#include <engine/graphics.h>
#include <game/mapitems.h>
#include <game/layers.h>
#include "flow.h"

CFlow::CFlow()
{
	m_pCells = 0;
	m_Height = 0;
	m_Width = 0;
	m_Spacing = 16;
}
	
void CFlow::DbgRender()
{
	if(!m_pCells)
		return;

	IGraphics::CLineItem Array[1024];
	int NumItems = 0;
	Graphics()->TextureSet(-1);
	Graphics()->LinesBegin();
	for(int y = 0; y < m_Height; y++)
		for(int x = 0; x < m_Width; x++)
		{
			vec2 Pos(x*m_Spacing, y*m_Spacing);
			vec2 Vel = m_pCells[y*m_Width+x].m_Vel * 0.01f;
			Array[NumItems++] = IGraphics::CLineItem(Pos.x, Pos.y, Pos.x+Vel.x, Pos.y+Vel.y);
			if(NumItems == 1024)
			{
				Graphics()->LinesDraw(Array, 1024);
				NumItems = 0;
			}
		}
	
	if(NumItems)
		Graphics()->LinesDraw(Array, NumItems);
	Graphics()->LinesEnd();
}

void CFlow::Init()
{
	if(m_pCells)
	{
		mem_free(m_pCells);
		m_pCells = 0;
	}
	
	CMapItemLayerTilemap *pTilemap = Layers()->GameLayer();
	m_Width = pTilemap->m_Width*32/m_Spacing;
	m_Height = pTilemap->m_Height*32/m_Spacing;

	// allocate and clear	
	m_pCells = (CCell *)mem_alloc(sizeof(CCell)*m_Width*m_Height, 1);
	for(int y = 0; y < m_Height; y++)
		for(int x = 0; x < m_Width; x++)
			m_pCells[y*m_Width+x].m_Vel = vec2(0.0f, 0.0f);
}

void CFlow::Update()
{
	if(!m_pCells)
		return;
		
	for(int y = 0; y < m_Height; y++)
		for(int x = 0; x < m_Width; x++)
			m_pCells[y*m_Width+x].m_Vel *= 0.85f;
}

vec2 CFlow::Get(vec2 Pos)
{
	if(!m_pCells)
		return vec2(0,0);
	
	int x = (int)(Pos.x / m_Spacing);
	int y = (int)(Pos.y / m_Spacing);
	if(x < 0 || y < 0 || x >= m_Width || y >= m_Height)
		return vec2(0,0);
	
	return m_pCells[y*m_Width+x].m_Vel;	
}

void CFlow::Add(vec2 Pos, vec2 Vel, float Size)
{
	if(!m_pCells)
		return;
		
	int x = (int)(Pos.x / m_Spacing);
	int y = (int)(Pos.y / m_Spacing);
	if(x < 0 || y < 0 || x >= m_Width || y >= m_Height)
		return;
	
	m_pCells[y*m_Width+x].m_Vel += Vel;
}