Force values to 0.0f in QuadUVMatrix::set

BUG=skia:5002
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1749373002

Review URL: https://codereview.chromium.org/1749373002
This commit is contained in:
robertphillips 2016-03-01 14:49:44 -08:00 committed by Commit bot
parent 9c0b02a557
commit 87a223401d

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@ -267,9 +267,7 @@ void GrPathUtils::QuadUVMatrix::set(const SkPoint qPts[3]) {
double scale = 1.0/det;
// compute adjugate matrix
double a0, a1, a2, a3, a4, a5, a6, a7, a8;
a0 = y1-y2;
a1 = x2-x1;
double a2, a3, a4, a5, a6, a7, a8;
a2 = x1*y2-x2*y1;
a3 = y2-y0;
@ -290,15 +288,11 @@ void GrPathUtils::QuadUVMatrix::set(const SkPoint qPts[3]) {
m[SkMatrix::kMScaleY] = (float)(a7*scale);
m[SkMatrix::kMTransY] = (float)(a8*scale);
m[SkMatrix::kMPersp0] = (float)((a0 + a3 + a6)*scale);
m[SkMatrix::kMPersp1] = (float)((a1 + a4 + a7)*scale);
// kMPersp0 & kMPersp1 should algebraically be zero
m[SkMatrix::kMPersp0] = 0.0f;
m[SkMatrix::kMPersp1] = 0.0f;
m[SkMatrix::kMPersp2] = (float)((a2 + a5 + a8)*scale);
// The matrix should not have perspective.
SkDEBUGCODE(static const SkScalar gTOL = 1.f / 100.f);
SkASSERT(SkScalarAbs(m.get(SkMatrix::kMPersp0)) < gTOL);
SkASSERT(SkScalarAbs(m.get(SkMatrix::kMPersp1)) < gTOL);
// It may not be normalized to have 1.0 in the bottom right
float m33 = m.get(SkMatrix::kMPersp2);
if (1.f != m33) {