Files
test/source/blender/compositor/operations/COM_KeyingScreenOperation.cc
Omar Emara 75c947a467 Compositor: Use RBF Interpolation in Keying Screen node
This patch changes the interpolation algorithm utilized by the Keying
Screen node to a Gaussian Radial Basis Function Interpolation. This is
proposed because the current Voronoi triangulation based interpolation
has the following properties:

- Not temporally stable since the triangulation can abruptly change as
  tracking markers change position.
- Not smooth in the mathematical sense, which is also readily visible in
  the artists sense.
- Computationally expensive due to the triangulation and naive
  rasterization algorithm.

On the other hand, the RBF interpolation method is temporally stable and
continuous, smooth and infinitely differentiable, and relatively simple
to compute assuming low number of markers, which is typically the case
for keying screen objects.

This breaks backward compatibility, but the keying screen is only used
as a secondary input for keying in typical compositor setups, so one
should expect minimal difference in outputs.

Pull Request: https://projects.blender.org/blender/blender/pulls/112480
2023-10-04 07:07:04 +02:00

237 lines
6.9 KiB
C++

/* SPDX-FileCopyrightText: 2012 Blender Authors
*
* SPDX-License-Identifier: GPL-2.0-or-later */
#include "COM_KeyingScreenOperation.h"
#include "DNA_defaults.h"
#include "BLI_array.hh"
#include "BLI_math_color.h"
#include "BLI_math_geom.h"
#include "BLI_math_vector.hh"
#include "BLI_math_vector_types.hh"
#include "BKE_movieclip.h"
#include "BKE_tracking.h"
#include "IMB_imbuf.h"
#include "IMB_imbuf_types.h"
namespace blender::compositor {
KeyingScreenOperation::KeyingScreenOperation()
{
this->add_output_socket(DataType::Color);
movie_clip_ = nullptr;
framenumber_ = 0;
tracking_object_[0] = 0;
flags_.complex = true;
cached_marker_points_ = nullptr;
}
void KeyingScreenOperation::init_execution()
{
init_mutex();
if (execution_model_ == eExecutionModel::FullFrame) {
BLI_assert(cached_marker_points_ == nullptr);
if (movie_clip_) {
cached_marker_points_ = compute_marker_points();
}
}
else {
cached_marker_points_ = nullptr;
}
}
void KeyingScreenOperation::deinit_execution()
{
delete cached_marker_points_;
cached_marker_points_ = nullptr;
}
Array<KeyingScreenOperation::MarkerPoint> *KeyingScreenOperation::compute_marker_points()
{
MovieTracking *tracking = &movie_clip_->tracking;
const MovieTrackingObject *tracking_object = nullptr;
if (tracking_object_[0]) {
tracking_object = BKE_tracking_object_get_named(tracking, tracking_object_);
if (!tracking_object) {
return nullptr;
}
}
else {
tracking_object = BKE_tracking_object_get_active(tracking);
}
BLI_assert(tracking_object != nullptr);
int clip_frame = BKE_movieclip_remap_scene_to_clip_frame(movie_clip_, framenumber_);
/* count sites */
int sites_total = 0;
LISTBASE_FOREACH (MovieTrackingTrack *, track, &tracking_object->tracks) {
const MovieTrackingMarker *marker = BKE_tracking_marker_get(track, clip_frame);
if (marker->flag & MARKER_DISABLED) {
continue;
}
float pos[2];
add_v2_v2v2(pos, marker->pos, track->offset);
if (!IN_RANGE_INCL(pos[0], 0.0f, 1.0f) || !IN_RANGE_INCL(pos[1], 0.0f, 1.0f)) {
continue;
}
sites_total++;
}
if (!sites_total) {
return nullptr;
}
MovieClipUser user = *DNA_struct_default_get(MovieClipUser);
BKE_movieclip_user_set_frame(&user, clip_frame);
ImBuf *ibuf = BKE_movieclip_get_ibuf(movie_clip_, &user);
if (!ibuf) {
return nullptr;
}
Array<MarkerPoint> *marker_points = new Array<MarkerPoint>(sites_total);
int track_index = 0;
LISTBASE_FOREACH_INDEX (MovieTrackingTrack *, track, &tracking_object->tracks, track_index) {
const MovieTrackingMarker *marker = BKE_tracking_marker_get(track, clip_frame);
