зеркало из https://github.com/mozilla/popcorn-js.git
122 строки
3.2 KiB
Plaintext
122 строки
3.2 KiB
Plaintext
// All Examples Written by Casey Reas and Ben Fry
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// unless otherwise stated.
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float baseX1, baseY1, baseX2, baseY2;
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float baseLength;
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float[] xCoords, yCoords;
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float ellipseX, ellipseY, ellipseRadius = 6;
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float directionX, directionY;
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float ellipseSpeed = 3.5;
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float velocityX, velocityY;
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void setup(){
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size(200, 200);
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frameRate(30);
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fill(128);
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smooth();
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baseX1 = 0;
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baseY1 = height-150;
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baseX2 = width;
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baseY2 = height;
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// start ellipse at middle top of screen
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ellipseX = width/2;
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// calculate initial random direction
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directionX = random(0.1, 0.99);
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directionY = random(0.1, 0.99);
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// normalize direction vector
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float directionVectLength = sqrt(directionX*directionX +
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directionY*directionY);
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directionX /= directionVectLength;
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directionY /= directionVectLength;
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}
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void draw(){
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// draw background
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fill(0, 12);
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noStroke();
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rect(0, 0, width, height);
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// calculate length of base top
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baseLength = dist(baseX1, baseY1, baseX2, baseY2);
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xCoords = new float[ceil(baseLength)];
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yCoords = new float[ceil(baseLength)];
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// fill base top coordinate array
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for (int i=0; i<xCoords.length; i++){
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xCoords[i] = baseX1 + ((baseX2-baseX1)/baseLength)*i;
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yCoords[i] = baseY1 + ((baseY2-baseY1)/baseLength)*i;
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}
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// draw base
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fill(200);
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quad(baseX1, baseY1, baseX2, baseY2, baseX2, height, 0, height);
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// calculate base top normal
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float baseDeltaX = (baseX2-baseX1)/baseLength;
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float baseDeltaY = (baseY2-baseY1)/baseLength;
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float normalX = -baseDeltaY;
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float normalY = baseDeltaX;
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// draw ellipse
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noFill();
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stroke(200);
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ellipse(ellipseX, ellipseY, ellipseRadius*2, ellipseRadius*2);
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// calculate ellipse velocity
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velocityX = directionX * ellipseSpeed;
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velocityY = directionY * ellipseSpeed;
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// move elipse
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ellipseX += velocityX;
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ellipseY += velocityY;
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// normalized incidence vector
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float incidenceVectorX = -directionX;
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float incidenceVectorY = -directionY;
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// detect and handle collision
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for (int i=0; i<xCoords.length; i++){
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// check distance between ellipse and base top coordinates
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if (dist(ellipseX, ellipseY, xCoords[i], yCoords[i]) < ellipseRadius){
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// calculate dot product of incident vector and base top normal
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float dot = incidenceVectorX*normalX + incidenceVectorY*normalY;
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// calculate reflection vector
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float reflectionVectorX = 2*normalX*dot - incidenceVectorX;
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float reflectionVectorY = 2*normalY*dot - incidenceVectorY;
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// assign reflection vector to direction vector
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directionX = reflectionVectorX;
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directionY = reflectionVectorY;
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// draw base top normal at collision point
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stroke(255, 128, 0);
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line(ellipseX, ellipseY, ellipseX-normalX*100,
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ellipseY-normalY*100);
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}
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}
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// detect boundary collision
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// right
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if (ellipseX > width-ellipseRadius){
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ellipseX = width-ellipseRadius;
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directionX *= -1;
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}
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// left
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if (ellipseX < ellipseRadius){
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ellipseX = ellipseRadius;
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directionX *= -1;
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}
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// top
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if (ellipseY < ellipseRadius){
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ellipseY = ellipseRadius;
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directionY *= -1;
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// randomize base top
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baseY1 = random(height-100, height);
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baseY2 = random(height-100, height);
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}
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}
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