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Justine Tunney 2020-06-15 07:18:57 -07:00
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ 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; version 2 of the License. │
│ │
│ 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 │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/macros.h"
#include "libc/math.h"
#include "libc/mem/mem.h"
#include "libc/nexgen32e/nexgen32e.h"
#include "libc/runtime/runtime.h"
#include "tool/viz/lib/convolve.h"
#include "tool/viz/lib/graphic.h"
#define LCB {
#define RCB }
#define BROADCAST(X) LCB X, X, X, X RCB
#define FLIP(A, B, C) LCB C, B, A RCB
forceinline void ConvolveGradient(unsigned yn, unsigned xn,
float (*img)[yn][xn][4], unsigned KW,
const float (*ky)[KW][KW][4],
const float (*kx)[KW][KW][4]) {
size_t size;
unsigned y, x, i, j, k;
float py[4], px[4], (*tmp)[yn][xn][4];
tmp = mapanon((size = ROUNDUP(sizeof(float) * 4 * xn * yn, FRAMESIZE)));
for (y = 0; y < yn - KW + 1; ++y) {
for (x = 0; x < xn - KW + 1; ++x) {
for (k = 0; k < 4; ++k) py[k] = 0;
for (k = 0; k < 4; ++k) px[k] = 0;
for (i = 0; i < KW; ++i) {
for (j = 0; j < KW; ++j) {
for (k = 0; k < 4; ++k) {
py[k] += (*ky)[i][j][k] * (*img)[y + i][x + j][k];
px[k] += (*kx)[i][j][k] * (*img)[y + i][x + j][k];
}
}
}
for (k = 0; k < 4; ++k) {
(*tmp)[y + KW / 2][x + KW / 2][k] = sqrt(py[k] * py[k] + px[k] * px[k]);
}
}
}
memcpy(img, tmp, sizeof(float) * 4 * xn * yn);
munmap(tmp, size);
}
void sobel(struct Graphic* g) {
static const float kSobelEmbossKernelY[3][3][4] =
FLIP(FLIP(BROADCAST(+1), BROADCAST(+2), BROADCAST(+1)),
FLIP(BROADCAST(+0), BROADCAST(+0), BROADCAST(+0)),
FLIP(BROADCAST(-1), BROADCAST(-2), BROADCAST(-1)));
static const float kSobelEmbossKernelX[3][3][4] =
FLIP(FLIP(BROADCAST(-1), BROADCAST(+0), BROADCAST(+1)),
FLIP(BROADCAST(-2), BROADCAST(+0), BROADCAST(+2)),
FLIP(BROADCAST(-1), BROADCAST(+0), BROADCAST(+1)));
if (g->yn >= 3 && g->xn >= 3) {
ConvolveGradient(g->yn, g->xn, g->b.p, 3, &kSobelEmbossKernelY,
&kSobelEmbossKernelX);
}
}