代码是参考three.js中的stlLoader.js写的.
需要注意的地方,java中byte取值-128~127
package test_stl.test_entry; import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.regex.Matcher;
import java.util.regex.Pattern; /**
* 注意java byte范围-128~127
*
* @author ephuizi@gmail.com
*
*/
public class STLUtils {
// final private static Pattern ASCII_PATTERN_FACET =
// Pattern.compile("facet([\\s\\S]*?)endfacet");
final private static Pattern ASCII_PATTERN_NORMAL = Pattern
.compile("normal[\\s]+([\\-+]?[0-9]+\\.?[0-9]*([eE][\\-+]?[0-9]+)?)+[\\s]+([\\-+]?[0-9]*\\.?[0-9]+([eE][\\-+]?[0-9]+)?)+[\\s]+([\\-+]?[0-9]*\\.?[0-9]+([eE][\\-+]?[0-9]+)?)+");
final private static Pattern ASCII_PATTERN_VERTEX = Pattern
.compile("vertex[\\s]+([\\-+]?[0-9]+\\.?[0-9]*([eE][\\-+]?[0-9]+)?)+[\\s]+([\\-+]?[0-9]*\\.?[0-9]+([eE][\\-+]?[0-9]+)?)+[\\s]+([\\-+]?[0-9]*\\.?[0-9]+([eE][\\-+]?[0-9]+)?)+"); /**
* 判断是否stl格式
*
* @param stlPath
* @return true binary false ascii
*/
public static boolean isBinary(String stlPath) {
long expect = 0;// 以binnary方式计算的文件大小;
int face_size = (32 / 8 * 3) + ((32 / 8 * 3) * 3) + (16 / 8);// 一个三角片大小
int n_facetNum = 0;// 三角片数量
RandomAccessFile stl = null;
try {
stl = new RandomAccessFile(stlPath, "r"); stl.seek(80);
byte[] arr = { 0, 0, 0, 0 };
stl.read(arr);
n_facetNum = STLFaceNum(arr); expect = 80 + (32 / 8) + (n_facetNum * face_size);
if (expect == stl.length()) {
stl.close();
return true;
} // some binary files will have different size from expected,
// checking characters lower than ASCII to confirm is binary
long fileLength = stl.length();
stl.seek(0);
for (long index = 0; index < fileLength; index++) {
if (stl.readByte() < 0) {
stl.close();
return true;
}
} stl.close();
return false; } catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} return false;
} /**
* 用于正数,因为负数存储是补码 第81~84四个字节
*
* @param arr
* @return
*/
public static int STLFaceNum(byte[] arr) {
if (arr != null && arr.length == 4) {
int a = arr[0] & (0xFF);// 防止低位转二进制后是变成负数
int b = (arr[1] << 8) & (0xFFFF);
int c = (arr[2] << 16) & (0xFFFFFF);
int d = (arr[3] << 24) & (0xFFFFFFFF);
return a + b + c + d;
}
return -1;
} /**
* resolve binary stl file
*
* @param stlPath
* @return
*/
public static STLFile parseBinary(String stlPath) { RandomAccessFile stl = null;
try {
stl = new RandomAccessFile(stlPath, "r"); stl.seek(80);
byte[] arr = { 0, 0, 0, 0 };
stl.read(arr);
int facetNum = STLFaceNum(arr); float r = 0, g = 0, b = 0;
boolean hasColors = false;
float[] colors = null;
float defaultR = 0, defaultG = 0, defaultB = 0, alpha = 0;
// process STL header
// check for default color in header ("COLOR=rgba" sequence). for (int index = 0; index < 80 - 10; index++) {
stl.seek(index);
// 6字节("COLOR=")
if (stl.readInt() == 0x434F4C4F /* COLO */&& (stl.readByte() == 0x52 /* 'R' */)
&& (stl.readByte() == 0x3D /* '=' */)) {
hasColors = true; colors = new float[facetNum * 3 * 3];// 一个面三个点每个点(r,b,g) defaultR = STLUtils.toFloat(stl.readByte()) / 255;//
defaultG = STLUtils.toFloat(stl.readByte()) / 255;//
defaultB = STLUtils.toFloat(stl.readByte()) / 255;//
alpha = STLUtils.toFloat(stl.readByte()) / 255;//
break;
}
} int dataOffset = 84;
int offset = 0; float[] vertices = new float[facetNum * 3 * 3];
float[] normals = new float[facetNum * 3 * 3];// 三角面片法向量的3个分量值数据 byte temp[] = { 0, 0, 0, 0 }; int max = 0;// 第一个三角片z轴高度