if (marker->flag & MARKER_DISABLED) {
continue;
}
const float2 position = float2(marker->pos) + float2(track->offset);
if (!IN_RANGE_INCL(position.x, 0.0f, 1.0f) || !IN_RANGE_INCL(position.y, 0.0f, 1.0f)) {
continue;
}
ImBuf *pattern_ibuf = BKE_tracking_get_pattern_imbuf(ibuf, track, marker, true, false);
MarkerPoint &marker_point = (*marker_points)[track_index];
marker_point.position = position;
marker_point.color = float4(0.0f);
if (pattern_ibuf) {
for (int j = 0; j < pattern_ibuf->x * pattern_ibuf->y; j++) {
if (pattern_ibuf->float_buffer.data) {
marker_point.color += float4(&pattern_ibuf->float_buffer.data[4 * j]);
}
else {
uchar *rrgb = pattern_ibuf->byte_buffer.data;
marker_point.color += float4(srgb_to_linearrgb(float(rrgb[4 * j + 0]) / 255.0f),
srgb_to_linearrgb(float(rrgb[4 * j + 1]) / 255.0f),
srgb_to_linearrgb(float(rrgb[4 * j + 2]) / 255.0f),
srgb_to_linearrgb(float(rrgb[4 * j + 3]) / 255.0f));
}
}
marker_point.color /= pattern_ibuf->x * pattern_ibuf->y;
IMB_freeImBuf(pattern_ibuf);
}
}
IMB_freeImBuf(ibuf);
return marker_points;
}
void *KeyingScreenOperation::initialize_tile_data(rcti * /* rect*/)
{
if (movie_clip_ == nullptr) {
return nullptr;
}
if (!cached_marker_points_) {
lock_mutex();
if (cached_marker_points_ == nullptr) {
cached_marker_points_ = compute_marker_points();
}
unlock_mutex();
}
return nullptr;
}
void KeyingScreenOperation::determine_canvas(const rcti &preferred_area, rcti &r_area)
{
r_area = COM_AREA_NONE;
if (movie_clip_) {
MovieClipUser user = *DNA_struct_default_get(MovieClipUser);
int width, height;
int clip_frame = BKE_movieclip_remap_scene_to_clip_frame(movie_clip_, framenumber_);
BKE_movieclip_user_set_frame(&user, clip_frame);
BKE_movieclip_get_size(movie_clip_, &user, &width, &height);
r_area = preferred_area;
r_area.xmax = r_area.xmin + width;
r_area.ymax = r_area.ymin + height;
}
}
void KeyingScreenOperation::execute_pixel(float output[4], int x, int y, void * /* data */)
{
if (!cached_marker_points_) {
copy_v4_fl(output, 0.0f);
return;
}
const int2 size = int2(this->get_width(), this->get_height());
const float2 normalized_pixel_location = float2(x, y) / float2(size);
const float squared_shape_parameter = math::square(1.0f / smoothness_);
float4 weighted_sum = float4(0.0f);
float sum_of_weights = 0.0f;
for (const MarkerPoint &marker_point : *cached_marker_points_) {
const float2 difference = normalized_pixel_location - marker_point.position;
const float squared_distance = math::dot(difference, difference);
const float gaussian = math::exp(-squared_distance * squared_shape_parameter);
weighted_sum += marker_point.color * gaussian;
sum_of_weights += gaussian;
}
weighted_sum /= sum_of_weights;
copy_v4_v4(output, weighted_sum);
}
void KeyingScreenOperation::update_memory_buffer_partial(MemoryBuffer *output,
const rcti &area,
Span<MemoryBuffer *> inputs)
{
if (!cached_marker_points_) {
output->fill(area, COM_COLOR_TRANSPARENT);
return;
}
const int2 size = int2(this->get_width(), this->get_height());
const float squared_shape_parameter = math::square(1.0f / smoothness_);
for (BuffersIterator<float> it = output->iterate_with(inputs, area); !it.is_end(); ++it) {
const float2 normalized_pixel_location = float2(it.x, it.y) / float2(size);
float4 weighted_sum = float4(0.0f);
float sum_of_weights = 0.0f;
for (const MarkerPoint &marker_point : *cached_marker_points_) {
const float2 difference = normalized_pixel_location - marker_point.position;
const float squared_distance = math::dot(difference, difference);
const float gaussian = math::exp(-squared_distance * squared_shape_parameter);
weighted_sum += marker_point.color * gaussian;
sum_of_weights += gaussian;
}
weighted_sum /= sum_of_weights;
copy_v4_v4(it.out, weighted_sum);
}
}
} // namespace blender::compositor