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https://github.com/ocornut/imgui.git
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303 lines
14 KiB
C++
303 lines
14 KiB
C++
// ImGui SDL2 binding with OpenGL (legacy, fixed pipeline)
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// In this binding, ImTextureID is used to store an OpenGL 'GLuint' texture identifier. Read the FAQ about ImTextureID in imgui.cpp.
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// (SDL is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan graphics context creation, etc.)
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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 sdl_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 <SDL.h>
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#include <SDL_syswm.h>
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#include <SDL_opengl.h>
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#include "imgui.h"
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#include "imgui_impl_sdl_gl2.h"
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// Data
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static double g_Time = 0.0f;
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static bool g_MousePressed[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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// 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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void ImGui_ImplSdlGL2_RenderDrawLists(ImDrawData* draw_data)
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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_ImplSdlGL2_GetClipboardText(void*)
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{
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return SDL_GetClipboardText();
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}
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static void ImGui_ImplSdlGL2_SetClipboardText(void*, const char* text)
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{
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SDL_SetClipboardText(text);
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}
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// You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
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// - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application.
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// - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application.
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// Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
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bool ImGui_ImplSdlGL2_ProcessEvent(SDL_Event* event)
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{
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ImGuiIO& io = ImGui::GetIO();
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switch (event->type)
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{
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case SDL_MOUSEWHEEL:
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{
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if (event->wheel.x > 0) io.MouseWheelH += 1;
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if (event->wheel.x < 0) io.MouseWheelH -= 1;
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if (event->wheel.y > 0) io.MouseWheel += 1;
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if (event->wheel.y < 0) io.MouseWheel -= 1;
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return true;
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}
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case SDL_MOUSEBUTTONDOWN:
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{
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if (event->button.button == SDL_BUTTON_LEFT) g_MousePressed[0] = true;
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if (event->button.button == SDL_BUTTON_RIGHT) g_MousePressed[1] = true;
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if (event->button.button == SDL_BUTTON_MIDDLE) g_MousePressed[2] = true;
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return true;
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}
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case SDL_TEXTINPUT:
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{
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io.AddInputCharactersUTF8(event->text.text);
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return true;
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}
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case SDL_KEYDOWN:
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case SDL_KEYUP:
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{
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int key = event->key.keysym.sym & ~SDLK_SCANCODE_MASK;
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io.KeysDown[key] = (event->type == SDL_KEYDOWN);
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io.KeyShift = ((SDL_GetModState() & KMOD_SHIFT) != 0);
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io.KeyCtrl = ((SDL_GetModState() & KMOD_CTRL) != 0);
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io.KeyAlt = ((SDL_GetModState() & KMOD_ALT) != 0);
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io.KeySuper = ((SDL_GetModState() & KMOD_GUI) != 0);
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return true;
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}
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}
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return false;
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}
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bool ImGui_ImplSdlGL2_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->GetTexDataAsAlpha8(&pixels, &width, &height);
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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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glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
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glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, width, height, 0, GL_ALPHA, 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_ImplSdlGL2_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_ImplSdlGL2_Init(SDL_Window* window)
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{
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ImGuiIO& io = ImGui::GetIO();
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io.KeyMap[ImGuiKey_Tab] = SDLK_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array.
