7a395e2e7f
The last good commit wasf57e4c5b98. After this one more fix was committed, this one is preserved as well:67bd678887.
73 lines
2.6 KiB
C++
73 lines
2.6 KiB
C++
/* SPDX-FileCopyrightText: 2011 Blender Authors
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*
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* SPDX-License-Identifier: GPL-2.0-or-later */
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#include "COM_ChromaMatteOperation.h"
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namespace blender::compositor {
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ChromaMatteOperation::ChromaMatteOperation()
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{
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add_input_socket(DataType::Color);
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add_input_socket(DataType::Color);
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add_output_socket(DataType::Value);
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flags_.can_be_constant = true;
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}
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void ChromaMatteOperation::update_memory_buffer_partial(MemoryBuffer *output,
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const rcti &area,
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Span<MemoryBuffer *> inputs)
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{
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const float acceptance = settings_->t1; /* In radians. */
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const float cutoff = settings_->t2; /* In radians. */
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const float gain = settings_->fstrength;
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for (BuffersIterator<float> it = output->iterate_with(inputs, area); !it.is_end(); ++it) {
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const float *in_image = it.in(0);
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const float *in_key = it.in(1);
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/* Store matte(alpha) value in [0] to go with
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* #COM_SetAlphaMultiplyOperation and the Value output. */
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/* Algorithm from book "Video Demystified", does not include the spill reduction part. */
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/* Find theta, the angle that the color space should be rotated based on key. */
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/* Rescale to `-1.0..1.0`. */
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// const float image_Y = (in_image[0] * 2.0f) - 1.0f; // UNUSED
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const float image_cb = (in_image[1] * 2.0f) - 1.0f;
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const float image_cr = (in_image[2] * 2.0f) - 1.0f;
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// const float key_Y = (in_key[0] * 2.0f) - 1.0f; // UNUSED
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const float key_cb = (in_key[1] * 2.0f) - 1.0f;
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const float key_cr = (in_key[2] * 2.0f) - 1.0f;
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const float theta = atan2(key_cr, key_cb);
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/* Rotate the cb and cr into x/z space. */
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const float x_angle = image_cb * cosf(theta) + image_cr * sinf(theta);
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const float z_angle = image_cr * cosf(theta) - image_cb * sinf(theta);
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/* If within the acceptance angle. */
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/* If kfg is <0 then the pixel is outside of the key color. */
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const float kfg = x_angle - (fabsf(z_angle) / tanf(acceptance / 2.0f));
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if (kfg > 0.0f) { /* Found a pixel that is within key color. */
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const float beta = atan2(z_angle, x_angle);
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float alpha = 1.0f - (kfg / gain);
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/* Ff beta is within the cutoff angle. */
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if (fabsf(beta) < (cutoff / 2.0f)) {
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alpha = 0.0f;
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}
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/* Don't make something that was more transparent less transparent. */
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it.out[0] = alpha < in_image[3] ? alpha : in_image[3];
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}
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else { /* Pixel is outside key color. */
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it.out[0] = in_image[3]; /* Make pixel just as transparent as it was before. */
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}
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}
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}
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} // namespace blender::compositor
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