/
particlefx.c
executable file
·87 lines (81 loc) · 2.24 KB
/
particlefx.c
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#include "vec2d.h"
#include "screen.h"
#include "objects.h"
#include "preferences.h"
#include "random.h"
#define kMaxParticles 64
#define kMaxPFX 64
#define E 2.71828182846
#define kParticleDuration 0.5
typedef struct{
int active;
int numParticles;
int layer;
UInt32 fxStartFrame;
UInt16 color16;
UInt8 color;
t2DPoint pos;
t2DPoint p[kMaxParticles*4];
} tParticleFX;
tParticleFX gParticleFX[kMaxPFX];
void NewParticleFX(t2DPoint pos,t2DPoint velo,int num,UInt8 color,int layer,float spread)
{
int numFX;
for(numFX=0;numFX<kMaxPFX&&gParticleFX[numFX].active;numFX++);
if(numFX<kMaxPFX)
{
int i;
tParticleFX *fx=&gParticleFX[numFX];
fx->numParticles=num;
fx->active=true;
fx->layer=layer;
fx->fxStartFrame=gFrameCount;
fx->pos=pos;
if(gPrefs.hiColor)
fx->color16=((UInt16*)*g16BitClut)[color];
else
fx->color=color;
num*=4;
if(num>kMaxParticles)num=kMaxParticles;
for(i=0;i<num;i++)
fx->p[i]=VEC2D_Sum(velo,P2D(RanFl(-spread,spread),RanFl(-spread,spread)));
}
}
void DrawParticleFXZoomed(float xDrawStart,float yDrawStart,float zoom,int layer)
{
int numFX;
float invZoom=1/zoom;
for(numFX=0;numFX<kMaxPFX;numFX++)
if(gParticleFX[numFX].active&&gParticleFX[numFX].layer==layer)
{
tParticleFX *fx=&gParticleFX[numFX];
float dt=(gFrameCount-fx->fxStartFrame)*kFrameDuration;
int numDrawParticles=fx->numParticles*invZoom*invZoom;
int i;
if(numDrawParticles>4*kMaxParticles)
numDrawParticles=4*kMaxParticles;
if(dt<kParticleDuration)
if(gPrefs.hiColor)
for(i=0;i<numDrawParticles;i++)
{
float epdt=-pow(E,-dt);
t2DPoint pos=VEC2D_Sum(fx->pos,P2D(fx->p[i].x*epdt+fx->p[i].x,fx->p[i].y*epdt+fx->p[i].y));
int x=(pos.x-xDrawStart)*invZoom,y=(yDrawStart-pos.y)*invZoom;
if(x>0&&y>0)
if(x<gXSize&&y<gYSize)
*((UInt16*)(gBaseAddr+y*gRowBytes+x*2))=fx->color16;
}
else
for(i=0;i<numDrawParticles;i++)
{
float epdt=-pow(E,-dt);
t2DPoint pos=VEC2D_Sum(fx->pos,P2D(fx->p[i].x*epdt+fx->p[i].x,fx->p[i].y*epdt+fx->p[i].y));
int x=(pos.x-xDrawStart)*invZoom,y=(yDrawStart-pos.y)*invZoom;
if(x>0&&y>0)
if(x<gXSize&&y<gYSize)
*(gBaseAddr+y*gRowBytes+x)=fx->color;
}
else
fx->active=false;
}
}