/// <summary>
/// Creates an <see cref="OrientedBoundingBox">OrientedBoundingBox</see> from a <see cref="BoundingBox">BoundingBox</see>.
/// </summary>
/// <param name="box">A <see cref="BoundingBox">BoundingBox</see> to create the <see cref="OrientedBoundingBox">OrientedBoundingBox</see> from</param>
/// <returns>The generated <see cref="OrientedBoundingBox">OrientedBoundingBox</see></returns>
public static OrientedBoundingBox FromAABB(BoundingBox box)
{
var center = BoundingVolumesExtensions.GetCenter(box);
var extents = BoundingVolumesExtensions.GetExtents(box);
return(new OrientedBoundingBox(center, extents));
}
/// <inheritdoc />
public override void Draw(GameTime gameTime)
{
// Set the DiffuseColor to white to draw this Robot
RobotEffect.DiffuseColor = Color.White.ToVector3();
Robot.Draw(RobotWorld, Camera.View, Camera.Projection);
// Set the DiffuseColor to red to draw this Robot
RobotEffect.DiffuseColor = Color.Red.ToVector3();
Robot.Draw(RobotTwoWorld, Camera.View, Camera.Projection);
// Draw the Chair
Chair.Draw(ChairWorld, Camera.View, Camera.Projection);
// Draw the Tank
Tank.Draw(TankWorld, Camera.View, Camera.Projection);
// Draw bounding volumes
Game.Gizmos.DrawCube(BoundingVolumesExtensions.GetCenter(RobotBox), BoundingVolumesExtensions.GetExtents(RobotBox) * 2f, Color.Yellow);
Game.Gizmos.DrawCube(ChairOBBWorld, TouchingChair ? Color.Orange : Color.Green);
Game.Gizmos.DrawSphere(_tankSphere.Center, _tankSphere.Radius * Vector3.One, TouchingTank ? Color.Orange : Color.Purple);
Game.Gizmos.DrawCylinder(RobotTwoCylinder.Transform, TouchingOtherRobot ? Color.Orange : Color.White);
base.Draw(gameTime);
}
/// <inheritdoc />
public override void Draw(GameTime gameTime)
{
// Calculate the ViewProjection matrix
var viewProjection = Camera.View * Camera.Projection;
// Draw the Robot
Robot.Draw(RobotWorld, Camera.View, Camera.Projection);
// Set the WorldViewProjection and Texture for the Floor and draw it
TilingEffect.Parameters["WorldViewProjection"].SetValue(FloorWorld * viewProjection);
TilingEffect.Parameters["Texture"].SetValue(FloorTexture);
Quad.Draw(TilingEffect);
// Draw each Wall
// First, set the Wall Texture
TilingEffect.Parameters["Texture"].SetValue(WallTexture);
for (int index = 0; index < WallWorldMatrices.Length - 1; index++)
{
// Set the WorldViewProjection matrix for each Wall
TilingEffect.Parameters["WorldViewProjection"].SetValue(WallWorldMatrices[index] * viewProjection);
// Draw the Wall
Quad.Draw(TilingEffect);
}
// Draw the traversing Wall
// For this, disable Back-Face Culling as we want to draw both sides of the Quad
// Save the past RasterizerState
var rasterizerState = GraphicsDevice.RasterizerState;
// Use a RasterizerState which has Back-Face Culling disabled
GraphicsDevice.RasterizerState = RasterizerState.CullNone;
// Set the WorldViewProjection matrix and draw the Wall
TilingEffect.Parameters["WorldViewProjection"].SetValue(WallWorldMatrices[WallWorldMatrices.Length - 1] * viewProjection);
Quad.Draw(TilingEffect);
// Restore the old RasterizerState
GraphicsDevice.RasterizerState = rasterizerState;
// Draw Gizmos for Bounding Boxes and Robot Cylinder
for (int index = 0; index < WallBoxes.Length; index++)
{
var box = WallBoxes[index];
var center = BoundingVolumesExtensions.GetCenter(box);
var extents = BoundingVolumesExtensions.GetExtents(box);
Game.Gizmos.DrawCube(center, extents * 2f, Color.Red);
}
Game.Gizmos.DrawCylinder(RobotCylinder.Transform, Color.Yellow);
base.Draw(gameTime);
}
/// <summary>
/// Solves the intersection between the Robot and a collider.
/// </summary>
/// <param name="collider">The collider the Robot intersected with</param>
/// <param name="colliderIndex">The index of the collider in the collider array the Robot intersected with</param>
/// <returns>True if the collider was a step and it was climbed, False otherwise</returns>
private bool SolveStepCollision(BoundingBox collider, int colliderIndex)
{
// Get the collider properties to check if it's a step
// Also, to calculate penetration
var extents = BoundingVolumesExtensions.GetExtents(collider);
var colliderCenter = BoundingVolumesExtensions.GetCenter(collider);
// Is this collider a step?
// If not, exit
if (extents.Y >= 6f)
{
return(false);
}
// Is the base of the cylinder close to the step top?
