Use SkFixedMul instead of SkFixedMul_lowprec
It seems that SkFixedMul_lowprec doesn't have too much performance gain (maybe
1%). But its precision loss is siginificant. No serious issues have been found
in convex cases, but things get much trickier for concave shapes. I'm removing
it now to improve the stability and reliability of our algorithm, which may
potentially benefit our Chrome landing. (Even if we do not remove
SkFixedMul_lowprec now, we eventually will remove it when we land concave AAA
code.)
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4926
Change-Id: Iae5739a3780bb77ce6237888eee51a502fea5cf2
Reviewed-on: https://skia-review.googlesource.com/4926
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Yuqian Li <liyuqian@google.com>
diff --git a/src/core/SkAnalyticEdge.cpp b/src/core/SkAnalyticEdge.cpp
index ee7eda7..33e94e7 100644
--- a/src/core/SkAnalyticEdge.cpp
+++ b/src/core/SkAnalyticEdge.cpp
@@ -139,7 +139,7 @@
slope = dy >> 10 > 0 ? quickSkFDot6Div(dx >> 10, dy >> 10) : SK_MaxS32;
if (SkAbs32(dy) >= SK_Fixed1 * 2) { // only snap when dy is large enough
newSnappedY = SkTMin<SkFixed>(fQEdge.fQLastY, SkFixedRoundToFixed(newy));
- newSnappedX = newx + SkFixedMul_lowprec(slope, newSnappedY - newy);
+ newSnappedX = newx + SkFixedMul(slope, newSnappedY - newy);
} else {
newSnappedY = SkTMin(fQEdge.fQLastY, snapY(newy));
newSnappedX = newx;
diff --git a/src/core/SkAnalyticEdge.h b/src/core/SkAnalyticEdge.h
index a55ab2a..7f5e62c 100644
--- a/src/core/SkAnalyticEdge.h
+++ b/src/core/SkAnalyticEdge.h
@@ -10,11 +10,6 @@
#include "SkEdge.h"
-inline SkFixed SkFixedMul_lowprec(SkFixed a, SkFixed b) {
- SkASSERT(((int64_t)a >> 8) * (b >> 8) <= SK_MaxS32);
- return (a >> 8) * (b >> 8);
-}
-
struct SkAnalyticEdge {
// Similar to SkEdge, the conic edges will be converted to quadratic edges
enum Type {
@@ -55,7 +50,7 @@
} else if (y != fY) {
// Drop lower digits as our alpha only has 8 bits
// (fDX and y - fUpperY may be greater than SK_Fixed1)
- fX = fUpperX + SkFixedMul_lowprec(fDX, y - fUpperY);
+ fX = fUpperX + SkFixedMul(fDX, y - fUpperY);
fY = y;
}
}
diff --git a/src/core/SkScan_AAAPath.cpp b/src/core/SkScan_AAAPath.cpp
index a9f3654..bd0d9b0 100644
--- a/src/core/SkScan_AAAPath.cpp
+++ b/src/core/SkScan_AAAPath.cpp
@@ -473,7 +473,7 @@
// The alpha of right-triangle (a, a*b), in 16 bits
static inline SkFixed partialTriangleToAlpha16(SkFixed a, SkFixed b) {
SkASSERT(a <= SK_Fixed1);
- // SkFixedMul_lowprec(SkFixedMul_lowprec(a, a), b) >> 1
+ // SkFixedMul(SkFixedMul(a, a), b) >> 1
// return ((((a >> 8) * (a >> 8)) >> 8) * (b >> 8)) >> 1;
return (a >> 11) * (a >> 11) * (b >> 11);
}
@@ -520,8 +520,8 @@
} else {
SkFixed first = SK_Fixed1 - l; // horizontal edge length of the left-most triangle
SkFixed last = r - ((R - 1) << 16); // horizontal edge length of the right-most triangle
- SkFixed firstH = SkFixedMul_lowprec(first, dY); // vertical edge of the left-most triangle
- alphas[0] = SkFixedMul_lowprec(first, firstH) >> 9; // triangle alpha
+ SkFixed firstH = SkFixedMul(first, dY); // vertical edge of the left-most triangle
+ alphas[0] = SkFixedMul(first, firstH) >> 9; // triangle alpha
SkFixed alpha16 = firstH + (dY >> 1); // rectangle plus triangle
for (int i = 1; i < R - 1; i++) {
alphas[i] = alpha16 >> 8;
@@ -544,8 +544,8 @@
} else {
SkFixed first = SK_Fixed1 - l; // horizontal edge length of the left-most triangle
