C4MapScriptAlgoPolygon Class Reference

#include <C4MapScript.h>

Inheritance diagram for C4MapScriptAlgoPolygon:

Collaboration diagram for C4MapScriptAlgoPolygon:

Public Member Functions
	C4MapScriptAlgoPolygon (const C4PropList *props)
bool	operator() (int32_t x, int32_t y, uint8_t &fg, uint8_t &bg) const override

Protected Member Functions
bool	GetXYProps (const C4PropList *props, C4PropertyName k, int32_t *out_xy, bool zero_defaults)

Detailed Description

Definition at line 138 of file C4MapScript.h.

Constructor & Destructor Documentation

C4MapScriptAlgoPolygon()

C4MapScriptAlgoPolygon::C4MapScriptAlgoPolygon

(

const C4PropList *

props

)

Definition at line 139 of file C4MapScriptAlgo.cpp.

{
    // Get MAPALGO_Polygon properties
    C4Value vptx, vpty;
    props->GetProperty(P_X, &vptx); props->GetProperty(P_Y, &vpty);
    C4ValueArray *ptx = vptx.getArray(), *pty = vpty.getArray();
    if (!ptx || !pty || ptx->GetSize() != pty->GetSize())
        throw C4AulExecError(R"(C4MapScriptAlgoPolygon: Expected two equally sized int arrays in properties "X" and "Y".)");
    poly.resize(ptx->GetSize());
    for (int32_t i=0; i<ptx->GetSize(); ++i)
    {
        poly[i].x = ptx->GetItem(i).getInt();
        poly[i].y = pty->GetItem(i).getInt();
    }
    wdt = props->GetPropertyInt(P_Wdt);
    if (!wdt) wdt = 1;
    empty = !!props->GetPropertyInt(P_Empty);
    open = !!props->GetPropertyInt(P_Open);
    if (open && !empty) throw C4AulExecError("C4MapScriptAlgoPolygon: Only empty polygons may be open.");
}

References C4Value::getArray(), C4Value::getInt(), C4ValueArray::GetItem(), C4PropList::GetProperty(), C4PropList::GetPropertyInt(), C4ValueArray::GetSize(), P_Empty, P_Open, P_Wdt, P_X, and P_Y.

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Member Function Documentation

GetXYProps()

bool C4MapScriptAlgo::GetXYProps ( const C4PropList *  props, C4PropertyName  k, int32_t *  out_xy, bool  zero_defaults  )

protectedinherited

Definition at line 26 of file C4MapScriptAlgo.cpp.

{
    // Evaluate property named "k" in proplist props to store two numbers in out_xy:
    // If props->k is a single integer, fill both numbers in out_xy with it
    // If props->k is an array, check that it contains two numbers and store them in out_xy
    if (!props->HasProperty(&Strings.P[k]))
    {
        if (zero_defaults) out_xy[0] = out_xy[1] = 0;
        return false;
    }
    C4Value val; C4ValueArray *arr;
    props->GetProperty(k, &val);
    if ((arr = val.getArray()))
    {
        if (arr->GetSize() != 2)
            throw C4AulExecError(FormatString(R"(C4MapScriptAlgo: Expected either integer or array with two integer elements in property "%s".)", Strings.P[k].GetCStr()).getData());
        out_xy[0] = arr->GetItem(0).getInt();
        out_xy[1] = arr->GetItem(1).getInt();
    }
    else
    {
        out_xy[0] = out_xy[1] = val.getInt();
    }
    return true;
}

References FormatString(), C4Value::getArray(), C4String::GetCStr(), StdStrBuf::getData(), C4Value::getInt(), C4ValueArray::GetItem(), C4PropList::GetProperty(), C4ValueArray::GetSize(), C4PropList::HasProperty(), C4StringTable::P, and Strings.

Referenced by C4MapScriptAlgoBorder::C4MapScriptAlgoBorder(), and C4MapScriptAlgoTurbulence::C4MapScriptAlgoTurbulence().

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operator()()

bool C4MapScriptAlgoPolygon::operator() ( int32_t  x, int32_t  y, uint8_t &  fg, uint8_t &  bg  ) const

overridevirtual

Implements C4MapScriptAlgo.

Definition at line 160 of file C4MapScriptAlgo.cpp.

{
    // Evaluate MAPALGO_Polygon at x,y: Return 1 for pixels within the polygon or its borders, 0 otherwise
    int32_t crossings = 0;
    for (size_t i=0; i<poly.size(); ++i)
    {
        Pt pt1 = poly[i];
        Pt pt2 = poly[(i+1)%poly.size()];
        // check border line distance
        int32_t pdx = pt2.x-pt1.x, pdy = pt2.y-pt1.y, dx = x-pt1.x, dy = y-pt1.y;
        if (i!=poly.size()-1 || !open)
        {
            int64_t d = dx*pdy-dy*pdx;
            int32_t lsq = (pdx*pdx+pdy*pdy);
            if (d*d < wdt*wdt*lsq) // check distance perpendicular to line
            {
                if (Inside(dx*pdx+dy*pdy, 0, lsq)) // check if point lies within pt1 and pt2
                    return true; // x/y lies on this line
            }
        }
        // check point distance
        if (dx*dx+dy*dy < wdt*wdt) return true; // x/y lies close to edge point
        // filling of polygon: point is contained if it crosses an off number of borders
        if (!empty && (pt1.y<=y) != (pt2.y<=y)) // crossing vertically?
        {
            // does line pt1-pt2 intersect line (x,y)-(inf,y)?
            crossings += (dx>dy*pdx/pdy);
        }
    }
    // x/y lies inside polygon
    return (crossings % 2)==1;
}

References Inside().

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The documentation for this class was generated from the following files:

• C4MapScript.h
• C4MapScriptAlgo.cpp