File Filter.h¶

// Copyright (c) 2021-present Sparky Studios. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#pragma once

#ifndef _AM_DSP_FILTER_H
#define _AM_DSP_FILTER_H

#include <SparkyStudios/Audio/Amplitude/Core/AudioBuffer.h>
#include <SparkyStudios/Audio/Amplitude/Core/Memory.h>

#include <map>
#include <vector>

namespace SparkyStudios::Audio::Amplitude
{
    class Filter;

    class AM_API_PUBLIC FilterInstance
    {
    public:
        explicit FilterInstance(Filter* parent);

        virtual ~FilterInstance();

        AmResult Initialize(AmUInt32 paramCount);

        virtual void AdvanceFrame(AmTime deltaTime);

        virtual void Process(const AudioBuffer& in, AudioBuffer& out, AmUInt64 frames, AmUInt32 sampleRate);

        virtual AmReal32 GetParameter(AmUInt32 parameterIndex);

        virtual void SetParameter(AmUInt32 parameterIndex, AmReal32 value);

    protected:
        virtual void ProcessChannel(const AudioBuffer& in, AudioBuffer& out, AmUInt16 channel, AmUInt64 frames, AmUInt32 sampleRate);

        virtual AmAudioSample ProcessSample(AmAudioSample sample, AmUInt16 channel, AmUInt32 sampleRate);

        Filter* m_parent;

        AmUInt32 m_numParamsChanged;

        std::vector<AmReal32> m_parameters;
    };

    class AM_API_PUBLIC Filter
    {
        friend class FilterInstance;

    public:
        explicit Filter(AmString name);

        virtual ~Filter();

        [[nodiscard]] virtual AmUInt32 GetParameterCount() const;

        [[nodiscard]] virtual AmString GetParameterName(AmUInt32 index) const;

        [[nodiscard]] virtual eParameterType GetParameterType(AmUInt32 index) const;

        [[nodiscard]] virtual AmReal32 GetParameterMax(AmUInt32 index) const;

        [[nodiscard]] virtual AmReal32 GetParameterMin(AmUInt32 index) const;

        virtual std::shared_ptr<FilterInstance> CreateInstance() = 0;

        [[nodiscard]] const AmString& GetName() const;

        static void Register(std::shared_ptr<Filter> filter);

        static void Unregister(std::shared_ptr<const Filter> filter);

        static std::shared_ptr<Filter> Find(const AmString& name);

        static std::shared_ptr<FilterInstance> Construct(const AmString& name);

        static void LockRegistry();

        static void UnlockRegistry();

        static const std::map<AmString, std::shared_ptr<Filter>>& GetRegistry();

    protected:
        AmString m_name;
    };
} // namespace SparkyStudios::Audio::Amplitude

#endif // _AM_DSP_FILTER_H