Rotating Sprites: Mystery or Mirth?

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Dark GDK / Rotating Sprites: Mystery or Mirth?

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skull driveshaft

Years of Service

User Offline

Joined: 4th Jan 2008

Location:

Posted: 4th Jan 2008 07:16

Link

Here's the code I came up with after smashing things.

Is there a better way? Why is it so slow?

+ Code Snippet

	int scaler = 100;
        int angle = 0;

        while ( LoopGDK ( ) )
	{
		int xPOS = dbMouseMoveX();
		int yPOS = dbMouseMoveY();

		if ( dbMouseClick() == 1)
		{
			if ( xPOS > 0)
			{
				scaler = scaler + 3;
			}
	
			if ( xPOS < 0)
			{
				scaler = scaler - 3;
			}
		}

		if ( dbMouseClick() == 2)
		{
			if ( yPOS > 0)
			{
				angle = dbWrapValue(angle++);
			}

			if ( yPOS < 0)
			{
				angle = dbWrapValue(angle--);
			}
		}

		if (scaler <= 0)
		{
			scaler = 1;
		}

		dbRotateSprite (1, angle);
		dbScaleSprite (1, scaler);

		dbSync ( );
	}

why doesn't it work the way I want it to!

Profile PM

tempicek

Years of Service

User Offline

Joined: 27th Nov 2007

Location: Prague

Posted: 4th Jan 2008 15:47

Link

Quote: "Is there a better way? Why is it so slow?"

It's so slow because you rotate/scale the image by a constant factor without regards to distance mouse has moved. You are checking only if it moved, not how much. Moreove it's dependent on how often the while loop is performed (which depends on refresh rate and machine speed), which is wrong solution in most cases. Try to use this way and modify as you need:

+ Code Snippet

		int xPOS = dbMouseMoveX();
		int yPOS = dbMouseMoveY();

		if ( dbMouseClick() == 1)
		{
			scaler += 3 * xPOS;
		}

		if ( dbMouseClick() == 2)
		{
			angle = dbWrapValue(angle += 2 * yPOS);
		}

		if (scaler <= 0)
		{
			scaler = 1;
		}

		dbRotateSprite (1, angle);
		dbScaleSprite (1, scaler);

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Dark GDK / Rotating Sprites: Mystery or Mirth?