/Engine/imgui/imgui_draw.cpp

// dear imgui, v1.50 WIP
// (drawing and font code)

// Contains implementation for
// - ImDrawList
// - ImDrawData
// - ImFontAtlas
// - ImFont
// - Default font data

#if defined(_MSC_VER) && !defined(_CRT_SECURE_NO_WARNINGS)
#define _CRT_SECURE_NO_WARNINGS
#endif

#include "imgui.h"
#define IMGUI_DEFINE_MATH_OPERATORS
#define IMGUI_DEFINE_PLACEMENT_NEW
#include "imgui_internal.h"

#include <stdio.h>      // vsnprintf, sscanf, printf
#if !defined(alloca)
#ifdef _WIN32
#include <malloc.h>     // alloca
#elif (defined(__FreeBSD__) || defined(FreeBSD_kernel) || defined(__DragonFly__)) && !defined(__GLIBC__)
#include <stdlib.h>     // alloca. FreeBSD uses stdlib.h unless GLIBC
#else
#include <alloca.h>     // alloca
#endif
#endif

#ifdef _MSC_VER
#pragma warning (disable: 4505) // unreferenced local function has been removed (stb stuff)
#pragma warning (disable: 4996) // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen
#define snprintf _snprintf
#endif

#ifdef __clang__
#pragma clang diagnostic ignored "-Wold-style-cast"         // warning : use of old-style cast                              // yes, they are more terse.
#pragma clang diagnostic ignored "-Wfloat-equal"            // warning : comparing floating point with == or != is unsafe   // storing and comparing against same constants ok.
#pragma clang diagnostic ignored "-Wglobal-constructors"    // warning : declaration requires a global destructor           // similar to above, not sure what the exact difference it.
#pragma clang diagnostic ignored "-Wsign-conversion"        // warning : implicit conversion changes signedness             //
#if __has_warning("-Wreserved-id-macro")
#pragma clang diagnostic ignored "-Wreserved-id-macro"      // warning : macro name is a reserved identifier                //
#endif
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wunused-function"          // warning: 'xxxx' defined but not used
#pragma GCC diagnostic ignored "-Wdouble-promotion"         // warning: implicit conversion from 'float' to 'double' when passing argument to function
#pragma GCC diagnostic ignored "-Wconversion"               // warning: conversion to 'xxxx' from 'xxxx' may alter its value
#endif

//-------------------------------------------------------------------------
// STB libraries implementation
//-------------------------------------------------------------------------

//#define IMGUI_STB_NAMESPACE     ImGuiStb
//#define IMGUI_DISABLE_STB_RECT_PACK_IMPLEMENTATION
//#define IMGUI_DISABLE_STB_TRUETYPE_IMPLEMENTATION

#ifdef IMGUI_STB_NAMESPACE
namespace IMGUI_STB_NAMESPACE
{
#endif

#ifdef _MSC_VER
#pragma warning (push)
#pragma warning (disable: 4456)                             // declaration of 'xx' hides previous local declaration
#endif

#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wold-style-cast"         // warning : use of old-style cast                              // yes, they are more terse.
#pragma clang diagnostic ignored "-Wunused-function"
#pragma clang diagnostic ignored "-Wmissing-prototypes"
#endif

#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wtype-limits"              // warning: comparison is always true due to limited range of data type [-Wtype-limits]
#endif

#define STBRP_ASSERT(x)    IM_ASSERT(x)
#ifndef IMGUI_DISABLE_STB_RECT_PACK_IMPLEMENTATION
#define STBRP_STATIC
#define STB_RECT_PACK_IMPLEMENTATION
#endif
#include "stb_rect_pack.h"

#define STBTT_malloc(x,u)  ((void)(u), ImGui::MemAlloc(x))
#define STBTT_free(x,u)    ((void)(u), ImGui::MemFree(x))
#define STBTT_assert(x)    IM_ASSERT(x)
#ifndef IMGUI_DISABLE_STB_TRUETYPE_IMPLEMENTATION
#define STBTT_STATIC
#define STB_TRUETYPE_IMPLEMENTATION
#else
#define STBTT_DEF extern
#endif
#include "stb_truetype.h"

#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif

#ifdef __clang__
#pragma clang diagnostic pop
#endif

#ifdef _MSC_VER
#pragma warning (pop)
#endif

#ifdef IMGUI_STB_NAMESPACE
} // namespace ImGuiStb
using namespace IMGUI_STB_NAMESPACE;
#endif

//-----------------------------------------------------------------------------
// ImDrawList
//-----------------------------------------------------------------------------

static const ImVec4 GNullClipRect(-8192.0f, -8192.0f, +8192.0f, +8192.0f); // Large values that are easy to encode in a few bits+shift

void ImDrawList::Clear()
{
    CmdBuffer.resize(0);
    IdxBuffer.resize(0);
    VtxBuffer.resize(0);
    _VtxCurrentIdx = 0;
    _VtxWritePtr = NULL;
    _IdxWritePtr = NULL;
    _ClipRectStack.resize(0);
    _TextureIdStack.resize(0);
    _Path.resize(0);
    _ChannelsCurrent = 0;
    _ChannelsCount = 1;
    // NB: Do not clear channels so our allocations are re-used after the first frame.
}

void ImDrawList::ClearFreeMemory()
{
    CmdBuffer.clear();
    IdxBuffer.clear();
    VtxBuffer.clear();
    _VtxCurrentIdx = 0;
    _VtxWritePtr = NULL;
    _IdxWritePtr = NULL;
    _ClipRectStack.clear();
    _TextureIdStack.clear();
    _Path.clear();
    _ChannelsCurrent = 0;
    _ChannelsCount = 1;
    for (int i = 0; i < _Channels.Size; i++)
    {
        if (i == 0) memset(&_Channels[0], 0, sizeof(_Channels[0]));  // channel 0 is a copy of CmdBuffer/IdxBuffer, don't destruct again
        _Channels[i].CmdBuffer.clear();
        _Channels[i].IdxBuffer.clear();
    }
    _Channels.clear();
}

// Use macros because C++ is a terrible language, we want guaranteed inline, no code in header, and no overhead in Debug mode
#define GetCurrentClipRect()    (_ClipRectStack.Size ? _ClipRectStack.Data[_ClipRectStack.Size-1]  : GNullClipRect)
#define GetCurrentTextureId()   (_TextureIdStack.Size ? _TextureIdStack.Data[_TextureIdStack.Size-1] : NULL)

void ImDrawList::AddDrawCmd()
{
    ImDrawCmd draw_cmd;
    draw_cmd.ClipRect = GetCurrentClipRect();
    draw_cmd.TextureId = GetCurrentTextureId();

    IM_ASSERT(draw_cmd.ClipRect.x <= draw_cmd.ClipRect.z && draw_cmd.ClipRect.y <= draw_cmd.ClipRect.w);
    CmdBuffer.push_back(draw_cmd);
}

void ImDrawList::AddCallback(ImDrawCallback callback, void* callback_data)
{
    ImDrawCmd* current_cmd = CmdBuffer.Size ? &CmdBuffer.back() : NULL;
    if (!current_cmd || current_cmd->ElemCount != 0 || current_cmd->UserCallback != NULL)
    {
        AddDrawCmd();
        current_cmd = &CmdBuffer.back();
    }
    current_cmd->UserCallback = callback;
    current_cmd->UserCallbackData = callback_data;

    AddDrawCmd(); // Force a new command after us (see comment below)
}

// Our scheme may appears a bit unusual, basically we want the most-common calls AddLine AddRect etc. to not have to perform any check so we always have a command ready in the stack.
// The cost of figuring out if a new command has to be added or if we can merge is paid in those Update** functions only.
void ImDrawList::UpdateClipRect()
{
    // If current command is used with different settings we need to add a new command
    const ImVec4 curr_clip_rect = GetCurrentClipRect();
    ImDrawCmd* curr_cmd = CmdBuffer.Size > 0 ? &CmdBuffer.Data[CmdBuffer.Size-1] : NULL;
    if (!curr_cmd || (curr_cmd->ElemCount != 0 && memcmp(&curr_cmd->ClipRect, &curr_clip_rect, sizeof(ImVec4)) != 0) || curr_cmd->UserCallback != NULL)
    {
        AddDrawCmd();
        return;
    }

