From 0f631febfc3f670e8e9eb60ec4f89659ad7d0c71 Mon Sep 17 00:00:00 2001 From: Christophe Piveteau Date: Fri, 15 Aug 2014 13:40:56 +0200 Subject: Add some comments --- src/Entities/Minecart.cpp | 31 +++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 10 deletions(-) diff --git a/src/Entities/Minecart.cpp b/src/Entities/Minecart.cpp index 8e11d8a07..0455c9ab3 100644 --- a/src/Entities/Minecart.cpp +++ b/src/Entities/Minecart.cpp @@ -875,17 +875,23 @@ bool cMinecart::TestEntityCollision(NIBBLETYPE a_RailMeta) { Vector3d Distance = MinecartCollisionCallback.GetCollidedEntityPosition() - Vector3d(GetPosX(), 0, GetPosZ()); + // Prevent division by small numbers Distance.z = std::max(Distance.z, 0.001); + /* Check to which side the minecart is to be pushed. + Let's consider a z-x-coordinate system where the minecart is the center (0/0). + The minecart moves along the line z = -x, the perpendicular line to this is z = x. + In order to decide to which side the minecart is to be pushed, it must be checked on what side of the perpendicular line the pushing entity is located. + */ if ( ((Distance.z > 0) && ((Distance.x / Distance.z) >= 1)) || ((Distance.z < 0) && ((Distance.x / Distance.z) <= 1)) ) { - if ((-GetSpeedX() * 0.4) < 0.01) + if ((-GetSpeedX() * 0.4 / sqrt(2)) < 0.01) { - AddSpeedX(-4/sqrt(2)); - AddSpeedZ(4/sqrt(2)); + AddSpeedX(-4 / sqrt(2)); + AddSpeedZ(4 / sqrt(2)); } else { @@ -893,10 +899,10 @@ bool cMinecart::TestEntityCollision(NIBBLETYPE a_RailMeta) SetSpeedZ(GetSpeedZ() * 0.4); } } - else if ((GetSpeedX() * 0.4) < 0.01) + else if ((GetSpeedX() * 0.4 / sqrt(2)) < 0.01) { - AddSpeedX(4/sqrt(2)); - AddSpeedZ(-4/sqrt(2)); + AddSpeedX(4 / sqrt(2)); + AddSpeedZ(-4 / sqrt(2)); } else { @@ -910,8 +916,13 @@ bool cMinecart::TestEntityCollision(NIBBLETYPE a_RailMeta) { Vector3d Distance = MinecartCollisionCallback.GetCollidedEntityPosition() - Vector3d(GetPosX(), 0, GetPosZ()); + // Prevent division by small numbers Distance.z = std::max(Distance.z, 0.001); + /* Check to which side the minecart is to be pushed. + Let's consider a z-x-coordinate system where the minecart is the center (0/0). + The minecart moves along the line z = x, the perpendicular line to this is z = -x. + In order to decide to which side the minecart is to be pushed, it must be checked on what side of the perpendicular line the pushing entity is located. */ if ( ((Distance.z > 0) && ((Distance.x / Distance.z) <= -1)) || ((Distance.z < 0) && ((Distance.x / Distance.z) >= -1)) @@ -919,8 +930,8 @@ bool cMinecart::TestEntityCollision(NIBBLETYPE a_RailMeta) { if ((GetSpeedX() * 0.4) < 0.01) { - AddSpeedX(4/sqrt(2)); - AddSpeedZ(4/sqrt(2)); + AddSpeedX(4 / sqrt(2)); + AddSpeedZ(4 / sqrt(2)); } else { @@ -930,8 +941,8 @@ bool cMinecart::TestEntityCollision(NIBBLETYPE a_RailMeta) } else if ((-GetSpeedX() * 0.4) < 0.01) { - AddSpeedX(-4/sqrt(2)); - AddSpeedZ(-4/sqrt(2)); + AddSpeedX(-4 / sqrt(2)); + AddSpeedZ(-4 / sqrt(2)); } else { -- cgit v1.2.3