd->ClipRect.w), (int)(pcmd->ClipRect.z - pcmd->ClipRect.x), (int)(pcmd->ClipRect.w - pcmd->ClipRect.y));
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glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer);
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}
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idx_buffer += pcmd->ElemCount;
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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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glBindTexture(GL_TEXTURE_2D, (GLuint)last_texture);
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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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glPolygonMode(GL_FRONT, last_polygon_mode[0]); glPolygonMode(GL_BACK, last_polygon_mode[1]);
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glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
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glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
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}
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static const char* ImGui_ImplGlfwGL2_GetClipboardText(void* user_data)
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{
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return glfwGetClipboardString((GLFWwindow*)user_data);
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}
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static void ImGui_ImplGlfwGL2_SetClipboardText(void* user_data, const char* text)
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{
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glfwSetClipboardString((GLFWwindow*)user_data, text);
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}
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void ImGui_ImplGlfwGL2_MouseButtonCallback(GLFWwindow*, int button, int action, int /*mods*/)
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{
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if (action == GLFW_PRESS && button >= 0 && button < 3)
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g_MouseJustPressed[button] = true;
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}
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void ImGui_ImplGlfwGL2_ScrollCallback(GLFWwindow*, double xoffset, double yoffset)
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{
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ImGuiIO& io = ImGui::GetIO();
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io.MouseWheelH += (float)xoffset;
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io.MouseWheel += (float)yoffset;
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}
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void ImGui_ImplGlfwGL2_KeyCallback(GLFWwindow*, int key, int, 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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(void)mods; // Modifiers are not reliable across systems
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io.KeyCtrl = io.KeysDown[GLFW_KEY_LEFT_CONTROL] || io.KeysDown[GLFW_KEY_RIGHT_CONTROL];
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io.KeyShift = io.KeysDown[GLFW_KEY_LEFT_SHIFT] || io.KeysDown[GLFW_KEY_RIGHT_SHIFT];
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io.KeyAlt = io.KeysDown[GLFW_KEY_LEFT_ALT] || io.KeysDown[GLFW_KEY_RIGHT_ALT];
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io.KeySuper = io.KeysDown[GLFW_KEY_LEFT_SUPER] || io.KeysDown[GLFW_KEY_RIGHT_SUPER];
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}
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void ImGui_ImplGlfwGL2_CharCallback(GLFWwindow*, unsigned int c)
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{
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ImGuiIO& io = ImGui::GetIO();
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if (c > 0 && c < 0x10000)
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io.AddInputCharacter((unsigned short)c);
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}
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bool ImGui_ImplGlfwGL2_CreateDeviceObjects()
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{
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// Build texture atlas
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ImGuiIO& io = ImGui::GetIO();
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unsigned char* pixels;
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int width, height;
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io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height); // Load as RGBA 32-bits (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.
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// Upload texture to graphics system
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GLint last_texture;
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glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
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glGenTextures(1, &g_FontTexture);
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glBindTexture(GL_TEXTURE_2D, g_FontTexture);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
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// Store our identifier
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io.Fonts->TexID = (void *)(intptr_t)g_FontTexture;
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// Restore state
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glBindTexture(GL_TEXTURE_2D, last_texture);
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return true;
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}
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void ImGui_ImplGlfwGL2_InvalidateDeviceObjects()
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{
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if (g_FontTexture)
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{
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glDeleteTextures(1, &g_FontTexture);
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ImGui::GetIO().Fonts->TexID = 0;
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g_FontTexture = 0;
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}
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}
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bool ImGui_ImplGlfwGL2_Init(GLFWwindow* window, bool install_callbacks)
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{
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g_Window = window;
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ImGuiIO& io = ImGui::GetIO();
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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_PageUp] = GLFW_KEY_PAGE_UP;
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io.KeyMap[ImGuiKey_PageDown] = GLFW_KEY_PAGE_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_Insert] = GLFW_KEY_INSERT;
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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_Space] = GLFW_KEY_SPACE;
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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 = ImGui_ImplGlfwGL2_RenderDrawLists; // Alternatively you can set this to NULL and call ImGui::GetDrawData() after ImGui::Render() to get the same ImDrawData pointer.
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io.SetClipboardTextFn = ImGui_ImplGlfwGL2_SetClipboardText;
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io.GetClipboardTextFn = ImGui_ImplGlfwGL2_GetClipboardText;
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io.ClipboardUserData = g_Window;
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#ifdef _WIN32
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io.ImeWindowHandle = glfwGetWin32Window(g_Window);
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#endif
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if (install_callbacks)
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{
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glfwSetMouseButtonCallback(window, ImGui_ImplGlfwGL2_MouseButtonCallback);
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glfwSetScrollCallback(window, ImGui_ImplGlfwGL2_ScrollCallback);
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glfwSetKeyCallback(window, ImGui_ImplGlfwGL2_KeyCallback);
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glfwSetCharCallback(window, ImGui_ImplGlfwGL2_CharCallback);
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}
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return true;
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}
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void ImGui_ImplGlfwGL2_Shutdown()
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{
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ImGui_ImplGlfwGL2_InvalidateDeviceObjects();
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}
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void ImGui_ImplGlfwGL2_NewFrame()
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{
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if (!g_FontTexture)
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ImGui_ImplGlfwGL2_CreateDeviceObjects();
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ImGuiIO& io = ImGui::GetIO();
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// Setup display size (every frame to accommodate for window resizing)
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int w, h;
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int display_w, display_h;
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glfwGetWindowSize(g_Window, &w, &h);
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glfwGetFramebufferSize(g_Window, &display_w, &display_h);
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io.DisplaySize = ImVec2((float)w, (float)h);
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io.DisplayFramebufferScale = ImVec2(w > 0 ? ((float)display_w / w) : 0, h > 0 ? ((float)display_h / h) : 0);
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// Setup time step
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double current_time = glfwGetTime();
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io.DeltaTime = g_Time > 0.0 ? (float)(current_time - g_Time) : (float)(1.0f/60.0f);
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g_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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if (glfwGetWindowAttrib(g_Window, GLFW_FOCUSED))
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{
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if (io.WantMoveMouse)
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{
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glfwSetCursorPos(g_Window, (double)io.MousePos.x, (double)io.MousePos.y); // Set mouse position if requested by io.WantMoveMouse flag (used when io.NavMovesTrue is enabled by user and using directional navigation)
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}
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else
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{
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double mouse_x, mouse_y;
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glfwGetCursorPos(g_Window, &mouse_x, &mouse_y);
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io.MousePos = ImVec2((float)mouse_x, (float)mouse_y);
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}
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}
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else
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{
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io.MousePos = ImVec2(-FLT_MAX,-FLT_MAX);
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}
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for (int i = 0; i < 3; i++)
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{
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// 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[i] = g_MouseJustPressed[i] || glfwGetMouseButton(g_Window, i) != 0;
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g_MouseJustPressed[i] = false;
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}
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// Hide OS mouse cursor if ImGui is drawing it
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glfwSetInputMode(g_Window, GLFW_CURSOR, io.MouseDrawCursor ? GLFW_CURSOR_HIDDEN : GLFW_CURSOR_NORMAL);
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// Start the frame. This call will update the io.WantCaptureMouse, io.WantCaptureKeyboard flag that you can use to dispatch inputs (or not) to your application.
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ImGui::NewFrame();
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}
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