是否可以将 jcsg 库与处理一起使用?

Is it possible to use jcsg library with Processing?

Processing 是一个创意编码平台 - 语言、IDE 和生态系统 - 由 Processing 社区在 Processing Foundation https://processing.org 的支持下维护。处理 Java 模式通常可以受益于 Java 库中的代码。

JCSG 是 Java 基于 BSP 的 CSG(构造立体几何)实现 https://github.com/miho/JCSG

仅从 Processing 就可以跳过几个环节,但是是的,您可以在 Processing 中使用任何 Java 库。 (只需将库 .jar 拖到保存的草图之上)

首先,您需要将 JCSG .jar library along with the VVecMath .jar 库编译为 运行 示例代码。

要做到这一点,您需要 Gradle。如果您使用了 Android SDK / Android Studio / IntelliJ / etc.

,则可以从头开始安装它或使用系统中的现有安装

正如 readme 提到的那样,在 OSX/Linux/etc 上。来自每个库文件夹 运行:

bash gradlew assemble

在 Windows 运行:

gradlew assemble

在我的例子中,我使用了 Android Studio 附带的 Gradle 安装,我的 mac:

bash /Applications/IDEsAndEditors/Android\ Studio.app/Contents/plugins/android/lib/templates/gradle/wrapper/gradlew assemble

编译 .jar 文件后,您只需将它们放入保存的 Processing sketch 中即可。这将创建一个 code 文件夹。在此阶段,您可以使用该草图中的库。

(提示:转到 Processing > Preferences 并使用 Ctrl+Space 启用 Code completion 以便更容易地查看可用的方法和属性(像 eclipse/IntelliJ/NetBeans/etc 这样的 IDE。默认情况下这样做))

我做了一个快速测试,但是 JCSG 保存的 OBJ 文件无法被 Processing 的 built-in PShape OBJ 加载器解析。

import java.nio.file.Paths;

PShape csgResult;

void setup(){
  size(900,900,P3D);
  // we use cube and sphere as base geometries
  CSG cube = new Cube(2).toCSG();
  CSG sphere = new Sphere(1.25).toCSG();

  // perform union, difference and intersection
  CSG cubePlusSphere = cube.union(sphere);
  CSG cubeMinusSphere = cube.difference(sphere);
  CSG cubeIntersectSphere = cube.intersect(sphere);

  // translate geometries to prevent overlapping 
  CSG union = cube.
          union(sphere.transformed(Transform.unity().translateX(3))).
          union(cubePlusSphere.transformed(Transform.unity().translateX(6))).
          union(cubeMinusSphere.transformed(Transform.unity().translateX(9))).
          union(cubeIntersectSphere.transformed(Transform.unity().translateX(12)));

  // save union as stl
  try {
      FileUtil.write(
              Paths.get(sketchPath("sample.obj")),
              union.toObjString()
      );
  } catch (IOException ex) {
      ex.printStackTrace();
  }

  //load shape into Processing
  csgResult = loadShape(sketchPath("sample.obj"));

}

void draw(){
  background(0);
  translate(width * 0.5, height * 0.5,0);
  scale(sin(frameCount * 0.1) * 100);
  if(csgResult != null){
    shape(csgResult);
  }
}

我做了测试,顶点在那里,面丢失了:

感觉可以试试STL格式和不同的Processing库加载, 否则访问顶点并直接在 Processing 中绘制它们,考虑到 units/scales JSCG 和 Processing 之间的不同:

import java.nio.file.Paths;

CSG union;

void setup(){
  size(900,900,P3D);
  stroke(255);
  //strokeWeight(3);
  // we use cube and sphere as base geometries
  CSG cube = new Cube(2).toCSG();
  CSG sphere = new Sphere(1.25).toCSG();

  // perform union, difference and intersection
  CSG cubePlusSphere = cube.union(sphere);
  CSG cubeMinusSphere = cube.difference(sphere);
  CSG cubeIntersectSphere = cube.intersect(sphere);

  // translate geometries to prevent overlapping 
  union = cube.
          union(sphere.transformed(Transform.unity().translateX(3))).
          union(cubePlusSphere.transformed(Transform.unity().translateX(6))).
          union(cubeMinusSphere.transformed(Transform.unity().translateX(9))).
          union(cubeIntersectSphere.transformed(Transform.unity().translateX(12)));

}

void drawCSG(CSG mesh,float scale){
  beginShape(POINTS);
  for(Polygon p : mesh.getPolygons()){
    for(Vertex v : p.vertices){
      vertex((float)v.pos.getX() * scale,(float)v.pos.getY() * scale,(float)v.pos.getZ() * scale);
    }
  }
  endShape();
}

void draw(){
  background(0);
  translate(width * 0.5, height * 0.5,0);
  rotateY(map(mouseX,0,width,-PI,PI));
  rotateX(map(mouseY,0,height,PI,-PI));

  drawCSG(union,sin(frameCount * 0.01) * 100);
}

您可以下载上面的草图(带有 pre-compiled 库)here (and the JCSG generated documentation here)。请务必阅读库的 documentation/source 代码以获得更高级的用法。

更新: 为了提高效率,您可以在设置中使用 createShape() to create a group of PShape 对象一次,然后简单地在 draw() 中渲染(与我之前的示例相反遍历所有的多边形和顶点):

// the PShape reference which will contain the converted 
PShape csgResult;

void setup(){
  size(900,900,P3D);
  noStroke();
  // JCSG sample code:
    // we use cube and sphere as base geometries
    CSG cube = new Cube(2).toCSG();
    CSG sphere = new Sphere(1.25).toCSG();

    // perform union, difference and intersection
    CSG cubePlusSphere = cube.union(sphere);
    CSG cubeMinusSphere = cube.difference(sphere);
    CSG cubeIntersectSphere = cube.intersect(sphere);

    // translate geometries to prevent overlapping 
    CSG union = cube.
            union(sphere.transformed(Transform.unity().translateX(3))).
            union(cubePlusSphere.transformed(Transform.unity().translateX(6))).
            union(cubeMinusSphere.transformed(Transform.unity().translateX(9))).
            union(cubeIntersectSphere.transformed(Transform.unity().translateX(12)));

    // translate merged geometry back by half the total translation to pivot around centre
    union = union.transformed(Transform.unity().translateX(-6));

  // Convert CSG to PShape -> Note: CSG units are small so we scale them up so the shapes are visible in Processing
  csgResult = CSGToPShape(union,45);
}
// re-usable function to convert a CSG mesh to a Processing PShape
PShape CSGToPShape(CSG mesh,float scale){
  // allocate a PShape group
  PShape csgResult = createShape(GROUP);
  // for each CSG polygon (Note: these can have 3,4 or more vertices)
  for(Polygon p : mesh.getPolygons()){
    // make a child PShape
    PShape polyShape = createShape();
    // begin setting vertices to it
    polyShape.beginShape();
    // for each vertex in the polygon
    for(Vertex v : p.vertices){
      // add each (scaled) polygon vertex 
      polyShape.vertex((float)v.pos.getX() * scale,(float)v.pos.getY() * scale,(float)v.pos.getZ() * scale);
    }
    // finish this polygon
    polyShape.endShape();
    //append the child PShape to the parent
    csgResult.addChild(polyShape);
  }
  return csgResult;
}

void draw(){
  background(0);
  lights();
  translate(width * 0.5, height * 0.5,0);
  rotateY(map(mouseX,0,width,-PI,PI));
  rotateX(map(mouseY,0,height,PI,-PI));
  shape(csgResult);
}