How to check if an object is hitting another object during animation.

Question

Hello and thanks for your time and help. I am building a mini golf game using HTML 5 Canvas. I have a golf ball that is able to be hit around with a specific power and direction and stoping and slowing down accordingly.

However, i am stuck on finding a optimal way of detecting wether the ball is hitting or over an obstacle on the course. I have each of the obstacle objects stored in an array. So it is easy to access the x,y,height, and width of the object. I was thinking it would be best to have a for loop that goes through each of the objects checking if the ball is hitting any of them during animation. Also the x and y of the golf ball is easily accessible, its values are stored in a dictionary.

Any suggestions of testing to see if any of the obstacles are being hit?

Here is the code on how i am testing for the boundaries and having the ball bounce back correctly

function animateGolfBall(timestamp){
    if(powerBar.widthChange != 0){
        context.clearRect(0, 0, canvasTag.width, canvasTag.height);    

        if (golfBall.x > canvasTag.width - 5 || golfBall.x < 5 ) {
           golfBall.angle = 180 - golfBall.angle;
           updateGolfBall();
           drawEverything();
        } 

        else if (golfBall.y > canvasTag.height - 5 || golfBall.y < 5) {
            golfBall.angle = 360 - golfBall.angle;
            updateGolfBall();
            drawEverything();
        }
        else{
            updateGolfBall();
            drawEverything();
        }

        window.requestAnimationFrame(animateGolfBall);
        powerBar.widthChange -= 1;
    }
    else{
        golfBall.isMoving = false;
        drawEverything();
    }
}

Here is the code where the obstacles are being redrawn, and where i believe the check should be placed to see if the golf ball is hitting them

function drawObstacle(){  
    for(var i = 0; i < obsticles.length; i++){
        obsticles[i].createSquare(obsticles[i].squareX/canvasTag.width,
                                  obsticles[i].squareY/canvasTag.height,
                                  obsticles[i].squareWidth/canvasTag.width,
                                  0,
                                  obsticles[i].squareHeight/canvasTag.height,
                                  0,"pink",3,"yellow"); 


       // if { need help with logic here

            //And what to put here, and how ever many logical statements will be needed    

       // } 

}

Any help or tips would be much appreciated. If you need more code or i wasn't clear on something please let me know and ill update my question.

Answer 1

This is called collision detection. There are many ways to deal with collisions. Depending on the shape of your objects (are they circles or squares or car-shaped) and what you want to happen when a collision occurs. Does the ball bounce back? Does it stop? Is it of the most importance that the collision is detected at the edge of the object?

You can read about simple collision detection working with either square or circle shaped objects here.