//
// Copyright 2016 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
//    names, trademarks, service marks, or product names of the Licensor
//    and its affiliates, except as required to comply with Section 4(c) of
//    the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
#ifndef PXR_IMAGING_HDX_DRAW_TARGET_TASK_H
#define PXR_IMAGING_HDX_DRAW_TARGET_TASK_H

#include "pxr/pxr.h"
#include "pxr/imaging/hdx/api.h"
#include "pxr/imaging/hdx/version.h"

#include "pxr/imaging/hd/task.h"

#include "pxr/base/gf/vec4f.h"

PXR_NAMESPACE_OPEN_SCOPE

using HdxDrawTargetRenderPassUniquePtr =
    std::unique_ptr<class HdxDrawTargetRenderPass>;
using HdStSimpleLightingShaderSharedPtr =
    std::shared_ptr<class HdStSimpleLightingShader>;
class HdStDrawTarget;

// Not strictly necessary here.
// But without it, would require users of the class to include it anyway

class HdxDrawTargetTask  : public HdTask
{
public:
    HDX_API
    HdxDrawTargetTask(HdSceneDelegate* delegate, SdfPath const& id);

    HDX_API
    ~HdxDrawTargetTask() override;

    /// Sync the render pass resources
    HDX_API
    void Sync(HdSceneDelegate* delegate,
              HdTaskContext* ctx,
              HdDirtyBits* dirtyBits) override;

    /// Prepare the tasks resources
    HDX_API
    void Prepare(HdTaskContext* ctx,
                 HdRenderIndex* renderIndex) override;
    
    /// Execute render pass task
    HDX_API
    void Execute(HdTaskContext* ctx) override;

    /// Collect Render Tags used by the task.
    HDX_API
    const TfTokenVector &GetRenderTags() const override;

private:
    struct _RenderPassInfo;
    unsigned _currentDrawTargetSetVersion;

    using _RenderPassInfoVector = std::vector<_RenderPassInfo>;
    _RenderPassInfoVector _renderPassesInfo;
    std::vector< HdxDrawTargetRenderPassUniquePtr > _renderPasses;

    // Raster State - close match to render task
    // but doesn't have enableHardwareShading
    // as that has to be enabled for draw targets.
//    typedef std::vector<GfVec4d> ClipPlanesVector;
//    ClipPlanesVector _clipPlanes;
    GfVec4f _overrideColor;
    GfVec4f _wireframeColor;
    bool _enableLighting;
    float _alphaThreshold;

    /// Polygon Offset State
    bool _depthBiasUseDefault;
    bool _depthBiasEnable;
    float _depthBiasConstantFactor;
    float _depthBiasSlopeFactor;

    HdCompareFunction _depthFunc;

    // Viewer's Render Style
    HdCullStyle _cullStyle;

    // Alpha sample alpha to coverage
    bool _enableSampleAlphaToCoverage;
    TfTokenVector _renderTags;

    HdxDrawTargetTask() = delete;
    HdxDrawTargetTask(const HdxDrawTargetTask &) = delete;
    HdxDrawTargetTask &operator =(const HdxDrawTargetTask &) = delete;
};

struct HdxDrawTargetTaskParams
{
    HdxDrawTargetTaskParams()
        : overrideColor(0.0)
        , wireframeColor(0.0)
        , enableLighting(false)
        , alphaThreshold(0.0)
        , depthBiasUseDefault(true)
        , depthBiasEnable(false)
        , depthBiasConstantFactor(0.0f)
        , depthBiasSlopeFactor(1.0f)
        , depthFunc(HdCmpFuncLEqual)
        , cullStyle(HdCullStyleBackUnlessDoubleSided)
        {}

//    ClipPlanesVector clipPlanes;
    GfVec4f overrideColor;
    GfVec4f wireframeColor;
    bool enableLighting;
    float alphaThreshold;

    // Depth Bias Raster State
    // When use default is true - state
    // is inherited and onther values are
    // ignored.  Otherwise the raster state
    // is set using the values specified.

    bool depthBiasUseDefault;
    bool depthBiasEnable;
    float depthBiasConstantFactor;
    float depthBiasSlopeFactor;

    HdCompareFunction depthFunc;

    // Viewer's Render Style
    HdCullStyle cullStyle;
};

// VtValue requirements
HDX_API
std::ostream& operator<<(std::ostream& out, const HdxDrawTargetTaskParams& pv);
HDX_API
bool operator==(
    const HdxDrawTargetTaskParams& lhs, 
    const HdxDrawTargetTaskParams& rhs);
HDX_API
bool operator!=(
    const HdxDrawTargetTaskParams& lhs, 
    const HdxDrawTargetTaskParams& rhs);

PXR_NAMESPACE_CLOSE_SCOPE

#endif // PXR_IMAGING_HDX_DRAW_TARGET_TASK_H