ddnet/src/game/client/components/items.cpp

/* (c) Magnus Auvinen. See licence.txt in the root of the distribution for more information. */
/* If you are missing that file, acquire a complete release at teeworlds.com.                */
#include <engine/graphics.h>
#include <engine/demo.h>
#include <game/generated/protocol.h>
#include <game/generated/client_data.h>
#include <engine/shared/config.h>

#include <game/extrainfo.h>
#include <game/client/gameclient.h>
#include <game/client/ui.h>
#include <game/client/render.h>

#include <game/client/components/flow.h>
#include <game/client/components/effects.h>

#include "items.h"
#include <stdio.h>

#include <engine/serverbrowser.h>

void CItems::OnReset()
{
	m_NumExtraProjectiles = 0;
}

void CItems::RenderProjectile(const CNetObj_Projectile *pCurrent, int ItemID)
{
	// get positions
	float Curvature = 0;
	float Speed = 0;
	if(pCurrent->m_Type == WEAPON_GRENADE)
	{
		Curvature = m_pClient->m_Tuning[g_Config.m_ClDummy].m_GrenadeCurvature;
		Speed = m_pClient->m_Tuning[g_Config.m_ClDummy].m_GrenadeSpeed;
	}
	else if(pCurrent->m_Type == WEAPON_SHOTGUN)
	{
		Curvature = m_pClient->m_Tuning[g_Config.m_ClDummy].m_ShotgunCurvature;
		Speed = m_pClient->m_Tuning[g_Config.m_ClDummy].m_ShotgunSpeed;
	}
	else if(pCurrent->m_Type == WEAPON_GUN)
	{
		Curvature = m_pClient->m_Tuning[g_Config.m_ClDummy].m_GunCurvature;
		Speed = m_pClient->m_Tuning[g_Config.m_ClDummy].m_GunSpeed;
	}

	bool LocalPlayerInGame = false;

	if(m_pClient->m_Snap.m_pLocalInfo)
		LocalPlayerInGame = m_pClient->m_aClients[m_pClient->m_Snap.m_pLocalInfo->m_ClientID].m_Team != -1;

	static float s_LastGameTickTime = Client()->GameTickTime();
	if(m_pClient->m_Snap.m_pGameInfoObj && !(m_pClient->m_Snap.m_pGameInfoObj->m_GameStateFlags&GAMESTATEFLAG_PAUSED))
		s_LastGameTickTime = Client()->GameTickTime();

	float Ct;
	if(m_pClient->Predict() && m_pClient->AntiPingGrenade() && LocalPlayerInGame && !(Client()->State() == IClient::STATE_DEMOPLAYBACK))
		Ct = ((float)(Client()->PredGameTick() - 1 - pCurrent->m_StartTick) + Client()->PredIntraGameTick())/(float)SERVER_TICK_SPEED;
	else
		Ct = (Client()->PrevGameTick() - pCurrent->m_StartTick)/(float)SERVER_TICK_SPEED + s_LastGameTickTime;
	if(Ct < 0)
		return; // projectile haven't been shot yet

	vec2 StartPos;
	vec2 StartVel;

	CServerInfo Info;
	Client()->GetServerInfo(&Info);
	ExtractInfo(pCurrent, &StartPos, &StartVel, IsDDNet(&Info));

	vec2 Pos = CalcPos(StartPos, StartVel, Curvature, Speed, Ct);
	vec2 PrevPos = CalcPos(StartPos, StartVel, Curvature, Speed, Ct-0.001f);

	Graphics()->TextureSet(g_pData->m_aImages[IMAGE_GAME].m_Id);
	Graphics()->SetColor(1.f, 1.f, 1.f, 1.f);

	int QuadOffset = 2 + 4 + NUM_WEAPONS + clamp(pCurrent->m_Type, 0, NUM_WEAPONS - 1);

	vec2 Vel = Pos-PrevPos;
	//vec2 pos = mix(vec2(prev->x, prev->y), vec2(current->x, current->y), Client()->IntraGameTick());