    // Try to merge with previous command if it matches, else use current command
    ImDrawCmd* prev_cmd = CmdBuffer.Size > 1 ? curr_cmd - 1 : NULL;
    if (curr_cmd->ElemCount == 0 && prev_cmd && memcmp(&prev_cmd->ClipRect, &curr_clip_rect, sizeof(ImVec4)) == 0 && prev_cmd->TextureId == GetCurrentTextureId() && prev_cmd->UserCallback == NULL)
        CmdBuffer.pop_back();
    else
        curr_cmd->ClipRect = curr_clip_rect;
}

void ImDrawList::UpdateTextureID()
{
    // If current command is used with different settings we need to add a new command
    const ImTextureID curr_texture_id = GetCurrentTextureId();
    ImDrawCmd* curr_cmd = CmdBuffer.Size ? &CmdBuffer.back() : NULL;
    if (!curr_cmd || (curr_cmd->ElemCount != 0 && curr_cmd->TextureId != curr_texture_id) || curr_cmd->UserCallback != NULL)
    {
        AddDrawCmd();
        return;
    }

    // Try to merge with previous command if it matches, else use current command
    ImDrawCmd* prev_cmd = CmdBuffer.Size > 1 ? curr_cmd - 1 : NULL;
    if (prev_cmd && prev_cmd->TextureId == curr_texture_id && memcmp(&prev_cmd->ClipRect, &GetCurrentClipRect(), sizeof(ImVec4)) == 0 && prev_cmd->UserCallback == NULL)
        CmdBuffer.pop_back();
    else
        curr_cmd->TextureId = curr_texture_id;
}

#undef GetCurrentClipRect
#undef GetCurrentTextureId

// Render-level scissoring. This is passed down to your render function but not used for CPU-side coarse clipping. Prefer using higher-level ImGui::PushClipRect() to affect logic (hit-testing and widget culling)
void ImDrawList::PushClipRect(ImVec2 cr_min, ImVec2 cr_max, bool intersect_with_current_clip_rect)
{
    ImVec4 cr(cr_min.x, cr_min.y, cr_max.x, cr_max.y);
    if (intersect_with_current_clip_rect && _ClipRectStack.Size)
    {
        ImVec4 current = _ClipRectStack.Data[_ClipRectStack.Size-1];
        if (cr.x < current.x) cr.x = current.x;
        if (cr.y < current.y) cr.y = current.y;
        if (cr.z > current.z) cr.z = current.z;
        if (cr.w > current.w) cr.w = current.w;
    }
    cr.z = ImMax(cr.x, cr.z);
    cr.w = ImMax(cr.y, cr.w);

    _ClipRectStack.push_back(cr);
    UpdateClipRect();
}

void ImDrawList::PushClipRectFullScreen()
{
    PushClipRect(ImVec2(GNullClipRect.x, GNullClipRect.y), ImVec2(GNullClipRect.z, GNullClipRect.w));
    //PushClipRect(GetVisibleRect());   // FIXME-OPT: This would be more correct but we're not supposed to access ImGuiContext from here?
}

void ImDrawList::PopClipRect()
{
    IM_ASSERT(_ClipRectStack.Size > 0);
    _ClipRectStack.pop_back();
    UpdateClipRect();
}

void ImDrawList::PushTextureID(const ImTextureID& texture_id)
{
    _TextureIdStack.push_back(texture_id);
    UpdateTextureID();
}

void ImDrawList::PopTextureID()
{
    IM_ASSERT(_TextureIdStack.Size > 0);
    _TextureIdStack.pop_back();
    UpdateTextureID();
}

void ImDrawList::ChannelsSplit(int channels_count)
{
    IM_ASSERT(_ChannelsCurrent == 0 && _ChannelsCount == 1);
    int old_channels_count = _Channels.Size;
    if (old_channels_count < channels_count)
        _Channels.resize(channels_count);
    _ChannelsCount = channels_count;

    // _Channels[] (24 bytes each) hold storage that we'll swap with this->_CmdBuffer/_IdxBuffer
    // The content of _Channels[0] at this point doesn't matter. We clear it to make state tidy in a debugger but we don't strictly need to.
    // When we switch to the next channel, we'll copy _CmdBuffer/_IdxBuffer into _Channels[0] and then _Channels[1] into _CmdBuffer/_IdxBuffer
    memset(&_Channels[0], 0, sizeof(ImDrawChannel));
    for (int i = 1; i < channels_count; i++)
    {
        if (i >= old_channels_count)
        {
            IM_PLACEMENT_NEW(&_Channels[i]) ImDrawChannel();
        }
        else
        {
            _Channels[i].CmdBuffer.resize(0);
            _Channels[i].IdxBuffer.resize(0);
        }
        if (_Channels[i].CmdBuffer.Size == 0)
        {
            ImDrawCmd draw_cmd;
            draw_cmd.ClipRect = _ClipRectStack.back();
            draw_cmd.TextureId = _TextureIdStack.back();
            _Channels[i].CmdBuffer.push_back(draw_cmd);
        }
    }
}

void ImDrawList::ChannelsMerge()
{
    // Note that we never use or rely on channels.Size because it is merely a buffer that we never shrink back to 0 to keep all sub-buffers ready for use.
    if (_ChannelsCount <= 1)
        return;

    ChannelsSetCurrent(0);
    if (CmdBuffer.Size && CmdBuffer.back().ElemCount == 0)
        CmdBuffer.pop_back();

    int new_cmd_buffer_count = 0, new_idx_buffer_count = 0;
    for (int i = 1; i < _ChannelsCount; i++)
    {
        ImDrawChannel& ch = _Channels[i];
        if (ch.CmdBuffer.Size && ch.CmdBuffer.back().ElemCount == 0)
            ch.CmdBuffer.pop_back();
        new_cmd_buffer_count += ch.CmdBuffer.Size;
        new_idx_buffer_count += ch.IdxBuffer.Size;
    }
    CmdBuffer.resize(CmdBuffer.Size + new_cmd_buffer_count);
    IdxBuffer.resize(IdxBuffer.Size + new_idx_buffer_count);

    ImDrawCmd* cmd_write = CmdBuffer.Data + CmdBuffer.Size - new_cmd_buffer_count;
    _IdxWritePtr = IdxBuffer.Data + IdxBuffer.Size - new_idx_buffer_count;
    for (int i = 1; i < _ChannelsCount; i++)
    {
        ImDrawChannel& ch = _Channels[i];
        if (int sz = ch.CmdBuffer.Size) { memcpy(cmd_write, ch.CmdBuffer.Data, sz * sizeof(ImDrawCmd)); cmd_write += sz; }
        if (int sz = ch.IdxBuffer.Size) { memcpy(_IdxWritePtr, ch.IdxBuffer.Data, sz * sizeof(ImDrawIdx)); _IdxWritePtr += sz; }
    }
    AddDrawCmd();
    _ChannelsCount = 1;
}

void ImDrawList::ChannelsSetCurrent(int idx)
{
    IM_ASSERT(idx < _ChannelsCount);
    if (_ChannelsCurrent == idx) return;
    memcpy(&_Channels.Data[_ChannelsCurrent].CmdBuffer, &CmdBuffer, sizeof(CmdBuffer)); // copy 12 bytes, four times
    memcpy(&_Channels.Data[_ChannelsCurrent].IdxBuffer, &IdxBuffer, sizeof(IdxBuffer));
    _ChannelsCurrent = idx;
    memcpy(&CmdBuffer, &_Channels.Data[_ChannelsCurrent].CmdBuffer, sizeof(CmdBuffer));
    memcpy(&IdxBuffer, &_Channels.Data[_ChannelsCurrent].IdxBuffer, sizeof(IdxBuffer));
    _IdxWritePtr = IdxBuffer.Data + IdxBuffer.Size;
}

