mirror of
https://github.com/libretro/scummvm.git
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136 lines
4.3 KiB
C++
136 lines
4.3 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/*
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* This file is based on, or a modified version of code from TinyGL (C) 1997-2022 Fabrice Bellard,
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* which is licensed under the MIT license (see LICENSE).
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* It also has modifications by the ResidualVM-team, which are covered under the GPLv2 (or later).
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*/
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#include "graphics/tinygl/zgl.h"
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namespace TinyGL {
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// linear interpolation with xf, yf normalized to 2^16
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#define INTERP_NORM_BITS 16
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#define INTERP_NORM (1 << INTERP_NORM_BITS)
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static inline int interpolate(int v00, int v01, int v10, int xf, int yf) {
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return v00 + (((v01 - v00) * xf + (v10 - v00) * yf) >> INTERP_NORM_BITS);
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}
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// TODO: more accurate resampling
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void GLContext::gl_resizeImage(Graphics::PixelBuffer &dest, int xsize_dest, int ysize_dest,
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const Graphics::PixelBuffer &src, int xsize_src, int ysize_src) {
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int point1_offset, point2_offset, point3_offset, dest_offset = 0;
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int point_y_offset, point_offset;
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float x1, y1, x1inc, y1inc;
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int xi, yi, xf, yf, curr_yf;
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bool space_below, space_right;
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uint8 r00, g00, b00, a00;
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uint8 r01, g01, b01, a01;
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uint8 r10, g10, b10, a10;
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x1inc = (float)(xsize_src - 1) / (float)(xsize_dest - 1);
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y1inc = (float)(ysize_src - 1) / (float)(ysize_dest - 1);
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y1 = 0;
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for (int y = 0; y < ysize_dest; y++) {
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x1 = 0;
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yi = (int)floorf(y1);
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yf = (int)((y1 - yi) * INTERP_NORM);
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point_y_offset = yi * xsize_src;
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space_below = (yi + 1) < ysize_src;
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for (int x = 0; x < xsize_dest; x++) {
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xi = (int)floorf(x1);
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xf = (int)((x1 - xi) * INTERP_NORM);
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point1_offset = point_offset = point_y_offset + xi;
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space_right = (xi + 1) < xsize_src;
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if ((xf + yf) <= INTERP_NORM) {
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curr_yf = yf;
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if (space_right)
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point2_offset = point_offset + 1;
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else
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point2_offset = point_offset;
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if (space_below)
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point3_offset = point_offset + xsize_src;
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else
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point3_offset = point_offset;
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} else {
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xf = INTERP_NORM - xf;
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curr_yf = INTERP_NORM - yf;
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if (space_right) {
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point1_offset += 1;
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point3_offset = point_offset + 1;
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} else
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point3_offset = point_offset;
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if (space_below) {
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point1_offset += xsize_src;
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point2_offset = point_offset + xsize_src;
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} else
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point2_offset = point_offset;
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}
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src.getARGBAt(point1_offset, a00, r00, g00, b00);
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src.getARGBAt(point2_offset, a01, r01, g01, b01);
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src.getARGBAt(point3_offset, a10, r10, g10, b10);
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dest.setPixelAt(
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dest_offset++,
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interpolate(a00, a01, a10, xf, curr_yf),
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interpolate(r00, r01, r10, xf, curr_yf),
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interpolate(g00, g01, g10, xf, curr_yf),
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interpolate(b00, b01, b10, xf, curr_yf)
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);
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x1 += x1inc;
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}
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y1 += y1inc;
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}
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}
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#define FRAC_BITS 16
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// resizing with no interlating nor nearest pixel
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void GLContext::gl_resizeImageNoInterpolate(Graphics::PixelBuffer &dest, int xsize_dest, int ysize_dest,
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const Graphics::PixelBuffer &src, int xsize_src, int ysize_src) {
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int dest_offset = 0;
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int x1, y1, x1inc, y1inc;
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int yi;
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uint8 r, g, b, a;
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x1inc = (int)((float)((xsize_src) << FRAC_BITS) / (float)(xsize_dest));
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y1inc = (int)((float)((ysize_src) << FRAC_BITS) / (float)(ysize_dest));
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y1 = 0;
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for (int y = 0; y < ysize_dest; y++) {
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yi = (y1 >> FRAC_BITS) * xsize_src;
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x1 = 0;
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for (int x = 0; x < xsize_dest; x++) {
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src.getARGBAt(yi + (x1 >> FRAC_BITS), a, r, g, b);
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dest.setPixelAt(dest_offset++, a, r, g, b);
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x1 += x1inc;
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}
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y1 += y1inc;
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}
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}
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} // end of namespace TinyGL
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