[SOLVED] Smoothly interpolate between two points?

Emmsii · October 29, 2014, 3:02pm

What would be the best way to smoothly interpolate between two points? For example, I have a player that is controlled by WASD, I also have a ‘camera’ which would follow the player’s x & y position smoothly. Then the game would render the level+player based off the cameras position.

Also I’m not sure how to make the camera x & y slow down the closer it gets to the player x & y. Any ideas?

Its pretty subtle in this example.

chTQaTEvXy0

kalkitus · October 29, 2014, 4:04pm

I believe you are looking for a lerp function http://en.wikipedia.org/wiki/Linear_interpolation

float lerp(float point1, float point2, float alpha)
{
    return point1 + alpha * (point2 - point1);
}

Emmsii · October 29, 2014, 4:10pm

Thats it! Just implemented it and it works perfectly. Thanks!

basil · October 29, 2014, 4:11pm

kalkitus:

I believe you are looking for a lerp function http://en.wikipedia.org/wiki/Linear_interpolation
float lerp(float point1, float point2, float alpha)
{
    return point1 + alpha * (point2 - point1);
}


float cubic_scurve3(float alpha)
{
  return alpha*alpha*( 3.0f - 2.0f*alpha );
}

float smoothed = lerp(point1, point2, cubic_scruve3(alpha));

BurntPizza · October 29, 2014, 4:12pm

Just for some examples of more elaborate ones.

Nate · October 29, 2014, 8:07pm

github.com

libgdx/libgdx/blob/master/gdx/src/com/badlogic/gdx/math/Interpolation.java

/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.math;

/** Takes a linear value in the range of 0-1 and outputs a (usually) non-linear, interpolated value.
 * @author Nathan Sweet */

This file has been truncated. show original

See InterpolationTest in libgdx to visualize them.