SRect.cpp

 
/*
 * Copyright 2006 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
#include <souistd.h>
#include "matrix/SRect.h"
 
SNSBEGIN
 
void SRect::sort()
{
    if (fLeft > fRight)
    {
        STSwap<float>(fLeft, fRight);
    }
    if (fTop > fBottom)
    {
        STSwap<float>(fTop, fBottom);
    }
}
 
void SRect::toQuad(SPoint quad[4]) const
{
    SASSERT(quad);
 
    quad[0].set(fLeft, fTop);
    quad[1].set(fRight, fTop);
    quad[2].set(fRight, fBottom);
    quad[3].set(fLeft, fBottom);
}
 
bool SRect::setBoundsCheck(const SPoint pts[], int count)
{
    SASSERT((pts && count > 0) || count == 0);
 
    bool isFinite = true;
 
    if (count <= 0)
    {
        memset(this, 0, sizeof(SRect));
    }
    else
    {
        float l, t, r, b;
 
        l = r = pts[0].fX;
        t = b = pts[0].fY;
 
        // If all of the points are finite, accum should stay 0. If we encounter
        // a NaN or infinity, then accum should become NaN.
        float accum = 0;
        accum *= l;
        accum *= t;
 
        for (int i = 1; i < count; i++)
        {
            float x = pts[i].fX;
            float y = pts[i].fY;
 
            accum *= x;
            accum *= y;
 
            // we use if instead of if/else, so we can generate min/max
            // float instructions (at least on SSE)
            if (x < l)
                l = x;
            if (x > r)
                r = x;
 
            if (y < t)
                t = y;
            if (y > b)
                b = y;
        }
 
        SASSERT(!accum || !SFloatIsFinite(accum));
        if (accum)
        {
            l = t = r = b = 0;
            isFinite = false;
        }
        this->set(l, t, r, b);
    }
 
    return isFinite;
}
 
// http://www.blackpawn.com/texts/pointinpoly/default.html
// return true if pt is inside triangle; false if outside or on the line
bool STriangle::contains(const SPoint &pt) const
{
    // Compute vectors
    SPoint v0 = fPts[2] - fPts[0];
    SPoint v1 = fPts[1] - fPts[0];
    SPoint v2 = pt - fPts[0];
 
    // Compute dot products
    double dot00 = v0.dot(v0);
    double dot01 = v0.dot(v1);
    double dot02 = v0.dot(v2);
    double dot11 = v1.dot(v1);
    double dot12 = v1.dot(v2);
 
    double w = dot00 * dot11 - dot01 * dot01;
    if (w == 0)
    {
        return false;
    }
    double wSign = w < 0 ? -1 : 1;
    double u = (dot11 * dot02 - dot01 * dot12) * wSign;
    if (u <= 0)
    {
        return false;
    }
    double v = (dot00 * dot12 - dot01 * dot02) * wSign;
    if (v <= 0)
    {
        return false;
    }
    return u + v < w * wSign;
}
 
bool SQuad::contains(const SPoint &pt) const
{
    bool bRet = false;
    if (!bRet)
    {
        STriangle tri;
        tri.fPts[0] = fPts[0];
        tri.fPts[1] = fPts[1];
        tri.fPts[2] = fPts[2];
        bRet = tri.contains(pt);
    }
    if (!bRet)
    {
        STriangle tri;
        tri.fPts[0] = fPts[0];
        tri.fPts[1] = fPts[2];
        tri.fPts[2] = fPts[3];
        bRet = tri.contains(pt);
    }
    return bRet;
}
 
SNSEND