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/*
* Copyright 2011-2017 Blender Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
CCL_NAMESPACE_BEGIN
/* Determines pixel coordinates and offset for the current thread.
* Returns whether the thread should do any work.
*
* All coordinates are relative to the denoising buffer!
*
* Window is the rect that should be processed.
* co is filled with (x, y, dx, dy).
*/
ccl_device_inline bool get_nlm_coords_window(int w, int h, int r, int stride,
int4 *rect, int4 *co, int *ofs,
int4 window)
{
/* Determine the pixel offset that this thread should apply. */
int s = 2*r+1;
int si = ccl_global_id(1);
int sx = si % s;
int sy = si / s;
if(sy >= s) {
return false;
}
/* Pixels still need to lie inside the denoising buffer after applying the offset,
* so determine the area for which this is the case. */
int dx = sx - r;
int dy = sy - r;
*rect = make_int4(max(0, -dx), max(0, -dy),
w - max(0, dx), h - max(0, dy));
/* Find the intersection of the area that we want to process (window) and the area
* that can be processed (rect) to get the final area for this offset. */
int4 clip_area = rect_clip(window, *rect);
/* If the radius is larger than one of the sides of the window,
* there will be shifts for which there is no usable pixel at all. */
if(!rect_is_valid(clip_area)) {
return false;
}
/* Map the linear thread index to pixels inside the clip area. */
int x, y;
if(!local_index_to_coord(clip_area, ccl_global_id(0), &x, &y)) {
return false;
}
*co = make_int4(x, y, dx, dy);
*ofs = (sy*s + sx) * stride;
return true;
}
ccl_device_inline bool get_nlm_coords(int w, int h, int r, int stride,
int4 *rect, int4 *co, int *ofs)
{
return get_nlm_coords_window(w, h, r, stride, rect, co, ofs, make_int4(0, 0, w, h));
}
ccl_device_inline void kernel_filter_nlm_calc_difference(int x, int y,
int dx, int dy,
const ccl_global float *ccl_restrict weight_image,
const ccl_global float *ccl_restrict variance_image,
const ccl_global float *ccl_restrict scale_image,
ccl_global float *difference_image,
int4 rect, int stride,
int channel_offset,
float a, float k_2)
{
int idx_p = y*stride + x, idx_q = (y+dy)*stride + (x+dx);
int numChannels = channel_offset? 3 : 1;
float diff = 0.0f;
float scale_fac = 1.0f;
if(scale_image) {
scale_fac = clamp(scale_image[idx_p] / scale_image[idx_q], 0.25f, 4.0f);
}
for(int c = 0; c < numChannels; c++, idx_p += channel_offset, idx_q += channel_offset) {
float cdiff = weight_image[idx_p] - scale_fac*weight_image[idx_q];
float pvar = variance_image[idx_p];
float qvar = sqr(scale_fac)*variance_image[idx_q];
diff += (cdiff*cdiff - a*(pvar + min(pvar, qvar))) / (1e-8f + k_2*(pvar+qvar));
}
if(numChannels > 1) {
diff *= 1.0f/numChannels;
}
difference_image[y*stride + x] = diff;
}
ccl_device_inline void kernel_filter_nlm_blur(int x, int y,
const ccl_global float *ccl_restrict difference_image,
ccl_global float *out_image,
int4 rect, int stride, int f)
{
float sum = 0.0f;
const int low = max(rect.y, y-f);
const int high = min(rect.w, y+f+1);
for(int y1 = low; y1 < high; y1++) {
sum += difference_image[y1*stride + x];
}
sum *= 1.0f/(high-low);
out_image[y*stride + x] = sum;
}
ccl_device_inline void kernel_filter_nlm_calc_weight(int x, int y,
const ccl_global float *ccl_restrict difference_image,
ccl_global float *out_image,
int4 rect, int stride, int f)
{
float sum = 0.0f;
const int low = max(rect.x, x-f);
const int high = min(rect.z, x+f+1);
for(int x1 = low; x1 < high; x1++) {
sum += difference_image[y*stride + x1];
}
sum *= 1.0f/(high-low);
out_image[y*stride + x] = fast_expf(-max(sum, 0.0f));
}
ccl_device_inline void kernel_filter_nlm_update_output(int x, int y,
int dx, int dy,
const ccl_global float *ccl_restrict difference_image,
const ccl_global float *ccl_restrict image,
ccl_global float *out_image,
ccl_global float *accum_image,
int4 rect, int channel_offset,
int stride, int f)
{
float sum = 0.0f;
const int low = max(rect.x, x-f);
const int high = min(rect.z, x+f+1);
for(int x1 = low; x1 < high; x1++) {
sum += difference_image[y*stride + x1];
}
sum *= 1.0f/(high-low);
int idx_p = y*stride + x, idx_q = (y+dy)*stride + (x+dx);
if(out_image) {
atomic_add_and_fetch_float(accum_image + idx_p, sum);
float val = image[idx_q];
if(channel_offset) {
val += image[idx_q + channel_offset];
val += image[idx_q + 2*channel_offset];
val *= 1.0f/3.0f;
}
atomic_add_and_fetch_float(out_image + idx_p, sum*val);
}
else {
accum_image[idx_p] = sum;
}
}
ccl_device_inline void kernel_filter_nlm_construct_gramian(int x, int y,
int dx, int dy,
const ccl_global float *ccl_restrict difference_image,
const ccl_global float *ccl_restrict buffer,
const ccl_global float *ccl_restrict transform,
ccl_global int *rank,
ccl_global float *XtWX,
ccl_global float3 *XtWY,
int4 rect,
int4 filter_window,
int stride, int f,
int pass_stride,
int localIdx)
{
const int low = max(rect.x, x-f);
const int high = min(rect.z, x+f+1);
float sum = 0.0f;
for(int x1 = low; x1 < high; x1++) {
sum += difference_image[y*stride + x1];
}
float weight = sum * (1.0f/(high - low));
/* Reconstruction data is only stored for pixels inside the filter window,
* so compute the pixels's index in there. */
int storage_ofs = coord_to_local_index(filter_window, x, y);
transform += storage_ofs;
rank += storage_ofs;
XtWX += storage_ofs;
XtWY += storage_ofs;
kernel_filter_construct_gramian(x, y,
rect_size(filter_window),
dx, dy,
stride,
pass_stride,
buffer,
transform, rank,
weight, XtWX, XtWY,
localIdx);
}
ccl_device_inline void kernel_filter_nlm_normalize(int x, int y,
ccl_global float *out_image,
const ccl_global float *ccl_restrict accum_image,
int stride)
{
out_image[y*stride + x] /= accum_image[y*stride + x];
}
CCL_NAMESPACE_END
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