XCEngine/new_editor/app/Rendering/Viewport/SceneViewportRenderPlan.h

#pragma once

#include "Rendering/Viewport/SceneViewportPassSpecs.h"
#include "Rendering/Viewport/ViewportRenderTargets.h"
#include "Scene/EditorSceneRuntime.h"

#include <XCEngine/Components/CameraComponent.h>
#include <XCEngine/Components/GameObject.h>
#include <XCEngine/RHI/RHIEnums.h>
#include <XCEngine/Core/Math/Color.h>
#include <XCEngine/Rendering/Execution/CameraFramePlan.h>
#include <XCEngine/Rendering/RenderPass.h>

#include <functional>
#include <memory>

namespace XCEngine::UI::Editor::App {

struct SceneViewportRenderPlan {
    ::XCEngine::Rendering::RenderPassSequence postScenePasses = {};
    bool usesGridPass = false;
    bool usesSelectionOutline = false;
    bool hasClearColorOverride = true;
    ::XCEngine::Math::Color clearColorOverride =
        ::XCEngine::Math::Color(0.27f, 0.27f, 0.27f, 1.0f);

    bool HasPostScenePasses() const {
        return postScenePasses.GetPassCount() > 0u;
    }
};

using SceneViewportGridPassFactory = std::function<
    std::unique_ptr<::XCEngine::Rendering::RenderPass>(
        const SceneViewportGridPassData&)>;
using SceneViewportSelectionOutlinePassFactory = std::function<
    std::unique_ptr<::XCEngine::Rendering::RenderPass>(
        ViewportRenderTargets*,
        const std::vector<std::uint64_t>&,
        const SceneViewportSelectionOutlineStyle&)>;

struct SceneViewportRenderPlanBuildResult {
    SceneViewportRenderPlan plan = {};
    const char* warningStatusText = nullptr;
};

inline SceneViewportSelectionOutlineStyle BuildSceneViewportSelectionOutlineStyle(
    bool debugSelectionMask = false) {
    SceneViewportSelectionOutlineStyle style = {};
    style.debugSelectionMask = debugSelectionMask;
    return style;
}

inline bool CanRenderSceneViewportSelectionOutline(
    const ViewportRenderTargets& targets) {
    return targets.selectionMaskView != nullptr &&
        targets.selectionMaskShaderView != nullptr &&
        targets.depthView != nullptr &&
        targets.depthShaderView != nullptr;
}

inline SceneViewportGridPassData BuildSceneViewportGridPassData(
    const SceneViewportRenderRequest& request) {
    SceneViewportGridPassData data = {};
    if (request.camera == nullptr ||
        request.camera->GetGameObject() == nullptr ||
        request.camera->GetGameObject()->GetTransform() == nullptr) {
        return data;
    }

    const auto* transform = request.camera->GetGameObject()->GetTransform();
    data.valid = true;
    data.cameraPosition = transform->GetPosition();
    data.cameraForward = transform->GetForward();
    data.cameraRight = transform->GetRight();
    data.cameraUp = transform->GetUp();
    data.verticalFovDegrees = request.camera->GetFieldOfView();
    data.nearClipPlane = request.camera->GetNearClipPlane();
    data.farClipPlane = request.camera->GetFarClipPlane();
    data.orbitDistance = request.orbitDistance;
    return data;
}

inline SceneViewportRenderPlanBuildResult BuildSceneViewportRenderPlan(
    ViewportRenderTargets& targets,
    const SceneViewportRenderRequest& request,
    const SceneViewportGridPassFactory& gridPassFactory,
    const SceneViewportSelectionOutlinePassFactory& selectionOutlinePassFactory) {
    SceneViewportRenderPlanBuildResult result = {};
    const SceneViewportGridPassData gridPassData =
        BuildSceneViewportGridPassData(request);
    if (gridPassData.valid && gridPassFactory != nullptr) {
        std::unique_ptr<::XCEngine::Rendering::RenderPass> gridPass =
            gridPassFactory(gridPassData);
        if (gridPass != nullptr) {
            result.plan.postScenePasses.AddPass(std::move(gridPass));
            result.plan.usesGridPass = true;
        }
    }

    if (request.selectedObjectIds.empty()) {
        return result;
    }

    if (!CanRenderSceneViewportSelectionOutline(targets) ||
        selectionOutlinePassFactory == nullptr) {
        result.warningStatusText = "Scene selection outline resources are unavailable";
        return result;
    }

    std::unique_ptr<::XCEngine::Rendering::RenderPass> selectionOutlinePass =
        selectionOutlinePassFactory(
            &targets,
            request.selectedObjectIds,
            BuildSceneViewportSelectionOutlineStyle(request.debugSelectionMask));
    if (selectionOutlinePass != nullptr) {
        result.plan.postScenePasses.AddPass(std::move(selectionOutlinePass));
        result.plan.usesSelectionOutline = true;
        return result;
    }

    result.warningStatusText = "Scene selection outline pass creation failed";
    return result;
}

inline void ApplySceneViewportRenderPlan(
    const ViewportRenderTargets& targets,
    SceneViewportRenderPlan& plan,
    ::XCEngine::Rendering::CameraFramePlan& framePlan) {
    framePlan.preScenePasses = nullptr;
    framePlan.postScenePasses = nullptr;
    framePlan.overlayPasses = nullptr;
    framePlan.request.objectId = {};

    if (plan.HasPostScenePasses()) {
        framePlan.postScenePasses = &plan.postScenePasses;
    }

    if (targets.objectIdView == nullptr || targets.objectIdDepthView == nullptr) {
        framePlan.request.hasClearColorOverride = plan.hasClearColorOverride;
        framePlan.request.clearColorOverride = plan.clearColorOverride;
        return;
    }

    framePlan.request.objectId.surface = BuildViewportObjectIdSurface(targets);
    framePlan.request.objectId.surface.SetRenderArea(
        framePlan.request.surface.GetRenderArea());
    framePlan.request.hasClearColorOverride = plan.hasClearColorOverride;
    framePlan.request.clearColorOverride = plan.clearColorOverride;
}

inline void MarkSceneViewportRenderSuccess(
    ViewportRenderTargets& targets,
    const SceneViewportRenderPlan& plan,
    const ::XCEngine::Rendering::CameraFramePlan& framePlan) {
    targets.colorState = ::XCEngine::RHI::ResourceStates::PixelShaderResource;
    targets.objectIdState =
        framePlan.request.objectId.IsRequested()
            ? ::XCEngine::RHI::ResourceStates::PixelShaderResource
            : ::XCEngine::RHI::ResourceStates::Common;
    targets.selectionMaskState =
        plan.usesSelectionOutline
            ? ::XCEngine::RHI::ResourceStates::PixelShaderResource
            : ::XCEngine::RHI::ResourceStates::Common;
    targets.hasValidObjectIdFrame = framePlan.request.objectId.IsRequested();
}

} // namespace XCEngine::UI::Editor::App