SkFixed last = r - ((R - 1) << 16); // horizontal edge length of the right-most triangle
- SkFixed lastH = SkFixedMul_lowprec(last, dY); // vertical edge of the right-most triangle
- alphas[R-1] = SkFixedMul_lowprec(last, lastH) >> 9; // triangle alpha
+ SkFixed lastH = SkFixedMul(last, dY); // vertical edge of the right-most triangle
+ alphas[R-1] = SkFixedMul(last, lastH) >> 9; // triangle alpha
SkFixed alpha16 = lastH + (dY >> 1); // rectangle plus triangle
for (int i = R - 2; i > 0; i--) {
alphas[i] = alpha16 >> 8;
@@ -983,13 +983,13 @@
if (partialTop > 0) { // blit first partial row
if (partialLeft > 0) {
blitter->blitAntiH(fullLeft - 1, fullTop - 1,
- f2a(SkFixedMul_lowprec(partialTop, partialLeft)));
+ f2a(SkFixedMul(partialTop, partialLeft)));
}
blitter->blitAntiH(fullLeft, fullTop - 1, fullRite - fullLeft,
f2a(partialTop));
if (partialRite > 0) {
blitter->blitAntiH(fullRite, fullTop - 1,
- f2a(SkFixedMul_lowprec(partialTop, partialRite)));
+ f2a(SkFixedMul(partialTop, partialRite)));
}
blitter->flush_if_y_changed(y, y + partialTop);
}
@@ -1007,18 +1007,18 @@
if (partialBot > 0) { // blit last partial row
if (partialLeft > 0) {
blitter->blitAntiH(fullLeft - 1, fullBot,
- f2a(SkFixedMul_lowprec(partialBot, partialLeft)));
+ f2a(SkFixedMul(partialBot, partialLeft)));
}
blitter->blitAntiH(fullLeft, fullBot, fullRite - fullLeft, f2a(partialBot));
if (partialRite > 0) {
blitter->blitAntiH(fullRite, fullBot,
- f2a(SkFixedMul_lowprec(partialBot, partialRite)));
+ f2a(SkFixedMul(partialBot, partialRite)));
}
}
} else { // left and rite are within the same pixel
if (partialTop > 0) {
blitter->getRealBlitter()->blitV(fullLeft - 1, fullTop - 1, 1,
- f2a(SkFixedMul_lowprec(partialTop, rite - left)));
+ f2a(SkFixedMul(partialTop, rite - left)));
blitter->flush_if_y_changed(y, y + partialTop);
}
if (fullBot > fullTop) {
@@ -1027,7 +1027,7 @@
}
if (partialBot > 0) {
blitter->getRealBlitter()->blitV(fullLeft - 1, fullBot, 1,
- f2a(SkFixedMul_lowprec(partialBot, rite - left)));
+ f2a(SkFixedMul(partialBot, rite - left)));
}
}
@@ -1067,8 +1067,8 @@
count--;
SkFixed nextY = SkFixedCeilToFixed(y + 1);
SkFixed dY = nextY - y;
- SkFixed nextLeft = left + SkFixedMul_lowprec(dLeft, dY);
- SkFixed nextRite = rite + SkFixedMul_lowprec(dRite, dY);
+ SkFixed nextLeft = left + SkFixedMul(dLeft, dY);
+ SkFixed nextRite = rite + SkFixedMul(dRite, dY);
SkASSERT((left & kSnapMask) >= leftBound && (rite & kSnapMask) <= riteBound &&
(nextLeft & kSnapMask) >= leftBound &&
(nextRite & kSnapMask) <= riteBound);
@@ -1105,8 +1105,8 @@
// Smooth jumping to integer y may make the last nextLeft/nextRite out of bound.
// Take them back into the bound here.
// Note that we substract kSnapHalf later so we have to add them to leftBound/riteBound
- SkFixed nextLeft = SkTMax(left + SkFixedMul_lowprec(dLeft, dY), leftBound + kSnapHalf);
- SkFixed nextRite = SkTMin(rite + SkFixedMul_lowprec(dRite, dY), riteBound + kSnapHalf);
+ SkFixed nextLeft = SkTMax(left + SkFixedMul(dLeft, dY), leftBound + kSnapHalf);
+ SkFixed nextRite = SkTMin(rite + SkFixedMul(dRite, dY), riteBound + kSnapHalf);
SkASSERT((left & kSnapMask) >= leftBound && (rite & kSnapMask) <= riteBound &&
(nextLeft & kSnapMask) >= leftBound && (nextRite & kSnapMask) <= riteBound);
blit_trapezoid_row(blitter, y >> 16, left & kSnapMask, rite & kSnapMask,