// NB: this can be called with negative count for removing primitives (as long as the result does not underflow)
void ImDrawList::PrimReserve(int idx_count, int vtx_count)
{
    ImDrawCmd& draw_cmd = CmdBuffer.Data[CmdBuffer.Size-1];
    draw_cmd.ElemCount += idx_count;

    int vtx_buffer_size = VtxBuffer.Size;
    VtxBuffer.resize(vtx_buffer_size + vtx_count);
    _VtxWritePtr = VtxBuffer.Data + vtx_buffer_size;

    int idx_buffer_size = IdxBuffer.Size;
    IdxBuffer.resize(idx_buffer_size + idx_count);
    _IdxWritePtr = IdxBuffer.Data + idx_buffer_size;
}

// Fully unrolled with inline call to keep our debug builds decently fast.
void ImDrawList::PrimRect(const ImVec2& a, const ImVec2& c, ImU32 col)
{
    ImVec2 b(c.x, a.y), d(a.x, c.y), uv(GImGui->FontTexUvWhitePixel);
    ImDrawIdx idx = (ImDrawIdx)_VtxCurrentIdx;
    _IdxWritePtr[0] = idx; _IdxWritePtr[1] = (ImDrawIdx)(idx+1); _IdxWritePtr[2] = (ImDrawIdx)(idx+2);
    _IdxWritePtr[3] = idx; _IdxWritePtr[4] = (ImDrawIdx)(idx+2); _IdxWritePtr[5] = (ImDrawIdx)(idx+3);
    _VtxWritePtr[0].pos = a; _VtxWritePtr[0].uv = uv; _VtxWritePtr[0].col = col;
    _VtxWritePtr[1].pos = b; _VtxWritePtr[1].uv = uv; _VtxWritePtr[1].col = col;
    _VtxWritePtr[2].pos = c; _VtxWritePtr[2].uv = uv; _VtxWritePtr[2].col = col;
    _VtxWritePtr[3].pos = d; _VtxWritePtr[3].uv = uv; _VtxWritePtr[3].col = col;
    _VtxWritePtr += 4;
    _VtxCurrentIdx += 4;
    _IdxWritePtr += 6;
}

void ImDrawList::PrimRectUV(const ImVec2& a, const ImVec2& c, const ImVec2& uv_a, const ImVec2& uv_c, ImU32 col)
{
    ImVec2 b(c.x, a.y), d(a.x, c.y), uv_b(uv_c.x, uv_a.y), uv_d(uv_a.x, uv_c.y);
    ImDrawIdx idx = (ImDrawIdx)_VtxCurrentIdx;
    _IdxWritePtr[0] = idx; _IdxWritePtr[1] = (ImDrawIdx)(idx+1); _IdxWritePtr[2] = (ImDrawIdx)(idx+2);
    _IdxWritePtr[3] = idx; _IdxWritePtr[4] = (ImDrawIdx)(idx+2); _IdxWritePtr[5] = (ImDrawIdx)(idx+3);
    _VtxWritePtr[0].pos = a; _VtxWritePtr[0].uv = uv_a; _VtxWritePtr[0].col = col;
    _VtxWritePtr[1].pos = b; _VtxWritePtr[1].uv = uv_b; _VtxWritePtr[1].col = col;
    _VtxWritePtr[2].pos = c; _VtxWritePtr[2].uv = uv_c; _VtxWritePtr[2].col = col;
    _VtxWritePtr[3].pos = d; _VtxWritePtr[3].uv = uv_d; _VtxWritePtr[3].col = col;
    _VtxWritePtr += 4;
    _VtxCurrentIdx += 4;
    _IdxWritePtr += 6;
}

void ImDrawList::PrimQuadUV(const ImVec2& a, const ImVec2& b, const ImVec2& c, const ImVec2& d, const ImVec2& uv_a, const ImVec2& uv_b, const ImVec2& uv_c, const ImVec2& uv_d, ImU32 col)
{
    ImDrawIdx idx = (ImDrawIdx)_VtxCurrentIdx;
    _IdxWritePtr[0] = idx; _IdxWritePtr[1] = (ImDrawIdx)(idx+1); _IdxWritePtr[2] = (ImDrawIdx)(idx+2);
    _IdxWritePtr[3] = idx; _IdxWritePtr[4] = (ImDrawIdx)(idx+2); _IdxWritePtr[5] = (ImDrawIdx)(idx+3);
    _VtxWritePtr[0].pos = a; _VtxWritePtr[0].uv = uv_a; _VtxWritePtr[0].col = col;
    _VtxWritePtr[1].pos = b; _VtxWritePtr[1].uv = uv_b; _VtxWritePtr[1].col = col;
    _VtxWritePtr[2].pos = c; _VtxWritePtr[2].uv = uv_c; _VtxWritePtr[2].col = col;
    _VtxWritePtr[3].pos = d; _VtxWritePtr[3].uv = uv_d; _VtxWritePtr[3].col = col;
    _VtxWritePtr += 4;
    _VtxCurrentIdx += 4;
    _IdxWritePtr += 6;
}

// TODO: Thickness anti-aliased lines cap are missing their AA fringe.
void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32 col, bool closed, float thickness, bool anti_aliased)
{
    if (points_count < 2)
        return;

    const ImVec2 uv = GImGui->FontTexUvWhitePixel;
    anti_aliased &= GImGui->Style.AntiAliasedLines;
    //if (ImGui::GetIO().KeyCtrl) anti_aliased = false; // Debug

    int count = points_count;
    if (!closed)
        count = points_count-1;

    const bool thick_line = thickness > 1.0f;
    if (anti_aliased)
    {
        // Anti-aliased stroke
        const float AA_SIZE = 1.0f;
        const ImU32 col_trans = col & IM_COL32(255,255,255,0);

        const int idx_count = thick_line ? count*18 : count*12;
        const int vtx_count = thick_line ? points_count*4 : points_count*3;
        PrimReserve(idx_count, vtx_count);

        // Temporary buffer
        ImVec2* temp_normals = (ImVec2*)alloca(points_count * (thick_line ? 5 : 3) * sizeof(ImVec2));
        ImVec2* temp_points = temp_normals + points_count;

        for (int i1 = 0; i1 < count; i1++)
        {
            const int i2 = (i1+1) == points_count ? 0 : i1+1;
            ImVec2 diff = points[i2] - points[i1];
            diff *= ImInvLength(diff, 1.0f);
            temp_normals[i1].x = diff.y;
            temp_normals[i1].y = -diff.x;
        }
        if (!closed)
            temp_normals[points_count-1] = temp_normals[points_count-2];

        if (!thick_line)
        {
            if (!closed)
            {
                temp_points[0] = points[0] + temp_normals[0] * AA_SIZE;
                temp_points[1] = points[0] - temp_normals[0] * AA_SIZE;
                temp_points[(points_count-1)*2+0] = points[points_count-1] + temp_normals[points_count-1] * AA_SIZE;
                temp_points[(points_count-1)*2+1] = points[points_count-1] - temp_normals[points_count-1] * AA_SIZE;
            }

            // FIXME-OPT: Merge the different loops, possibly remove the temporary buffer.
            unsigned int idx1 = _VtxCurrentIdx;
            for (int i1 = 0; i1 < count; i1++)
            {
                const int i2 = (i1+1) == points_count ? 0 : i1+1;
                unsigned int idx2 = (i1+1) == points_count ? _VtxCurrentIdx : idx1+3;

