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;// 6 defaultG = STLUtils.toFloat(stl.readByte()) / 255;// 7 defaultB = STLUtils.toFloat(stl.readByte()) / 255;// 8 alpha = STLUtils.toFloat(stl.readByte()) / 255;// 9 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);// 4 stl.read(temp);
float normalY = STLUtils.toFloat(temp);// 4 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:\\\hree.js-master\\\\examples\\\\models\\\\stl\\\\ascii\\\\pr2_head_pan.stl\";// ascii path = \"F:\\\hree.js-master\\\\examples\\\\models\\\\stl\\\\binary\\\\pr2_head_pan.stl\";// // binary
path = \"F:\\\hree.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; }}
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