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io.KeyMap[ImGuiKey_LeftArrow] = SDL_SCANCODE_LEFT;
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io.KeyMap[ImGuiKey_RightArrow] = SDL_SCANCODE_RIGHT;
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io.KeyMap[ImGuiKey_UpArrow] = SDL_SCANCODE_UP;
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io.KeyMap[ImGuiKey_DownArrow] = SDL_SCANCODE_DOWN;
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io.KeyMap[ImGuiKey_PageUp] = SDL_SCANCODE_PAGEUP;
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io.KeyMap[ImGuiKey_PageDown] = SDL_SCANCODE_PAGEDOWN;
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io.KeyMap[ImGuiKey_Home] = SDL_SCANCODE_HOME;
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io.KeyMap[ImGuiKey_End] = SDL_SCANCODE_END;
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io.KeyMap[ImGuiKey_Insert] = SDL_SCANCODE_INSERT;
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io.KeyMap[ImGuiKey_Delete] = SDLK_DELETE;
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io.KeyMap[ImGuiKey_Backspace] = SDLK_BACKSPACE;
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io.KeyMap[ImGuiKey_Enter] = SDLK_RETURN;
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io.KeyMap[ImGuiKey_Escape] = SDLK_ESCAPE;
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io.KeyMap[ImGuiKey_A] = SDLK_a;
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io.KeyMap[ImGuiKey_C] = SDLK_c;
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io.KeyMap[ImGuiKey_V] = SDLK_v;
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io.KeyMap[ImGuiKey_X] = SDLK_x;
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io.KeyMap[ImGuiKey_Y] = SDLK_y;
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io.KeyMap[ImGuiKey_Z] = SDLK_z;
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io.RenderDrawListsFn = ImGui_ImplSdlGL2_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_ImplSdlGL2_SetClipboardText;
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io.GetClipboardTextFn = ImGui_ImplSdlGL2_GetClipboardText;
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io.ClipboardUserData = NULL;
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#ifdef _WIN32
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SDL_SysWMinfo wmInfo;
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SDL_VERSION(&wmInfo.version);
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SDL_GetWindowWMInfo(window, &wmInfo);
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io.ImeWindowHandle = wmInfo.info.win.window;
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#else
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(void)window;
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#endif
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return true;
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}
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void ImGui_ImplSdlGL2_Shutdown()
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{
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ImGui_ImplSdlGL2_InvalidateDeviceObjects();
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ImGui::Shutdown();
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}
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void ImGui_ImplSdlGL2_NewFrame(SDL_Window *window)
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{
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if (!g_FontTexture)
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ImGui_ImplSdlGL2_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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SDL_GetWindowSize(window, &w, &h);
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SDL_GL_GetDrawableSize(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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Uint32 time = SDL_GetTicks();
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double current_time = time / 1000.0;
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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 mouse inputs (we already got mouse wheel, keyboard keys & characters from our event handler)
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int mx, my;
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Uint32 mouse_buttons = SDL_GetMouseState(&mx, &my);
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io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
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io.MouseDown[0] = g_MousePressed[0] || (mouse_buttons & SDL_BUTTON(SDL_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] = g_MousePressed[1] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_RIGHT)) != 0;
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io.MouseDown[2] = g_MousePressed[2] || (mouse_buttons & SDL_BUTTON(SDL_BUTTON_MIDDLE)) != 0;
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g_MousePressed[0] = g_MousePressed[1] = g_MousePressed[2] = false;
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// We need to use SDL_CaptureMouse() to easily retrieve mouse coordinates outside of the client area. This is only supported from SDL 2.0.4 (released Jan 2016)
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#if (SDL_MAJOR_VERSION >= 2) && (SDL_MINOR_VERSION >= 0) && (SDL_PATCHLEVEL >= 4)
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if ((SDL_GetWindowFlags(window) & (SDL_WINDOW_MOUSE_FOCUS | SDL_WINDOW_MOUSE_CAPTURE)) != 0)
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io.MousePos = ImVec2((float)mx, (float)my);
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bool any_mouse_button_down = false;
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for (int n = 0; n < IM_ARRAYSIZE(io.MouseDown); n++)
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any_mouse_button_down |= io.MouseDown[n];
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if (any_mouse_button_down && (SDL_GetWindowFlags(window) & SDL_WINDOW_MOUSE_CAPTURE) == 0)
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SDL_CaptureMouse(SDL_TRUE);
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if (!any_mouse_button_down && (SDL_GetWindowFlags(window) & SDL_WINDOW_MOUSE_CAPTURE) != 0)
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SDL_CaptureMouse(SDL_FALSE);
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#else
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if ((SDL_GetWindowFlags(window) & SDL_WINDOW_INPUT_FOCUS) != 0)
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io.MousePos = ImVec2((float)mx, (float)my);
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#endif
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// Hide OS mouse cursor if ImGui is drawing it
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SDL_ShowCursor(io.MouseDrawCursor ? 0 : 1);
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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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