74 lines
1.3 KiB
Plaintext
74 lines
1.3 KiB
Plaintext
/**
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Bryn Mawr College, Department of Computer Science <br>
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Classic starfield using 2D transformations and z-scaling.
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*/
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// Array of stars
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Star[] stars = new Star[400];
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void setup() {
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size(600, 600);
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smooth();
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stroke(255);
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strokeWeight(5);
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// Init all stars
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for (int i=0; i<stars.length; i++)
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stars[i] = new Star();
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}
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void draw() {
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background(0);
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// Draw all stars wrt center of screen
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translate(0.5*width, 0.5*height);
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// Update and draw all stars
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for (int i=0; i<stars.length; i++) {
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stars[i].update();
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stars[i].draw();
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}
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}
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class Star {
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// Star coordinates in 3D
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float x;
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float y;
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float z;
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Star() {
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x = random(-5000, 5000);
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y = random(-5000, 5000);
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z = random(0, 2000);
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}
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void update() {
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z-=10; // Move star closer to viewport
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if (z <= 0.0) // Reset star if it passes viewport
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reset();
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}
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void reset() {
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// Reset star to a position far away
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x = random(-5000, 5000);
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y = random(-5000, 5000);
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z = 2000.0;
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}
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void draw() {
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// Project star only viewport
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float offsetX = 100.0*(x/z);
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float offsetY = 100.0*(y/z);
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float scaleZ = 0.0001*(2000.0-z);
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// Draw this star
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pushMatrix();
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translate(offsetX, offsetY);
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scale(scaleZ);
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ellipse(0,0,20,20);
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popMatrix();
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}
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}
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