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Remove sk_bzero usage from SkMatrix44 for improved performance.

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sk_bzero is not efficient for initializing small chunks of memory. Instead,
directly initializing matrix values when needed results in substantial
performance improvements.

BUG=skia:1558
R=reed@google.com

Review URL: https://codereview.chromium.org/23090008

git-svn-id: http://skia.googlecode.com/svn/trunk@10988 2bbb7eff-a529-9590-31e7-b0007b416f81
This commit is contained in:
shawnsingh@chromium.org 2013-08-28 18:55:25 +00:00
parent 98ed8fa4bf
commit 5a6cd35b19
1 changed files with 72 additions and 21 deletions
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91
src/utils/SkMatrix44.cpp
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@ -180,8 +180,22 @@ const SkMatrix44& SkMatrix44::I() {
}
void SkMatrix44::setIdentity() {
sk_bzero(fMat, sizeof(fMat));
fMat[0][0] = fMat[1][1] = fMat[2][2] = fMat[3][3] = 1;
fMat[0][0] = 1;
fMat[0][1] = 0;
fMat[0][2] = 0;
fMat[0][3] = 0;
fMat[1][0] = 0;
fMat[1][1] = 1;
fMat[1][2] = 0;
fMat[1][3] = 0;
fMat[2][0] = 0;
fMat[2][1] = 0;
fMat[2][2] = 1;
fMat[2][3] = 0;
fMat[3][0] = 0;
fMat[3][1] = 0;
fMat[3][2] = 0;
fMat[3][3] = 1;
this->setTypeMask(kIdentity_Mask);
}
@ -452,9 +466,6 @@ double SkMatrix44::determinant() const {
///////////////////////////////////////////////////////////////////////////////
// just picked a small value. not sure how to pick the "right" one
#define TOO_SMALL_FOR_DETERMINANT (1.e-8)
static inline double dabs(double x) {
if (x < 0) {
x = -x;
@ -465,7 +476,7 @@ static inline double dabs(double x) {
bool SkMatrix44::invert(SkMatrix44* inverse) const {
if (this->isIdentity()) {
if (inverse) {
*inverse = *this;
inverse->setIdentity();
return true;
}
}
@ -479,24 +490,56 @@ bool SkMatrix44::invert(SkMatrix44* inverse) const {
if (0 == fMat[0][0] * fMat[1][1] * fMat[2][2]) {
return false;
}
if (inverse) {
sk_bzero(inverse->fMat, sizeof(inverse->fMat));
double invXScale = 1 / fMat[0][0];
double invYScale = 1 / fMat[1][1];
double invZScale = 1 / fMat[2][2];
double a00 = fMat[0][0];
double a11 = fMat[1][1];
double a22 = fMat[2][2];
double a30 = fMat[3][0];
double a31 = fMat[3][1];
double a32 = fMat[3][2];
inverse->fMat[3][0] = -fMat[3][0] * invXScale;
inverse->fMat[3][1] = -fMat[3][1] * invYScale;
inverse->fMat[3][2] = -fMat[3][2] * invZScale;
double b00 = a00 * a11;
double b07 = -a22 * a30;
double b09 = -a22 * a31;
double b11 = a22;
inverse->fMat[0][0] = invXScale;
inverse->fMat[1][1] = invYScale;
inverse->fMat[2][2] = invZScale;
// Calculate the determinant
double det = b00 * b11;
double invdet = 1.0 / det;
// If det is zero, we want to return false. However, we also want to return false
// if 1/det overflows to infinity (i.e. det is denormalized). Both of these are
// handled by checking that 1/det is finite.
if (!sk_float_isfinite(invdet)) {
return false;
}
if (NULL == inverse) {
return true;
}
b00 *= invdet;
b07 *= invdet;
b09 *= invdet;
b11 *= invdet;
inverse->fMat[0][0] = SkDoubleToMScalar(a11 * b11);
inverse->fMat[0][1] = 0;
inverse->fMat[0][2] = 0;
inverse->fMat[0][3] = 0;
inverse->fMat[1][0] = 0;
inverse->fMat[1][1] = SkDoubleToMScalar(a00 * b11);
inverse->fMat[1][2] = 0;
inverse->fMat[1][3] = 0;
inverse->fMat[2][0] = 0;
inverse->fMat[2][1] = 0;
inverse->fMat[2][2] = SkDoubleToMScalar(b00);
inverse->fMat[2][3] = 0;
inverse->fMat[3][0] = SkDoubleToMScalar(a11 * b07);
inverse->fMat[3][1] = SkDoubleToMScalar(a00 * b09);
inverse->fMat[3][2] = SkDoubleToMScalar(-a32 * b00);
inverse->fMat[3][3] = 1;
inverse->setTypeMask(this->getType());
}
return true;
}
@ -883,14 +926,22 @@ void SkMatrix44::dump() const {
// TODO: make this support src' perspective elements
//
static void initFromMatrix(SkMScalar dst[4][4], const SkMatrix& src) {
sk_bzero(dst, 16 * sizeof(SkMScalar));
dst[0][0] = SkScalarToMScalar(src[SkMatrix::kMScaleX]);
dst[1][0] = SkScalarToMScalar(src[SkMatrix::kMSkewX]);
dst[2][0] = 0;
dst[3][0] = SkScalarToMScalar(src[SkMatrix::kMTransX]);
dst[0][1] = SkScalarToMScalar(src[SkMatrix::kMSkewY]);
dst[1][1] = SkScalarToMScalar(src[SkMatrix::kMScaleY]);
dst[2][1] = 0;
dst[3][1] = SkScalarToMScalar(src[SkMatrix::kMTransY]);
dst[2][2] = dst[3][3] = 1;
dst[0][2] = 0;
dst[1][2] = 0;
dst[2][2] = 1;
dst[3][2] = 0;
dst[0][3] = 0;
dst[1][3] = 0;
dst[2][3] = 0;
dst[3][3] = 1;
}
SkMatrix44::SkMatrix44(const SkMatrix& src) {