168 lines
4.0 KiB
C++
168 lines
4.0 KiB
C++
/*
|
||
This uses $LK,"fixed-point","FI:::/TempleOS/Demo/Lectures/FixedPoint.CPP"$ arithmetic
|
||
because it used to be faster than floating
|
||
point. See $LK-A,"::/TempleOS/Demo/Lectures/FixedPoint.CPP"$.
|
||
|
||
The decimal place is between
|
||
bits 31 and 32.
|
||
*/
|
||
|
||
|
||
#define NUM_BALLS 64
|
||
#define BALL_RADIUS 5
|
||
|
||
I64 ball_x[NUM_BALLS],ball_y[NUM_BALLS],
|
||
ball_velocity_x[NUM_BALLS],ball_velocity_y[NUM_BALLS];
|
||
|
||
U0 DrawIt(CTask *,CDC *dc)
|
||
{
|
||
I64 i;
|
||
dc->color=RED;
|
||
for (i=0;i<NUM_BALLS;i++)
|
||
GrCircle(dc,ball_x[i].i32[1],ball_y[i].i32[1],BALL_RADIUS);
|
||
}
|
||
|
||
|
||
|
||
|
||
/****
|
||
|
||
|
||
|
||
$SP,"",1$
|
||
|
||
|
||
|
||
|
||
|
||
|
||
Initial and final velocity vects
|
||
with normal and tangential components.
|
||
All masses are identical, so they
|
||
have been dropped from the equations.
|
||
|
||
|
||
Conservation of Momentum:
|
||
|
||
V1$SY,3$it$SY,0$+V2$SY,3$it$SY,0$=V1$SY,3$ft$SY,0$+V2$SY,3$ft$SY,0$
|
||
|
||
V1$SY,3$in$SY,0$+V2$SY,3$in$SY,0$=V1$SY,3$fn$SY,0$+V2$SY,3$fn$SY,0$
|
||
|
||
|
||
|
||
Conservation of Energy:
|
||
|
||
|V1$SY,3$i$SY,0$|$SY,-3$2$SY,0$+|V2$SY,3$i$SY,0$|$SY,-3$2$SY,0$=|V1$SY,3$f$SY,0$|$SY,-3$2$SY,0$+|V2$SY,3$f$SY,0$|$SY,-3$2$SY,0$
|
||
|
||
|
||
****/
|
||
|
||
U0 AnimateTask(I64)
|
||
{
|
||
CTask *task=Fs->parent_task;
|
||
I64 i,j,h,v,distdist,
|
||
dia=(2*BALL_RADIUS)<<32,
|
||
diadia=SqrI64(2*BALL_RADIUS)<<32,
|
||
delta_x,delta_y,v_t1,v_n1,v_t2,v_n2;
|
||
F64 dist;
|
||
while (TRUE) {
|
||
h=task->win_pixel_width;
|
||
v=task->win_pixel_height;
|
||
for (i=0;i<NUM_BALLS;i++) {
|
||
ball_x[i]+=ball_velocity_x[i];
|
||
ball_y[i]+=ball_velocity_y[i];
|
||
if (ball_x[i]<BALL_RADIUS<<32) {
|
||
ball_velocity_x[i]*=-1;
|
||
ball_x[i]=BALL_RADIUS<<32;
|
||
}
|
||
if (ball_x[i]>=(h-BALL_RADIUS)<<32) {
|
||
ball_velocity_x[i]*=-1;
|
||
ball_x[i]=(h-BALL_RADIUS)<<32;
|
||
}
|
||
if (ball_y[i]<BALL_RADIUS<<32) {
|
||
ball_velocity_y[i]*=-1;
|
||
ball_y[i]=BALL_RADIUS<<32;
|
||
}
|
||
if (ball_y[i]>=(v-BALL_RADIUS)<<32) {
|
||
ball_velocity_y[i]*=-1;
|
||
ball_y[i]=(v-BALL_RADIUS)<<32;
|
||
}
|
||
}
|
||
for (i=0;i<NUM_BALLS;i++) {
|
||
for (j=i+1;j<NUM_BALLS;j++) {
|
||
delta_x=ball_x[i]-ball_x[j];
|
||
delta_y=ball_y[i]-ball_y[j];
|
||
|
||
//We shift 16 because multiplying
|
||
//two 32 shifted would yield 64 shifted
|
||
//and we want a 32 shifted result.
