moving the OpenGL examples to the core

java/examples/OpenGL/Animation/Yellowtail/Gesture.pde

@@ -0,0 +1,256 @@
+class Gesture {
+
+  float  damp = 5.0;
+  float  dampInv = 1.0 / damp;
+  float  damp1 = damp - 1;
+
+  int w;
+  int h;
+  int capacity;
+
+  Vec3f path[];
+  int crosses[];
+  Polygon polygons[];
+  int nPoints;
+  int nPolys;
+
+  float jumpDx, jumpDy;
+  boolean exists;
+  float INIT_TH = 14;
+  float thickness = INIT_TH;
+
+  Gesture(int mw, int mh) {
+    w = mw;
+    h = mh;
+    capacity = 600;
+    path = new Vec3f[capacity];
+    polygons = new Polygon[capacity];
+    crosses  = new int[capacity];
+    for (int i=0;i<capacity;i++) {
+      polygons[i] = new Polygon();
+      polygons[i].npoints = 4;
+      path[i] = new Vec3f();
+      crosses[i] = 0;
+    }
+    nPoints = 0;
+    nPolys = 0;
+
+    exists = false;
+    jumpDx = 0;
+    jumpDy = 0;
+  }
+
+  void clear() {
+    nPoints = 0;
+    exists = false;
+    thickness = INIT_TH;
+  }
+
+  void clearPolys() {
+    nPolys = 0;
+  }
+
+  void addPoint(float x, float y) {
+
+    if (nPoints >= capacity) {
+      // there are all sorts of possible solutions here,
+      // but for abject simplicity, I don't do anything.
+    } 
+    else {
+      float v = distToLast(x, y);
+      float p = getPressureFromVelocity(v);
+      path[nPoints++].set(x,y,p);
+
+      if (nPoints > 1) {
+        exists = true;
+        jumpDx = path[nPoints-1].x - path[0].x;
+        jumpDy = path[nPoints-1].y - path[0].y;
+      }
+    }
+
+  }
+
+  float getPressureFromVelocity(float v) {
+    final float scale = 18;
+    final float minP = 0.02;
+    final float oldP = (nPoints > 0) ? path[nPoints-1].p : 0;
+    return ((minP + max(0, 1.0 - v/scale)) + (damp1*oldP))*dampInv;
+  }
+
+  void setPressures() {
+    // pressures vary from 0...1
+    float pressure;
+    Vec3f tmp;
+    float t = 0;
+    float u = 1.0 / (nPoints - 1)*TWO_PI;
+    for (int i = 0; i < nPoints; i++) {
+      pressure = sqrt((1.0 - cos(t))*0.5);
+      path[i].p = pressure;
+      t += u;
+    }
+  }
+
+  float distToLast(float ix, float iy) {
+    if (nPoints > 0) {
+      Vec3f v = path[nPoints-1];
+      float dx = v.x - ix;
+      float dy = v.y - iy;
+      return mag(dx, dy);
+    } 
+    else {
+      return 30;
+    }
+  }
+
+  void compile() {
+    // compute the polygons from the path of Vec3f's
+    if (exists) {
+      clearPolys();
+
+      Vec3f p0, p1, p2;
+      float radius0, radius1;
+      float ax, bx, cx, dx;
+      float ay, by, cy, dy;
+      int   axi, bxi, cxi, dxi, axip, axid;
+      int   ayi, byi, cyi, dyi, ayip, ayid;
+      float p1x, p1y;
+      float dx01, dy01, hp01, si01, co01;
+      float dx02, dy02, hp02, si02, co02;
+      float dx13, dy13, hp13, si13, co13;
+      float taper = 1.0;
+
+      int  nPathPoints = nPoints - 1;
+      int  lastPolyIndex = nPathPoints - 1;
+      float npm1finv =  1.0 / max(1, nPathPoints - 1);
+
+      // handle the first point
+      p0 = path[0];
+      p1 = path[1];
+      radius0 = p0.p * thickness;
+      dx01 = p1.x - p0.x;
+      dy01 = p1.y - p0.y;
+      hp01 = sqrt(dx01*dx01 + dy01*dy01);
+      if (hp01 == 0) {
+        hp02 = 0.0001;
+      }
+      co01 = radius0 * dx01 / hp01;
