/** * @file llviewerlayer.cpp * @brief LLViewerLayer class implementation * * $LicenseInfo:firstyear=2002&license=viewerlgpl$ * Second Life Viewer Source Code * Copyright (C) 2010, Linden Research, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; * version 2.1 of the License only. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA * * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA * $/LicenseInfo$ */ #include "llviewerprecompiledheaders.h" #include "llviewerlayer.h" #include "llerror.h" #include "llmath.h" LLViewerLayer::LLViewerLayer(const S32 width, const F32 scale) { mWidth = width; mScale = scale; mScaleInv = 1.f/scale; mDatap = new F32[width*width]; for (S32 i = 0; i < width*width; i++) { *(mDatap + i) = 0.f; } } LLViewerLayer::~LLViewerLayer() { delete[] mDatap; mDatap = NULL; } F32 LLViewerLayer::getValue(const S32 x, const S32 y) const { // llassert(x >= 0); // llassert(x < mWidth); // llassert(y >= 0); // llassert(y < mWidth); return *(mDatap + x + y*mWidth); } F32 LLViewerLayer::getValueScaled(const F32 x, const F32 y) const { S32 x1, x2, y1, y2; F32 x_frac, y_frac; x_frac = x*mScaleInv; x1 = llfloor(x_frac); x2 = x1 + 1; x_frac -= x1; y_frac = y*mScaleInv; y1 = llfloor(y_frac); y2 = y1 + 1; y_frac -= y1; x1 = llmin((S32)mWidth-1, x1); x1 = llmax(0, x1); x2 = llmin((S32)mWidth-1, x2); x2 = llmax(0, x2); y1 = llmin((S32)mWidth-1, y1); y1 = llmax(0, y1); y2 = llmin((S32)mWidth-1, y2); y2 = llmax(0, y2); // Take weighted average of all four points (bilinear interpolation) S32 row1 = y1 * mWidth; S32 row2 = y2 * mWidth; // Access in squential order in memory, and don't use immediately. F32 row1_left = mDatap[ row1 + x1 ]; F32 row1_right = mDatap[ row1 + x2 ]; F32 row2_left = mDatap[ row2 + x1 ]; F32 row2_right = mDatap[ row2 + x2 ]; F32 row1_interp = row1_left - x_frac * (row1_left - row1_right); F32 row2_interp = row2_left - x_frac * (row2_left - row2_right); return row1_interp - y_frac * (row1_interp - row2_interp); }