将C转换为vb.net问题 [英] translating C to vb.net problem

问题描述

好的，我用C语言编写了这段代码，但我想在vb.net中做同样的功能.我尝试了许多变体，但没有人能正常工作.

ok i got this code write in C and i want to make a the same function but in vb.net. I''ve tryed many variants but no one work properly.

float CMapAndreas::FindZ_For2DCoord(float X, float Y)
{
	if(X < -3000.0f || X > 3000.0f || Y > 3000.0f || Y < -3000.0f) return 0.0f;

	unsigned short *m_pPointData;
	int iGridX = ((int)X) + 3000;
	int iGridY = (((int)Y) - 3000) * -1;
	int iDataPos;
	FILE *mapFile;

	m_pPointData = (unsigned short *)calloc(1,sizeof(unsigned short));
	mapFile = fopen(MAP_ANDREAS_HMAP_FILE_FULL,"rb");
	iDataPos = (iGridY * 6000) + iGridX;

	fseek(mapFile, iDataPos * sizeof(unsigned short), SEEK_SET);
	fread(&m_pPointData[0], 1, sizeof(unsigned short), mapFile);

	return (float)m_pPointData[0] / 100.0f;
}

Public Function GetZFromXY(ByVal X As Single, ByVal Y As Single) As Single
    If Not (-3000.0 < X < 3000.0 Or -3000.0 < Y < 3000.0) Then Return 0.0
    Dim Z As UShort, Reader As New IO.BinaryReader(New IO.FileStream(My.Application.Info.DirectoryPath & "\SAfull.hmap", IO.FileMode.Open))
    Dim iGridX As Integer = (CInt(X)) + 3000
    Dim iGridY As Integer = ((CInt(Y)) - 3000) * -1
    Dim iDataPos As Integer = (iGridY * 6000) + iGridX
    Reader.BaseStream.Seek(iDataPos * 16, IO.SeekOrigin.Begin)
    Z = Reader.ReadUInt16()
    Reader.Close()
    Return Z / 100
End Function

有人可以帮我吗?

Anyone can help me with this?

推荐答案

我首先看到的是:不要将System.IO.FileStream用作BinaryReader构造函数的参数，请使用:System.IO.File.Open(fileName, FileMode.Open).请参见以下代码示例: http://msdn.microsoft.com/zh-CN /library/system.io.binaryreader.aspx#Y2689 [ ^ ].

第二件事:Z被声明为System.UInt32，并且您需要float.除以100之前，请强制类型转换Z以浮点:

First thing I see: don''t use System.IO.FileStream for a parameter to BinaryReader constructor, use instead: System.IO.File.Open(fileName, FileMode.Open). See this code sample: http://msdn.microsoft.com/en-us/library/system.io.binaryreader.aspx#Y2689[^].

Second thing: Z is declared as System.UInt32 and you need float. Before dividing by 100, typecast Z to float:

Return CSng(Z)/100

否则，您将失去小数部分，如果Z < 100，您将得到0，这是您不期望的.

-SA

Otherwise you will loose fractional part, if Z < 100 you will get 0, something you don''t expect.

—SA

Public Function GetZFromXY(ByVal X As Single, ByVal Y As Single) As Single
    If Not (-3000.0 < X < 3000.0 Or -3000.0 < Y < 3000.0) Then Return 0.0
    Dim Z As UShort, Reader As New IO.BinaryReader(IO.File.Open(My.Application.Info.DirectoryPath & "\SAfull.hmap", IO.FileMode.Open))
    Dim iGridX As Integer = (CInt(X)) + 3000
    Dim iGridY As Integer = ((CInt(Y)) - 3000) * -1
    Dim iDataPos As Integer = (iGridY * 6000) + iGridX
    Reader.BaseStream.Seek(iDataPos * 2, IO.SeekOrigin.Begin)
    Z = Reader.ReadUInt16()
    Reader.Close()
    Return CSng(Z) / 100
End Function

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