blender
/
blender
136
404
Fork 586
Code Issues 6.2k Pull Requests 754 Projects 19 Wiki Activity

Cycles: Use new CDF evaluation utility for the pixel filter 

Filter table should stay exactly the same, no changes in the render
results are expected at all.
This commit is contained in:
Sergey Sharybin 2015-10-26 20:23:18 +05:00
parent 548ef2d88b
commit c07c066685
1 changed files with 17 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
intern/cycles/render/film.cpp
View File

@ -26,6 +26,7 @@
#include "util_debug.h"
#include "util_foreach.h"
#include "util_math.h"
#include "util_math_cdf.h"
CCL_NAMESPACE_BEGIN
@ -214,11 +215,8 @@ static float filter_func_gaussian(float v, float width)
static vector<float> filter_table(FilterType type, float width)
{
const int filter_table_size = FILTER_TABLE_SIZE-1;
vector<float> filter_table_cdf(filter_table_size+1);
vector<float> filter_table(filter_table_size+1);
vector<float> filter_table(FILTER_TABLE_SIZE);
float (*filter_func)(float, float) = NULL;
int i, half_size = filter_table_size/2;
switch(type) {
case FILTER_BOX:
@ -231,37 +229,23 @@ static vector<float> filter_table(FilterType type, float width)
assert(0);
}
/* compute cumulative distribution function */
filter_table_cdf[0] = 0.0f;
for(i = 0; i < filter_table_size; i++) {
float x = i*width*0.5f/(filter_table_size-1);
float y = filter_func(x, width);
filter_table_cdf[i+1] += filter_table_cdf[i] + fabsf(y);
}
/* Create importance sampling table. */
for(i = 0; i <= filter_table_size; i++)
filter_table_cdf[i] /= filter_table_cdf[filter_table_size];
/* create importance sampling table */
for(i = 0; i <= half_size; i++) {
float x = i/(float)half_size;
int index = upper_bound(filter_table_cdf.begin(), filter_table_cdf.end(), x) - filter_table_cdf.begin();
float t;
/* TODO(sergey): With the even filter table size resolution we can not
* really make it nice symmetric importance map without sampling full range
* (meaning, we would need to sample full filter range and not use the
* make_symmetric argument).
*
* Current code matches exactly initial filter table code, but we should
* consider either making FILTER_TABLE_SIZE odd value or sample full filter.
*/
if(index < filter_table_size+1) {
t = (x - filter_table_cdf[index])/(filter_table_cdf[index+1] - filter_table_cdf[index]);
}
else {
t = 0.0f;
index = filter_table_size;
}
float y = ((index + t)/(filter_table_size))*width;
filter_table[half_size+i] = 0.5f*(1.0f + y);
filter_table[half_size-i] = 0.5f*(1.0f - y);
}
util_cdf_inverted(FILTER_TABLE_SIZE,
0.0f,
width * 0.5f,
function_bind(filter_func, _1, width),
true,
filter_table);
return filter_table;
}