Removing a drawn pixel

[Noon22]

Hey, I'm quite new to DirectX and I've found Chili's Framework very helpful. I've made just a simple Space Invaders game to test myself, and I feel I've done OK. However I'd like to know how to remove a certain pixel if a condition is met. (In my case, if the Enemy reaches the player or the missile reaches the Enemy/Top of screen). I'm using the PutPixel command, so I'd be grateful if anyone could tell me how to achieve this.

[Musi]

Sounds like you mean collision detection. The simplest way is to make a box around the enemy and then test every frame to see if the pixel is inside the box. Also, to see if the pixel has gone past the top of the screen you just have to test if the Y coordinate is less than 0.

[Noon22]

Alright, thanks I fixed my previous issue with your help, however I would like to know how to have it so when I press space once, it places a pixel above X, (and doesn't keep updating its x position) and keep moving upwards. I made a Boolean which sets itself to true once space is pressed, however then when I store the X position of the player into another variable, it keeps updating, because the Boolean is set to true. Any idea how to go about solving this?

[albinopapa]

There are two states for the keys pressed and released so maybe you could use an if statement that;

Code: Select all

if(SpaceIsPressed)
{
     PutPixel (?,?,?,?,?);
}

That way the PutPixel line will be skipped if the spacebar is not pressed.

[Musi]

Hmm, can't say why the new X variable is updating without seeing the code. If i have to guess, id say you're making the pixels X coordinate = players X coordinate every frame when it should only be done once when its created.

[Noon22]

Thanks, I fixed it by initializing it outside of the Loop with your help.