mirror of
https://github.com/Drezil/imgui.git
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381 lines
14 KiB
C++
381 lines
14 KiB
C++
// ImGui SDL2 binding with OpenGL3
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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_sdl_gl3.h"
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// SDL,GL3W
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#include <SDL.h>
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#include <SDL_syswm.h>
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#include <GL/gl3w.h>
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// Data
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static SDL_Window* g_Window = NULL;
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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 float g_MouseWheel = 0.0f;
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static GLuint g_FontTexture = 0;
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static int g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
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static int g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0;
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static int g_AttribLocationPosition = 0, g_AttribLocationUV = 0, g_AttribLocationColor = 0;
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static unsigned int g_VboHandle = 0, g_VaoHandle = 0, g_ElementsHandle = 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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// 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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void ImGui_ImplSdlGL3_RenderDrawLists(ImDrawData* draw_data)
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{
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// Backup GL state
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GLint last_program; glGetIntegerv(GL_CURRENT_PROGRAM, &last_program);
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GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
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GLint last_array_buffer; glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
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GLint last_element_array_buffer; glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING, &last_element_array_buffer);
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GLint last_vertex_array; glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
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GLint last_blend_src; glGetIntegerv(GL_BLEND_SRC, &last_blend_src);
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GLint last_blend_dst; glGetIntegerv(GL_BLEND_DST, &last_blend_dst);
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GLint last_blend_equation_rgb; glGetIntegerv(GL_BLEND_EQUATION_RGB, &last_blend_equation_rgb);
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GLint last_blend_equation_alpha; glGetIntegerv(GL_BLEND_EQUATION_ALPHA, &last_blend_equation_alpha);
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GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
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GLboolean last_enable_blend = glIsEnabled(GL_BLEND);
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GLboolean last_enable_cull_face = glIsEnabled(GL_CULL_FACE);
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GLboolean last_enable_depth_test = glIsEnabled(GL_DEPTH_TEST);
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GLboolean last_enable_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
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// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled
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glEnable(GL_BLEND);
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glBlendEquation(GL_FUNC_ADD);
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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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glActiveTexture(GL_TEXTURE0);
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// Handle cases of screen coordinates != from framebuffer coordinates (e.g. retina displays)
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ImGuiIO& io = ImGui::GetIO();
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float fb_height = io.DisplaySize.y * io.DisplayFramebufferScale.y;
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draw_data->ScaleClipRects(io.DisplayFramebufferScale);
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// Setup orthographic projection matrix
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glViewport(0, 0, (GLsizei)io.DisplaySize.x, (GLsizei)io.DisplaySize.y);
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const float ortho_projection[4][4] =
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{
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{ 2.0f/io.DisplaySize.x, 0.0f, 0.0f, 0.0f },
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{ 0.0f, 2.0f/-io.DisplaySize.y, 0.0f, 0.0f },
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{ 0.0f, 0.0f, -1.0f, 0.0f },
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{-1.0f, 1.0f, 0.0f, 1.0f },
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};
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glUseProgram(g_ShaderHandle);
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glUniform1i(g_AttribLocationTex, 0);
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glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
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glBindVertexArray(g_VaoHandle);
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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 ImDrawIdx* idx_buffer_offset = 0;
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glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
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glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)cmd_list->VtxBuffer.size() * sizeof(ImDrawVert), (GLvoid*)&cmd_list->VtxBuffer.front(), GL_STREAM_DRAW);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ElementsHandle);
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glBufferData(GL_ELEMENT_ARRAY_BUFFER, (GLsizeiptr)cmd_list->IdxBuffer.size() * sizeof(ImDrawIdx), (GLvoid*)&cmd_list->IdxBuffer.front(), GL_STREAM_DRAW);
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for (const ImDrawCmd* pcmd = cmd_list->CmdBuffer.begin(); pcmd != cmd_list->CmdBuffer.end(); pcmd++)
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{
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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_offset);
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}
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idx_buffer_offset += pcmd->ElemCount;
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}
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}
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// Restore modified GL state
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glUseProgram(last_program);
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glBindTexture(GL_TEXTURE_2D, last_texture);
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glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, last_element_array_buffer);
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glBindVertexArray(last_vertex_array);
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glBlendEquationSeparate(last_blend_equation_rgb, last_blend_equation_alpha);
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glBlendFunc(last_blend_src, last_blend_dst);
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if (last_enable_blend) glEnable(GL_BLEND); else glDisable(GL_BLEND);
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if (last_enable_cull_face) glEnable(GL_CULL_FACE); else glDisable(GL_CULL_FACE);
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if (last_enable_depth_test) glEnable(GL_DEPTH_TEST); else glDisable(GL_DEPTH_TEST);
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if (last_enable_scissor_test) glEnable(GL_SCISSOR_TEST); else glDisable(GL_SCISSOR_TEST);
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glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
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}
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static const char* ImGui_ImplSdlGL3_GetClipboardText()
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{
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return SDL_GetClipboardText();
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}
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static void ImGui_ImplSdlGL3_SetClipboardText(const char* text)
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{
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SDL_SetClipboardText(text);
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}
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bool ImGui_ImplSdlGL3_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.y > 0)
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g_MouseWheel = 1;
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if (event->wheel.y < 0)
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g_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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ImGuiIO& io = ImGui::GetIO();
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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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return true;
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}
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}
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return false;
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}
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void ImGui_ImplSdlGL3_CreateFontsTexture()
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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 for OpenGL3 demo because it is more likely to be compatible with user's existing shader.
