src/libjin/math/je_ranged_value.cpp


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71

#include "je_ranged_value.h"

namespace JinEngine
{
    namespace Math
    {

        RangedValue::RangedValue()
            : mCount(0)
        {
        }

        RangedValue::RangedValue(float* points, uint n)
            : mCount(n)
        {
            for (uint i = 0; i < n; ++i)
            {
                float x = points[2*i];
                float y = points[2*i + 1];
                mXAxis.push_back(x);
                mYAxis.push_back(y);
            }
        }

        void RangedValue::addPoint(float x, float y)
        {
            mXAxis.push_back(x);
            mYAxis.push_back(y);
            ++mCount;
        }

        void RangedValue::removePoint(uint i)
        {
            mXAxis.erase(mXAxis.begin() + i);
            mYAxis.erase(mYAxis.begin() + i);
            --mCount;
        }

        void RangedValue::insertPoint(uint i, float x, float y)
        {
            mXAxis.insert(mXAxis.begin() + i, x);
            mYAxis.insert(mYAxis.begin() + i, y);
            ++mCount;
        }

        float RangedValue::getValue(float x)
        {
            int endIndex = -1;
            int n = mCount;
            for (int i = 1; i < n; i++) {
                float t = mXAxis[i];
                if (t > x) {
                    endIndex = i;
                    break;
                }
            }
            if (endIndex == -1) return mYAxis[n - 1];
            int startIndex = endIndex - 1;
            float startValue = mYAxis[startIndex];
            float startX = mXAxis[startIndex];
            return startValue + (mYAxis[endIndex] - startValue) * ((x - startX) / (mXAxis[endIndex] - startX));
        }

        void RangedValue::clear()
        {
            mXAxis.clear();
            mYAxis.clear();
        }

    }
}