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correction to 3D hrrpuv opacity computation - addresses smokeview issue 2537 #2538

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Merged
gforney merged 3 commits into from
Jan 21, 2026
Merged

correction to 3D hrrpuv opacity computation - addresses smokeview issue 2537 #2538

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dbb4526
smokeview source: output hrrpuv alpha in center of mesh when pp_OPACI…
gforney Jan 21, 2026
fb83194
smokeview source: correct hrrpuv opacity computation - addresses smok…
gforney Jan 21, 2026
0694cc6
smokeview source: simplify InitAlphas routine
gforney Jan 21, 2026
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40 changes: 22 additions & 18 deletions Source/smokeview/IOsmoke.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1304,28 +1304,25 @@ void InitAlphas(unsigned char *smokealphanew, unsigned char *firealphanew, float
return;
}
if(smoke3d_frame_inc != 1)new_dx *= (float)smoke3d_frame_inc;
if(use_smoke_density == 1){;
for(i = 1; i < 255; i++){
float soot_density, soot_opacity;
int soot_alpha, fire_alpha;
for(i = 1; i < 255; i++){
float soot_density, soot_opacity;
int soot_alpha;

if(use_smoke_density == 1){;
soot_density = maxval*(float)i/255.0;
soot_opacity = 254.0*(1.0 - exp(-new_extinct*new_dx*soot_density));
soot_alpha = CLAMP(soot_opacity+0.5, 0, 254);
smokealphanew[i] = (unsigned char)soot_alpha;
fire_alpha = CLAMP(emission_factor*soot_opacity+0.5, 0, 254);
firealphanew[i] = (unsigned char)fire_alpha;
}
}
else{
for(i = 1; i<255; i++){
float soot_density, soot_opacity;
int soot_alpha, fire_alpha;

else{
soot_density = -log(1.0-(float)i/254.0)/(base_extinct*base_dx);
soot_opacity = 254.0*(1.0-exp(-new_extinct*new_dx*soot_density))+0.5;
soot_alpha = CLAMP(soot_opacity+0.5, 0, 254);
smokealphanew[i] = (unsigned char)soot_alpha;
}
soot_opacity = 254.0*(1.0 - exp(-new_extinct*new_dx*soot_density));
soot_alpha = CLAMP(soot_opacity+0.5, 0, 254);
smokealphanew[i] = (unsigned char)soot_alpha;
if(use_opacity_depth==1){
firealphanew[i] = (unsigned char)i;
}
else{
int fire_alpha;

fire_alpha = CLAMP(emission_factor*soot_opacity+0.5, 0, 254);
firealphanew[i] = (unsigned char)fire_alpha;
}
Expand Down Expand Up @@ -2722,6 +2719,13 @@ void DrawSmokeFrame(void){
}
if(smoke3di->smokeframe_loaded!=NULL&&smoke3di->smokeframe_loaded[smoke3di->ismoke3d_time]==0)continue;
}
#ifdef pp_OPACITY_DEBUG
char alabel[256];
float *xyz;
sprintf(alabel, "%i\n", smoke3di->fire_alpha);
xyz = smokemesh->boxmiddle_smv;
Output3Text(foregroundcolor, xyz[0], xyz[1], xyz[2], alabel);
#endif
#ifdef pp_GPU
if(usegpu_local == 1) {
DrawSmoke3DGPU(smoke3di);
Expand Down
1 change: 1 addition & 0 deletions Source/smokeview/options.h
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@

//#define pp_SHOW_UPDATE // show what is being updated in the UpdateShowScene routine
//#define pp_TERRAIN_HIDE // hide terrain when hiding internal blockages
//#define pp_OPACITY_DEBUG // output hrrpuv opacity in center of each mesh

//*** options: windows

Expand Down