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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
*/
/*
* This file is based on, or a modified version of code from TinyGL (C) 1997-2022 Fabrice Bellard,
* which is licensed under the MIT license (see LICENSE).
* It also has modifications by the ResidualVM-team, which are covered under the GPLv2 (or later).
*/
#include "graphics/tinygl/zgl.h"
namespace TinyGL {
// linear interpolation with xf, yf normalized to 2^16
#define INTERP_NORM_BITS 16
#define INTERP_NORM (1 << INTERP_NORM_BITS)
static inline int interpolate(int v00, int v01, int v10, int xf, int yf) {
return v00 + (((v01 - v00) * xf + (v10 - v00) * yf) >> INTERP_NORM_BITS);
}
// TODO: more accurate resampling
void GLContext::gl_resizeImage(Graphics::PixelBuffer &dest, int xsize_dest, int ysize_dest,
const Graphics::PixelBuffer &src, int xsize_src, int ysize_src) {
int point1_offset, point2_offset, point3_offset, dest_offset = 0;
int point_y_offset, point_offset;
float x1, y1, x1inc, y1inc;
int xi, yi, xf, yf, curr_yf;
bool space_below, space_right;
uint8 r00, g00, b00, a00;
uint8 r01, g01, b01, a01;
uint8 r10, g10, b10, a10;
x1inc = (float)(xsize_src - 1) / (float)(xsize_dest - 1);
y1inc = (float)(ysize_src - 1) / (float)(ysize_dest - 1);
y1 = 0;
for (int y = 0; y < ysize_dest; y++) {
x1 = 0;
yi = (int)floorf(y1);
yf = (int)((y1 - yi) * INTERP_NORM);
point_y_offset = yi * xsize_src;
space_below = (yi + 1) < ysize_src;
for (int x = 0; x < xsize_dest; x++) {
xi = (int)floorf(x1);
xf = (int)((x1 - xi) * INTERP_NORM);
point1_offset = point_offset = point_y_offset + xi;
space_right = (xi + 1) < xsize_src;
if ((xf + yf) <= INTERP_NORM) {
curr_yf = yf;
if (space_right)
point2_offset = point_offset + 1;
else
point2_offset = point_offset;
if (space_below)
point3_offset = point_offset + xsize_src;
else
point3_offset = point_offset;
} else {
xf = INTERP_NORM - xf;
curr_yf = INTERP_NORM - yf;
if (space_right) {
point1_offset += 1;
point3_offset = point_offset + 1;
} else
point3_offset = point_offset;
if (space_below) {
point1_offset += xsize_src;
point2_offset = point_offset + xsize_src;
} else
point2_offset = point_offset;
}
src.getARGBAt(point1_offset, a00, r00, g00, b00);
src.getARGBAt(point2_offset, a01, r01, g01, b01);
src.getARGBAt(point3_offset, a10, r10, g10, b10);
dest.setPixelAt(
dest_offset++,
interpolate(a00, a01, a10, xf, curr_yf),
interpolate(r00, r01, r10, xf, curr_yf),
interpolate(g00, g01, g10, xf, curr_yf),
interpolate(b00, b01, b10, xf, curr_yf)
);
x1 += x1inc;
}
y1 += y1inc;
}
}
#define FRAC_BITS 16
// resizing with no interlating nor nearest pixel
void GLContext::gl_resizeImageNoInterpolate(Graphics::PixelBuffer &dest, int xsize_dest, int ysize_dest,
const Graphics::PixelBuffer &src, int xsize_src, int ysize_src) {
int dest_offset = 0;
int x1, y1, x1inc, y1inc;
int yi;
uint8 r, g, b, a;
x1inc = (int)((float)((xsize_src) << FRAC_BITS) / (float)(xsize_dest));
y1inc = (int)((float)((ysize_src) << FRAC_BITS) / (float)(ysize_dest));
y1 = 0;
for (int y = 0; y < ysize_dest; y++) {
yi = (y1 >> FRAC_BITS) * xsize_src;
x1 = 0;
for (int x = 0; x < xsize_dest; x++) {
src.getARGBAt(yi + (x1 >> FRAC_BITS), a, r, g, b);
dest.setPixelAt(dest_offset++, a, r, g, b);
x1 += x1inc;
}
y1 += y1inc;
}
}
} // end of namespace TinyGL
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