Commit: 019ce363b01bba0afe12a9b4c3f8a6409ea344fe
Author: Bastien Montagne
Date: Sat Apr 9 22:42:52 2016 +0200
Branches: master
https://developer.blender.org/rB019ce363b01bba0afe12a9b4c3f8a6409ea344fe
Cleanup a bit particle distribution code.
Also do proper intial/final checks to avoid adding particle on zero-weight
extreme items,
instead of using cheap tricks like 'small offset'...
===================================================================
M source/blender/blenkernel/intern/particle_distribute.c
===================================================================
diff --git a/source/blender/blenkernel/intern/particle_distribute.c
b/source/blender/blenkernel/intern/particle_distribute.c
index b871e3e..9185c09 100644
--- a/source/blender/blenkernel/intern/particle_distribute.c
+++ b/source/blender/blenkernel/intern/particle_distribute.c
@@ -915,7 +915,7 @@ static int
psys_thread_context_init_distribute(ParticleThreadContext *ctx, Parti
element_weight = MEM_callocN(sizeof(float)*totelem,
"particle_distribution_weights");
particle_element= MEM_callocN(sizeof(int)*totpart,
"particle_distribution_indexes");
- element_sum = MEM_callocN(sizeof(float)*(totelem+1),
"particle_distribution_sum");
+ element_sum = MEM_mallocN(sizeof(*element_sum) * totelem,
"particle_distribution_sum");
jitter_offset = MEM_callocN(sizeof(float)*totelem,
"particle_distribution_jitoff");
/* Calculate weights from face areas */
@@ -1010,9 +1010,10 @@ static int
psys_thread_context_init_distribute(ParticleThreadContext *ctx, Parti
inv_totweight = (totweight > 0.f ? 1.f/totweight : 0.f);
/* Calculate cumulative weights */
- element_sum[0] = 0.0f;
- for (i=0; i<totelem; i++)
- element_sum[i+1] = element_sum[i] + element_weight[i] *
inv_totweight;
+ element_sum[0] = element_weight[0] * inv_totweight;
+ for (i = 1; i < totelem; i++) {
+ element_sum[i] = element_sum[i - 1] + element_weight[i] *
inv_totweight;
+ }
/* Finally assign elements to particles */
if ((part->flag&PART_TRAND) ||
(part->simplify_flag&PART_SIMPLIFY_ENABLE)) {
@@ -1020,7 +1021,7 @@ static int
psys_thread_context_init_distribute(ParticleThreadContext *ctx, Parti
for (p=0; p<totpart; p++) {
/* In theory element_sum[totelem] should be 1.0, but
due to float errors this is not necessarily always true, so scale pos
accordingly. */
- pos= BLI_frand() * element_sum[totelem];
+ pos= BLI_frand() * element_sum[totelem - 1];
particle_element[p] =
distribute_binary_search(element_sum, totelem, pos);
particle_element[p] = MIN2(totelem-1,
particle_element[p]);
jitter_offset[particle_element[p]] = pos;
@@ -1029,7 +1030,7 @@ static int
psys_thread_context_init_distribute(ParticleThreadContext *ctx, Parti
else {
double step, pos;
- step= (totpart < 2) ? 0.5 : 1.0/(double)totpart;
+ step = (totpart < 2) ? 0.5 : 1.0 / (double)totpart;
/* This is to address tricky issues with vertex-emitting when
user tries (and expects) exact 1-1 vert/part
* distribution (see T47983 and its two example files). It
allows us to consider pos as
* 'midpoint between v and v+1' (or 'p and p+1', depending
whether we have more vertices than particles or not),
@@ -1038,22 +1039,25 @@ static int
psys_thread_context_init_distribute(ParticleThreadContext *ctx, Parti
pos = (totpart < totelem) ? 0.5 / (double)totelem :
step * 0.5; /* We choose the smaller step. */
}
else {
- pos = 1e-6; /* tiny offset to avoid zero weight face */
+ pos = 0.0;
}
- i= 0;
- for (p=0; p<totpart; p++, pos+=step) {
- while ((i < totelem) && (pos > (double)element_sum[i +
1]))
- i++;
+ /* Avoid initial zero-weight items. */
+ for (i = 0; (element_sum[i] == 0.0) && (i < totelem - 1); i++);
- particle_element[p] = MIN2(totelem-1, i);
+ for (p = 0; p < totpart; p++, pos += step) {
+ for ( ; (pos > (double)element_sum[i]) && (i < totelem
- 1); i++);
- /* avoid zero weight face */
- if (p == totpart-1 &&
element_weight[particle_element[p]] == 0.0f)
- particle_element[p] = particle_element[p-1];
+ particle_element[p] = i;
jitter_offset[particle_element[p]] = pos;
}
+
+ /* Avoid final zero weight items. */
+ BLI_assert(p == totpart);
+ if (element_weight[particle_element[--p]] == 0.0f) {
+ particle_element[p] = particle_element[p - 1];
+ }
}
MEM_freeN(element_sum);
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