New Corner Pin node: uses explicit corner values for a plane warp transformation.

This was suggested by Christopher Barrett (terrachild). Corner pin is a common feature in compositing.

The corners for the plane warping can be defined by using vector node inputs to allow using perspective plane transformations without having to go via the MovieClip editor tracking data.
Uses the same math as the PlaneTrack node, but without the link to MovieClip and Object.

{F78199}

The code for PlaneTrack operations has been restructured a bit to share it with the CornerPin node.

* PlaneDistortCommonOperation.h/.cpp: Shared generic code for warping images based on 4 plane corners and a perspective matrix generated from these. Contains operation base classes for both the WarpImage and Mask operations.

* PlaneTrackOperation.h/.cpp: Current plane track node operations, based on the common code above. These add pointers to MovieClip and Object which define the track data from wich to read the corners.

* PlaneCornerPinOperation.h/.cpp: New corner pin variant, using explicit input sockets for the plane corners.

One downside of the current compositor design is that there is no concept of invariables (constants) that don't vary over the image space. This has already been an issue for Blur nodes (size input is usually constant except when "variable size" is enabled) and a few others. For the corner pin node it is necessary that the corner input sockets are also invariant. They have to be evaluated for each tile now, otherwise the data is not available. This in turn makes it necessary to make the operation "complex" and request full input buffers, which adds unnecessary overhead.

