imgui_stats_drawer.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
 *                                                                           *
 * Copyright(C) 2021-2025                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
 *                                                                           *
 * All rights reserved.                                                      *
 *                                                                           *
 * This program is free software; you can redistribute it and/or modify      *
 * it under the terms of the Mozilla Public License Version 2.0 as published *
 * by the Mozilla Foundation; either version 2 of the License, or            *
 * (at your option) any later version.                                       *
 *                                                                           *
 * This program is distributed in the hope that it will be useful,           *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the              *
 * Mozilla Public License Version 2.0                                        *
 * (https://www.mozilla.org/en-US/MPL/2.0/) for more details.                *
 ****************************************************************************/
 
#ifndef VCL_IMGUI_IMGUI_STATS_DRAWER_H
#define VCL_IMGUI_IMGUI_STATS_DRAWER_H
 
#include <imgui.h>
#include <vclib/render/drawers/plain_drawer.h>
 
#include <algorithm>
#include <vector>
 
#ifdef VCLIB_RENDER_BACKEND_BGFX
#include <bgfx/bgfx.h>
#elif defined(VCLIB_RENDER_BACKEND_OPENGL2)
// include OpenGL headers
#ifdef __APPLE__
#include <OpenGL/gl.h>
#else
#ifdef _WIN32
// dirty trick to avoid including all headers distributed by Khronos
#define GL_SHADING_LANGUAGE_VERSION 0x8B8C
#include <windows.h>
#endif
#include <GL/gl.h>
#endif
#endif
 
namespace vcl::imgui {
 
template<typename DerivedDrawer>
class ImguiStatsDrawer : public vcl::PlainDrawer<DerivedDrawer>
{
    // frame times
    static constexpr size_t FRAME_COUNT = 256;
    std::vector<float>      mFrameTimes = std::vector<float>(FRAME_COUNT, 0.0f);
 
#ifdef VCLIB_RENDER_BACKEND_OPENGL2
    // OpenGL information
    const GLubyte* mGlRendererString  = nullptr;
    const GLubyte* mGlVendorString    = nullptr;
    const GLubyte* mGlVersionString   = nullptr;
    const GLubyte* mGlslVersionString = nullptr;
#endif
 
public:
    using vcl::PlainDrawer<DerivedDrawer>::PlainDrawer;
    using Base = vcl::PlainDrawer<DerivedDrawer>;
 
    void onDraw(uint viewId)
    {
        Base::onDraw(viewId);
 
        ImGuiIO& io = ImGui::GetIO();
        ImGui::Begin("Stats", nullptr);
 
#ifdef VCLIB_RENDER_BACKEND_BGFX
        // map renderer type to string
        static const std::unordered_map<uint16_t, const char*> sVendorIdNames =
            {
                {BGFX_PCI_ID_NONE,                "None"     },
                {BGFX_PCI_ID_SOFTWARE_RASTERIZER, "Software" },
                {BGFX_PCI_ID_AMD,                 "AMD"      },
                {BGFX_PCI_ID_APPLE,               "Apple"    },
                {BGFX_PCI_ID_INTEL,               "Intel"    },
                {BGFX_PCI_ID_NVIDIA,              "NVIDIA"   },
                {BGFX_PCI_ID_MICROSOFT,           "Microsoft"},
                {BGFX_PCI_ID_ARM,                 "ARM"      },
        };
 
        ImGui::SeparatorText("BGFX");
        // get bgfx information
        ImGui::Text(
            "Renderer: %s",
            bgfx::getRendererName(bgfx::getCaps()->rendererType));
        auto it = sVendorIdNames.find(bgfx::getCaps()->vendorId);
        ImGui::Text(
            "Vendor ID: %s",
            it != sVendorIdNames.end() ? it->second : "Unknown");
        ImGui::Text("Device ID: %d", bgfx::getCaps()->deviceId);
        ImGui::Text("GPUs: %d", bgfx::getCaps()->numGPUs);
 
        ImGui::Separator();
 
        // get bgfx stats
        const bgfx::Stats* stats = bgfx::getStats();
        ImGui::Text("Submitted calls:");
        ImGui::Text(
            "\t%d draw - %d compute - %d blit",
            stats->numDraw,
            stats->numCompute,
            stats->numBlit);
        ImGui::Text("Backbuffer size: %d x %d", stats->width, stats->height);
        if (stats->gpuMemoryUsed > 0) {
            ImGui::Text(
                "GPU mem: %d / %d MB",
                int(stats->gpuMemoryUsed / (1024 * 1024)),
                int(stats->gpuMemoryMax / (1024 * 1024)));
        }
        ImGui::Text(
            "Texture memory: %d MB",
            int(stats->textureMemoryUsed / (1024 * 1024)));
        ImGui::Text(
            "RT memory: %d MB", int(stats->rtMemoryUsed / (1024 * 1024)));
 
        // frame times
        const double toMsCpu = 1000.0 / stats->cpuTimerFreq;
        const double toMsGpu = 1000.0 / stats->gpuTimerFreq;
        // const double frameMs = double(stats->cpuTimeFrame)*toMsCpu;
 
        ImGui::Text(
            "Submit CPU %0.3f, GPU %0.3f (L: %d) ms",
            double(stats->cpuTimeEnd - stats->cpuTimeBegin) * toMsCpu,
            double(stats->gpuTimeEnd - stats->gpuTimeBegin) * toMsGpu,
            stats->maxGpuLatency);
 
#elif defined(VCLIB_RENDER_BACKEND_OPENGL2)
        // Display OpenGL information
        if (mGlRendererString == nullptr) {
            mGlRendererString  = glGetString(GL_RENDERER);
            mGlVendorString    = glGetString(GL_VENDOR);
            mGlVersionString   = glGetString(GL_VERSION);
            mGlslVersionString = glGetString(GL_SHADING_LANGUAGE_VERSION);
        }
        ImGui::SeparatorText("OpenGL");
        ImGui::Text("Renderer: %s", mGlRendererString);
        ImGui::Text("Vendor: %s", mGlVendorString);
        ImGui::Text("Version: %s", mGlVersionString);
        ImGui::Text("GLSL Version: %s", mGlslVersionString);
 
#endif
        ImGui::Separator();
 
        // Update frame times
        std::rotate(
            mFrameTimes.begin(), mFrameTimes.begin() + 1, mFrameTimes.end());
        mFrameTimes.back() = io.Framerate;
 
        // Display ImGui information
        ImGui::Text(
            "Display size: %g x %g", io.DisplaySize.x, io.DisplaySize.y);
        ImGui::Text(
            "Framebuffer scale: %g x %g",
            io.DisplayFramebufferScale.x,
            io.DisplayFramebufferScale.y);
        ImGui::Separator();
 
        // Display framerate plot
        ImGui::PlotLines(
            "FPS",
            mFrameTimes.data(),
            int(mFrameTimes.size()),
            0,
            nullptr,
            -5.0f,
            120.0f,
            ImVec2(200, 0));
 
        // Display framerate
        ImGui::Text(
            "%.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
 
        ImGui::End();
    }
};
 
} // namespace vcl::imgui
 
#endif // VCL_IMGUI_IMGUI_STATS_DRAWER_H