                // Average normals
                ImVec2 dm = (temp_normals[i1] + temp_normals[i2]) * 0.5f;
                float dmr2 = dm.x*dm.x + dm.y*dm.y;
                if (dmr2 > 0.000001f)
                {
                    float scale = 1.0f / dmr2;
                    if (scale > 100.0f) scale = 100.0f;
                    dm *= scale;
                }
                dm *= AA_SIZE;
                temp_points[i2*2+0] = points[i2] + dm;
                temp_points[i2*2+1] = points[i2] - dm;

                // Add indexes
                _IdxWritePtr[0] = (ImDrawIdx)(idx2+0); _IdxWritePtr[1] = (ImDrawIdx)(idx1+0); _IdxWritePtr[2] = (ImDrawIdx)(idx1+2);
                _IdxWritePtr[3] = (ImDrawIdx)(idx1+2); _IdxWritePtr[4] = (ImDrawIdx)(idx2+2); _IdxWritePtr[5] = (ImDrawIdx)(idx2+0);
                _IdxWritePtr[6] = (ImDrawIdx)(idx2+1); _IdxWritePtr[7] = (ImDrawIdx)(idx1+1); _IdxWritePtr[8] = (ImDrawIdx)(idx1+0);
                _IdxWritePtr[9] = (ImDrawIdx)(idx1+0); _IdxWritePtr[10]= (ImDrawIdx)(idx2+0); _IdxWritePtr[11]= (ImDrawIdx)(idx2+1);
                _IdxWritePtr += 12;

                idx1 = idx2;
            }

            // Add vertexes
            for (int i = 0; i < points_count; i++)
            {
                _VtxWritePtr[0].pos = points[i];          _VtxWritePtr[0].uv = uv; _VtxWritePtr[0].col = col;
                _VtxWritePtr[1].pos = temp_points[i*2+0]; _VtxWritePtr[1].uv = uv; _VtxWritePtr[1].col = col_trans;
                _VtxWritePtr[2].pos = temp_points[i*2+1]; _VtxWritePtr[2].uv = uv; _VtxWritePtr[2].col = col_trans;
                _VtxWritePtr += 3;
            }
        }
        else
        {
            const float half_inner_thickness = (thickness - AA_SIZE) * 0.5f;
            if (!closed)
            {
                temp_points[0] = points[0] + temp_normals[0] * (half_inner_thickness + AA_SIZE);
                temp_points[1] = points[0] + temp_normals[0] * (half_inner_thickness);
                temp_points[2] = points[0] - temp_normals[0] * (half_inner_thickness);
                temp_points[3] = points[0] - temp_normals[0] * (half_inner_thickness + AA_SIZE);
                temp_points[(points_count-1)*4+0] = points[points_count-1] + temp_normals[points_count-1] * (half_inner_thickness + AA_SIZE);
                temp_points[(points_count-1)*4+1] = points[points_count-1] + temp_normals[points_count-1] * (half_inner_thickness);
                temp_points[(points_count-1)*4+2] = points[points_count-1] - temp_normals[points_count-1] * (half_inner_thickness);
                temp_points[(points_count-1)*4+3] = points[points_count-1] - temp_normals[points_count-1] * (half_inner_thickness + AA_SIZE);
            }

            // FIXME-OPT: Merge the different loops, possibly remove the temporary buffer.
            unsigned int idx1 = _VtxCurrentIdx;
            for (int i1 = 0; i1 < count; i1++)
            {
                const int i2 = (i1+1) == points_count ? 0 : i1+1;
                unsigned int idx2 = (i1+1) == points_count ? _VtxCurrentIdx : idx1+4;

                // Average normals
                ImVec2 dm = (temp_normals[i1] + temp_normals[i2]) * 0.5f;
                float dmr2 = dm.x*dm.x + dm.y*dm.y;
                if (dmr2 > 0.000001f)
                {
                    float scale = 1.0f / dmr2;
                    if (scale > 100.0f) scale = 100.0f;
                    dm *= scale;
                }
                ImVec2 dm_out = dm * (half_inner_thickness + AA_SIZE);
                ImVec2 dm_in = dm * half_inner_thickness;
                temp_points[i2*4+0] = points[i2] + dm_out;
                temp_points[i2*4+1] = points[i2] + dm_in;
                temp_points[i2*4+2] = points[i2] - dm_in;
                temp_points[i2*4+3] = points[i2] - dm_out;

                // Add indexes
                _IdxWritePtr[0]  = (ImDrawIdx)(idx2+1); _IdxWritePtr[1]  = (ImDrawIdx)(idx1+1); _IdxWritePtr[2]  = (ImDrawIdx)(idx1+2);
                _IdxWritePtr[3]  = (ImDrawIdx)(idx1+2); _IdxWritePtr[4]  = (ImDrawIdx)(idx2+2); _IdxWritePtr[5]  = (ImDrawIdx)(idx2+1);
                _IdxWritePtr[6]  = (ImDrawIdx)(idx2+1); _IdxWritePtr[7]  = (ImDrawIdx)(idx1+1); _IdxWritePtr[8]  = (ImDrawIdx)(idx1+0);
                _IdxWritePtr[9]  = (ImDrawIdx)(idx1+0); _IdxWritePtr[10] = (ImDrawIdx)(idx2+0); _IdxWritePtr[11] = (ImDrawIdx)(idx2+1);
                _IdxWritePtr[12] = (ImDrawIdx)(idx2+2); _IdxWritePtr[13] = (ImDrawIdx)(idx1+2); _IdxWritePtr[14] = (ImDrawIdx)(idx1+3);
                _IdxWritePtr[15] = (ImDrawIdx)(idx1+3); _IdxWritePtr[16] = (ImDrawIdx)(idx2+3); _IdxWritePtr[17] = (ImDrawIdx)(idx2+2);
                _IdxWritePtr += 18;

                idx1 = idx2;
            }

            // Add vertexes
            for (int i = 0; i < points_count; i++)
            {
                _VtxWritePtr[0].pos = temp_points[i*4+0]; _VtxWritePtr[0].uv = uv; _VtxWritePtr[0].col = col_trans;
                _VtxWritePtr[1].pos = temp_points[i*4+1]; _VtxWritePtr[1].uv = uv; _VtxWritePtr[1].col = col;
                _VtxWritePtr[2].pos = temp_points[i*4+2]; _VtxWritePtr[2].uv = uv; _VtxWritePtr[2].col = col;
                _VtxWritePtr[3].pos = temp_points[i*4+3]; _VtxWritePtr[3].uv = uv; _VtxWritePtr[3].col = col_trans;
                _VtxWritePtr += 4;
            }
        }
        _VtxCurrentIdx += (ImDrawIdx)vtx_count;
    }
    else
    {
        // Non Anti-aliased Stroke
        const int idx_count = count*6;
        const int vtx_count = count*4;      // FIXME-OPT: Not sharing edges
        PrimReserve(idx_count, vtx_count);

        for (int i1 = 0; i1 < count; i1++)
        {
            const int i2 = (i1+1) == points_count ? 0 : i1+1;
            const ImVec2& p1 = points[i1];
            const ImVec2& p2 = points[i2];
            ImVec2 diff = p2 - p1;
            diff *= ImInvLength(diff, 1.0f);

            const float dx = diff.x * (thickness * 0.5f);
            const float dy = diff.y * (thickness * 0.5f);
            _VtxWritePtr[0].pos.x = p1.x + dy; _VtxWritePtr[0].pos.y = p1.y - dx; _VtxWritePtr[0].uv = uv; _VtxWritePtr[0].col = col;
            _VtxWritePtr[1].pos.x = p2.x + dy; _VtxWritePtr[1].pos.y = p2.y - dx; _VtxWritePtr[1].uv = uv; _VtxWritePtr[1].col = col;
            _VtxWritePtr[2].pos.x = p2.x - dy; _VtxWritePtr[2].pos.y = p2.y + dx; _VtxWritePtr[2].uv = uv; _VtxWritePtr[2].col = col;
            _VtxWritePtr[3].pos.x = p1.x - dy; _VtxWritePtr[3].pos.y = p1.y + dx; _VtxWritePtr[3].uv = uv; _VtxWritePtr[3].col = col;
            _VtxWritePtr += 4;

