Complex Shape Colission

Chrisir

Re: Complex Shape Colission

10 months ago

timpulver brought up this

The question was how to do collision detection (spaceship - bullet).

Easiest solution would be to check the colour of the screen where the bullet is currently at, like

Copy code

loadPixels();
if(pixels[bulletX, bulletY] == color(255, 0, 0)){
// red ship was hit
}
else if...

krazed_lo..

Re: Re: Complex Shape Colission

10 months ago

My partner and I have been working on this since last night. Where exactly do we paste this code and how do we set it so that a message will pop up that says you win or lose if you hit/ miss the object needed to win? For our program specifically , we want the ball to hit a blue ship for a win and if it hits anything else or goes off screen it will count as a loss.

int y; // The rising cannon integer
int rise; // Same^
// some things that the computer needs to remember
int x = 150; // the position of the critter
int dir = 1; // which way is it moving +1 = right, -1 = left
int z; // The Mother Ship's movement integer
int climb; // Same ^^
void setup() {
y=1;
rise=2;
climb= 2;
size(1000, 1000);
}
void draw() {
if (mousePressed){
background(150);
frameRate(1000);
// Blue MotherShip
fill(0,0,255); // Blue
noStroke();
rect( 750 - z, 60, 10, 10); // 1st line
rect( 760 - z, 50, 10, 20); // 2nd line
rect( 770 - z, 43, 10, 45); // 3rd line
rect( 780 - z, 34, 10, 64); // 4th line
rect( 790-z, 34, 10, 54);//5th line
rect( 800 - z, 20 , 10, 60); // 6th line
rect( 810 - z, 20 , 10, 60); // 7th line
rect( 820 - z, 20 , 10, 68); // 8th line
rect( 830 - z, 20 , 10, 68); // 9th line
rect(840 - z, 20, 10, 60);//10th line
rect(850-z, 20, 10, 60); //11th line
rect( 860 - z, 34, 10, 55); // 12th line
rect(870 -z, 34, 10, 65);//13th line
rect( 880 - z, 43, 10, 45); // 14th line
rect( 890 - z, 50, 10, 20); // 15th line
rect( 900 - z, 60, 10, 10); // 16th line
// Red SubShip
fill(255,0,0);
noStroke();
rect(740-0, 160, 10, 10); // 1st line
rect( 750 - 0, 150, 10, 20); // 1st line
rect( 760 - 0, 160, 10, 10); // 2nd line
rect( 770 - 0, 160, 10, 20); // 3rd line
rect( 780 - 0, 160, 10, 20); // 4th line
rect( 790-0, 160, 10, 10);//5th line
rect( 800 - 0, 150 , 10, 20); // 6th line
rect( 810 - 0, 160 , 10, 10); // 7th line
// Yellow-> Green Subship
fill(0,255,0);
rect(200-0, 160, 10, 10); // 1st line
rect( 210 - 0, 150, 10, 20); // 1st line
rect( 220 - 0, 160, 10, 10); // 2nd line
rect( 230 - 0, 160, 10, 20); // 3rd line
rect( 240 - 0, 160, 10, 20); // 4th line
rect( 250-0, 160, 10, 10);//5th line
rect( 260 - 0, 150 , 10, 20); // 6th line
rect( 270 - 0, 160 , 10, 10); // 7th line
// Camoflauged SubShip
fill (0);
rect(460, 300, 10, 10); // 1st line
rect( 470 - 0, 290, 10, 20); // 1st line
rect( 480 - 0, 300, 10, 10); // 2nd line
rect( 490 - 0, 300, 10, 20); // 3rd line
rect( 500 - 0, 300, 10, 20); // 4th line
rect( 510-0, 300, 10, 10);//5th line
rect( 520 - 0, 290 , 10, 20); // 6th line
rect( 530 - 0, 300 , 10, 10); // 7th line
// Purple SubShip
fill(237, 171, 29);
rect(50, 300, 10, 10); // 1st line
rect( 60 - 0, 290, 10, 20); // 1st line
rect( 70 - 0, 300, 10, 10); // 2nd line
rect( 80 - 0, 300, 10, 20); // 3rd line
rect( 90 - 0, 300, 10, 20); // 4th line
rect( 100-0, 300, 10, 10);//5th line