boolean isBegin = true; stl.seek(dataOffset);
for (int face = 0; face < facetNum; face++) {
// 法向量12个字节
stl.read(temp);
float normalX = STLUtils.toFloat(temp);//
stl.read(temp);
float normalY = STLUtils.toFloat(temp);//
stl.read(temp);
float normalZ = STLUtils.toFloat(temp);// 4 // 顶点坐标36字节
for (int i = 1; i <= 3; i++) {
stl.read(temp);
vertices[offset] = STLUtils.toFloat(temp);
stl.read(temp);
vertices[offset + 1] = STLUtils.toFloat(temp);
stl.read(temp);
vertices[offset + 2] = STLUtils.toFloat(temp);
if (isBegin) {
isBegin = false;
max = (int) (vertices[offset + 2]);
} normals[offset] = normalX;
normals[offset + 1] = normalY;
normals[offset + 2] = normalZ; offset += 3;// 增加位移
}
// color2字节
if (hasColors) { int packedColor = STLUtils.toInt(stl.readByte()) | STLUtils.toInt(stl.readByte()) << 8 & 0xFFFF; if ((packedColor & 0x8000) == 0) { // facet has its own
// unique color r = (packedColor & 0x1F) / 31;
g = ((packedColor >> 5) & 0x1F) / 31;
b = ((packedColor >> 10) & 0x1F) / 31;
} else { r = defaultR;
g = defaultG;
b = defaultB;
}
} else {
// 无颜色 丢弃2字节
stl.readByte();
stl.readByte();
} // 补充颜色
if (hasColors) {
colors[face * 9 + 0] = r;
colors[face * 9 + 1] = g;
colors[face * 9 + 2] = b;
colors[face * 9 + 3] = r;
colors[face * 9 + 4] = g;
colors[face * 9 + 5] = b;
colors[face * 9 + 6] = r;
colors[face * 9 + 7] = g;
colors[face * 9 + 8] = b;
} }
stl.close();
return new STLFile(max, facetNum, alpha, hasColors, vertices, normals, colors); } catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null; } public static STLFile parseASCII(String stlPath) {
int facetNum = asciiFacetNum(stlPath); RandomAccessFile stl = null;
try {
stl = new RandomAccessFile(stlPath, "r");
float[] vertices = new float[facetNum * 3 * 3];
float[] normals = new float[facetNum * 3 * 3];// 三角面片法向量的3个分量值数据 final String FACET_END = "endfacet";
StringBuffer bf = new StringBuffer();// record one-facet int facetIndex = 0;
String line = null;
while ((line = stl.readLine()) != null) {
bf.append(line);
if (line.length() > 8 && line.length() < 15 && line.contains(FACET_END)) {
// one facet
String oneFacet = bf.toString();
Matcher nMatcher = ASCII_PATTERN_NORMAL.matcher(oneFacet);
if (!nMatcher.find())
continue;
String normal = nMatcher.group(); Matcher mV = ASCII_PATTERN_VERTEX.matcher(oneFacet);
if (!mV.find())
continue;
String v1 = mV.group();// 第一个顶点
if (!mV.find())
continue;
String v2 = mV.group();// 第二个顶点
if (!mV.find())
continue;
String v3 = mV.group();// 第三个顶点 // 解析法向量
String GAP = " "; int nfIndex = facetIndex * 9;
String[] n_f_arr = normal.split(GAP);
normals[nfIndex + 6] = normals[nfIndex + 3] = normals[nfIndex] = Float.parseFloat(n_f_arr[1]);
normals[nfIndex + 1 + 6] = normals[nfIndex + 1 + 3] = normals[nfIndex + 1] = Float
.parseFloat(n_f_arr[2]);
normals[nfIndex + 2 + 6] = normals[nfIndex + 2 + 3] = normals[nfIndex + 2] = Float
.parseFloat(n_f_arr[3]);
// 解析顶点
String[] v1_f_arr = v1.split(GAP);
vertices[nfIndex + 0] = Float.parseFloat(v1_f_arr[1]);// x
vertices[nfIndex + 1] = Float.parseFloat(v1_f_arr[2]);// y
vertices[nfIndex + 2] = Float.parseFloat(v1_f_arr[3]);// z String[] v2_f_arr = v2.split(GAP);
vertices[nfIndex + 3] = Float.parseFloat(v2_f_arr[1]);