+      si01 = radius0 * dy01 / hp01;
+      ax = p0.x - si01; 
+      ay = p0.y + co01;
+      bx = p0.x + si01; 
+      by = p0.y - co01;
+
+      int xpts[];
+      int ypts[];
+
+      int LC = 20;
+      int RC = w-LC;
+      int TC = 20;
+      int BC = h-TC;
+      float mint = 0.618;
+      float tapow = 0.4;
+
+      // handle the middle points
+      int i = 1;
+      Polygon apoly;
+      for (i = 1; i < nPathPoints; i++) {
+        taper = pow((lastPolyIndex-i)*npm1finv,tapow);
+
+        p0 = path[i-1];
+        p1 = path[i  ];
+        p2 = path[i+1];
+        p1x = p1.x;
+        p1y = p1.y;
+        radius1 = Math.max(mint,taper*p1.p*thickness);
+
+        // assumes all segments are roughly the same length...
+        dx02 = p2.x - p0.x;
+        dy02 = p2.y - p0.y;
+        hp02 = (float) Math.sqrt(dx02*dx02 + dy02*dy02);
+        if (hp02 != 0) {
+          hp02 = radius1/hp02;
+        }
+        co02 = dx02 * hp02;
+        si02 = dy02 * hp02;
+
+        // translate the integer coordinates to the viewing rectangle
+        axi = axip = (int)ax;
+        ayi = ayip = (int)ay;
+        axi=(axi<0)?(w-((-axi)%w)):axi%w;
+        axid = axi-axip;
+        ayi=(ayi<0)?(h-((-ayi)%h)):ayi%h;
+        ayid = ayi-ayip;
+
+        // set the vertices of the polygon
+        apoly = polygons[nPolys++];
+        xpts = apoly.xpoints;
+        ypts = apoly.ypoints;
+        xpts[0] = axi = axid + axip;
+        xpts[1] = bxi = axid + (int) bx;
+        xpts[2] = cxi = axid + (int)(cx = p1x + si02);
+        xpts[3] = dxi = axid + (int)(dx = p1x - si02);
+        ypts[0] = ayi = ayid + ayip;
+        ypts[1] = byi = ayid + (int) by;
+        ypts[2] = cyi = ayid + (int)(cy = p1y - co02);
+        ypts[3] = dyi = ayid + (int)(dy = p1y + co02);
+
+        // keep a record of where we cross the edge of the screen
+        crosses[i] = 0;
+        if ((axi<=LC)||(bxi<=LC)||(cxi<=LC)||(dxi<=LC)) { 
+          crosses[i]|=1; 
+        }
+        if ((axi>=RC)||(bxi>=RC)||(cxi>=RC)||(dxi>=RC)) { 
+          crosses[i]|=2; 
+        }
+        if ((ayi<=TC)||(byi<=TC)||(cyi<=TC)||(dyi<=TC)) { 
+          crosses[i]|=4; 
+        }
+        if ((ayi>=BC)||(byi>=BC)||(cyi>=BC)||(dyi>=BC)) { 
+          crosses[i]|=8; 
+        }
+
+        //swap data for next time
+        ax = dx; 
+        ay = dy;
+        bx = cx; 
+        by = cy;
+      }
+
+      // handle the last point
+      p2 = path[nPathPoints];
+      apoly = polygons[nPolys++];
+      xpts = apoly.xpoints;
+      ypts = apoly.ypoints;
+
+      xpts[0] = (int)ax;
+      xpts[1] = (int)bx;
+      xpts[2] = (int)(p2.x);
+      xpts[3] = (int)(p2.x);
+
+      ypts[0] = (int)ay;
+      ypts[1] = (int)by;
+      ypts[2] = (int)(p2.y);
+      ypts[3] = (int)(p2.y);
+
+    }
+  }
+
+  void smooth() {
+    // average neighboring points
+
+    final float weight = 18;
+    final float scale  = 1.0 / (weight + 2);
+    int nPointsMinusTwo = nPoints - 2;
+    Vec3f lower, upper, center;
+
+    for (int i = 1; i < nPointsMinusTwo; i++) {
+      lower = path[i-1];
+      center = path[i];
+      upper = path[i+1];
+
+      center.x = (lower.x + weight*center.x + upper.x)*scale;
+      center.y = (lower.y + weight*center.y + upper.y)*scale;
+    }
+  }
+}
+