            _IdxWritePtr[0] = (ImDrawIdx)(_VtxCurrentIdx); _IdxWritePtr[1] = (ImDrawIdx)(_VtxCurrentIdx+1); _IdxWritePtr[2] = (ImDrawIdx)(_VtxCurrentIdx+2);
            _IdxWritePtr[3] = (ImDrawIdx)(_VtxCurrentIdx); _IdxWritePtr[4] = (ImDrawIdx)(_VtxCurrentIdx+2); _IdxWritePtr[5] = (ImDrawIdx)(_VtxCurrentIdx+3);
            _IdxWritePtr += 6;
            _VtxCurrentIdx += 4;
        }
    }
}

void ImDrawList::AddConvexPolyFilled(const ImVec2* points, const int points_count, ImU32 col, bool anti_aliased)
{
    const ImVec2 uv = GImGui->FontTexUvWhitePixel;
    anti_aliased &= GImGui->Style.AntiAliasedShapes;
    //if (ImGui::GetIO().KeyCtrl) anti_aliased = false; // Debug

    if (anti_aliased)
    {
        // Anti-aliased Fill
        const float AA_SIZE = 1.0f;
        const ImU32 col_trans = col & IM_COL32(255,255,255,0);
        const int idx_count = (points_count-2)*3 + points_count*6;
        const int vtx_count = (points_count*2);
        PrimReserve(idx_count, vtx_count);

        // Add indexes for fill
        unsigned int vtx_inner_idx = _VtxCurrentIdx;
        unsigned int vtx_outer_idx = _VtxCurrentIdx+1;
        for (int i = 2; i < points_count; i++)
        {
            _IdxWritePtr[0] = (ImDrawIdx)(vtx_inner_idx); _IdxWritePtr[1] = (ImDrawIdx)(vtx_inner_idx+((i-1)<<1)); _IdxWritePtr[2] = (ImDrawIdx)(vtx_inner_idx+(i<<1));
            _IdxWritePtr += 3;
        }

        // Compute normals
        ImVec2* temp_normals = (ImVec2*)alloca(points_count * sizeof(ImVec2));
        for (int i0 = points_count-1, i1 = 0; i1 < points_count; i0 = i1++)
        {
            const ImVec2& p0 = points[i0];
            const ImVec2& p1 = points[i1];
            ImVec2 diff = p1 - p0;
            diff *= ImInvLength(diff, 1.0f);
            temp_normals[i0].x = diff.y;
            temp_normals[i0].y = -diff.x;
        }

        for (int i0 = points_count-1, i1 = 0; i1 < points_count; i0 = i1++)
        {
            // Average normals
            const ImVec2& n0 = temp_normals[i0];
            const ImVec2& n1 = temp_normals[i1];
            ImVec2 dm = (n0 + n1) * 0.5f;
            float dmr2 = dm.x*dm.x + dm.y*dm.y;
            if (dmr2 > 0.000001f)
            {
                float scale = 1.0f / dmr2;
                if (scale > 100.0f) scale = 100.0f;
                dm *= scale;
            }
            dm *= AA_SIZE * 0.5f;

            // Add vertices
            _VtxWritePtr[0].pos = (points[i1] - dm); _VtxWritePtr[0].uv = uv; _VtxWritePtr[0].col = col;        // Inner
            _VtxWritePtr[1].pos = (points[i1] + dm); _VtxWritePtr[1].uv = uv; _VtxWritePtr[1].col = col_trans;  // Outer
            _VtxWritePtr += 2;

            // Add indexes for fringes
            _IdxWritePtr[0] = (ImDrawIdx)(vtx_inner_idx+(i1<<1)); _IdxWritePtr[1] = (ImDrawIdx)(vtx_inner_idx+(i0<<1)); _IdxWritePtr[2] = (ImDrawIdx)(vtx_outer_idx+(i0<<1));
            _IdxWritePtr[3] = (ImDrawIdx)(vtx_outer_idx+(i0<<1)); _IdxWritePtr[4] = (ImDrawIdx)(vtx_outer_idx+(i1<<1)); _IdxWritePtr[5] = (ImDrawIdx)(vtx_inner_idx+(i1<<1));
            _IdxWritePtr += 6;
        }
        _VtxCurrentIdx += (ImDrawIdx)vtx_count;
    }
    else
    {
        // Non Anti-aliased Fill
        const int idx_count = (points_count-2)*3;
        const int vtx_count = points_count;
        PrimReserve(idx_count, vtx_count);
        for (int i = 0; i < vtx_count; i++)
        {
            _VtxWritePtr[0].pos = points[i]; _VtxWritePtr[0].uv = uv; _VtxWritePtr[0].col = col;
            _VtxWritePtr++;
        }
        for (int i = 2; i < points_count; i++)
        {
            _IdxWritePtr[0] = (ImDrawIdx)(_VtxCurrentIdx); _IdxWritePtr[1] = (ImDrawIdx)(_VtxCurrentIdx+i-1); _IdxWritePtr[2] = (ImDrawIdx)(_VtxCurrentIdx+i);
            _IdxWritePtr += 3;
        }
        _VtxCurrentIdx += (ImDrawIdx)vtx_count;
    }
}

void ImDrawList::PathArcToFast(const ImVec2& centre, float radius, int amin, int amax)
{
    static ImVec2 circle_vtx[12];
    static bool circle_vtx_builds = false;
    const int circle_vtx_count = IM_ARRAYSIZE(circle_vtx);
    if (!circle_vtx_builds)
    {
        for (int i = 0; i < circle_vtx_count; i++)
        {
            const float a = ((float)i / (float)circle_vtx_count) * 2*IM_PI;
            circle_vtx[i].x = cosf(a);
            circle_vtx[i].y = sinf(a);
        }
        circle_vtx_builds = true;
    }

    if (amin > amax) return;
    if (radius == 0.0f)
    {
        _Path.push_back(centre);
    }
    else
    {
        _Path.reserve(_Path.Size + (amax - amin + 1));
        for (int a = amin; a <= amax; a++)
        {
            const ImVec2& c = circle_vtx[a % circle_vtx_count];
            _Path.push_back(ImVec2(centre.x + c.x * radius, centre.y + c.y * radius));
        }
    }
}

void ImDrawList::PathArcTo(const ImVec2& centre, float radius, float amin, float amax, int num_segments)
{
    if (radius == 0.0f)
        _Path.push_back(centre);
    _Path.reserve(_Path.Size + (num_segments + 1));
    for (int i = 0; i <= num_segments; i++)
    {
        const float a = amin + ((float)i / (float)num_segments) * (amax - amin);
        _Path.push_back(ImVec2(centre.x + cosf(a) * radius, centre.y + sinf(a) * radius));
    }
}

static void PathBezierToCasteljau(ImVector<ImVec2>* path, float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4, float tess_tol, int level)
{
    float dx = x4 - x1;
    float dy = y4 - y1;
    float d2 = ((x2 - x4) * dy - (y2 - y4) * dx);
    float d3 = ((x3 - x4) * dy - (y3 - y4) * dx);
    d2 = (d2 >= 0) ? d2 : -d2;
    d3 = (d3 >= 0) ? d3 : -d3;
    if ((d2+d3) * (d2+d3) < tess_tol * (dx*dx + dy*dy))
    {
        path->push_back(ImVec2(x4, y4));
    }
    else if (level < 10)
    {
        float x12 = (x1+x2)*0.5f,       y12 = (y1+y2)*0.5f;
        float x23 = (x2+x3)*0.5f,       y23 = (y2+y3)*0.5f;
        float x34 = (x3+x4)*0.5f,       y34 = (y3+y4)*0.5f;
        float x123 = (x12+x23)*0.5f,    y123 = (y12+y23)*0.5f;
        float x234 = (x23+x34)*0.5f,    y234 = (y23+y34)*0.5f;
        float x1234 = (x123+x234)*0.5f, y1234 = (y123+y234)*0.5f;