|
||
distdist=SqrI64(delta_x>>16)+SqrI64(delta_y>>16);
|
||
|
||
//We work with square instead of sqrt
|
||
//to avoid unnecessarily calculating
|
||
//square roots (They are slow.)
|
||
if (distdist && distdist<=diadia) {
|
||
dist=Sqrt(distdist); //shifted 16 bits
|
||
delta_x/=dist; //shifted 16
|
||
delta_y/=dist;
|
||
|
||
v_t1=(ball_velocity_x[i]>>16*delta_y-
|
||
ball_velocity_y[i]>>16*delta_x)>>16;
|
||
v_n1=(ball_velocity_x[i]>>16*delta_x+
|
||
ball_velocity_y[i]>>16*delta_y)>>16;
|
||
v_t2=(ball_velocity_x[j]>>16*delta_y-
|
||
ball_velocity_y[j]>>16*delta_x)>>16;
|
||
v_n2=(ball_velocity_x[j]>>16*delta_x+
|
||
ball_velocity_y[j]>>16*delta_y)>>16;
|
||
|
||
if (ball_velocity_x[i]>>16*ball_velocity_x[j]>>16+
|
||
ball_velocity_y[i]>>16*ball_velocity_y[j]>>16<=0) {
|
||
ball_velocity_x[i]= v_t1*delta_y-v_n1*delta_x;
|
||
ball_velocity_y[i]=-v_t1*delta_x-v_n1*delta_y;
|
||
ball_velocity_x[j]= v_t2*delta_y-v_n2*delta_x;
|
||
ball_velocity_y[j]=-v_t2*delta_x-v_n2*delta_y;
|
||
} else {
|
||
ball_velocity_x[i]= v_t1*delta_y+v_n2*delta_x;
|
||
ball_velocity_y[i]=-v_t1*delta_x+v_n2*delta_y;
|
||
ball_velocity_x[j]= v_t2*delta_y+v_n1*delta_x;
|
||
ball_velocity_y[j]=-v_t2*delta_x+v_n1*delta_y;
|
||
}
|
||
|
||
//Correct for overlap
|
||
dist=0x10000+(dia/0x10000-dist)/2;
|
||
ball_x[i]+=dist*delta_x;
|
||
ball_y[i]+=dist*delta_y;
|
||
ball_x[j]-=dist*delta_x;
|
||
ball_y[j]-=dist*delta_y;
|
||
}
|
||
}
|
||
}
|
||
Sleep(1);
|
||
}
|
||
}
|
||
|
||
U0 Init()
|
||
{
|
||
I64 i;
|
||
for (i=0;i<NUM_BALLS;i++) {
|
||
ball_x[i]=(RandU16%(Fs->win_pixel_width-BALL_RADIUS*2)+BALL_RADIUS)<<32;
|
||
ball_y[i]=(RandU16%(Fs->win_pixel_height-BALL_RADIUS*2)+BALL_RADIUS)<<32;
|
||
ball_velocity_x[i]=RandI32/4;
|
||
ball_velocity_y[i]=RandI32/4;
|
||
}
|
||
}
|
||
|
||
U0 Collision()
|
||
{
|
||
SettingsPush; //See $LK,"SettingsPush","MN:SettingsPush"$
|
||
Init;
|
||
Fs->animate_task=Spawn(&AnimateTask,NULL,"Animate",,Fs);
|
||
DocCursor;
|
||
DocClear;
|
||
Fs->draw_it=&DrawIt;
|
||
GetChar;
|
||
SettingsPop;
|
||
}
|
||
|
||
Collision;
|
||
W d ôÿÿÿ € !r Œ èÿÿÿ!r � ˆ ðÿÿÿv_t � v_n |