32 lines
918 B
C
32 lines
918 B
C
// SPDX-License-Identifier: MPL-2.0
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// Copyright (c) Yuxuan Shui <yshuiv7@gmail.com>
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#pragma once
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#include <stdlib.h>
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#include "compiler.h"
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/// Code for generating convolution kernels
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typedef struct conv {
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int size;
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double *rsum;
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double data[];
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} conv;
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/// Calculate the sum of a rectangle part of the convolution kernel
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/// the rectangle is defined by top left (x, y), and a size (width x height)
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double attr_const sum_kernel(const conv *map, int x, int y, int width, int height);
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double attr_const sum_kernel_normalized(const conv *map, int x, int y, int width, int height);
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/// Create a kernel with gaussian distribution of radius r
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conv *gaussian_kernel(double r);
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/// preprocess kernels to make shadow generation faster
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/// shadow_sum[x*d+y] is the sum of the kernel from (0, 0) to (x, y), inclusive
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void shadow_preprocess(conv *map);
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static inline void free_conv(conv *k) {
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free(k->rsum);
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free(k);
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}
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