[Bf-blender-cvs] [abf6f9f] master: Fix T48118: Vertex Groups not masking particle hair emission correctly
Bastien Montagne
noreply at git.blender.org
Sat Apr 30 16:58:06 CEST 2016
Commit: abf6f9f6cf72e7ce0bb5feb9af328fc350e3d700
Author: Bastien Montagne
Date: Sat Apr 30 16:51:06 2016 +0200
Branches: master
https://developer.blender.org/rBabf6f9f6cf72e7ce0bb5feb9af328fc350e3d700
Fix T48118: Vertex Groups not masking particle hair emission correctly
Own regression from rB019ce363b01bba0af, not totally sure why removing the heading
zero value in element_sum broke binary search distribution in random branch, but...
New code makes thing sooo much simpler, by simply getting rid of all zero-weight
items in element_sum (at the cost of adding a temporary extra index mapping array),
that way neither random nor 'even ordered' distribution code has to wory anymore
about skipping zero-weighted items!
===================================================================
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 f1dfed0..f6bddfa 100644
--- a/source/blender/blenkernel/intern/particle_distribute.c
+++ b/source/blender/blenkernel/intern/particle_distribute.c
@@ -390,23 +390,26 @@ static void psys_uv_to_w(float u, float v, int quad, float *w)
/* Find the index in "sum" array before "value" is crossed. */
static int distribute_binary_search(float *sum, int n, float value)
{
- int mid, low=0, high=n;
+ int mid, low = 0, high = n - 1;
- if (value == 0.f)
- return 0;
+ if (sum[low] >= value)
+ return low;
+
+ if (sum[high] < value)
+ return high;
- while (low <= high) {
- mid= (low + high)/2;
+ while (low < high) {
+ mid = (low + high) / 2;
- if (sum[mid] < value && value <= sum[mid+1])
+ if ((sum[mid] < value) && (sum[mid + 1] >= value))
return mid;
- if (sum[mid] >= value)
- high= mid - 1;
- else if (sum[mid] < value)
- low= mid + 1;
- else
- return mid;
+ if (sum[mid] >= value) {
+ high = mid - 1;
+ }
+ else if (sum[mid] < value) {
+ low = mid + 1;
+ }
}
return low;
@@ -778,7 +781,7 @@ static int psys_thread_context_init_distribute(ParticleThreadContext *ctx, Parti
int cfrom=0;
int totelem=0, totpart, *particle_element=0, children=0, totseam=0;
int jitlevel= 1, distr;
- float *element_weight=NULL,*element_sum=NULL,*jitter_offset=NULL, *vweight=NULL;
+ float *element_weight=NULL,*jitter_offset=NULL, *vweight=NULL;
float cur, maxweight=0.0, tweight, totweight, inv_totweight, co[3], nor[3], orco[3];
if (ELEM(NULL, ob, psys, psys->part))
@@ -915,7 +918,6 @@ 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_mallocN(sizeof(*element_sum) * totelem, "particle_distribution_sum");
jitter_offset = MEM_callocN(sizeof(float)*totelem, "particle_distribution_jitoff");
/* Calculate weights from face areas */
@@ -1003,27 +1005,55 @@ static int psys_thread_context_init_distribute(ParticleThreadContext *ctx, Parti
}
/* Calculate total weight of all elements */
- totweight= 0.0f;
- for (i=0;i<totelem; i++)
+ int totmapped = 0;
+ totweight = 0.0f;
+ for (i = 0; i < totelem; i++) {
+ if (element_weight[i] != 0.0f) {
+ totmapped++;
+ }
totweight += element_weight[i];
+ }
+
+ if (totweight == 0.0f) {
+ /* We are not allowed to distribute particles anywhere... */
+ return 0;
+ }
inv_totweight = (totweight > 0.f ? 1.f/totweight : 0.f);
- /* Calculate cumulative weights */
- 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;
+ /* Calculate cumulative weights.
+ * We remove all null-weighted elements from element_sum, and create a new mapping
+ * 'activ'_elem_index -> orig_elem_index.
+ * This simplifies greatly the filtering of zero-weighted items - and can be much mor efficient
+ * especially in random case (reducing a lot the size of binary-searched array)...
+ */
+ float *element_sum = MEM_mallocN(sizeof(*element_sum) * totmapped, __func__);
+ int *element_map = MEM_mallocN(sizeof(*element_map) * totmapped, __func__);
+ int i_mapped = 0;
+
+ for (i = 0; i < totelem && element_weight[i] == 0.0f; i++);
+ element_sum[i_mapped] = element_weight[i] * inv_totweight;
+ element_map[i_mapped] = i;
+ i_mapped++;
+ for (i++; i < totelem; i++) {
+ if (element_weight[i] != 0.0f) {
+ element_sum[i_mapped] = element_sum[i_mapped - 1] + element_weight[i] * inv_totweight;
+ element_map[i_mapped] = i;
+ i_mapped++;
+ }
}
+
+ BLI_assert(i_mapped == totmapped);
/* Finally assign elements to particles */
- if ((part->flag&PART_TRAND) || (part->simplify_flag&PART_SIMPLIFY_ENABLE)) {
+ if ((part->flag & PART_TRAND) || (part->simplify_flag & PART_SIMPLIFY_ENABLE)) {
float pos;
- 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 - 1];
- particle_element[p] = distribute_binary_search(element_sum, totelem, pos);
- particle_element[p] = MIN2(totelem-1, particle_element[p]);
+ for (p = 0; p < totpart; p++) {
+ /* In theory element_sum[totelem - 1] should be 1.0,
+ * but due to float errors this is not necessarily always true, so scale pos accordingly. */
+ pos = BLI_frand() * element_sum[totmapped - 1];
+ particle_element[p] = element_map[distribute_binary_search(element_sum, totmapped, pos)];
jitter_offset[particle_element[p]] = pos;
}
}
@@ -1036,31 +1066,23 @@ static int psys_thread_context_init_distribute(ParticleThreadContext *ctx, Parti
* 'midpoint between v and v+1' (or 'p and p+1', depending whether we have more vertices than particles or not),
* and avoid stumbling over float imprecisions in element_sum. */
if (from == PART_FROM_VERT) {
- pos = (totpart < totelem) ? 0.5 / (double)totelem : step * 0.5; /* We choose the smaller step. */
+ pos = (totpart < totmapped) ? 0.5 / (double)totmapped : step * 0.5; /* We choose the smaller step. */
}
else {
pos = 0.0;
}
- /* Avoid initial zero-weight items. */
- for (i = 0; (element_sum[i] == 0.0f) && (i < totelem - 1); i++);
-
- for (p = 0; p < totpart; p++, pos += step) {
- for ( ; (pos > (double)element_sum[i]) && (i < totelem - 1); i++);
+ for (i = 0, p = 0; p < totpart; p++, pos += step) {
+ for ( ; (i < totmapped - 1) && (pos > (double)element_sum[i]); i++);
- particle_element[p] = i;
+ particle_element[p] = element_map[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);
+ MEM_freeN(element_map);
/* For hair, sort by origindex (allows optimization's in rendering), */
/* however with virtual parents the children need to be in random order. */
More information about the Bf-blender-cvs
mailing list