Final Liang-Barsky Implementation

Author: whateverxforever

GraphicsLab_LiangBarsky/p5/empty-example/sketch.js

@@ -1,112 +1,96 @@
 // Defining Boundaries of the clipping window
 let xmin = 100,
-    xmax = 500,
-    ymin = 200,
-    ymax = 400;
+  xmax = 500,
+  ymin = 200,
+  ymax = 400;
 
 function liangbarskyClipping(x1, y1, x2, y2) {
 
-    if (x1 > x2) {
-        let temp = x2;
-        x2 = x1;
-        x1 = temp;
-        temp = y2;
-        y2 = y1;
-        y1 = temp;
+  if (x1 > x2) {
+    let temp = x2;
+    x2 = x1;
+    x1 = temp;
+    temp = y2;
+    y2 = y1;
+    y1 = temp;
+  }
+
+
+  console.log("Original coords: " +
+    x1 + " " + y1 + " " + x2 + " " + y2);
+
+  let p = new Array(),
+    q = new Array(),
+    t = new Array();
+
+  let dx = x2 - x1,
+    dy = y2 - y1,
+    tmin = 0,
+    tmax = 1;
+
+  p[0] = -(x2 - x1);
+  p[1] = (x2 - x1);
+  p[2] = -(y2 - y1);
+  p[3] = (y2 - y1);
+  q[0] = x1 - xmin;
+  q[1] = xmax - x1;
+  q[2] = y1 - ymin;
+  q[3] = ymax - y1;
+
+  for (let i = 0; i < 4; i++) {
+    if (p[i] < 0) {
+      tmin = max(tmin, q[i] / p[i]);
+    } else if (p[i] > 0) {
+      tmax = min(tmax, q[i] / p[i]);
+    } else {
+      if (q[i] < 0) {
+        tmax = 0;
+        tmin = 1;
+        break;
+      }
     }
+  }
+
+  //cout<<tmin<<" "<<tmax<<endl;
+  if (tmin < tmax) {
+    stroke(255, 0, 0);
+    console.log("Final Coords: " + x1 + tmin * dx + " " + y1 + tmin * dy + " " + x1 + tmax * dx + " " + y1 + tmax * dy)
+    line(x1 + tmin * dx, y1 + tmin * dy, x1 + tmax * dx, y1 + tmax * dy);
+  } else {
+    console.log("Line is outside the boudary");
+  }
+}
 
+function setup() {
+  createCanvas(600, 600);
 
-    console.log("Original coords: " +
-        x1 + " " + y1 + " " + x2 + " " + y2);
-
-    let p1 = -(x2 - x1),
-        p2 = -p1,
-        p3 = -(y2 - y1),
-        p4 = -p3;
-
-    let q1 = x1 - xmin,
-        q2 = xmax - x1,
-        q3 = y1 - ymin,
-        q4 = ymax - y1;
-
-    let posarray = new Array();
-    let negarray = new Array();
-
-    posarray.push(1);
-    negarray.push(0);
-
-    if ((p1 == 0 && q1 < 0) || (p3 == 0 && q3 < 0)) {
-        return;
-    }
-
-    if (p1 != 0) {
-        let r1 = q1 / p1,
-            r2 = q2 / p2;
-        if (p1 < 0) {
-            negarray.push(r1);
-            posarray.push(r2);
-        } else {
-            negarray.push(r2);
-            posarray.push(r1);
-        }
-    }
-    if (p3 != 0) {
-        let r3 = q3 / p3,
-            r4 = q4 / p4;
-        if (p3 < 0) {
-            negarray.push(r3);
-            posarray.push(r4);
-        } else {
-            negarray.push(r4);
-            posarray.push(r3);
-        }
-    }
-
-    let rn1 = max(negarray),
-        rn2 = min(posarray);
-
-    if (rn1 > rn2) {
-        return;
-    }
-
-    let xn1 = x1 + p2 * rn1,
-        yn1 = y1 + p4 * rn1,
-        xn2 = x2 + p2 * rn2,
-        yn2 = y2 + p4 * rn2;
-
-
-    console.log("Clipped coords: " +
-        xn1 + " " + yn1 + " " + xn2 + " " + yn2);
 
-    stroke(0, 255, 255);
-    line(xn1, yn1, xn2, yn2);
 
-    return;
 }
 
-function setup() {
-    createCanvas(600, 600);
-    background(21);
-
-    rectMode(CENTER);
+function draw() {
+  // put drawing code here
+  background(21);
+
+  rectMode(CENTER);
+  stroke(255);
+  strokeWeight(2);
+  noFill();
+  rect(300, 300, 400, 200);
+  strokeWeight(0.5);
+
+  for (let i = 0; i < 5; i++) {
+    let x1 = random(0, width),
+      y1 = random(0, height),
+      x2 = random(0, width),
+      y2 = random(0, height);
     stroke(255);
-    strokeWeight(2);
-    noFill();
-    rect(300, 300, 400, 200);
-
-    for (let i = 0; i < 1; i++) {
-        let x1 = random(0, width),
-            y1 = random(0, height),
-            x2 = random(0, width),
-            y2 = random(0, height);
-        stroke(255);
-        line(x1, y1, x2, y2);
-
-        liangbarskyClipping(x1, y1, x2, y2);
-    }
+    line(x1, y1, x2, y2);
+
+    liangbarskyClipping(x1, y1, x2, y2);
+  }
+
+  frameRate(0.5);
 
-}
 
-function draw() {
-    // put drawing code here
 }