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Fix T48118: Vertex Groups not masking particle hair emission correctly

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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!
This commit is contained in:
Bastien Montagne 2016-04-30 16:51:06 +02:00
parent b1f6cd5a6a
commit abf6f9f6cf
1 changed files with 61 additions and 39 deletions
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100
source/blender/blenkernel/intern/particle_distribute.c
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@ -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;
while (low <= high) {
mid= (low + high)/2;
if (sum[high] < value)
return high;
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 (i = 0, p = 0; p < totpart; p++, pos += step) {
for ( ; (i < totmapped - 1) && (pos > (double)element_sum[i]); i++);
for (p = 0; p < totpart; p++, pos += step) {
for ( ; (pos > (double)element_sum[i]) && (i < totelem - 1); 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. */