83 lines
3.6 KiB
C
83 lines
3.6 KiB
C
/*
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* This file is part of libplacebo.
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*
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* libplacebo is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* libplacebo is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with libplacebo. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef LIBPLACEBO_DITHER_H_
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#define LIBPLACEBO_DITHER_H_
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#include <libplacebo/common.h>
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PL_API_BEGIN
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// Generates a deterministic NxN bayer (ordered) dither matrix, storing the
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// result in `data`. `size` must be a power of two. The resulting matrix will
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// be roughly uniformly distributed within the range [0,1).
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PL_API void pl_generate_bayer_matrix(float *data, int size);
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// Generates a random NxN blue noise texture. storing the result in `data`.
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// `size` must be a positive power of two no larger than 256. The resulting
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// texture will be roughly uniformly distributed within the range [0,1).
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//
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// Note: This function is very, *very* slow for large sizes. Generating a
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// dither matrix with size 256 can take several seconds on a modern processor.
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PL_API void pl_generate_blue_noise(float *data, int size);
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// Defines the border of all error diffusion kernels
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#define PL_EDF_MIN_DX (-2)
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#define PL_EDF_MAX_DX (2)
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#define PL_EDF_MAX_DY (2)
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struct pl_error_diffusion_kernel {
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const char *name; // Short and concise identifier
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const char *description; // Longer / friendly name
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// The minimum value such that a (y, x) -> (y, x + y * shift) mapping will
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// make all error pushing operations affect next column (and after it)
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// only.
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//
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// Higher shift values are significantly more computationally intensive.
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int shift;
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// The diffusion factor for (y, x) is pattern[y][x - PL_EDF_MIN_DX] / divisor.
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int pattern[PL_EDF_MAX_DY + 1][PL_EDF_MAX_DX - PL_EDF_MIN_DX + 1];
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int divisor;
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};
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// Algorithms with shift=1:
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PL_API extern const struct pl_error_diffusion_kernel pl_error_diffusion_simple;
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PL_API extern const struct pl_error_diffusion_kernel pl_error_diffusion_false_fs;
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// Algorithms with shift=2:
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PL_API extern const struct pl_error_diffusion_kernel pl_error_diffusion_sierra_lite;
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PL_API extern const struct pl_error_diffusion_kernel pl_error_diffusion_floyd_steinberg;
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PL_API extern const struct pl_error_diffusion_kernel pl_error_diffusion_atkinson;
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// Algorithms with shift=3, probably too heavy for low end GPUs:
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PL_API extern const struct pl_error_diffusion_kernel pl_error_diffusion_jarvis_judice_ninke;
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PL_API extern const struct pl_error_diffusion_kernel pl_error_diffusion_stucki;
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PL_API extern const struct pl_error_diffusion_kernel pl_error_diffusion_burkes;
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PL_API extern const struct pl_error_diffusion_kernel pl_error_diffusion_sierra2;
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PL_API extern const struct pl_error_diffusion_kernel pl_error_diffusion_sierra3;
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// A list of built-in error diffusion kernels, terminated by NULL
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PL_API extern const struct pl_error_diffusion_kernel * const pl_error_diffusion_kernels[];
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PL_API extern const int pl_num_error_diffusion_kernels; // excluding trailing NULL
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// Find the error diffusion kernel with the given name, or NULL on failure.
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PL_API const struct pl_error_diffusion_kernel *pl_find_error_diffusion_kernel(const char *name);
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PL_API_END
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#endif // LIBPLACEBO_DITHER_H_
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