	// add particle for this projectile
	if(pCurrent->m_Type == WEAPON_GRENADE)
	{
		m_pClient->m_pEffects->SmokeTrail(Pos, Vel*-1);
		static float s_Time = 0.0f;
		static float s_LastLocalTime = Client()->LocalTime();

		if(Client()->State() == IClient::STATE_DEMOPLAYBACK)
		{
			const IDemoPlayer::CInfo *pInfo = DemoPlayer()->BaseInfo();
			if(!pInfo->m_Paused)
				s_Time += (Client()->LocalTime()-s_LastLocalTime)*pInfo->m_Speed;
		}
		else
		{
			if(m_pClient->m_Snap.m_pGameInfoObj && !(m_pClient->m_Snap.m_pGameInfoObj->m_GameStateFlags&GAMESTATEFLAG_PAUSED))
				s_Time += Client()->LocalTime()-s_LastLocalTime;
		}

		Graphics()->QuadsSetRotation(s_Time*pi*2*2 + ItemID);
		s_LastLocalTime = Client()->LocalTime();
	}
	else
	{
		m_pClient->m_pEffects->BulletTrail(Pos);

		if(length(Vel) > 0.00001f)
			Graphics()->QuadsSetRotation(GetAngle(Vel));
		else
			Graphics()->QuadsSetRotation(0);

	}

	Graphics()->RenderQuadContainerAsSprite(m_ItemsQuadContainerIndex, QuadOffset, Pos.x, Pos.y);
}

void CItems::RenderPickup(const CNetObj_Pickup *pPrev, const CNetObj_Pickup *pCurrent)
{
	Graphics()->TextureSet(g_pData->m_aImages[IMAGE_GAME].m_Id);
	Graphics()->QuadsSetRotation(0);
	Graphics()->SetColor(1.f, 1.f, 1.f, 1.f);

	int QuadOffset = 2;

	vec2 Pos = mix(vec2(pPrev->m_X, pPrev->m_Y), vec2(pCurrent->m_X, pCurrent->m_Y), Client()->IntraGameTick());
	float Angle = 0.0f;
	if(pCurrent->m_Type == POWERUP_WEAPON)
	{
		Angle = 0; //-pi/6;//-0.25f * pi * 2.0f;
		QuadOffset += 4 + clamp(pCurrent->m_Subtype, 0, NUM_WEAPONS - 1);
	}
	else
	{
		const int c[] = {
			SPRITE_PICKUP_HEALTH,
			SPRITE_PICKUP_ARMOR,
			SPRITE_PICKUP_WEAPON,
			SPRITE_PICKUP_NINJA
			};
		QuadOffset += pCurrent->m_Type;

		if(c[pCurrent->m_Type] == SPRITE_PICKUP_NINJA)
		{
			m_pClient->m_pEffects->PowerupShine(Pos, vec2(96,18));
			Pos.x -= 10.0f;
		}
	}

	Graphics()->QuadsSetRotation(Angle);

	static float s_Time = 0.0f;
	static float s_LastLocalTime = Client()->LocalTime();
	float Offset = Pos.y/32.0f + Pos.x/32.0f;
	if(Client()->State() == IClient::STATE_DEMOPLAYBACK)
	{
		const IDemoPlayer::CInfo *pInfo = DemoPlayer()->BaseInfo();
		if(!pInfo->m_Paused)
			s_Time += (Client()->LocalTime()-s_LastLocalTime)*pInfo->m_Speed;
	}
	else
	{
		if(m_pClient->m_Snap.m_pGameInfoObj && !(m_pClient->m_Snap.m_pGameInfoObj->m_GameStateFlags&GAMESTATEFLAG_PAUSED))
			s_Time += Client()->LocalTime()-s_LastLocalTime;
	}
	Pos.x += cosf(s_Time*2.0f+Offset)*2.5f;
	Pos.y += sinf(s_Time*2.0f+Offset)*2.5f;
	s_LastLocalTime = Client()->LocalTime();

	Graphics()->RenderQuadContainerAsSprite(m_ItemsQuadContainerIndex, QuadOffset, Pos.x, Pos.y);
}

void CItems::RenderFlag(const CNetObj_Flag *pPrev, const CNetObj_Flag *pCurrent, const CNetObj_GameData *pPrevGameData, const CNetObj_GameData *pCurGameData)
{
	float Angle = 0.0f;
	float Size = 42.0f;

	Graphics()->TextureSet(g_pData->m_aImages[IMAGE_GAME].m_Id);
	Graphics()->QuadsSetRotation(0);
	Graphics()->SetColor(1.f, 1.f, 1.f, 1.f);
	int QuadOffset = 0;

	if(pCurrent->m_Team != TEAM_RED)
		++QuadOffset;

