mirror of
https://github.com/scummvm/scummvm.git
synced 2026-05-21 05:40:43 +00:00
Vladimir Menshakov
123 lines
3.5 KiB
C++
123 lines
3.5 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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#include "video/4xm_utils.h"
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#include "common/bitstream.h"
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#include "common/debug.h"
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#include "common/memstream.h"
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namespace Video {
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namespace FourXM {
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#define FIX_1_082392200 70936
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#define FIX_1_414213562 92682
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#define FIX_1_847759065 121095
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#define FIX_2_613125930 171254
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#define MULTIPLY(var, const) ((int)((var) * (unsigned)(const)) >> 16)
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void idct(int16_t block[64], int shift) {
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int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
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int tmp10, tmp11, tmp12, tmp13;
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int z5, z10, z11, z12, z13;
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int i;
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int temp[64];
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for (i = 0; i < 8; i++) {
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tmp10 = block[8 * 0 + i] + block[8 * 4 + i];
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tmp11 = block[8 * 0 + i] - block[8 * 4 + i];
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tmp13 = block[8 * 2 + i] + block[8 * 6 + i];
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tmp12 = MULTIPLY(block[8 * 2 + i] - block[8 * 6 + i], FIX_1_414213562) - tmp13;
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tmp0 = tmp10 + tmp13;
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tmp3 = tmp10 - tmp13;
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tmp1 = tmp11 + tmp12;
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tmp2 = tmp11 - tmp12;
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z13 = block[8 * 5 + i] + block[8 * 3 + i];
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z10 = block[8 * 5 + i] - block[8 * 3 + i];
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z11 = block[8 * 1 + i] + block[8 * 7 + i];
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z12 = block[8 * 1 + i] - block[8 * 7 + i];
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tmp7 = z11 + z13;
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tmp11 = MULTIPLY(z11 - z13, FIX_1_414213562);
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z5 = MULTIPLY(z10 + z12, FIX_1_847759065);
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tmp10 = MULTIPLY(z12, FIX_1_082392200) - z5;
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tmp12 = MULTIPLY(z10, -FIX_2_613125930) + z5;
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tmp6 = tmp12 - tmp7;
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tmp5 = tmp11 - tmp6;
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tmp4 = tmp10 + tmp5;
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temp[8 * 0 + i] = tmp0 + tmp7;
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temp[8 * 7 + i] = tmp0 - tmp7;
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temp[8 * 1 + i] = tmp1 + tmp6;
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temp[8 * 6 + i] = tmp1 - tmp6;
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temp[8 * 2 + i] = tmp2 + tmp5;
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temp[8 * 5 + i] = tmp2 - tmp5;
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temp[8 * 4 + i] = tmp3 + tmp4;
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temp[8 * 3 + i] = tmp3 - tmp4;
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}
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for (i = 0; i < 8 * 8; i += 8) {
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tmp10 = temp[0 + i] + temp[4 + i];
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tmp11 = temp[0 + i] - temp[4 + i];
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tmp13 = temp[2 + i] + temp[6 + i];
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tmp12 = MULTIPLY(temp[2 + i] - temp[6 + i], FIX_1_414213562) - tmp13;
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tmp0 = tmp10 + tmp13;
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tmp3 = tmp10 - tmp13;
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tmp1 = tmp11 + tmp12;
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tmp2 = tmp11 - tmp12;
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z13 = temp[5 + i] + temp[3 + i];
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z10 = temp[5 + i] - temp[3 + i];
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z11 = temp[1 + i] + temp[7 + i];
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z12 = temp[1 + i] - temp[7 + i];
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tmp7 = z11 + z13;
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tmp11 = MULTIPLY(z11 - z13, FIX_1_414213562);
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z5 = MULTIPLY(z10 + z12, FIX_1_847759065);
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tmp10 = MULTIPLY(z12, FIX_1_082392200) - z5;
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tmp12 = MULTIPLY(z10, -FIX_2_613125930) + z5;
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tmp6 = tmp12 - tmp7;
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tmp5 = tmp11 - tmp6;
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tmp4 = tmp10 + tmp5;
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block[0 + i] = (tmp0 + tmp7) >> shift;
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block[7 + i] = (tmp0 - tmp7) >> shift;
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block[1 + i] = (tmp1 + tmp6) >> shift;
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block[6 + i] = (tmp1 - tmp6) >> shift;
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block[2 + i] = (tmp2 + tmp5) >> shift;
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block[5 + i] = (tmp2 - tmp5) >> shift;
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block[4 + i] = (tmp3 + tmp4) >> shift;
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block[3 + i] = (tmp3 - tmp4) >> shift;
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}
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}
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} // namespace FourXM
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} // namespace Video
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