vertices[nfIndex + 4] = Float.parseFloat(v2_f_arr[2]);
vertices[nfIndex + 5] = Float.parseFloat(v2_f_arr[3]); String[] v3_f_arr = v3.split(GAP);
vertices[nfIndex + 6] = Float.parseFloat(v3_f_arr[1]);
vertices[nfIndex + 7] = Float.parseFloat(v3_f_arr[2]);
vertices[nfIndex + 8] = Float.parseFloat(v3_f_arr[3]); // set bf count=0
facetIndex++;
bf.setLength(0);
}
} stl.close();
int max = (int) vertices[2];
return new STLFile(max, facetNum, 0, false, vertices, normals, null); } catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
} /**
* 计算ascii-stl-file三角片数量
*
* @param stlPath
* @return
*/
public static final int asciiFacetNum(String stlPath) { RandomAccessFile stl = null;
int facetNum = 0;
try {
stl = new RandomAccessFile(stlPath, "r"); int lineNum = 0; int c = 0;
while (c != -1) {
switch (c = stl.read()) {
case -1:
case '\n':
lineNum++;
break;
case '\r':
stl.read();// to skip '\n'
lineNum++;
break;
default:
break;
}
} facetNum = lineNum / 7;
stl.close(); } catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return facetNum;
} /**
* -1 原码1000,0001 反码1111,1110 补码1111,1111 所以无符号值 255
*
* @param b
* @return
*/
public static int toInt(byte b) {
return (int) (b & 0xFF);
} /**
* -1 原码1000,0001 反码1111,1110 补码1111,1111 所以无符号值 255 带符号位
*
* @param b
* @return
*/
public static float toFloat(byte b) {
return (float) (b & 0xFF);
} /**
* 字节转换为浮点
*
* @param b
* 字节（至少4个字节）
* @param index
* 开始位置
* @return
*/
public static float toFloat(byte[] b) {
int l;
l = b[0];
l &= 0xff;
l |= ((int) b[1] << 8);
l &= 0xffff;
l |= ((int) b[2] << 16);
l &= 0xffffff;
l |= ((int) b[3] << 24);
return Float.intBitsToFloat(l);
} /**
* 浮点转换为字节
*
* @param f
* @return
*/
public static byte[] toByteArr(float f) { // 把float转换为byte[]
int fbit = Float.floatToIntBits(f); byte[] b = new byte[4];
for (int i = 0; i < 4; i++) {
b[i] = (byte) (fbit >> (24 - i * 8));
} // 翻转数组
int len = b.length;
// 建立一个与源数组元素类型相同的数组
byte[] dest = new byte[len];
// 为了防止修改源数组，将源数组拷贝一份副本
System.arraycopy(b, 0, dest, 0, len);
byte temp;
// 将顺位第i个与倒数第i个交换
for (int i = 0; i < len / 2; ++i) {
temp = dest[i];
dest[i] = dest[len - i - 1];
dest[len - i - 1] = temp;
} return dest; } public static void main(String args[]) { String path = "F:\\three.js-master\\examples\\models\\stl\\ascii\\pr2_head_pan.stl";// ascii
path = "F:\\three.js-master\\examples\\models\\stl\\binary\\pr2_head_pan.stl";//
// binary
path = "F:\\three.js-master\\examples\\models\\stl\\binary\\colored.stl";//
// binary-with-color
// path = "D:\\用户目录\\下载\\4s-keychain-keychain-kickstand-hHkUg.stl"; if (STLUtils.isBinary(path)) {
System.out.println(true);
STLUtils.parseBinary(path);
} else {
STLUtils.parseASCII(path);
} }
}
package test_stl.test_entry; /**
*
* @author ephuizi@gmail.com
*
*/
public class STLFile {
int max;// 第一个三角片的z高度
int facetNum;// 三角片数量
float alpha;
boolean hasColors = false;
float[] vertices;// 点 length=[faces * 3 * 3]
float[] normals;// 三角面片法向量的3个分量值数据length=[faces * 3 * 3]
float[] colors = null;// 点[r,g,b] public STLFile(int max, int facetNum, float alpha, boolean hasColors, float[] vertices, float[] normals,
float[] colors) {
this.max = max;
this.facetNum = facetNum;
this.alpha = alpha;
this.hasColors = hasColors;
this.vertices = vertices;
this.normals = normals;
this.colors = colors;
} }