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/*
* ***** BEGIN GPL LICENSE BLOCK *****
*
* 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.
*
* The Original Code is Copyright (C) 2012 by Blender Foundation.
* All rights reserved.
*
* The Original Code is: all of this file.
*
* Contributor(s): Sergey Sharybin
*
* ***** END GPL LICENSE BLOCK *****
*
*/
#include <math.h>
#include "BLI_math.h"
/**************************************************************************
* INTERPOLATIONS
*
* Reference and docs:
* http://wiki.blender.org/index.php/User:Damiles#Interpolations_Algorithms
***************************************************************************/
/* BICUBIC Interpolation functions
* More info: http://wiki.blender.org/index.php/User:Damiles#Bicubic_pixel_interpolation
* function assumes out to be zero'ed, only does RGBA */
static float P(float k)
{
float p1, p2, p3, p4;
p1 = MAX2(k + 2.0f, 0);
p2 = MAX2(k + 1.0f, 0);
p3 = MAX2(k, 0);
p4 = MAX2(k - 1.0f, 0);
return (float)(1.0f / 6.0f) * (p1 * p1 * p1 - 4.0f * p2 * p2 * p2 + 6.0f * p3 * p3 * p3 - 4.0f * p4 * p4 * p4);
}
#if 0
/* older, slower function, works the same as above */
static float P(float k)
{
return (float)(1.0f / 6.0f) * (pow(MAX2(k + 2.0f, 0), 3.0f) - 4.0f * pow(MAX2(k + 1.0f, 0), 3.0f) + 6.0f * pow(MAX2(k, 0), 3.0f) - 4.0f * pow(MAX2(k - 1.0f, 0), 3.0f));
}
#endif
/* BICUBIC INTERPOLATION */
void BLI_bicubic_interpolation(const float *buffer, float *output, int width, int height, int components, float u, float v)
{
int i, j, n, m, x1, y1;
float a, b, w, wx, wy[4], out[4];
const float *data;
/* sample area entirely outside image? */
if (ceil(u) < 0 || floor(u) > width - 1 || ceil(v) < 0 || floor(v) > height - 1) {
return;
}
i = (int)floor(u);
j = (int)floor(v);
a = u - i;
b = v - j;
zero_v4(out);
/* Optimized and not so easy to read */
/* avoid calling multiple times */
wy[0] = P(b - (-1));
wy[1] = P(b - 0);
wy[2] = P(b - 1);
wy[3] = P(b - 2);
for (n = -1; n <= 2; n++) {
x1 = i + n;
CLAMP(x1, 0, width - 1);
wx = P(n - a);
for (m = -1; m <= 2; m++) {
y1 = j + m;
CLAMP(y1, 0, height - 1);
/* normally we could do this */
/* w = P(n-a) * P(b-m); */
/* except that would call P() 16 times per pixel therefor pow() 64 times, better precalc these */
w = wx * wy[m + 1];
data = buffer + width * y1 * 4 + 4 * x1;
if (components == 1) {
out[0] += data[0] * w;
}
else if (components == 2) {
out[0] += data[0] * w;
out[1] += data[1] * w;
}
else if (components == 3) {
out[0] += data[0] * w;
out[1] += data[1] * w;
out[2] += data[2] * w;
}
else {
out[0] += data[0] * w;
out[1] += data[1] * w;
out[2] += data[2] * w;
out[3] += data[3] * w;
}
}
}
/* Done with optimized part */
#if 0
/* older, slower function, works the same as above */
for (n = -1; n <= 2; n++) {
for (m = -1; m <= 2; m++) {
x1 = i + n;
y1 = j + m;
if (x1 > 0 && x1 < width && y1 > 0 && y1 < height) {
data = in->rect_float + width * y1 * 4 + 4 * x1;
if (components == 1) {
out[0] += data[0] * P(n - a) * P(b - m);
}
else if (components == 2) {
out[0] += data[0] * P(n - a) * P(b - m);
out[1] += data[1] * P(n - a) * P(b - m);
}
else if (components == 3) {
out[0] += data[0] * P(n - a) * P(b - m);
out[1] += data[1] * P(n - a) * P(b - m);
out[2] += data[2] * P(n - a) * P(b - m);
}
else {
out[0] += data[0] * P(n - a) * P(b - m);
out[1] += data[1] * P(n - a) * P(b - m);
out[2] += data[2] * P(n - a) * P(b - m);
out[3] += data[3] * P(n - a) * P(b - m);
}
}
}
}
#endif
if (components == 1) {
output[0] = out[0];
}
else if (components == 2) {
output[0] = out[0];
output[1] = out[1];
}
else if (components == 3) {
output[0] = out[0];
output[1] = out[1];
output[2] = out[2];
}
else {
output[0] = out[0];
output[1] = out[1];
output[2] = out[2];
output[3] = out[3];
}
}
/* BILINEAR INTERPOLATION */
void BLI_bilinear_interpolation(const float *buffer, float *output, int width, int height, int components, float u, float v)
{
const float *row1, *row2, *row3, *row4;
float a, b;
float a_b, ma_b, a_mb, ma_mb;
float empty[4] = {0.0f, 0.0f, 0.0f, 0.0f};
int y1, y2, x1, x2;
/* ImBuf in must have a valid rect or rect_float, assume this is already checked */
x1 = (int)floor(u);
x2 = (int)ceil(u);
y1 = (int)floor(v);
y2 = (int)ceil(v);
/* sample area entirely outside image? */
if (x2 < 0 || x1 > width - 1 || y2 < 0 || y1 > height - 1) {
return;
}
/* sample including outside of edges of image */
if (x1 < 0 || y1 < 0) row1 = empty;
else row1 = buffer + width * y1 * 4 + 4 * x1;
if (x1 < 0 || y2 > height - 1) row2 = empty;
else row2 = buffer + width * y2 * 4 + 4 * x1;
if (x2 > width - 1 || y1 < 0) row3 = empty;
else row3 = buffer + width * y1 * 4 + 4 * x2;
if (x2 > width - 1 || y2 > height - 1) row4 = empty;
else row4 = buffer + width * y2 * 4 + 4 * x2;
a = u - floorf(u);
b = v - floorf(v);
a_b = a * b; ma_b = (1.0f - a) * b; a_mb = a * (1.0f - b); ma_mb = (1.0f - a) * (1.0f - b);
if (components == 1) {
output[0] = ma_mb * row1[0] + a_mb * row3[0] + ma_b * row2[0] + a_b * row4[0];
}
else if (components == 2) {
output[0] = ma_mb * row1[0] + a_mb * row3[0] + ma_b * row2[0] + a_b * row4[0];
output[1] = ma_mb * row1[1] + a_mb * row3[1] + ma_b * row2[1] + a_b * row4[1];
}
else if (components == 3) {
output[0] = ma_mb * row1[0] + a_mb * row3[0] + ma_b * row2[0] + a_b * row4[0];
output[1] = ma_mb * row1[1] + a_mb * row3[1] + ma_b * row2[1] + a_b * row4[1];
output[2] = ma_mb * row1[2] + a_mb * row3[2] + ma_b * row2[2] + a_b * row4[2];
}
else {
output[0] = ma_mb * row1[0] + a_mb * row3[0] + ma_b * row2[0] + a_b * row4[0];
output[1] = ma_mb * row1[1] + a_mb * row3[1] + ma_b * row2[1] + a_b * row4[1];
output[2] = ma_mb * row1[2] + a_mb * row3[2] + ma_b * row2[2] + a_b * row4[2];
output[3] = ma_mb * row1[3] + a_mb * row3[3] + ma_b * row2[3] + a_b * row4[3];
}
}
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