        PathBezierToCasteljau(path, x1,y1,        x12,y12,    x123,y123,  x1234,y1234, tess_tol, level+1);
        PathBezierToCasteljau(path, x1234,y1234,  x234,y234,  x34,y34,    x4,y4,       tess_tol, level+1);
    }
}

void ImDrawList::PathBezierCurveTo(const ImVec2& p2, const ImVec2& p3, const ImVec2& p4, int num_segments)
{
    ImVec2 p1 = _Path.back();
    if (num_segments == 0)
    {
        // Auto-tessellated
        PathBezierToCasteljau(&_Path, p1.x, p1.y, p2.x, p2.y, p3.x, p3.y, p4.x, p4.y, GImGui->Style.CurveTessellationTol, 0);
    }
    else
    {
        float t_step = 1.0f / (float)num_segments;
        for (int i_step = 1; i_step <= num_segments; i_step++)
        {
            float t = t_step * i_step;
            float u = 1.0f - t;
            float w1 = u*u*u;
            float w2 = 3*u*u*t;
            float w3 = 3*u*t*t;
            float w4 = t*t*t;
            _Path.push_back(ImVec2(w1*p1.x + w2*p2.x + w3*p3.x + w4*p4.x, w1*p1.y + w2*p2.y + w3*p3.y + w4*p4.y));
        }
    }
}

void ImDrawList::PathRect(const ImVec2& a, const ImVec2& b, float rounding, int rounding_corners)
{
    float r = rounding;
    r = ImMin(r, fabsf(b.x-a.x) * ( ((rounding_corners&(1|2))==(1|2)) || ((rounding_corners&(4|8))==(4|8)) ? 0.5f : 1.0f ) - 1.0f);
    r = ImMin(r, fabsf(b.y-a.y) * ( ((rounding_corners&(1|8))==(1|8)) || ((rounding_corners&(2|4))==(2|4)) ? 0.5f : 1.0f ) - 1.0f);

    if (r <= 0.0f || rounding_corners == 0)
    {
        PathLineTo(a);
        PathLineTo(ImVec2(b.x,a.y));
        PathLineTo(b);
        PathLineTo(ImVec2(a.x,b.y));
    }
    else
    {
        const float r0 = (rounding_corners & 1) ? r : 0.0f;
        const float r1 = (rounding_corners & 2) ? r : 0.0f;
        const float r2 = (rounding_corners & 4) ? r : 0.0f;
        const float r3 = (rounding_corners & 8) ? r : 0.0f;
        PathArcToFast(ImVec2(a.x+r0,a.y+r0), r0, 6, 9);
        PathArcToFast(ImVec2(b.x-r1,a.y+r1), r1, 9, 12);
        PathArcToFast(ImVec2(b.x-r2,b.y-r2), r2, 0, 3);
        PathArcToFast(ImVec2(a.x+r3,b.y-r3), r3, 3, 6);
    }
}

void ImDrawList::AddLine(const ImVec2& a, const ImVec2& b, ImU32 col, float thickness)
{
    if ((col & IM_COL32_A_MASK) == 0)
        return;
    PathLineTo(a + ImVec2(0.5f,0.5f));
    PathLineTo(b + ImVec2(0.5f,0.5f));
    PathStroke(col, false, thickness);
}

// a: upper-left, b: lower-right. we don't render 1 px sized rectangles properly.
void ImDrawList::AddRect(const ImVec2& a, const ImVec2& b, ImU32 col, float rounding, int rounding_corners_flags, float thickness)
{
    if ((col & IM_COL32_A_MASK) == 0)
        return;
    PathRect(a + ImVec2(0.5f,0.5f), b - ImVec2(0.5f,0.5f), rounding, rounding_corners_flags);
    PathStroke(col, true, thickness);
}

void ImDrawList::AddRectFilled(const ImVec2& a, const ImVec2& b, ImU32 col, float rounding, int rounding_corners_flags)
{
    if ((col & IM_COL32_A_MASK) == 0)
        return;
    if (rounding > 0.0f)
    {
        PathRect(a, b, rounding, rounding_corners_flags);
        PathFill(col);
    }
    else
    {
        PrimReserve(6, 4);
        PrimRect(a, b, col);
    }
}

void ImDrawList::AddRectFilledMultiColor(const ImVec2& a, const ImVec2& c, ImU32 col_upr_left, ImU32 col_upr_right, ImU32 col_bot_right, ImU32 col_bot_left)
{
    if (((col_upr_left | col_upr_right | col_bot_right | col_bot_left) & IM_COL32_A_MASK) == 0)
        return;

    const ImVec2 uv = GImGui->FontTexUvWhitePixel;
    PrimReserve(6, 4);
    PrimWriteIdx((ImDrawIdx)(_VtxCurrentIdx)); PrimWriteIdx((ImDrawIdx)(_VtxCurrentIdx+1)); PrimWriteIdx((ImDrawIdx)(_VtxCurrentIdx+2));
    PrimWriteIdx((ImDrawIdx)(_VtxCurrentIdx)); PrimWriteIdx((ImDrawIdx)(_VtxCurrentIdx+2)); PrimWriteIdx((ImDrawIdx)(_VtxCurrentIdx+3));
    PrimWriteVtx(a, uv, col_upr_left);
    PrimWriteVtx(ImVec2(c.x, a.y), uv, col_upr_right);
    PrimWriteVtx(c, uv, col_bot_right);
    PrimWriteVtx(ImVec2(a.x, c.y), uv, col_bot_left);
}

void ImDrawList::AddQuad(const ImVec2& a, const ImVec2& b, const ImVec2& c, const ImVec2& d, ImU32 col, float thickness)
{
    if ((col & IM_COL32_A_MASK) == 0)
        return;

    PathLineTo(a);
    PathLineTo(b);
    PathLineTo(c);
    PathLineTo(d);
    PathStroke(col, true, thickness);
}

void ImDrawList::AddQuadFilled(const ImVec2& a, const ImVec2& b, const ImVec2& c, const ImVec2& d, ImU32 col)
{
    if ((col & IM_COL32_A_MASK) == 0)
        return;

    PathLineTo(a);
    PathLineTo(b);
    PathLineTo(c);
    PathLineTo(d);
    PathFill(col);
}

void ImDrawList::AddTriangle(const ImVec2& a, const ImVec2& b, const ImVec2& c, ImU32 col, float thickness)
{
    if ((col & IM_COL32_A_MASK) == 0)
        return;

    PathLineTo(a);
    PathLineTo(b);
    PathLineTo(c);
    PathStroke(col, true, thickness);
}

void ImDrawList::AddTriangleFilled(const ImVec2& a, const ImVec2& b, const ImVec2& c, ImU32 col)
{
    if ((col & IM_COL32_A_MASK) == 0)
        return;

    PathLineTo(a);
    PathLineTo(b);
    PathLineTo(c);
    PathFill(col);
}

void ImDrawList::AddCircle(const ImVec2& centre, float radius, ImU32 col, int num_segments, float thickness)
{
    if ((col & IM_COL32_A_MASK) == 0)
        return;

    const float a_max = IM_PI*2.0f * ((float)num_segments - 1.0f) / (float)num_segments;
    PathArcTo(centre, radius-0.5f, 0.0f, a_max, num_segments);
    PathStroke(col, true, thickness);
}

void ImDrawList::AddCircleFilled(const ImVec2& centre, float radius, ImU32 col, int num_segments)
{
    if ((col & IM_COL32_A_MASK) == 0)
        return;

    const float a_max = IM_PI*2.0f * ((float)num_segments - 1.0f) / (float)num_segments;
    PathArcTo(centre, radius, 0.0f, a_max, num_segments);
    PathFill(col);
}

void ImDrawList::AddBezierCurve(const ImVec2& pos0, const ImVec2& cp0, const ImVec2& cp1, const ImVec2& pos1, ImU32 col, float thickness, int num_segments)
{
    if ((col & IM_COL32_A_MASK) == 0)
        return;