java/examples/OpenGL/Animation/Yellowtail/Vec3f.pde

@@ -0,0 +1,19 @@
+class Vec3f {
+  float x;
+  float y;
+  float p;  // Pressure
+
+  Vec3f() {
+    set(0, 0, 0);
+  }
+  
+  Vec3f(float ix, float iy, float ip) {
+    set(ix, iy, ip);
+  }
+
+  void set(float ix, float iy, float ip) {
+    x = ix;
+    y = iy;
+    p = ip;
+  }
+}

java/examples/OpenGL/Animation/Yellowtail/Yellowtail.pde

@@ -0,0 +1,189 @@
+/**
+ * Yellowtail
+ * by Golan Levin (www.flong.com). 
+ * 
+ * Click, drag, and release to create a kinetic gesture.
+ * 
+ * Yellowtail (1998-2000) is an interactive software system for the gestural 
+ * creation and performance of real-time abstract animation. Yellowtail repeats 
+ * a user's strokes end-over-end, enabling simultaneous specification of a 
+ * line's shape and quality of movement. Each line repeats according to its 
+ * own period, producing an ever-changing and responsive display of lively, 
+ * worm-like textures.
+ */
+
+
+import java.awt.Polygon;
+
+Gesture gestureArray[];
+final int nGestures = 36;  // Number of gestures
+final int minMove = 3;     // Minimum travel for a new point
+int currentGestureID;
+
+Polygon tempP;
+int tmpXp[];
+int tmpYp[];
+
+
+void setup() {
+  size(1024, 768, P2D);
+  background(0, 0, 0);
+  noStroke();
+
+  currentGestureID = -1;
+  gestureArray = new Gesture[nGestures];
+  for (int i = 0; i < nGestures; i++) {
+    gestureArray[i] = new Gesture(width, height);
+  }
+  clearGestures();
+}
+
+
+void draw() {
+  background(0);
+
+  updateGeometry();
+  fill(255, 255, 245);
+  for (int i = 0; i < nGestures; i++) {
+    renderGesture(gestureArray[i], width, height);
+  }
+}
+
+void mousePressed() {
+  currentGestureID = (currentGestureID+1) % nGestures;
+  Gesture G = gestureArray[currentGestureID];
+  G.clear();
+  G.clearPolys();
+  G.addPoint(mouseX, mouseY);
+}
+
+
+void mouseDragged() {
+  if (currentGestureID >= 0) {
+    Gesture G = gestureArray[currentGestureID];
+    if (G.distToLast(mouseX, mouseY) > minMove) {
+      G.addPoint(mouseX, mouseY);
+      G.smooth();
+      G.compile();
+    }
+  }
+}
+
+
+void keyPressed() {
+  if (key == '+' || key == '=') {
+    if (currentGestureID >= 0) {
+      float th = gestureArray[currentGestureID].thickness;
+      gestureArray[currentGestureID].thickness = min(96, th+1);
+      gestureArray[currentGestureID].compile();
+    }
+  } else if (key == '-') {
+    if (currentGestureID >= 0) {
+      float th = gestureArray[currentGestureID].thickness;
+      gestureArray[currentGestureID].thickness = max(2, th-1);
+      gestureArray[currentGestureID].compile();
+    }
+  } else if (key == ' ') {
+    clearGestures();
+  }
+}
+
+
+void renderGesture(Gesture gesture, int w, int h) {
+  if (gesture.exists) {
+    if (gesture.nPolys > 0) {
+      Polygon polygons[] = gesture.polygons;
+      int crosses[] = gesture.crosses;
+
+      int xpts[];
+      int ypts[];
+      Polygon p;
+      int cr;
+
+      beginShape(QUADS);
+      int gnp = gesture.nPolys;
+      for (int i=0; i<gnp; i++) {
+
+        p = polygons[i];
+        xpts = p.xpoints;
+        ypts = p.ypoints;
+
+        vertex(xpts[0], ypts[0]);
+        vertex(xpts[1], ypts[1]);
+        vertex(xpts[2], ypts[2]);
+        vertex(xpts[3], ypts[3]);
+
+        if ((cr = crosses[i]) > 0) {
+          if ((cr & 3)>0) {
+            vertex(xpts[0]+w, ypts[0]);
+            vertex(xpts[1]+w, ypts[1]);
+            vertex(xpts[2]+w, ypts[2]);
+            vertex(xpts[3]+w, ypts[3]);
+
+            vertex(xpts[0]-w, ypts[0]);
+            vertex(xpts[1]-w, ypts[1]);
+            vertex(xpts[2]-w, ypts[2]);
+            vertex(xpts[3]-w, ypts[3]);
+          }
+          if ((cr & 12)>0) {
+            vertex(xpts[0], ypts[0]+h);
+            vertex(xpts[1], ypts[1]+h);
+            vertex(xpts[2], ypts[2]+h);
+            vertex(xpts[3], ypts[3]+h);
+
+            vertex(xpts[0], ypts[0]-h);
+            vertex(xpts[1], ypts[1]-h);
+            vertex(xpts[2], ypts[2]-h);
+            vertex(xpts[3], ypts[3]-h);
+          }
+
+          // I have knowingly retained the small flaw of not
+          // completely dealing with the corner conditions
+          // (the case in which both of the above are true).
+        }
+      }
+      endShape();
+    }
+  }
+}
+
+void updateGeometry() {
+  Gesture J;
+  for (int g=0; g<nGestures; g++) {
+    if ((J=gestureArray[g]).exists) {
+      if (g!=currentGestureID) {
+        advanceGesture(J);
+      } else if (!mousePressed) {
+        advanceGesture(J);
+      }
+    }
+  }
+}
+
+void advanceGesture(Gesture gesture) {
+  // Move a Gesture one step
+  if (gesture.exists) { // check
+    int nPts = gesture.nPoints;
+    int nPts1 = nPts-1;
+    Vec3f path[];
+    float jx = gesture.jumpDx;
+    float jy = gesture.jumpDy;
+
+    if (nPts > 0) {
+      path = gesture.path;
+      for (int i = nPts1; i > 0; i--) {
+        path[i].x = path[i-1].x;
+        path[i].y = path[i-1].y;
+      }
+      path[0].x = path[nPts1].x - jx;
+      path[0].y = path[nPts1].y - jy;
+      gesture.compile();
+    }
+  }
+}
+
+void clearGestures() {
+  for (int i = 0; i < nGestures; i++) {
+    gestureArray[i].clear();
+  }
+}