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Mouse State in DirectX

Started by wisey May 11, 2012 at 6:04 PM 7 replies 2.2k views

Original Post

May 11, 2012 at 6:04 PM

Hi

I'm working with DirectX.

I want to be able to get my apps relative x and y position of the mouse. In Xna I did this:

MouseState mouseState = Mouse.GetState();
mouseActor.Position = new Vector2(mouseState.X, mouseState.Y);

Where MouseState and Mouse are usable types in xna.

because i want to be able to able to draw mouseActor in the location of the mouse pointer, and also have another actor drawn in the middle of the screen and i'm trying to draw a line between them.

It is really simple in xna but I thought it might be a tad more complicated in directX. I've read some forums and tutorials but I'm still none the wiser about how to get my problem implemented.

The reason I thought it might be simple is that I used this code to update the position of a sprite on screen, my player sprite, with an xbox controller.

http://ideone.com/HoGHm

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Wisey

Tispe

May 11, 2012 at 6:11 PM

Look at lParam with WM_MOUSEMOVE
mouse.x = LOWORD(lParam);
mouse.y = HIWORD(lParam);

wisey

May 11, 2012 at 7:16 PM

Hi Tispe

I have this code in my main function:

http://ideone.com/nIHIv

I suppose you are talking about the WndProc() function. I don't know what you mean really. Can you elaborate on what you said.

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Wisey

InvalidPointer

May 12, 2012 at 2:28 PM

Bah. I thumbs-downed Tispe's answer somehow and now I can't undo it. Sorry! That's where you want to look, though-- you'll want to handle the WM_MOUSEMOVE message in your WndProc function. It gets a little bit more complicated since Windows packs the X and Y values into a single 32-bit parameter-- the LOWORD and HIWORD macros will do the necessary bit shifting and masking to extract the two values out. Once you've got everybody on their own, you can send those two values to wherever they need to go; you can convert them to floats or just leave everything in integer values (there are some advantages and disadvantages to both)

wisey

May 12, 2012 at 4:10 PM

Please let me know if you know of a tutorial that explains how to do it. I'm going to have another crack at it right now.

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Wisey

wisey

May 12, 2012 at 7:51 PM

I've almost cracked it

http://ideone.com/PUM7l

My problem is in the case WM_MOUSEMOVE: section xPos and yPos are giving integer values for the screen position, but I don't know how to pass this information onto the objects that require this information in their rendering code. As you can see, I have tried creating a function called SetMousePosition that resides in another class which sets the value of xPos and yPos. But i've checked in the debugger and this information is not being set properly. Also, if the mouse pointer is outside of where the app resides on startup, then this causes a runtime error before xPos and yPos are even set.

Any ideas on how I might solve this?

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Wisey

Tispe

May 13, 2012 at 3:01 PM

If the application starts with the mouse beeing outside the client area then the values will be somehting like -834583459345, which you need to check for. If it is outside the range of the client area, discard them.

You could use a global variable to save the mouse position and use them directly in any function.

wisey

May 13, 2012 at 5:09 PM

For some reason my app miraculously started to work with the code I was talking about earlier.

http://ideone.com/LRW8d

I had other issues elsewhere in my engine that were causing problems. And when I finally got it working as I wanted, I had issues with memory leaks. I tracked the issue down by commenting out various code until the memory leak was isolated. I've talked to people on irc that say I need to learn and implement autopointers. They say that i'm not using my systems memory properly.

Part of my mission is to understand more about memory management and I must admit, my current understanding of c++ is limiting the speed at which I code.

Right. Back to the drawing board.

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Wisey

littletray26

May 31, 2012 at 11:12 PM

So far I've only just used like


 POINT cs;
 
 GetCursorPos(&cs);
 
 //Then accessing data is simple cs.x/cs.y

But that's probably the easiest way. Other ways would be using Windows Messages or RAW data.

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