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GRAPHICS: Move code for bilinear scaling out of TransparentSurface

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Cameron Cawley 2020-07-05 14:04:03 +01:00 • committed by Eugene Sandulenko
parent 42019d4252
commit b2f2069fb0
3 changed files with 207 additions and 155 deletions
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198
graphics/conversion.cpp
View file

@ -221,5 +221,201 @@ bool scaleBlit(byte *dst, const byte *src,
return true;
}
/*
The function below is adapted from SDL_rotozoom.c,
taken from SDL_gfx-2.0.18.
Its copyright notice:
=============================================================================
SDL_rotozoom.c: rotozoomer, zoomer and shrinker for 32bit or 8bit surfaces
Copyright (C) 2001-2012 Andreas Schiffler
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source
distribution.
Andreas Schiffler -- aschiffler at ferzkopp dot net
=============================================================================
The functions have been adapted for different structures and coordinate
systems.
*/
struct tColorRGBA { byte r; byte g; byte b; byte a; };
bool scaleBlitBilinear(byte *dst, const byte *src,
const uint dstPitch, const uint srcPitch,
const uint dstW, const uint dstH,
const uint srcW, const uint srcH,
const Graphics::PixelFormat &fmt) {
assert(fmt.bytesPerPixel == 4);
bool flipx = false, flipy = false; // TODO: See mirroring comment in RenderTicket ctor
int *sax = new int[dstW + 1];
int *say = new int[dstH + 1];
assert(sax && say);
/*
* Precalculate row increments
*/
int spixelw = (srcW - 1);
int spixelh = (srcH - 1);
int sx = (int)(65536.0f * (float) spixelw / (float) (dstW - 1));
int sy = (int)(65536.0f * (float) spixelh / (float) (dstH - 1));
/* Maximum scaled source size */
int ssx = (srcW << 16) - 1;
int ssy = (srcH << 16) - 1;
/* Precalculate horizontal row increments */
int csx = 0;
int *csax = sax;
for (uint x = 0; x <= dstW; x++) {
*csax = csx;
csax++;
csx += sx;
/* Guard from overflows */
if (csx > ssx) {
csx = ssx;
}
}
/* Precalculate vertical row increments */
int csy = 0;
int *csay = say;
for (uint y = 0; y <= dstH; y++) {
*csay = csy;
csay++;
csy += sy;
/* Guard from overflows */
if (csy > ssy) {
csy = ssy;
}
}
const tColorRGBA *sp = (const tColorRGBA *) src;
tColorRGBA *dp = (tColorRGBA *) dst;
int spixelgap = srcW;
if (flipx) {
sp += spixelw;
}
if (flipy) {
sp += spixelgap * spixelh;
}
csay = say;
for (uint y = 0; y < dstH; y++) {
const tColorRGBA *csp = sp;
csax = sax;
for (uint x = 0; x < dstW; x++) {
/*
* Setup color source pointers
*/
int ex = (*csax & 0xffff);
int ey = (*csay & 0xffff);
int cx = (*csax >> 16);
int cy = (*csay >> 16);
const tColorRGBA *c00, *c01, *c10, *c11;
c00 = sp;
c01 = sp;
c10 = sp;
if (cy < spixelh) {
if (flipy) {
c10 -= spixelgap;
} else {
c10 += spixelgap;
}
}
c11 = c10;
if (cx < spixelw) {
if (flipx) {
c01--;
c11--;
} else {
c01++;
c11++;
}
}
/*
* Draw and interpolate colors
*/
int t1, t2;
t1 = ((((c01->r - c00->r) * ex) >> 16) + c00->r) & 0xff;
t2 = ((((c11->r - c10->r) * ex) >> 16) + c10->r) & 0xff;
dp->r = (((t2 - t1) * ey) >> 16) + t1;
t1 = ((((c01->g - c00->g) * ex) >> 16) + c00->g) & 0xff;
t2 = ((((c11->g - c10->g) * ex) >> 16) + c10->g) & 0xff;
dp->g = (((t2 - t1) * ey) >> 16) + t1;
t1 = ((((c01->b - c00->b) * ex) >> 16) + c00->b) & 0xff;
t2 = ((((c11->b - c10->b) * ex) >> 16) + c10->b) & 0xff;
dp->b = (((t2 - t1) * ey) >> 16) + t1;
t1 = ((((c01->a - c00->a) * ex) >> 16) + c00->a) & 0xff;
t2 = ((((c11->a - c10->a) * ex) >> 16) + c10->a) & 0xff;
dp->a = (((t2 - t1) * ey) >> 16) + t1;
/*
* Advance source pointer x
*/
int *salastx = csax;
csax++;
int sstepx = (*csax >> 16) - (*salastx >> 16);
if (flipx) {
sp -= sstepx;
} else {
sp += sstepx;
}
/*
* Advance destination pointer x
*/
dp++;
}
/*
* Advance source pointer y
*/
int *salasty = csay;
csay++;
int sstepy = (*csay >> 16) - (*salasty >> 16);
sstepy *= spixelgap;
if (flipy) {
sp = csp - sstepy;
} else {
sp = csp + sstepy;
}
}
delete[] sax;
delete[] say;
return true;
}
} // End of namespace Graphics

6
graphics/conversion.h
View file

@ -78,6 +78,12 @@ bool scaleBlit(byte *dst, const byte *src,
const uint srcW, const uint srcH,
const Graphics::PixelFormat &fmt);
bool scaleBlitBilinear(byte *dst, const byte *src,
const uint dstPitch, const uint srcPitch,
const uint dstW, const uint dstH,
const uint srcW, const uint srcH,
const Graphics::PixelFormat &fmt);
} // End of namespace Graphics
#endif // GRAPHICS_CONVERSION_H