    PathLineTo(pos0);
    PathBezierCurveTo(cp0, cp1, pos1, num_segments);
    PathStroke(col, false, thickness);
}

void ImDrawList::AddText(const ImFont* font, float font_size, const ImVec2& pos, ImU32 col, const char* text_begin, const char* text_end, float wrap_width, const ImVec4* cpu_fine_clip_rect)
{
    if ((col & IM_COL32_A_MASK) == 0)
        return;

    if (text_end == NULL)
        text_end = text_begin + strlen(text_begin);
    if (text_begin == text_end)
        return;

    // Note: This is one of the few instance of breaking the encapsulation of ImDrawList, as we pull this from ImGui state, but it is just SO useful.
    // Might just move Font/FontSize to ImDrawList?
    if (font == NULL)
        font = GImGui->Font;
    if (font_size == 0.0f)
        font_size = GImGui->FontSize;

    IM_ASSERT(font->ContainerAtlas->TexID == _TextureIdStack.back());  // Use high-level ImGui::PushFont() or low-level ImDrawList::PushTextureId() to change font.

    ImVec4 clip_rect = _ClipRectStack.back();
    if (cpu_fine_clip_rect)
    {
        clip_rect.x = ImMax(clip_rect.x, cpu_fine_clip_rect->x);
        clip_rect.y = ImMax(clip_rect.y, cpu_fine_clip_rect->y);
        clip_rect.z = ImMin(clip_rect.z, cpu_fine_clip_rect->z);
        clip_rect.w = ImMin(clip_rect.w, cpu_fine_clip_rect->w);
    }
    font->RenderText(this, font_size, pos, col, clip_rect, text_begin, text_end, wrap_width, cpu_fine_clip_rect != NULL);
}

void ImDrawList::AddText(const ImVec2& pos, ImU32 col, const char* text_begin, const char* text_end)
{
    AddText(GImGui->Font, GImGui->FontSize, pos, col, text_begin, text_end);
}

void ImDrawList::AddImage(ImTextureID user_texture_id, const ImVec2& a, const ImVec2& b, const ImVec2& uv0, const ImVec2& uv1, ImU32 col)
{
    if ((col & IM_COL32_A_MASK) == 0)
        return;

    // FIXME-OPT: This is wasting draw calls.
    const bool push_texture_id = _TextureIdStack.empty() || user_texture_id != _TextureIdStack.back();
    if (push_texture_id)
        PushTextureID(user_texture_id);

    PrimReserve(6, 4);
    PrimRectUV(a, b, uv0, uv1, col);

    if (push_texture_id)
        PopTextureID();
}

//-----------------------------------------------------------------------------
// ImDrawData
//-----------------------------------------------------------------------------

// For backward compatibility: convert all buffers from indexed to de-indexed, in case you cannot render indexed. Note: this is slow and most likely a waste of resources. Always prefer indexed rendering!
void ImDrawData::DeIndexAllBuffers()
{
    ImVector<ImDrawVert> new_vtx_buffer;
    TotalVtxCount = TotalIdxCount = 0;
    for (int i = 0; i < CmdListsCount; i++)
    {
        ImDrawList* cmd_list = CmdLists[i];
        if (cmd_list->IdxBuffer.empty())
            continue;
        new_vtx_buffer.resize(cmd_list->IdxBuffer.Size);
        for (int j = 0; j < cmd_list->IdxBuffer.Size; j++)
            new_vtx_buffer[j] = cmd_list->VtxBuffer[cmd_list->IdxBuffer[j]];
        cmd_list->VtxBuffer.swap(new_vtx_buffer);
        cmd_list->IdxBuffer.resize(0);
        TotalVtxCount += cmd_list->VtxBuffer.Size;
    }
}

// Helper to scale the ClipRect field of each ImDrawCmd. Use if your final output buffer is at a different scale than ImGui expects, or if there is a difference between your window resolution and framebuffer resolution.
void ImDrawData::ScaleClipRects(const ImVec2& scale)
{
    for (int i = 0; i < CmdListsCount; i++)
    {
        ImDrawList* cmd_list = CmdLists[i];
        for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
        {
            ImDrawCmd* cmd = &cmd_list->CmdBuffer[cmd_i];
            cmd->ClipRect = ImVec4(cmd->ClipRect.x * scale.x, cmd->ClipRect.y * scale.y, cmd->ClipRect.z * scale.x, cmd->ClipRect.w * scale.y);
        }
    }
}

//-----------------------------------------------------------------------------
// ImFontAtlas
//-----------------------------------------------------------------------------

ImFontConfig::ImFontConfig()
{
    FontData = NULL;
    FontDataSize = 0;
    FontDataOwnedByAtlas = true;
    FontNo = 0;
    SizePixels = 0.0f;
    OversampleH = 3;
    OversampleV = 1;
    PixelSnapH = false;
    GlyphExtraSpacing = ImVec2(0.0f, 0.0f);
    GlyphRanges = NULL;
    MergeMode = false;
    MergeGlyphCenterV = false;
    DstFont = NULL;
    memset(Name, 0, sizeof(Name));
}

ImFontAtlas::ImFontAtlas()
{
    TexID = NULL;
    TexPixelsAlpha8 = NULL;
    TexPixelsRGBA32 = NULL;
    TexWidth = TexHeight = TexDesiredWidth = 0;
    TexUvWhitePixel = ImVec2(0, 0);
}

ImFontAtlas::~ImFontAtlas()
{
    Clear();
}

void    ImFontAtlas::ClearInputData()
{
    for (int i = 0; i < ConfigData.Size; i++)
        if (ConfigData[i].FontData && ConfigData[i].FontDataOwnedByAtlas)
        {
            ImGui::MemFree(ConfigData[i].FontData);
            ConfigData[i].FontData = NULL;
        }

    // When clearing this we lose access to the font name and other information used to build the font.
    for (int i = 0; i < Fonts.Size; i++)
        if (Fonts[i]->ConfigData >= ConfigData.Data && Fonts[i]->ConfigData < ConfigData.Data + ConfigData.Size)
        {
            Fonts[i]->ConfigData = NULL;
            Fonts[i]->ConfigDataCount = 0;
        }
    ConfigData.clear();
}

void    ImFontAtlas::ClearTexData()
{
    if (TexPixelsAlpha8)
        ImGui::MemFree(TexPixelsAlpha8);
    if (TexPixelsRGBA32)
        ImGui::MemFree(TexPixelsRGBA32);
    TexPixelsAlpha8 = NULL;
    TexPixelsRGBA32 = NULL;
}

void    ImFontAtlas::ClearFonts()
{
    for (int i = 0; i < Fonts.Size; i++)
    {
        Fonts[i]->~ImFont();
        ImGui::MemFree(Fonts[i]);
    }
    Fonts.clear();
}

void    ImFontAtlas::Clear()
{
    ClearInputData();
    ClearTexData();
    ClearFonts();
}

void    ImFontAtlas::GetTexDataAsAlpha8(unsigned char** out_pixels, int* out_width, int* out_height, int* out_bytes_per_pixel)
{
    // Build atlas on demand
    if (TexPixelsAlpha8 == NULL)
    {
        if (ConfigData.empty())
            AddFontDefault();
        Build();
    }