	Graphics()->QuadsSetRotation(Angle);

	vec2 Pos = mix(vec2(pPrev->m_X, pPrev->m_Y), vec2(pCurrent->m_X, pCurrent->m_Y), Client()->IntraGameTick());

	if(pCurGameData)
	{
		int FlagCarrier = (pCurrent->m_Team == TEAM_RED) ? pCurGameData->m_FlagCarrierRed : pCurGameData->m_FlagCarrierBlue;
		// use the flagcarriers position if available
		if(FlagCarrier >= 0 && m_pClient->m_Snap.m_aCharacters[FlagCarrier].m_Active)
			Pos = m_pClient->m_aClients[FlagCarrier].m_RenderPos;

		// make sure that the flag isn't interpolated between capture and return
		if(pPrevGameData &&
			((pCurrent->m_Team == TEAM_RED && pPrevGameData->m_FlagCarrierRed != pCurGameData->m_FlagCarrierRed) ||
			(pCurrent->m_Team == TEAM_BLUE && pPrevGameData->m_FlagCarrierBlue != pCurGameData->m_FlagCarrierBlue)))
			Pos = vec2(pCurrent->m_X, pCurrent->m_Y);
	}

	Graphics()->RenderQuadContainerAsSprite(m_ItemsQuadContainerIndex, QuadOffset, Pos.x, Pos.y-Size*0.75f);
}


void CItems::RenderLaser(const struct CNetObj_Laser *pCurrent, bool IsPredicted)
{
	ColorRGBA RGB;
	vec2 Pos = vec2(pCurrent->m_X, pCurrent->m_Y);
	vec2 From = vec2(pCurrent->m_FromX, pCurrent->m_FromY);
	vec2 Dir = normalize(Pos-From);

	float Ticks;
	if(IsPredicted)
		Ticks = (float)(Client()->PredGameTick() - pCurrent->m_StartTick) + Client()->PredIntraGameTick();
	else
		Ticks = (float)(Client()->GameTick() - pCurrent->m_StartTick) + Client()->IntraGameTick();
	float Ms = (Ticks/50.0f) * 1000.0f;
	float a = Ms / m_pClient->m_Tuning[g_Config.m_ClDummy].m_LaserBounceDelay;
	a = clamp(a, 0.0f, 1.0f);
	float Ia = 1-a;

	vec2 Out, Border;

	Graphics()->TextureSet(-1);
	Graphics()->QuadsBegin();

	// do outline
	RGB = color_cast<ColorRGBA>(ColorHSLA(g_Config.m_ClLaserOutlineColor));
	ColorRGBA OuterColor(RGB.r, RGB.g, RGB.b, 1.0f);
	Graphics()->SetColor(OuterColor.r, OuterColor.g, OuterColor.b, 1.0f);
	Out = vec2(Dir.y, -Dir.x) * (7.0f*Ia);

	IGraphics::CFreeformItem Freeform(
			From.x-Out.x, From.y-Out.y,
			From.x+Out.x, From.y+Out.y,
			Pos.x-Out.x, Pos.y-Out.y,
			Pos.x+Out.x, Pos.y+Out.y);
	Graphics()->QuadsDrawFreeform(&Freeform, 1);

	// do inner
	RGB = color_cast<ColorRGBA>(ColorHSLA(g_Config.m_ClLaserInnerColor));
	ColorRGBA InnerColor(RGB.r, RGB.g, RGB.b, 1.0f);
	Out = vec2(Dir.y, -Dir.x) * (5.0f*Ia);
	Graphics()->SetColor(InnerColor.r, InnerColor.g, InnerColor.b, 1.0f); // center

	Freeform = IGraphics::CFreeformItem(
			From.x-Out.x, From.y-Out.y,
			From.x+Out.x, From.y+Out.y,
			Pos.x-Out.x, Pos.y-Out.y,
			Pos.x+Out.x, Pos.y+Out.y);
	Graphics()->QuadsDrawFreeform(&Freeform, 1);

	Graphics()->QuadsEnd();

	// render head
	{
		int QuadOffset = 2 + 4 + NUM_WEAPONS * 2 + (Client()->GameTick() % 3);