158
graphics/transparent_surface.cpp
View file

@ -751,7 +751,7 @@ void TransparentSurface::setAlphaMode(AlphaType mode) {
/*
The below two functions are adapted from SDL_rotozoom.c,
The function below is adapted from SDL_rotozoom.c,
taken from SDL_gfx-2.0.18.
Its copyright notice:
@ -914,162 +914,12 @@ TransparentSurface *TransparentSurface::scaleT(uint16 newWidth, uint16 newHeight
TransparentSurface *target = new TransparentSurface();
int srcW = w;
int srcH = h;
int dstW = newWidth;
int dstH = newHeight;
target->create((uint16)dstW, (uint16)dstH, format);
target->create(newWidth, newHeight, format);
if (filteringMode == FILTER_BILINEAR) {
assert(format.bytesPerPixel == 4);
bool flipx = false, flipy = false; // TODO: See mirroring comment in RenderTicket ctor
int *sax = new int[dstW + 1];
int *say = new int[dstH + 1];
assert(sax && say);
/*
* Precalculate row increments
*/
int spixelw = (srcW - 1);
int spixelh = (srcH - 1);
int sx = (int)(65536.0f * (float) spixelw / (float) (dstW - 1));
int sy = (int)(65536.0f * (float) spixelh / (float) (dstH - 1));
/* Maximum scaled source size */
int ssx = (srcW << 16) - 1;
int ssy = (srcH << 16) - 1;
/* Precalculate horizontal row increments */
int csx = 0;
int *csax = sax;
for (int x = 0; x <= dstW; x++) {
*csax = csx;
csax++;
csx += sx;
/* Guard from overflows */
if (csx > ssx) {
csx = ssx;
}
}
/* Precalculate vertical row increments */
int csy = 0;
int *csay = say;
for (int y = 0; y <= dstH; y++) {
*csay = csy;
csay++;
csy += sy;
/* Guard from overflows */
if (csy > ssy) {
csy = ssy;
}
}
const tColorRGBA *sp = (const tColorRGBA *) getBasePtr(0, 0);
tColorRGBA *dp = (tColorRGBA *) target->getBasePtr(0, 0);
int spixelgap = srcW;
if (flipx) {
sp += spixelw;
}
if (flipy) {
sp += spixelgap * spixelh;
}
csay = say;
for (int y = 0; y < dstH; y++) {
const tColorRGBA *csp = sp;
csax = sax;
for (int x = 0; x < dstW; x++) {
/*
* Setup color source pointers
*/
int ex = (*csax & 0xffff);
int ey = (*csay & 0xffff);
int cx = (*csax >> 16);
int cy = (*csay >> 16);
const tColorRGBA *c00, *c01, *c10, *c11;
c00 = sp;
c01 = sp;
c10 = sp;
if (cy < spixelh) {
if (flipy) {
c10 -= spixelgap;
} else {
c10 += spixelgap;
}
}
c11 = c10;
if (cx < spixelw) {
if (flipx) {
c01--;
c11--;
} else {
c01++;
c11++;
}
}
/*
* Draw and interpolate colors
*/
int t1, t2;
t1 = ((((c01->r - c00->r) * ex) >> 16) + c00->r) & 0xff;
t2 = ((((c11->r - c10->r) * ex) >> 16) + c10->r) & 0xff;
dp->r = (((t2 - t1) * ey) >> 16) + t1;
t1 = ((((c01->g - c00->g) * ex) >> 16) + c00->g) & 0xff;
t2 = ((((c11->g - c10->g) * ex) >> 16) + c10->g) & 0xff;
dp->g = (((t2 - t1) * ey) >> 16) + t1;
t1 = ((((c01->b - c00->b) * ex) >> 16) + c00->b) & 0xff;
t2 = ((((c11->b - c10->b) * ex) >> 16) + c10->b) & 0xff;
dp->b = (((t2 - t1) * ey) >> 16) + t1;
t1 = ((((c01->a - c00->a) * ex) >> 16) + c00->a) & 0xff;
t2 = ((((c11->a - c10->a) * ex) >> 16) + c10->a) & 0xff;
dp->a = (((t2 - t1) * ey) >> 16) + t1;
/*
* Advance source pointer x
*/
int *salastx = csax;
csax++;
int sstepx = (*csax >> 16) - (*salastx >> 16);
if (flipx) {
sp -= sstepx;
} else {
sp += sstepx;
}
/*
* Advance destination pointer x
*/
dp++;
}
/*
* Advance source pointer y
*/
int *salasty = csay;
csay++;
int sstepy = (*csay >> 16) - (*salasty >> 16);
sstepy *= spixelgap;
if (flipy) {
sp = csp - sstepy;
} else {
sp = csp + sstepy;
}
}
delete[] sax;
delete[] say;
scaleBlitBilinear((byte *)target->getPixels(), (const byte *)getPixels(), target->pitch, pitch, target->w, target->h, w, h, format);
} else {
scaleBlit((byte *)target->getPixels(), (const byte *)getPixels(), target->pitch, pitch, dstW, dstH, srcW, srcH, format);
scaleBlit((byte *)target->getPixels(), (const byte *)getPixels(), target->pitch, pitch, target->w, target->h, w, h, format);
}
return target;