Method _TryMergeDrawCmds

tutorials/common/imgui/imgui_draw.cpp:481–491

Try to merge two last draw commands

// Try to merge two last draw commands
void ImDrawList::_TryMergeDrawCmds()
{
    IM_ASSERT_PARANOID(CmdBuffer.Size > 0);
    ImDrawCmd* curr_cmd = &CmdBuffer.Data[CmdBuffer.Size - 1];
    ImDrawCmd* prev_cmd = curr_cmd - 1;
    if (ImDrawCmd_HeaderCompare(curr_cmd, prev_cmd) == 0 && ImDrawCmd_AreSequentialIdxOffset(prev_cmd, curr_cmd) && curr_cmd->UserCallback == NULL && prev_cmd->UserCallback == NULL)
    {
        prev_cmd->ElemCount += curr_cmd->ElemCount;
        CmdBuffer.pop_back();
    }
}

// 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.