rect( 110 - 0, 290 , 10, 20); // 6th line
rect( 120 - 0, 300 , 10, 10); // 7th line
// Light Blue SubShip
fill(103, 224, 232);
rect(880, 300, 10, 10); // 1st line
rect( 890 - 0, 290, 10, 20); // 1st line
rect( 900 - 0, 300, 10, 10); // 2nd line
rect( 910 - 0, 300, 10, 20); // 3rd line
rect( 920 - 0, 300, 10, 20); // 4th line
rect( 930-0, 300, 10, 10);//5th line
rect( 940 - 0, 290 , 10, 20); // 6th line
rect( 950 - 0, 300 , 10, 10); // 7th line
if ( climb >1)// RULE FOR MOTHERSHIP
z= z+1;
if( rise >1)// RULE FOR CANNON
y= y+1;
// Hero Ship
fill(255,0,0); // Red
ellipse(x, 600, 60, 30);
fill(0);
ellipse(x, 550-y, 15,15);
}
else {
background (150);
frameRate(1000);
// Blue MotherShip
fill(0,0,255);
noStroke();
rect( 750 - 0, 60, 10, 10); // 1st line
rect( 760 - 0, 50, 10, 20); // 2nd line
rect( 770 - 0, 43, 10, 45); // 3rd line
rect( 780 - 0, 34, 10, 64); // 4th line
rect( 790-0, 34, 10, 54);//5th line
rect( 800 - 0, 20 , 10, 60); // 6th line
rect( 810 - 0, 20 , 10, 60); // 7th line
rect( 820 - 0, 20 , 10, 68); // 8th line
rect( 830 - 0, 20 , 10, 68); // 9th line
rect(840 - 0, 20, 10, 60);//10th line
rect(850-0, 20, 10, 60); //11th line
rect( 860 - 0, 34, 10, 55); // 12th line
rect(870 -0, 34, 10, 65);//13th line
rect( 880 - 0, 43, 10, 45); // 14th line
rect( 890 - 0, 50, 10, 20); // 15th line
rect( 900 - 0, 60, 10, 10); // 16th line
// Red SubShip
noStroke();
rect(740-0, 160, 10, 10); // 1st line
rect( 750 - 0, 150, 10, 20); // 1st line
rect( 760 - 0, 160, 10, 10); // 2nd line
rect( 770 - 0, 160, 10, 20); // 3rd line
rect( 780 - 0, 160, 10, 20); // 4th line
rect( 790-0, 160, 10, 10);//5th line
rect( 800 - 0, 150 , 10, 20); // 6th line
rect( 810 - 0, 160 , 10, 10); // 7th line
// Yellow Subship
noStroke();
fill(224,218,11);
rect(200-0, 160, 10, 10); // 1st line
rect( 210 - 0, 150, 10, 20); // 1st line
rect( 220 - 0, 160, 10, 10); // 2nd line
rect( 230 - 0, 160, 10, 20); // 3rd line
rect( 240 - 0, 160, 10, 20); // 4th line
rect( 250-0, 160, 10, 10);//5th line
rect( 260 - 0, 150 , 10, 20); // 6th line
rect( 270 - 0, 160 , 10, 10); // 7th line
// Purple SubShip
fill(123, 41, 142);
rect(50, 300, 10, 10); // 1st line
rect( 60 - 0, 290, 10, 20); // 1st line
rect( 70 - 0, 300, 10, 10); // 2nd line
rect( 80 - 0, 300, 10, 20); // 3rd line
rect( 90 - 0, 300, 10, 20); // 4th line
rect( 100-0, 300, 10, 10);//5th line
rect( 110 - 0, 290 , 10, 20); // 6th line
rect( 120 - 0, 300 , 10, 10); // 7th line
// Light Blue SubShip
fill(103, 224, 232);
rect(880, 300, 10, 10); // 1st line
rect( 890 - 0, 290, 10, 20); // 1st line
rect( 900 - 0, 300, 10, 10); // 2nd line
rect( 910 - 0, 300, 10, 20); // 3rd line
rect( 920 - 0, 300, 10, 20); // 4th line
rect( 930-0, 300, 10, 10);//5th line
rect( 940 - 0, 290 , 10, 20); // 6th line
rect( 950 - 0, 300 , 10, 10); // 7th line
// Start Line
fill( 237, 29, 199);
rect( 475, 545, 50, 10);
// Hero Ship
fill(0); //
fill(255,0,0);
ellipse(x, 600, 60, 30);
fill(0);
ellipse(x, 550, 15,15);
}
// adjust the position and direction
x = x + dir;
if (x < mouseX) {
dir = 1;
}
else if (x > mouseX) {
dir = -1;
}
else {
dir = 0;
}
}

cammie827

Re: Complex Shape Colission

10 months ago

I thought of this, but my game is drawn in "wireframe" style, so it's monochromatic, and nothing is filled.