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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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}
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bool ImGui_ImplSdlGL3_CreateDeviceObjects()
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{
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// Backup GL state
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GLint last_texture, last_array_buffer, last_vertex_array;
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glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
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glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
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glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
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const GLchar *vertex_shader =
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"#version 330\n"
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"uniform mat4 ProjMtx;\n"
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"in vec2 Position;\n"
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"in vec2 UV;\n"
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"in vec4 Color;\n"
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"out vec2 Frag_UV;\n"
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"out vec4 Frag_Color;\n"
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"void main()\n"
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"{\n"
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" Frag_UV = UV;\n"
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" Frag_Color = Color;\n"
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" gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
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"}\n";
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const GLchar* fragment_shader =
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"#version 330\n"
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"uniform sampler2D Texture;\n"
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"in vec2 Frag_UV;\n"
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"in vec4 Frag_Color;\n"
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"out vec4 Out_Color;\n"
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"void main()\n"
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"{\n"
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" Out_Color = Frag_Color * texture( Texture, Frag_UV.st);\n"
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"}\n";
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g_ShaderHandle = glCreateProgram();
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g_VertHandle = glCreateShader(GL_VERTEX_SHADER);
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g_FragHandle = glCreateShader(GL_FRAGMENT_SHADER);
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glShaderSource(g_VertHandle, 1, &vertex_shader, 0);
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glShaderSource(g_FragHandle, 1, &fragment_shader, 0);
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glCompileShader(g_VertHandle);
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glCompileShader(g_FragHandle);
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glAttachShader(g_ShaderHandle, g_VertHandle);
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glAttachShader(g_ShaderHandle, g_FragHandle);
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glLinkProgram(g_ShaderHandle);
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g_AttribLocationTex = glGetUniformLocation(g_ShaderHandle, "Texture");
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g_AttribLocationProjMtx = glGetUniformLocation(g_ShaderHandle, "ProjMtx");
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g_AttribLocationPosition = glGetAttribLocation(g_ShaderHandle, "Position");
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g_AttribLocationUV = glGetAttribLocation(g_ShaderHandle, "UV");
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g_AttribLocationColor = glGetAttribLocation(g_ShaderHandle, "Color");
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glGenBuffers(1, &g_VboHandle);
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glGenBuffers(1, &g_ElementsHandle);
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glGenVertexArrays(1, &g_VaoHandle);
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glBindVertexArray(g_VaoHandle);
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glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
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glEnableVertexAttribArray(g_AttribLocationPosition);
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glEnableVertexAttribArray(g_AttribLocationUV);
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glEnableVertexAttribArray(g_AttribLocationColor);
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#define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT))
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glVertexAttribPointer(g_AttribLocationPosition, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, pos));
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glVertexAttribPointer(g_AttribLocationUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, uv));
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glVertexAttribPointer(g_AttribLocationColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, col));
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#undef OFFSETOF
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ImGui_ImplSdlGL3_CreateFontsTexture();
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// Restore modified GL state
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glBindTexture(GL_TEXTURE_2D, last_texture);
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glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
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glBindVertexArray(last_vertex_array);
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return true;
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}
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void ImGui_ImplSdlGL3_InvalidateDeviceObjects()
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{
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if (g_VaoHandle) glDeleteVertexArrays(1, &g_VaoHandle);
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if (g_VboHandle) glDeleteBuffers(1, &g_VboHandle);
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if (g_ElementsHandle) glDeleteBuffers(1, &g_ElementsHandle);
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g_VaoHandle = g_VboHandle = g_ElementsHandle = 0;
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glDetachShader(g_ShaderHandle, g_VertHandle);
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glDeleteShader(g_VertHandle);
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g_VertHandle = 0;
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glDetachShader(g_ShaderHandle, g_FragHandle);
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glDeleteShader(g_FragHandle);
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g_FragHandle = 0;
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glDeleteProgram(g_ShaderHandle);
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g_ShaderHandle = 0;
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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_ImplSdlGL3_Init(SDL_Window *window)
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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] = 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_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_ImplSdlGL3_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_ImplSdlGL3_SetClipboardText;
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io.GetClipboardTextFn = ImGui_ImplSdlGL3_GetClipboardText;
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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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#endif
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return true;
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}
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void ImGui_ImplSdlGL3_Shutdown()
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{
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ImGui_ImplSdlGL3_InvalidateDeviceObjects();
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ImGui::Shutdown();
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}
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void ImGui_ImplSdlGL3_NewFrame()
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{
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if (!g_FontTexture)
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ImGui_ImplSdlGL3_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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SDL_GetWindowSize(g_Window, &w, &h);
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io.DisplaySize = ImVec2((float)w, (float)h);
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io.DisplayFramebufferScale = ImVec2(1.0f, 1.0f);
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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 inputs
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// (we already got mouse wheel, keyboard keys & characters from SDL_PollEvent())
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int mx, my;
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Uint32 mouseMask = SDL_GetMouseState(&mx, &my);
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if (SDL_GetWindowFlags(g_Window) & SDL_WINDOW_MOUSE_FOCUS)
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io.MousePos = ImVec2((float)mx, (float)my); // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
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else
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io.MousePos = ImVec2(-1, -1);
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io.MouseDown[0] = g_MousePressed[0] || (mouseMask & 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] || (mouseMask & SDL_BUTTON(SDL_BUTTON_RIGHT)) != 0;
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io.MouseDown[2] = g_MousePressed[2] || (mouseMask & SDL_BUTTON(SDL_BUTTON_MIDDLE)) != 0;
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g_MousePressed[0] = g_MousePressed[1] = g_MousePressed[2] = false;
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io.MouseWheel = g_MouseWheel;
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g_MouseWheel = 0.0f;
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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
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ImGui::NewFrame();
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}
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