IfcOpenShell/src/ifcviewer-wgpu/WgpuViewportWindow.h

/********************************************************************************
 *                                                                              *
 * This file is part of IfcOpenShell.                                           *
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 * IfcOpenShell is free software: you can redistribute it and/or modify         *
 * it under the terms of the Lesser GNU General Public License as published by  *
 * the Free Software Foundation, either version 3.0 of the License, or          *
 * (at your option) any later version.                                          *
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 * IfcOpenShell 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                 *
 * Lesser GNU General Public License for more details.                          *
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 * You should have received a copy of the Lesser GNU General Public License     *
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 ********************************************************************************/

#ifndef WGPUVIEWPORTWINDOW_H
#define WGPUVIEWPORTWINDOW_H

#include <QWindow>
#include <QColor>
#include <QString>

#include <webgpu/webgpu.h>

#include <cstdint>
#include <deque>
#include <unordered_map>

#include "SidecarCache.h"
#include "WgpuModelGpuData.h"

// Stage-2 wgpu viewport: opens a native QWindow, brings up a wgpu instance/
// adapter/device, configures a surface against the platform-native window
// handle, and clears to background_color_ on every UpdateRequest. Models
// loaded from `.ifcview` sidecars are uploaded as wgpu buffers (no draw
// path yet — that's stage 3).
//
// Mirrors the lifecycle shape of the GL ViewportWindow so subsequent stages
// can grow this into a full IFC renderer without restructuring the host.
class WgpuViewportWindow : public QWindow {
    Q_OBJECT
public:
    explicit WgpuViewportWindow(QWindow* parent = nullptr);
    ~WgpuViewportWindow();

    void setBackgroundColor(const QColor& color);

    // Queue a sidecar path to be loaded after wgpu init completes. Safe to
    // call before the window is exposed. The path is resolved against the
    // working directory and read via SidecarCache::readSidecar (which
    // normalises stem → .ifcview).
    void queueLoadSidecar(const QString& path);

    // Synchronous load + GPU upload. Requires wgpu init to have completed
    // (i.e. the window has been exposed at least once). Returns the
    // assigned model_id, or 0 on failure.
    uint32_t loadSidecar(const QString& path);

    // Restore a finalised model from a SidecarData struct: allocate wgpu
    // buffers, upload vertex/index/mesh/instance bytes, register in
    // models_gpu_. Replaces any existing state for model_id.
    void applyCachedModel(uint32_t model_id, SidecarData data);

    void removeModel(uint32_t model_id);
    void resetScene();

    size_t modelCount() const { return models_gpu_.size(); }

protected:
    void exposeEvent(QExposeEvent* event) override;
    void resizeEvent(QResizeEvent* event) override;
    bool event(QEvent* event) override;

private:
    bool initWgpu();
    bool createSurface();
    void configureSurface(int width_px, int height_px);
    void render();
    void shutdown();

    void flushPendingSidecarQueue();

    bool wgpu_initialized_ = false;
    bool surface_configured_ = false;
    int  configured_w_ = 0;
    int  configured_h_ = 0;

    WGPUInstance      instance_       = nullptr;
    WGPUAdapter       adapter_        = nullptr;
    WGPUDevice        device_         = nullptr;
    WGPUQueue         queue_          = nullptr;
    WGPUSurface       surface_        = nullptr;
    WGPUTextureFormat surface_format_ = WGPUTextureFormat_Undefined;

    QColor background_color_ = QColor("#202329");

    // Per-model state, keyed by viewport-assigned model_id.
    std::unordered_map<uint32_t, WgpuModelGpuData> models_gpu_;
    uint32_t next_model_id_ = 1;

    // Sidecar paths queued before init completes.
    std::deque<QString> pending_sidecars_;
};

#endif // WGPUVIEWPORTWINDOW_H