From e4998e1ea93253c177f2358dc37c39d117b2f6c4 Mon Sep 17 00:00:00 2001 From: Romain Guy Date: Thu, 15 Jan 2015 11:53:44 -0800 Subject: Fast loadInverse() implementation for the common case Most matrices used by the UI toolkit are translation matrices, whose inverses can be quickly computed by using the negated translation vector. Change-Id: I54a28a634a586085779bfc26f3a4160cd5ab2b22 --- libs/hwui/Matrix.cpp | 36 ++++++++++++++++++++++++++++++++---- 1 file changed, 32 insertions(+), 4 deletions(-) (limited to 'libs/hwui/Matrix.cpp') diff --git a/libs/hwui/Matrix.cpp b/libs/hwui/Matrix.cpp index 9f2014f89f46..061d26ab5954 100644 --- a/libs/hwui/Matrix.cpp +++ b/libs/hwui/Matrix.cpp @@ -203,6 +203,34 @@ void Matrix4::copyTo(SkMatrix& v) const { } void Matrix4::loadInverse(const Matrix4& v) { + // Fast case for common translation matrices + if (v.isPureTranslate()) { + // Reset the matrix + // Unnamed fields are never written to except by + // loadIdentity(), they don't need to be reset + data[kScaleX] = 1.0f; + data[kSkewX] = 0.0f; + + data[kScaleY] = 1.0f; + data[kSkewY] = 0.0f; + + data[kScaleZ] = 1.0f; + + data[kPerspective0] = 0.0f; + data[kPerspective1] = 0.0f; + data[kPerspective2] = 1.0f; + + // No need to deal with kTranslateZ because isPureTranslate() + // only returns true when the kTranslateZ component is 0 + data[kTranslateX] = -v.data[kTranslateX]; + data[kTranslateY] = -v.data[kTranslateY]; + data[kTranslateZ] = 0.0f; + + // A "pure translate" matrix can be identity or translation + mType = v.getType(); + return; + } + double scale = 1.0 / (v.data[kScaleX] * ((double) v.data[kScaleY] * v.data[kPerspective2] - (double) v.data[kTranslateY] * v.data[kPerspective1]) + @@ -212,18 +240,18 @@ void Matrix4::loadInverse(const Matrix4& v) { (double) v.data[kScaleY] * v.data[kPerspective0])); data[kScaleX] = (v.data[kScaleY] * v.data[kPerspective2] - - v.data[kTranslateY] * v.data[kPerspective1]) * scale; + v.data[kTranslateY] * v.data[kPerspective1]) * scale; data[kSkewX] = (v.data[kTranslateX] * v.data[kPerspective1] - v.data[kSkewX] * v.data[kPerspective2]) * scale; data[kTranslateX] = (v.data[kSkewX] * v.data[kTranslateY] - - v.data[kTranslateX] * v.data[kScaleY]) * scale; + v.data[kTranslateX] * v.data[kScaleY]) * scale; data[kSkewY] = (v.data[kTranslateY] * v.data[kPerspective0] - v.data[kSkewY] * v.data[kPerspective2]) * scale; data[kScaleY] = (v.data[kScaleX] * v.data[kPerspective2] - - v.data[kTranslateX] * v.data[kPerspective0]) * scale; + v.data[kTranslateX] * v.data[kPerspective0]) * scale; data[kTranslateY] = (v.data[kTranslateX] * v.data[kSkewY] - - v.data[kScaleX] * v.data[kTranslateY]) * scale; + v.data[kScaleX] * v.data[kTranslateY]) * scale; data[kPerspective0] = (v.data[kSkewY] * v.data[kPerspective1] - v.data[kScaleY] * v.data[kPerspective0]) * scale; -- cgit v1.2.3-59-g8ed1b