Chrisir

Re: Complex Shape Colission

10 months ago

funny, another guy from your class is in the other thread....

you could use an invisible canvas and paint it there virtually. Then you check the bullet on that. All positions must be the same of course.

http://www.processing.org/reference/createImage_.html

asimes

Re: Complex Shape Colission

10 months ago

Assuming that you are only interested in testing if the bullet is "inside" your object the test below will work. The basic idea is to treat the bullet as a point. Now that point has to be extended in some direction to become a line (it is extended to the right edge of the screen in my code) and you start with the assumption that the point (your bullet) is not inside the object. Every time the line passes through a line of your object (intersects a line) on the way to the right side of the screen, flip whether you are inside or outside the object. When you have "reached" the right side of the screen you will know if you are inside or outside the object based on how many lines you passed through (odd number inside, even number outside):

int numVerts = 4;
float pointX, pointY;
float[] polyX = new float[numVerts];
float[] polyY = new float[numVerts];
void setup() {
size(600, 600);
noFill();
smooth();
pointX = width/2;
pointY = height/2;
randomPoly();
pointInPoly();
}
void draw() {
background(255);
beginShape();
for (int i = 0; i < numVerts; i++) vertex(polyX[i], polyY[i]);
endShape(CLOSE);
ellipse(pointX, pointY, 3, 3);
}
void pointInPoly() {
boolean in = false;
// Treat the point as a line to the right edge of the screen
float a_x1 = pointX;
float a_y1 = pointY;
float a_x2 = width;
float a_y2 = pointY;
for (int i = 0; i < numVerts; i++) {
// Get end points of each polygon line
int i2 = (i+1)%numVerts;
float b_x1 = polyX[i];
float b_y1 = polyY[i];
float b_x2 = polyX[i2];
float b_y2 = polyY[i2];
// Delta x and y for lines a and b
float a_dx = a_x2-a_x1;
float a_dy = a_y2-a_y1;
float b_dx = b_x2-b_x1;
float b_dy = b_y2-b_y1;
// Test if lines are parallel
float dotP_Perp = a_dx*b_dy-a_dy*b_dx;
if (dotP_Perp != 0) {
// Differences in x1 and y1 of lines a and b
float ab_dx1 = b_x1-a_x1;
float ab_dy1 = b_y1-a_y1;
// Paramateric values of t of lines a and b
float a_t = (ab_dx1*a_dy-ab_dy1*a_dx)/dotP_Perp;
float b_t = (ab_dx1*b_dy-ab_dy1*b_dx)/dotP_Perp;
// Only interested if finite lines intersect
if (a_t >= 0 && a_t <= 1 && b_t >= 0 && b_t <= 1) in = !in;
}
}
println(in);
}
void randomPoly() {
for (int i = 0; i < numVerts; i++) {
polyX[i] = random(width);
polyY[i] = random(height);
}
}
void mousePressed() {
randomPoly();
pointInPoly();
}

EDIT: In my code the polygon is drawn as a series of lines that touch each other (vertex 1 touches 2 which touches 3 which touches 4 which touches 1 etc)

cammie827

Re: Complex Shape Colission

10 months ago

Thanks! This will do for my purposes. Can you explain how toe code works so that I may adapt it? I understand everything up to the parallel test. How does this determine wether or not a line has been intersected?

asimes

Re: Complex Shape Colission

10 months ago

Pretend this happens over time (it would be slower to do in time so I just test it in "one time step"). The point starts at the center of the screen and moves to the right of the screen. Every time it passes a line, whether it is inside or outside is flipped (is originally outside). When it has reached the right side of the screen, it has passed some number of lines and if that number was odd the point is inside the polygon.

- "Passing a line" is actually whether or not the line representing the point to right edge intersected another line.

- It is very important that no lines of your object go beyond the right side of the screen. If they do, then you will have make the "bullet to right side of the screen" line longer.

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