		Graphics()->TextureSet(g_pData->m_aImages[IMAGE_PARTICLES].m_Id);
		Graphics()->QuadsSetRotation(Client()->GameTick());
		Graphics()->SetColor(OuterColor.r, OuterColor.g, OuterColor.b, 1.0f);
		Graphics()->RenderQuadContainerAsSprite(m_ItemsQuadContainerIndex, QuadOffset, Pos.x, Pos.y);
		Graphics()->SetColor(InnerColor.r, InnerColor.g, InnerColor.b, 1.0f);
		Graphics()->RenderQuadContainerAsSprite(m_ItemsQuadContainerIndex, QuadOffset, Pos.x, Pos.y, 20.f/24.f, 20.f / 24.f);
	}
}

void CItems::OnRender()
{
	if(Client()->State() < IClient::STATE_ONLINE)
		return;

	bool UsePredicted = (GameClient()->Predict() && GameClient()->AntiPingWeapons() && GameClient()->AntiPingGrenade());
	if(UsePredicted)
	{
		for(auto *pProj = (CProjectile*) GameClient()->m_PredictedWorld.FindFirst(CGameWorld::ENTTYPE_PROJECTILE); pProj; pProj = (CProjectile*) pProj->NextEntity())
		{
			CNetObj_Projectile Data;
			if(pProj->m_Weapon != WEAPON_SHOTGUN || pProj->m_Explosive || pProj->m_Freeze)
				pProj->FillExtraInfo(&Data);
			else
				pProj->FillInfo(&Data);
			RenderProjectile(&Data, pProj->ID());
		}
		for(auto *pLaser = (CLaser*) GameClient()->m_PredictedWorld.FindFirst(CGameWorld::ENTTYPE_LASER); pLaser; pLaser = (CLaser*) pLaser->NextEntity())
		{
			if(pLaser->GetOwner() < 0 || (pLaser->GetOwner() >= 0 && !GameClient()->m_aClients[pLaser->GetOwner()].m_IsPredictedLocal))
				continue;
			CNetObj_Laser Data;
			pLaser->FillInfo(&Data);
			RenderLaser(&Data, true);
		}
		for(auto *pPickup = (CPickup*) GameClient()->m_PredictedWorld.FindFirst(CGameWorld::ENTTYPE_PICKUP); pPickup; pPickup = (CPickup*) pPickup->NextEntity())
		{
			if(auto *pPrev = (CPickup*) GameClient()->m_PrevPredictedWorld.GetEntity(pPickup->ID(), CGameWorld::ENTTYPE_PICKUP))
			{
				CNetObj_Pickup Data, Prev;
				pPickup->FillInfo(&Data);
				pPrev->FillInfo(&Prev);
				RenderPickup(&Prev, &Data);
			}
		}
	}

	int Num = Client()->SnapNumItems(IClient::SNAP_CURRENT);
	for(int i = 0; i < Num; i++)
	{
		IClient::CSnapItem Item;
		const void *pData = Client()->SnapGetItem(IClient::SNAP_CURRENT, i, &Item);

		if(Item.m_Type == NETOBJTYPE_PROJECTILE)
		{
			if(UsePredicted)
			{
				if(auto *pProj = (CProjectile*) GameClient()->m_GameWorld.FindMatch(Item.m_ID, Item.m_Type, pData))
				{
					if(pProj->m_LastRenderTick <= 0
					&& (pProj->m_Weapon != WEAPON_SHOTGUN || (!pProj->m_Freeze && !pProj->m_Explosive)) // skip ddrace shotgun bullets
					&& (pProj->m_Weapon == WEAPON_SHOTGUN || fabs(length(pProj->m_Direction) - 1.f) < 0.02) // workaround to skip grenades on ball mod
					&& (pProj->GetOwner() < 0 || !GameClient()->m_aClients[pProj->GetOwner()].m_IsPredictedLocal) // skip locally predicted projectiles
					&& !Client()->SnapFindItem(IClient::SNAP_PREV, Item.m_Type, Item.m_ID))
					{
						ReconstructSmokeTrail((const CNetObj_Projectile *)pData, Item.m_ID, pProj->m_DestroyTick, pProj->m_LifeSpan);
					}
					pProj->m_LastRenderTick = Client()->GameTick();
					continue;
				}
			}
			RenderProjectile((const CNetObj_Projectile *)pData, Item.m_ID);
		}
		else if(Item.m_Type == NETOBJTYPE_PICKUP)
		{
			if(UsePredicted)
				continue;
			const void *pPrev = Client()->SnapFindItem(IClient::SNAP_PREV, Item.m_Type, Item.m_ID);
			if(pPrev)
				RenderPickup((const CNetObj_Pickup *)pPrev, (const CNetObj_Pickup *)pData);
		}
		else if(Item.m_Type == NETOBJTYPE_LASER)
		{
			if(UsePredicted)
			{
				auto *pLaser = (CLaser*) GameClient()->m_GameWorld.FindMatch(Item.m_ID, Item.m_Type, pData);
				if(pLaser && pLaser->GetOwner() >= 0 && GameClient()->m_aClients[pLaser->GetOwner()].m_IsPredictedLocal)
					continue;
			}
			RenderLaser((const CNetObj_Laser *)pData);
		}
	}

