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Optimised calculatio of jump height.

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This commit is contained in:
UnknownShadow200 2014-12-23 15:42:18 +11:00
parent 46b93ff004
commit 345331c7ca
1 changed files with 19 additions and 26 deletions
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45
Entities/LocalPlayer.cs
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@ -78,7 +78,7 @@ namespace ClassicalSharp {
PlayerRenderer renderer; PlayerRenderer renderer;
public float JumpHeight { public float JumpHeight {
get { return jumpVelocity == 0 ? 0 : GetMaxHeight( jumpVelocity ); } get { return jumpVelocity == 0 ? 0 : (float)GetMaxHeight( jumpVelocity ); }
} }
public void CalculateJumpVelocity( float jumpHeight ) { public void CalculateJumpVelocity( float jumpHeight ) {
@ -86,40 +86,33 @@ namespace ClassicalSharp {
jumpVelocity = 0; jumpVelocity = 0;
return; return;
} }
// NOTE: There is probably still a better way of doing this.
float jumpV = 0.01f; float jumpV = 0.01f;
// Find the most appropriate starting velocity, this can ~half the time
// required in some circumstances. (8 -> 3 ms for max jump height of 1024 )
if( jumpHeight >= 256 ) jumpV = 10.0f; if( jumpHeight >= 256 ) jumpV = 10.0f;
if( jumpHeight >= 512 ) jumpV = 16.5f; if( jumpHeight >= 512 ) jumpV = 16.5f;
if( jumpHeight >= 768 ) jumpV = 22.5f; if( jumpHeight >= 768 ) jumpV = 22.5f;
float diff = float.PositiveInfinity;
while( true ) { while( GetMaxHeight( jumpV ) <= jumpHeight ) {
float height = GetMaxHeight( jumpV );
float newDiff = Math.Abs( height - jumpHeight );
if( newDiff > diff ) {
// 0.01 isn't subtracted because it's better to slightly
// overestimate jump height than underestimate it.
jumpVelocity = jumpV;
break;
}
diff = newDiff;
jumpV += 0.01f; jumpV += 0.01f;
} }
jumpVelocity = jumpV;
} }
static float GetMaxHeight( float velY ) { static double GetMaxHeight( float u ) {
float posY = 0f; // equation below comes from solving diff(x(t, u))= 0
float maxY = 0f; // We only work in discrete timesteps, so test both rounded up and down.
double t = 49.49831645 * Math.Log( 0.247483075 * u + 0.9899323 );
while( posY > -0.1f ) { return Math.Max( YPosAt( (int)t, u ), YPosAt( (int)t + 1, u ) );
posY += velY; }
velY *= 0.98f;
velY -= 0.08f; static double YPosAt( int t, float u ) {
if( posY > maxY ) maxY = posY; // v(t, u) = (4 + u) * (0.98^t) - 4, where u = initial velocity
} // x(t, u) = Σv(t, u) from 0 to t (since we work in discrete timesteps)
return maxY; // plugging into Wolfram Alpha gives 1 equation as
// e^(-0.0202027 t) * (-49u - 196) - 4t + 50u + 196
// which is the same as (0.98^t) * (-49u - 196) - 4t + 50u + 196
double a = Math.Exp( -0.0202027 * t ); //~0.98^t
return a * ( -49 * u - 196 ) - 4 * t + 50 * u + 196;
} }
void HandleInput( out float xMoving, out float zMoving ) { void HandleInput( out float xMoving, out float zMoving ) {