1 files changed, 194 insertions, 0 deletions

diff --git a/source/blender/compositor/operations/COM_PlaneDistortCommonOperation.cpp b/source/blender/compositor/operations/COM_PlaneDistortCommonOperation.cpp
new file mode 100644
index 00000000000..362d7f6d2d7
--- /dev/null
+++ b/source/blender/compositor/operations/COM_PlaneDistortCommonOperation.cpp
@@ -0,0 +1,194 @@
+/*
+ * Copyright 2013, Blender Foundation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Contributor:
+ *		Sergey Sharybin
+ *		Lukas Toenne
+ */
+
+#include "COM_PlaneDistortCommonOperation.h"
+
+#include "MEM_guardedalloc.h"
+
+extern "C" {
+#include "BLI_listbase.h"
+#include "BLI_math.h"
+#include "BLI_math_color.h"
+#include "BLI_jitter.h"
+
+#include "BKE_movieclip.h"
+#include "BKE_node.h"
+#include "BKE_tracking.h"
+}
+
+/* ******** PlaneDistort WarpImage ******** */
+
+BLI_INLINE void warpCoord(float x, float y, float matrix[3][3], float uv[2], float deriv[2][2])
+{
+	float vec[3] = {x, y, 1.0f};
+	mul_m3_v3(matrix, vec);
+	uv[0] = vec[0] / vec[2];
+	uv[1] = vec[1] / vec[2];
+
+	deriv[0][0] = (matrix[0][0] - matrix[0][2] * uv[0]) / vec[2];
+	deriv[1][0] = (matrix[0][1] - matrix[0][2] * uv[1]) / vec[2];
+	deriv[0][1] = (matrix[1][0] - matrix[1][2] * uv[0]) / vec[2];
+	deriv[1][1] = (matrix[1][1] - matrix[1][2] * uv[1]) / vec[2];
+}
+
+PlaneDistortWarpImageOperation::PlaneDistortWarpImageOperation() :
+    NodeOperation()
+{
+	this->addInputSocket(COM_DT_COLOR, COM_SC_NO_RESIZE);
+	this->addOutputSocket(COM_DT_COLOR);
+	this->m_pixelReader = NULL;
+	this->setComplex(true);
+}
+
+void PlaneDistortWarpImageOperation::calculateCorners(const float corners[4][2], bool normalized)
+{
+	if (normalized) {
+		for (int i = 0; i < 4; i++) {
+			this->m_frameSpaceCorners[i][0] = corners[i][0] * this->getWidth();
+			this->m_frameSpaceCorners[i][1] = corners[i][1] * this->getHeight();
+		}
+	}
+	else {
+		for (int i = 0; i < 4; i++) {
+			this->m_frameSpaceCorners[i][0] = corners[i][0];
+			this->m_frameSpaceCorners[i][1] = corners[i][1];
+		}
+	}
+}
+
+void PlaneDistortWarpImageOperation::calculatePerspectiveMatrix()
+{
+	const int width = this->m_pixelReader->getWidth();
+	const int height = this->m_pixelReader->getHeight();
+	float frame_corners[4][2] = {{0.0f, 0.0f},
+	                             {(float) width, 0.0f},
+	                             {(float) width, (float) height},
+	                             {0.0f, (float) height}};
+	BKE_tracking_homography_between_two_quads(this->m_frameSpaceCorners,
+	                                          frame_corners,
+	                                          this->m_perspectiveMatrix);
+}
+
+void PlaneDistortWarpImageOperation::initExecution()
+{
+	this->m_pixelReader = this->getInputSocketReader(0);
+}
+
+void PlaneDistortWarpImageOperation::deinitExecution()
+{
+	this->m_pixelReader = NULL;
+}
+
+void PlaneDistortWarpImageOperation::executePixelSampled(float output[4], float x, float y, PixelSampler sampler)
+{
+	float xy[2] = {x, y};
+	float uv[2];
+	float deriv[2][2];
+
+	pixelTransform(xy, uv, deriv);
+
+	m_pixelReader->readFiltered(output, uv[0], uv[1], deriv[0], deriv[1], COM_PS_BILINEAR);
+}
+
+void PlaneDistortWarpImageOperation::pixelTransform(const float xy[2], float r_uv[2], float r_deriv[2][2])
+{
+	warpCoord(xy[0], xy[1], m_perspectiveMatrix, r_uv, r_deriv);
+}
+
+bool PlaneDistortWarpImageOperation::determineDependingAreaOfInterest(rcti *input, ReadBufferOperation *readOperation, rcti *output)
+{
+	float UVs[4][2];
+	float deriv[2][2];
+
+	/* TODO(sergey): figure out proper way to do this. */
+	warpCoord(input->xmin - 2, input->ymin - 2, this->m_perspectiveMatrix, UVs[0], deriv);
+	warpCoord(input->xmax + 2, input->ymin - 2, this->m_perspectiveMatrix, UVs[1], deriv);
+	warpCoord(input->xmax + 2, input->ymax + 2, this->m_perspectiveMatrix, UVs[2], deriv);
+	warpCoord(input->xmin - 2, input->ymax + 2, this->m_perspectiveMatrix, UVs[3], deriv);
+
+	float min[2], max[2];
+	INIT_MINMAX2(min, max);
+	for (int i = 0; i < 4; i++) {
+		minmax_v2v2_v2(min, max, UVs[i]);
+	}
+
+	rcti newInput;
+
+	newInput.xmin = min[0] - 1;
+	newInput.ymin = min[1] - 1;
+	newInput.xmax = max[0] + 1;
+	newInput.ymax = max[1] + 1;
+
+	return NodeOperation::determineDependingAreaOfInterest(&newInput, readOperation, output);
+}
+
+
+/* ******** PlaneDistort Mask ******** */
+
+PlaneDistortMaskOperation::PlaneDistortMaskOperation() :
+    NodeOperation()
+{
+	addOutputSocket(COM_DT_VALUE);
+
+	/* Currently hardcoded to 8 samples. */
+	m_osa = 8;
+}
+
+void PlaneDistortMaskOperation::calculateCorners(const float corners[4][2], bool normalized)
+{
+	if (normalized) {
+		for (int i = 0; i < 4; i++) {
+			this->m_frameSpaceCorners[i][0] = corners[i][0] * this->getWidth();
+			this->m_frameSpaceCorners[i][1] = corners[i][1] * this->getHeight();
+		}
+	}
+	else {
+		for (int i = 0; i < 4; i++) {
+			this->m_frameSpaceCorners[i][0] = corners[i][0];
+			this->m_frameSpaceCorners[i][1] = corners[i][1];
+		}
+	}
+}
+
+void PlaneDistortMaskOperation::initExecution()
+{
+	BLI_jitter_init(m_jitter[0], m_osa);
+}
+
+void PlaneDistortMaskOperation::executePixelSampled(float output[4], float x, float y, PixelSampler sampler)
+{
+	float point[2];
+
+	int inside_counter = 0;
+	for (int sample = 0; sample < this->m_osa; sample++) {
+		point[0] = x + this->m_jitter[sample][0];
+		point[1] = y + this->m_jitter[sample][1];
+
+		if (isect_point_tri_v2(point, this->m_frameSpaceCorners[0], this->m_frameSpaceCorners[1], this->m_frameSpaceCorners[2]) ||
+		    isect_point_tri_v2(point, this->m_frameSpaceCorners[0], this->m_frameSpaceCorners[2], this->m_frameSpaceCorners[3]))
+		{
+			inside_counter++;
+		}
+	}
+
+	output[0] = (float) inside_counter / this->m_osa;
+}