	// render flag
	for(int i = 0; i < Num; i++)
	{
		IClient::CSnapItem Item;
		const void *pData = Client()->SnapGetItem(IClient::SNAP_CURRENT, i, &Item);

		if(Item.m_Type == NETOBJTYPE_FLAG)
		{
			const void *pPrev = Client()->SnapFindItem(IClient::SNAP_PREV, Item.m_Type, Item.m_ID);
			if(pPrev)
			{
				const void *pPrevGameData = Client()->SnapFindItem(IClient::SNAP_PREV, NETOBJTYPE_GAMEDATA, m_pClient->m_Snap.m_GameDataSnapID);
				RenderFlag(static_cast<const CNetObj_Flag *>(pPrev), static_cast<const CNetObj_Flag *>(pData),
							static_cast<const CNetObj_GameData *>(pPrevGameData), m_pClient->m_Snap.m_pGameDataObj);
			}
		}
	}

	// render extra projectiles
	for(int i = 0; i < m_NumExtraProjectiles; i++)
	{
		if(m_aExtraProjectiles[i].m_StartTick < Client()->GameTick())
		{
			m_aExtraProjectiles[i] = m_aExtraProjectiles[m_NumExtraProjectiles-1];
			m_NumExtraProjectiles--;
		}
		else if(!UsePredicted)
			RenderProjectile(&m_aExtraProjectiles[i], 0);
	}

	Graphics()->QuadsSetRotation(0);
	Graphics()->SetColor(1.f, 1.f, 1.f, 1.f);
}

void CItems::OnInit()
{
	Graphics()->QuadsSetRotation(0);
	Graphics()->SetColor(1.f, 1.f, 1.f, 1.f);

	m_ItemsQuadContainerIndex = Graphics()->CreateQuadContainer();

	RenderTools()->SelectSprite(SPRITE_FLAG_RED);
	RenderTools()->QuadContainerAddSprite(m_ItemsQuadContainerIndex, -21.f, -42.f, 42.f, 84.f);
	RenderTools()->SelectSprite(SPRITE_FLAG_BLUE);
	RenderTools()->QuadContainerAddSprite(m_ItemsQuadContainerIndex, -21.f, -42.f, 42.f, 84.f);


	RenderTools()->SelectSprite(SPRITE_PICKUP_HEALTH);
	RenderTools()->QuadContainerAddSprite(m_ItemsQuadContainerIndex, 64.f);
	RenderTools()->SelectSprite(SPRITE_PICKUP_ARMOR);
	RenderTools()->QuadContainerAddSprite(m_ItemsQuadContainerIndex, 64.f);
	RenderTools()->SelectSprite(SPRITE_PICKUP_WEAPON);
	RenderTools()->QuadContainerAddSprite(m_ItemsQuadContainerIndex, 64.f);
	RenderTools()->SelectSprite(SPRITE_PICKUP_NINJA);
	RenderTools()->QuadContainerAddSprite(m_ItemsQuadContainerIndex, 128.f);

	for(int i = 0; i < NUM_WEAPONS; ++i)
	{
		RenderTools()->SelectSprite(g_pData->m_Weapons.m_aId[i].m_pSpriteBody);
		RenderTools()->QuadContainerAddSprite(m_ItemsQuadContainerIndex, g_pData->m_Weapons.m_aId[i].m_VisualSize);
	}

	for(int i = 0; i < NUM_WEAPONS; ++i)
	{
		RenderTools()->SelectSprite(g_pData->m_Weapons.m_aId[i].m_pSpriteProj);
		RenderTools()->QuadContainerAddSprite(m_ItemsQuadContainerIndex, 32.f, false);
	}