    *out_pixels = TexPixelsAlpha8;
    if (out_width) *out_width = TexWidth;
    if (out_height) *out_height = TexHeight;
    if (out_bytes_per_pixel) *out_bytes_per_pixel = 1;
}

void    ImFontAtlas::GetTexDataAsRGBA32(unsigned char** out_pixels, int* out_width, int* out_height, int* out_bytes_per_pixel)
{
    // Convert to RGBA32 format on demand
    // Although it is likely to be the most commonly used format, our font rendering is 1 channel / 8 bpp
    if (!TexPixelsRGBA32)
    {
        unsigned char* pixels;
        GetTexDataAsAlpha8(&pixels, NULL, NULL);
        TexPixelsRGBA32 = (unsigned int*)ImGui::MemAlloc((size_t)(TexWidth * TexHeight * 4));
        const unsigned char* src = pixels;
        unsigned int* dst = TexPixelsRGBA32;
        for (int n = TexWidth * TexHeight; n > 0; n--)
            *dst++ = IM_COL32(255, 255, 255, (unsigned int)(*src++));
    }

    *out_pixels = (unsigned char*)TexPixelsRGBA32;
    if (out_width) *out_width = TexWidth;
    if (out_height) *out_height = TexHeight;
    if (out_bytes_per_pixel) *out_bytes_per_pixel = 4;
}

ImFont* ImFontAtlas::AddFont(const ImFontConfig* font_cfg)
{
    IM_ASSERT(font_cfg->FontData != NULL && font_cfg->FontDataSize > 0);
    IM_ASSERT(font_cfg->SizePixels > 0.0f);

    // Create new font
    if (!font_cfg->MergeMode)
    {
        ImFont* font = (ImFont*)ImGui::MemAlloc(sizeof(ImFont));
        IM_PLACEMENT_NEW(font) ImFont();
        Fonts.push_back(font);
    }

    ConfigData.push_back(*font_cfg);
    ImFontConfig& new_font_cfg = ConfigData.back();
	if (!new_font_cfg.DstFont)
	    new_font_cfg.DstFont = Fonts.back();
    if (!new_font_cfg.FontDataOwnedByAtlas)
    {
        new_font_cfg.FontData = ImGui::MemAlloc(new_font_cfg.FontDataSize);
        new_font_cfg.FontDataOwnedByAtlas = true;
        memcpy(new_font_cfg.FontData, font_cfg->FontData, (size_t)new_font_cfg.FontDataSize);
    }

    // Invalidate texture
    ClearTexData();
    return new_font_cfg.DstFont;
}

// Default font TTF is compressed with stb_compress then base85 encoded (see extra_fonts/binary_to_compressed_c.cpp for encoder)
static unsigned int stb_decompress_length(unsigned char *input);
static unsigned int stb_decompress(unsigned char *output, unsigned char *i, unsigned int length);
static const char*  GetDefaultCompressedFontDataTTFBase85();
static unsigned int Decode85Byte(char c)                                    { return c >= '\\' ? c-36 : c-35; }
static void         Decode85(const unsigned char* src, unsigned char* dst)
{
    while (*src)
    {
        unsigned int tmp = Decode85Byte(src[0]) + 85*(Decode85Byte(src[1]) + 85*(Decode85Byte(src[2]) + 85*(Decode85Byte(src[3]) + 85*Decode85Byte(src[4]))));
        dst[0] = ((tmp >> 0) & 0xFF); dst[1] = ((tmp >> 8) & 0xFF); dst[2] = ((tmp >> 16) & 0xFF); dst[3] = ((tmp >> 24) & 0xFF);   // We can't assume little-endianness.
        src += 5;
        dst += 4;
    }
}

// Load embedded ProggyClean.ttf at size 13, disable oversampling
ImFont* ImFontAtlas::AddFontDefault(const ImFontConfig* font_cfg_template)
{
    ImFontConfig font_cfg = font_cfg_template ? *font_cfg_template : ImFontConfig();
    if (!font_cfg_template)
    {
        font_cfg.OversampleH = font_cfg.OversampleV = 1;
        font_cfg.PixelSnapH = true;
    }
    if (font_cfg.Name[0] == '\0') strcpy(font_cfg.Name, "<default>");

    const char* ttf_compressed_base85 = GetDefaultCompressedFontDataTTFBase85();
    ImFont* font = AddFontFromMemoryCompressedBase85TTF(ttf_compressed_base85, 13.0f, &font_cfg, GetGlyphRangesDefault());
    return font;
}

ImFont* ImFontAtlas::AddFontFromFileTTF(const char* filename, float size_pixels, const ImFontConfig* font_cfg_template, const ImWchar* glyph_ranges)
{
    int data_size = 0;
    void* data = ImLoadFileToMemory(filename, "rb", &data_size, 0);
    if (!data)
    {
        IM_ASSERT(0); // Could not load file.
        return NULL;
    }
    ImFontConfig font_cfg = font_cfg_template ? *font_cfg_template : ImFontConfig();
    if (font_cfg.Name[0] == '\0')
    {
        // Store a short copy of filename into into the font name for convenience
        const char* p;
        for (p = filename + strlen(filename); p > filename && p[-1] != '/' && p[-1] != '\\'; p--) {}
        snprintf(font_cfg.Name, IM_ARRAYSIZE(font_cfg.Name), "%s", p);
    }
    return AddFontFromMemoryTTF(data, data_size, size_pixels, &font_cfg, glyph_ranges);
}

// NBM Transfer ownership of 'ttf_data' to ImFontAtlas, unless font_cfg_template->FontDataOwnedByAtlas == false. Owned TTF buffer will be deleted after Build().
ImFont* ImFontAtlas::AddFontFromMemoryTTF(void* ttf_data, int ttf_size, float size_pixels, const ImFontConfig* font_cfg_template, const ImWchar* glyph_ranges)
{
    ImFontConfig font_cfg = font_cfg_template ? *font_cfg_template : ImFontConfig();
    IM_ASSERT(font_cfg.FontData == NULL);
    font_cfg.FontData = ttf_data;
    font_cfg.FontDataSize = ttf_size;
    font_cfg.SizePixels = size_pixels;
    if (glyph_ranges)
        font_cfg.GlyphRanges = glyph_ranges;
    return AddFont(&font_cfg);
}

ImFont* ImFontAtlas::AddFontFromMemoryCompressedTTF(const void* compressed_ttf_data, int compressed_ttf_size, float size_pixels, const ImFontConfig* font_cfg_template, const ImWchar* glyph_ranges)
{
    const unsigned int buf_decompressed_size = stb_decompress_length((unsigned char*)compressed_ttf_data);
    unsigned char* buf_decompressed_data = (unsigned char *)ImGui::MemAlloc(buf_decompressed_size);
    stb_decompress(buf_decompressed_data, (unsigned char*)compressed_ttf_data, (unsigned int)compressed_ttf_size);

    ImFontConfig font_cfg = font_cfg_template ? *font_cfg_template : ImFontConfig();
    IM_ASSERT(font_cfg.FontData == NULL);
    font_cfg.FontDataOwnedByAtlas = true;
    return AddFontFromMemoryTTF(buf_decompressed_data, (int)buf_decompressed_size, size_pixels, &font_cfg, glyph_ranges);
}

ImFont* ImFontAtlas::AddFontFromMemoryCompressedBase85TTF(const char* compressed_ttf_data_base85, float size_pixels, const ImFontConfig* font_cfg, const ImWchar* glyph_ranges)
{
    int compressed_ttf_size = (((int)strlen(compressed_ttf_data_base85) + 4) / 5) * 4;
    void* compressed_ttf = ImGui::MemAlloc((size_t)compressed_ttf_size);
    Decode85((const unsigned char*)compressed_ttf_data_base85, (unsigned char*)compressed_ttf);
    ImFont* font = AddFontFromMemoryCompressedTTF(compressed_ttf, compressed_ttf_size, size_pixels, font_cfg, glyph_ranges);
    ImGui::MemFree(compressed_ttf);
    return font;
}

bool    ImFontAt