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Use atan2 for LIGH angle calculations

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atan2 gives the actual angle (in the range -pi to pi). acos and asin just
give the principal value (in the range 0 to pi, or -pi/2 to pi/2)
This commit is contained in:
jacksonmj 2012-06-29 00:04:46 +01:00
parent 167740e839
commit 966f1dcc23
2 changed files with 9 additions and 7 deletions
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10
src/elements/ligh.c
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@ -217,15 +217,19 @@ int update_LIGH(UPDATE_FUNC_ARGS)
{
int t=parts[near].type;
float n_angle; // angle to nearest part
float angle_diff;
rx=parts[near].x-x;
ry=parts[near].y-y;
if (rx*rx+ry*ry!=0)
n_angle = asin(-ry/sqrt(rx*rx+ry*ry));
if (rx!=0 || ry!=0)
n_angle = atan2f(-ry, rx);
else
n_angle = 0;
if (n_angle<0)
n_angle+=M_PI*2;
if (parts[i].life<5 || fabs(n_angle-parts[i].tmp*M_PI/180)<M_PI*0.8) // lightning strike
angle_diff = fabsf(n_angle-parts[i].tmp*M_PI/180);
if (angle_diff>M_PI)
angle_diff = M_PI*2 - angle_diff;
if (parts[i].life<5 || angle_diff<M_PI*0.8) // lightning strike
{
create_line_par(x, y, x+rx, y+ry, PT_LIGH, parts[i].temp, parts[i].life, parts[i].tmp-90, 0);

6
src/elements/sprk.c
View File

@ -78,19 +78,17 @@ int update_SPRK(UPDATE_FUNC_ARGS) {
r = pmap[y+ry][x+rx];
if (r)
continue;
if (rand()%(parts[i].tmp*parts[i].tmp/20+6)==0)
if (parts[i].tmp>4 && rand()%(parts[i].tmp*parts[i].tmp/20+6)==0)
{
int p=create_part(-1, x+rx*2, y+ry*2, PT_LIGH);
if (p!=-1)
{
if(parts[i].tmp<=4) //Prevent Arithmetic errors with zero values
continue;
parts[p].life=rand()%(2+parts[i].tmp/15)+parts[i].tmp/7;
if (parts[i].life>60)
parts[i].life=60;
parts[p].temp=parts[p].life*parts[i].tmp/2.5;
parts[p].tmp2=1;
parts[p].tmp=acos(1.0*rx/sqrt(rx*rx+ry*ry))/M_PI*360;
parts[p].tmp=atan2(-ry, rx)/M_PI*360;
parts[i].temp-=parts[i].tmp*2+parts[i].temp/5; // slight self-cooling
if (fabs(pv[y/CELL][x/CELL])!=0.0f)
{