Lerp Confusion - GameCreators Forum

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Greg_C

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Posted: 29th Feb 2012 07:05 Edited at: 29th Feb 2012 07:15

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T2
Maybe there is a better to do this and lerp isn't what I should be using but anyway here is what I am doing:

+ Code Snippet

m_lastposX = agk::GetSpriteXByOffset(m_spriteID); 
m_lastposY = agk::GetSpriteYByOffset(m_spriteID); 

m_posX = m_lastposX + (m_eggPosX - m_lastposX)*m_speed; 
m_posY = m_lastposY + (m_eggPosY - m_lastposY)*m_speed;

Two problems with this:

The first is sometimes my object will stop before it gets to the target position (m_eggPosX). the Second is I don't want to have it slow down as is it gets closer to the object I want it to keep the same constant speed. How would I go about doing this? is Lerp not the correct way to go about this?

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Greg_C

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Posted: 29th Feb 2012 09:28

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So I figured out a different way to go about it if anyone is interested:

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void ObjectBase::TurnToFace()
{

	float x = g_egg->GetPosX() - m_posX;
	float y = g_egg->GetPosY() - m_posY;

	float desiredAngle = (float)atan2(y,x);

	float SpriteAngle = desiredAngle*180/3.14;
	
	m_velocityX = cos((float)desiredAngle) * m_speed;
	m_velocityY = sin((float)desiredAngle) * m_speed;
	
	agk::SetSpritePhysicsVelocity(m_spriteID,m_velocityX,m_velocityY); 
	agk::SetSpriteAngle(m_spriteID, SpriteAngle);
}

So this basically takes the starting position of my object and the position I want it to go to and sends my object at a constant speed towards the final destination. This could be used as a missile as well if the final destination were to constantly move. Anyway this is what I was going for. Maybe it will help someone else.

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baxslash

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Posted: 29th Feb 2012 10:08

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Greg_C, looks like you got it figured but there are some Tier 1 solutions to this kind of thing in the UCF project thread that could easily be translated.

UCF Project (Useful Community Functions)

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Greg_C

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Posted: 29th Feb 2012 17:16

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Okay great I will have to look into these for the future.

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