struct CFVFVertexParticles
{
    float x, y, z;
    DWORD color;
};

struct CParticle
{
    int xPos, yPos, r1, g1, b1, r2, 
        g2, b2, LifeTime, VelX, VelY, Speed;
    bool Active;
};

CParticle Particles[300]; // 300 = max particles


IDirect3DVertexBuffer8 *ParticleVertBuffer;
CFVFVertexParticles *ParticleVerts;

// Provides fade effect NOTE: Cow_in_the_well gave me this... 

// so dont blame me if its wrong ;)

inline float Interpolate(float f1, float f2, float lerp)
{    
    return f2+((f1-f2)*lerp); 
}

// Called at app init...

ParticleVertBuffer = 0;

HRESULT hr = pd3dDevice->CreateVertexBuffer(300*sizeof(CFVFVertexParticles), D3DUSAGE_DYNAMIC, (D3DFVF_XYZ | D3DFVF_DIFFUSE), D3DPOOL_DEFAULT, &ParticleVertBuffer);

if(!ParticleVertBuffer)
{
    Log("ERROR: ParticleVertBuffer == NULL");
    Log("D3D error returned: ", 0);
    Log(DXGetErrorString8(hr));		
    return false;
}

ParticleVertBuffer->Lock(0, 0, (BYTE**)&ParticleVerts, 0);

for(int g = 0; g < 300; g++)
{
    ParticleVerts[g].x = 0.0f;
    ParticleVerts[g].y = 0.0f;
    ParticleVerts[g].color = 0xffffffff;
    ParticleVerts[g].z = 1.0f;
    Particles[g].Active = false;
}

ParticleVertBuffer->Unlock();

// Game code...

// r1 etc is first color and r2 etc is color to fade to

void CJester::StartParticle(int xPos, int yPos, int red1, int green1, int blue1, int red2, int green2, int blue2, int LifeTime, int angle, int Speed)
{
    for(int i = 0; i < 300; i++)
    {
        if(!Particles[i].Active)
        {
            Particles[i].Active = true;
	    Particles[i].r1 = red1;
	    Particles[i].g1 = green1;
            Particles[i].b1 = blue1;
	    Particles[i].r2 = red2;
	    Particles[i].g2 = green2;
	    Particles[i].b2 = blue2;
	    Particles[i].VelX = 200; // angle yet to be implimented...

	    Particles[i].VelY = 50; // so these are temp vals

	    Particles[i].LifeTime = LifeTime;
	    Particles[i].Speed = Speed;
	    Particles[i].xPos = xPos - 400; // switching co-ordinate systems...

	    Particles[i].yPos = yPos - 300;
	}
    }
}

// And here is where the work is done...

void CJester::ProcessParticles()
{
    int numActive = 0;
    int particleIndex = 0;
    for(int i = 0; i < 300; i++) if(Particles[i].Active) numActive++;

    ParticleVertBuffer->Lock(0, numActive*sizeof(CFVFVertexParticles), (BYTE**)&ParticleVerts, 0);

    for(int r = 0; r < 300; r++)
    {
        if(Particles[r].Active)
        {
	    if(timeGetTime() > Particles[r].LifeTime) Particles[r].Active = false;
			
	    Particles[r].yPos += Particles[r].VelY*(1.0f/Jester->GetFPS());
	    Particles[r].xPos += Particles[r].VelX*(1.0f/Jester->GetFPS());

	    int a = Interpolate(0, 255, (timeGetTime()-Particles[r].LifeTime)/timeGetTime());
	    int red = Interpolate(Particles[r].r1, Particles[r].r2, (timeGetTime()-Particles[r].LifeTime)/timeGetTime());
	    int g = Interpolate(Particles[r].g1, Particles[r].g2, (timeGetTime()-Particles[r].LifeTime)/timeGetTime());
	    int b = Interpolate(Particles[r].b1, Particles[r].b2, (timeGetTime()-Particles[r].LifeTime)/timeGetTime());

	    ParticleVerts[particleIndex].color = D3DCOLOR_ARGB(a,red,g,b);
	    ParticleVerts[particleIndex].x = Particles[r].xPos;
	    ParticleVerts[particleIndex].y = Particles[r].yPos;


	    particleIndex++;
        }
    }

    ParticleVertBuffer->Unlock();

    pd3dDevice->SetVertexShader(D3DFVF_XYZ | D3DFVF_DIFFUSE);
	
    pd3dDevice->SetStreamSource(0, ParticleVertBuffer, sizeof(CFVFVertexParticles));
    pd3dDevice->DrawPrimitive(D3DPT_POINTLIST, 0, numActive);
}