scummvm/graphics/scaler/downscaler.cpp
2021-12-26 18:48:43 +01:00

73 lines
2.8 KiB
C++

/* 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/>.
*
*/
#include "graphics/scaler/downscaler.h"
#include "graphics/scaler/intern.h"
int gBitFormat = 565;
#ifdef USE_ARM_SCALER_ASM
extern "C" {
void DownscaleAllByHalfARM(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch, int width, int height, int mask, int round);
}
void DownscaleAllByHalf(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch, int width, int height) {
// Rounding constants and masks used for different pixel formats
static const int roundingconstants[] = { 0x00200802, 0x00201002 };
static const int redbluegreenMasks[] = { 0x03E07C1F, 0x07E0F81F };
const int maskUsed = (gBitFormat == 565);
DownscaleAllByHalfARM(srcPtr, srcPitch, dstPtr, dstPitch, width, height, redbluegreenMasks[maskUsed], roundingconstants[maskUsed]);
}
#else
template<typename ColorMask>
void DownscaleAllByHalfTemplate(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch, int width, int height) {
uint8 *work;
uint16 srcPitch16 = (uint16)(srcPitch / sizeof(uint16));
while ((height -= 2) >= 0) {
work = dstPtr;
for (int i=0; i<width; i+=2) {
// Another lame filter attempt :)
uint16 color1 = *(((const uint16 *)srcPtr) + i);
uint16 color2 = *(((const uint16 *)srcPtr) + (i + 1));
uint16 color3 = *(((const uint16 *)srcPtr) + (i + srcPitch16));
uint16 color4 = *(((const uint16 *)srcPtr) + (i + srcPitch16 + 1));
*(((uint16 *)work) + 0) = interpolate16_1_1_1_1<ColorMask>(color1, color2, color3, color4);
work += sizeof(uint16);
}
srcPtr += 2 * srcPitch;
dstPtr += dstPitch;
}
}
void DownscaleAllByHalf(const uint8 *srcPtr, uint32 srcPitch, uint8 *dstPtr, uint32 dstPitch, int width, int height) {
if (gBitFormat == 565)
DownscaleAllByHalfTemplate<Graphics::ColorMasks<565> >(srcPtr, srcPitch, dstPtr, dstPitch, width, height);
else
DownscaleAllByHalfTemplate<Graphics::ColorMasks<555> >(srcPtr, srcPitch, dstPtr, dstPitch, width, height);
}
#endif