verus/Verus/src/Effects/Particles.h

// Copyright (C) 2021-2022, Dmitry Maluev (dmaluev@gmail.com). All rights reserved.
#pragma once

namespace verus::Effects
{
	enum class BillboardType : int
	{
		none,
		screenViewplaneOriented,
		screenViewpointOriented,
		worldViewplaneOriented,
		worldViewpointOriented,
		axial
	};

	class Particle
	{
	public:
		Point3  _position = Point3(0);
		Point3  _prevPosition = Point3(0);
		Vector3 _velocity = Vector3(0, 1, 0);
		Vector3 _axis = Vector3(0, 1, 0);
		Vector4 _tcOffset = Vector4(0);
		Vector4 _beginColor = Vector4::Replicate(1);
		Vector4 _endColor = Vector4::Replicate(1);
		void* _pUser = nullptr;
		float   _invTotalTime = 0;
		float   _timeLeft = -1;
		float   _beginAdditive = 0;
		float   _endAdditive = 0;
		float   _beginSize = 0;
		float   _endSize = 0;
		float   _beginSpin = 0;
		float   _endSpin = 0;
		bool    _inContact = false;
	};
	VERUS_TYPEDEFS(Particle);

	class Particles;
	class ParticlesDelegate
	{
	public:
		virtual void Particles_OnUpdate(Particles& particles, int index, RParticle particle,
			RVector3 up, RVector3 normal, RTransform3 matAim) = 0;
	};
	VERUS_TYPEDEFS(ParticlesDelegate);

	class Particles : public Object
	{
#include "../Shaders/Particles.inc.hlsl"

		enum PIPE
		{
			PIPE_MAIN,
			PIPE_BILLBOARDS,
			PIPE_COUNT
		};

		struct Vertex
		{
			glm::vec4 pos;
			glm::vec2 tc0;
			UINT32    color;
			float     psize;
		};
		VERUS_TYPEDEFS(Vertex);

		static CGI::ShaderPwn                s_shader;
		static CGI::PipelinePwns<PIPE_COUNT> s_pipe;
		static UB_ParticlesVS                s_ubParticlesVS;
		static UB_ParticlesFS                s_ubParticlesFS;

		Vector4            _tilesetSize = Vector4::Replicate(1);
		Vector3            _lifeTimeRange = Vector3(0, 1, 1);
		Vector3            _speedRange = Vector3(0, 1, 1);
		Vector3            _beginAdditiveRange = Vector3(0);
		Vector3            _endAdditiveRange = Vector3(0);
		Vector4            _beginColorMin = Vector4(0);
		Vector4            _beginColorDelta = Vector4(0);
		Vector4            _endColorMin = Vector4(0);
		Vector4            _endColorDelta = Vector4(0);
		Vector3            _beginSizeRange = Vector3(0, 1, 1);
		Vector3            _endSizeRange = Vector3(0, 1, 1);
		Vector3            _beginSpinRange = Vector3(0, 1, 1);
		Vector3            _endSpinRange = Vector3(0, 1, 1);
		Vector3            _gravity = Vector3(0, -9.8f, 0);
		String             _url;
		Vector<Particle>   _vParticles;
		Vector<Vertex>     _vVB;
		Vector<UINT16>     _vIB;
		CGI::GeometryPwn   _geo;
		CGI::TexturePwn    _tex;
		CGI::CSHandle      _csh;
		PParticlesDelegate _pDelegate = nullptr;
		const float* _pUserZone = nullptr;
		BillboardType      _billboardType = BillboardType::none;
		int                _tilesetX = 0;
		int                _tilesetY = 0;
		int                _indexCount = 0;
		int                _capacity = 0;
		int                _addAt = 0;
		int                _drawCount = 0;
		float              _ratio = 1;
		float              _brightness = 1;
		float              _bounceStrength = 0.5f;
		float              _gravityStrength = 1;
		float              _windStrength = 0;
		float              _flowRemainder = 0;
		float              _particlesPerSecond = 0;
		float              _zone = 0;
		bool               _collide = false;
		bool               _decal = false;
		bool               _flowEnabled = true;

	public:
		Particles();
		~Particles();

		static void InitStatic();
		static void DoneStatic();

		void Init(CSZ url);
		void Done();

		void Update(); // Call this after adding particles!
		void Draw();

		Str GetURL() const { return _C(_url); }
		int GetTilesetX() const { return _tilesetX; }
		int GetTilesetY() const { return _tilesetY; }
		int GetCapacity() const { return _capacity; }
		int GetDrawCount() const { return _drawCount; }

		PParticlesDelegate SetDelegate(PParticlesDelegate p) { return Utils::Swap(_pDelegate, p); }
		void SetUserZone(const float* pZone) { _pUserZone = pZone; }

		void GetLifeTime(float& mn, float& mx) const;
		void SetLifeTime(float mn, float mx);
		void GetSpeed(float& mn, float& mx) const;
		void SetSpeed(float mn, float mx);
		void GetBeginAdditive(float& mn, float& mx) const;
		void SetBeginAdditive(float mn, float mx);
		void GetBeginColor(RVector4 mn, RVector4 mx) const;
		void SetBeginColor(RcVector4 mn, RcVector4 mx);
		void GetEndColor(RVector4 mn, RVector4 mx) const;
		void SetEndColor(RcVector4 mn, RcVector4 mx);
		void GetEndAdditive(float& mn, float& mx) const;
		void SetEndAdditive(float mn, float mx);
		void GetBeginSize(float& mn, float& mx) const;
		void SetBeginSize(float mn, float mx);
		void GetEndSize(float& mn, float& mx) const;
		void SetEndSize(float mn, float mx);
		void GetBeginSpin(float& mn, float& mx) const;
		void SetBeginSpin(float mn, float mx);
		void GetEndSpin(float& mn, float& mx) const;
		void SetEndSpin(float mn, float mx);
		float GetBrightness() const { return _brightness; }
		void SetBrightness(float value) { _brightness = value; }
		float GetBounce() const { return _bounceStrength; }
		void SetBounce(float value) { _bounceStrength = value; }
		float GetGravity() const { return _gravityStrength; }
		void SetGravity(float value) { _gravityStrength = value; }
		float GetWind() const { return _windStrength; }
		void SetWind(float value) { _windStrength = value; }
		float GetParticlesPerSecond() const { return _particlesPerSecond; }
		void SetParticlesPerSecond(float value) { _particlesPerSecond = value; }
		float GetZone() const { return _zone; }
		void SetZone(float value) { _zone = value; }

		int Add(RcPoint3 pos, RcVector3 dir,
			float scale = 1, PcVector4 pUserColor = nullptr, void* pUser = nullptr);
		void AddFlow(RcPoint3 pos, RcVector3 dirOffset,
			float scale = 1, PcVector4 pUserColor = nullptr, float* pUserFlowRemainder = nullptr, float intensity = 1);
		bool IsFlowEnabled() const { return _flowEnabled; }
		void EnableFlow(bool b = true) { _flowEnabled = b; }

		bool TimeCorrectedVerletIntegration(RParticle particle, RPoint3 point, RVector3 normal);
		bool EulerIntegration(RParticle particle, RPoint3 point, RVector3 normal);

		void PushPointSprite(int index, RcVector4 color, float size, float additive);
		void PushBillboard(int index, RcVector4 color, RcTransform3 matW, float additive);
		Transform3 GetBillboardMatrix(int index, float size, float spin, RcVector3 up, RcVector3 normal, RTransform3 matAim);
	};
	VERUS_TYPEDEFS(Particles);
}