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/*
* Pure Data Packet system file. - image resampling routines
* Copyright (c) by Tom Schouten <pdp@zzz.kotnet.org>
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include "pdp_resample.h"
#include "pdp.h"
/*
efficient bilinear resampling ??
performance: how to eliminate divides? -> virtual coordinates 2^k x 2^k (conf. opengl)
i.e. 16 bit virtual coordinates: easy modular addressing
*/
s32 pdp_resample_bilin(s16 *image, s32 width, s32 height, s32 virt_x, s32 virt_y)
{
s32 fp_x, fp_y, frac_x, frac_y, f, offset, r_1, r_2;
virt_x &= 0xffff;
virt_y &= 0xffff;
fp_x = virt_x * (width - 1);
fp_y = virt_y * (height - 1);
frac_x = fp_x & (0xffff);
frac_y = fp_y & (0xffff);
offset = (fp_x >> 16) + (fp_y >> 16) * width;
image += offset;
f = 0x10000 - frac_x;
r_1 = ((f * (s32)(image[0]) + frac_x * (s32)(image[1])))>>16;
image += width;
r_2 = ((f * (s32)(image[0]) + frac_x * (s32)(image[1])))>>16;
f = 0x10000 - frac_y;
return ((f * r_1 + frac_y * r_2)>>16);
}
void pdp_resample_scale_bilin(s16 *src_image, s16 *dst_image, s32 src_w, s32 src_h, s32 dst_w, s32 dst_h)
{
s32 i,j;
s32 virt_x=0;
s32 virt_y=0; /* virtual coordinates in 30 bit */
s32 scale_x = 0x40000000 / dst_w;
s32 scale_y = 0x40000000 / dst_h;
for (j=0; j<dst_h; j++){
for (i=0; i<dst_w; i++){
*dst_image++ = pdp_resample_bilin(src_image, src_w, src_h, virt_x>>14, virt_y>>14);
virt_x += scale_x;
}
virt_x = 0;
virt_y += scale_y;
}
}
void pdp_resample_scale_nn(s16 *src_image, s16 *dst_image, s32 src_w, s32 src_h, s32 dst_w, s32 dst_h)
{
s32 i,j;
s32 x=0;
s32 y=0;
s32 frac_x=0;
s32 frac_y=0;
s32 scale_x = (src_w << 20 ) / dst_w;
s32 scale_y = (src_h << 20 ) / dst_h;
for (j=0; j<dst_h; j++){
for (i=0; i<dst_w; i++){
*dst_image++ = src_image[x+y];
frac_x += scale_x;
x = frac_x >> 20;
}
x = 0;
frac_x = 0;
frac_y += scale_y;
y = (frac_y >> 20) * src_w;
}
}
void pdp_resample_zoom_tiled_bilin(s16 *src_image, s16 *dst_image, s32 w, s32 h,
float zoom_x, float zoom_y, float center_x_relative, float center_y_relative)
{
float izx = 1.0f / zoom_x;
float izy = 1.0f / zoom_y;
s32 scale_x = (s32)((float)0x100000 * izx / (float)w);
s32 scale_y = (s32)((float)0x100000 * izy / (float)h);
s32 top_virt_x = (s32)((1.0f - izx) * (float)0x100000 * center_x_relative);
s32 top_virt_y = (s32)((1.0f - izy) * (float)0x100000 * center_y_relative);
s32 virt_x = top_virt_x;
s32 virt_y = top_virt_y;
s32 i,j;
for (j=0; j<h; j++){
for (i=0; i<w; i++){
*dst_image++ = pdp_resample_bilin(src_image, w, h, virt_x>>4, virt_y>>4);
virt_x += scale_x;
}
virt_x = top_virt_x;
virt_y += scale_y;
}
}
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