	RenderTools()->SelectSprite(SPRITE_PART_SPLAT01);
	RenderTools()->QuadContainerAddSprite(m_ItemsQuadContainerIndex, 24.f, false);
	RenderTools()->SelectSprite(SPRITE_PART_SPLAT02);
	RenderTools()->QuadContainerAddSprite(m_ItemsQuadContainerIndex, 24.f, false);
	RenderTools()->SelectSprite(SPRITE_PART_SPLAT03);
	RenderTools()->QuadContainerAddSprite(m_ItemsQuadContainerIndex, 24.f, false);
}

void CItems::AddExtraProjectile(CNetObj_Projectile *pProj)
{
	if(m_NumExtraProjectiles != MAX_EXTRA_PROJECTILES)
	{
		m_aExtraProjectiles[m_NumExtraProjectiles] = *pProj;
		m_NumExtraProjectiles++;
	}
}

void CItems::ReconstructSmokeTrail(const CNetObj_Projectile *pCurrent, int ItemID, int DestroyTick, int LifeSpan)
{
	bool LocalPlayerInGame = false;

	if(m_pClient->m_Snap.m_pLocalInfo)
		LocalPlayerInGame = m_pClient->m_aClients[m_pClient->m_Snap.m_pLocalInfo->m_ClientID].m_Team != -1;
	if(!m_pClient->AntiPingGrenade() || !m_pClient->AntiPingWeapons() || !LocalPlayerInGame)
		return;
	if(Client()->PredGameTick() == pCurrent->m_StartTick)
		return;

	// get positions
	float Curvature = 0;
	float Speed = 0;
	if(pCurrent->m_Type == WEAPON_GRENADE)
	{
		Curvature = m_pClient->m_Tuning[g_Config.m_ClDummy].m_GrenadeCurvature;
		Speed = m_pClient->m_Tuning[g_Config.m_ClDummy].m_GrenadeSpeed;
	}
	else if(pCurrent->m_Type == WEAPON_SHOTGUN)
	{
		Curvature = m_pClient->m_Tuning[g_Config.m_ClDummy].m_ShotgunCurvature;
		Speed = m_pClient->m_Tuning[g_Config.m_ClDummy].m_ShotgunSpeed;
	}
	else if(pCurrent->m_Type == WEAPON_GUN)
	{
		Curvature = m_pClient->m_Tuning[g_Config.m_ClDummy].m_GunCurvature;
		Speed = m_pClient->m_Tuning[g_Config.m_ClDummy].m_GunSpeed;
	}

	float Pt = ((float)(Client()->PredGameTick() - pCurrent->m_StartTick) + Client()->PredIntraGameTick())/(float)SERVER_TICK_SPEED;
	if(Pt < 0)
		return; // projectile haven't been shot yet

	float Gt = (Client()->PrevGameTick() - pCurrent->m_StartTick)/(float)SERVER_TICK_SPEED + Client()->GameTickTime();

	vec2 StartPos;
	vec2 StartVel;

	ExtractInfo(pCurrent, &StartPos, &StartVel, true);

	float T = Pt;
	if(DestroyTick >= 0)
		T = minimum(Pt, ((float)(DestroyTick - 1 - pCurrent->m_StartTick) + Client()->PredIntraGameTick())/(float)SERVER_TICK_SPEED);
	T = minimum(T, LifeSpan/(float)SERVER_TICK_SPEED);

	float MinTrailSpan = 0.4f * ((pCurrent->m_Type == WEAPON_GRENADE) ? 0.5f : 0.25f);
	float Step = maximum(Client()->FrameTimeAvg(), (pCurrent->m_Type == WEAPON_GRENADE) ? 0.02f : 0.01f);
	for(int i = 1+(int)(Gt/Step); i < (int)(T/Step); i++)
	{
		float t = Step * (float)i + 0.4f * Step * (frandom() - 0.5f);
		vec2 Pos = CalcPos(StartPos, StartVel, Curvature, Speed, t);
		vec2 PrevPos = CalcPos(StartPos, StartVel, Curvature, Speed, t-0.001f);
		vec2 Vel = Pos-PrevPos;
		float TimePassed = Pt-t;
		if(Pt - MinTrailSpan > 0.01f)
			TimePassed = minimum(TimePassed, (TimePassed-MinTrailSpan)/(Pt - MinTrailSpan)*(MinTrailSpan * 0.5f) + MinTrailSpan);
		// add particle for this projectile
		if(pCurrent->m_Type == WEAPON_GRENADE)
			m_pClient->m_pEffects->SmokeTrail(Pos, Vel*-1, TimePassed);
		else
			m_pClient->m_pEffects->BulletTrail(Pos, TimePassed);
	}
}