// If not, exit
var distanceToTop = MathF.Abs((RobotCylinder.Center.Y - RobotCylinder.HalfHeight) - (colliderCenter.Y + extents.Y));
if (distanceToTop >= 12f)
{
return(false);
}
// We want to climb the step
// It is climbable if we can reposition our cylinder in a way that
// it doesn't collide with anything else
var pastPosition = RobotCylinder.Center;
RobotCylinder.Center += Vector3.Up * distanceToTop;
for (int index = 0; index < Colliders.Length; index++)
{
if (index != colliderIndex && RobotCylinder.Intersects(Colliders[index]).Equals(BoxCylinderIntersection.Intersecting))
{
// We found a case in which the cylinder
// intersects with other colliders, so the climb is not possible
RobotCylinder.Center = pastPosition;
return(false);
}
}
// If we got here the climb was possible
// (And the Robot position was already updated)
return(true);
}
/// <inheritdoc />
public override void Draw(GameTime gameTime)
{
// Calculate the ViewProjection matrix
var viewProjection = Camera.View * Camera.Projection;
// Robot drawing
Robot.Draw(RobotWorld, Camera.View, Camera.Projection);
// Floor drawing
// Set the Technique inside the TilingEffect to "BaseTiling", we want to control the tiling on the floor
// Using its original Texture Coordinates
TilingEffect.CurrentTechnique = TilingEffect.Techniques["BaseTiling"];
// Set the Tiling value
TilingEffect.Parameters["Tiling"].SetValue(new Vector2(10f, 10f));
// Set the WorldViewProjection matrix
TilingEffect.Parameters["WorldViewProjection"].SetValue(FloorWorld * viewProjection);
// Set the Texture that the Floor will use
TilingEffect.Parameters["Texture"].SetValue(StonesTexture);
Quad.Draw(TilingEffect);
// Steps drawing
// Set the Technique inside the TilingEffect to "WorldTiling"
// We want to use the world position of the steps to define how to sample the Texture
TilingEffect.CurrentTechnique = TilingEffect.Techniques["WorldTiling"];
// Set the Texture that the Steps will use
TilingEffect.Parameters["Texture"].SetValue(CobbleTexture);
// Set the Tiling value
TilingEffect.Parameters["Tiling"].SetValue(Vector2.One * 0.05f);
// Draw every Step
for (int index = 0; index < StairsWorld.Length; index++)
{
// Get the World Matrix
var matrix = StairsWorld[index];
// Set the World Matrix
TilingEffect.Parameters["World"].SetValue(matrix);
// Set the WorldViewProjection Matrix
TilingEffect.Parameters["WorldViewProjection"].SetValue(matrix * viewProjection);
BoxPrimitive.Draw(TilingEffect);
}
// Draw the Box, setting every matrix and its Texture
BoxesEffect.World = BoxWorld;
BoxesEffect.View = Camera.View;
BoxesEffect.Projection = Camera.Projection;
BoxesEffect.Texture = WoodenTexture;
BoxPrimitive.Draw(BoxesEffect);
// Gizmos Drawing
for (int index = 0; index < Colliders.Length; index++)
{
var box = Colliders[index];
var center = BoundingVolumesExtensions.GetCenter(box);
var extents = BoundingVolumesExtensions.GetExtents(box);
Game.Gizmos.DrawCube(center, extents * 2f, Color.Red);
}
Game.Gizmos.DrawCylinder(RobotCylinder.Transform, Color.Yellow);
base.Draw(gameTime);
}
/// <summary>
/// Apply horizontal movement, detecting and solving collisions
/// </summary>
/// <param name="scaledVelocity">The current velocity scaled by deltaTime</param>
private void SolveVerticalMovement(Vector3 scaledVelocity)
{
// If the Robot has vertical velocity
if (scaledVelocity.Y == 0f)
{
return;
}
// Start by moving the Cylinder
RobotCylinder.Center += Vector3.Up * scaledVelocity.Y;
// Set the OnGround flag on false, update it later if we find a collision
OnGround = false;
// Collision detection
var collided = false;
var foundIndex = -1;
for (var index = 0; index < Colliders.Length; index++)
{
if (!RobotCylinder.Intersects(Colliders[index]).Equals(BoxCylinderIntersection.Intersecting))
{
continue;
}
// If we collided with something, set our velocity in Y to zero to reset acceleration
RobotVelocity = new Vector3(RobotVelocity.X, 0f, RobotVelocity.Z);
// Set our index and collision flag to true
// The index is to tell which collider the Robot intersects with
collided = true;
foundIndex = index;
break;
}
// We correct based on differences in Y until we don't collide anymore
// Not usual to iterate here more than once, but could happen
while (collided)
{
var collider = Colliders[foundIndex];
var colliderY = BoundingVolumesExtensions.GetCenter(collider).Y;
var cylinderY = RobotCylinder.Center.Y;
var extents = BoundingVolumesExtensions.GetExtents(collider);
float penetration;
// If we are on top of the collider, push up
// Also, set the OnGround flag to true
if (cylinderY > colliderY)
{
penetration = colliderY + extents.Y - cylinderY + RobotCylinder.HalfHeight;
OnGround = true;
}
// If we are on bottom of the collider, push down
else
{
penetration = -cylinderY - RobotCylinder.HalfHeight + colliderY - extents.Y;
}
// Move our Cylinder so we are not colliding anymore
RobotCylinder.Center += Vector3.Up * penetration;
collided = false;
// Check for collisions again
for (var index = 0; index < Colliders.Length; index++)
{
if (!RobotCylinder.Intersects(Colliders[index]).Equals(BoxCylinderIntersection.Intersecting))
{
continue;
}
// Iterate until we don't collide with anything anymore
collided = true;
foundIndex = index;
break;
}
}
}
/// <summary>
/// Calculates an OBB with a given set of points.
/// Tests every orientations between initValues and endValues, stepping through angle intervals with a given step size.
/// Goes on until it reaches a step less than 0.01
/// </summary>
/// <returns>A generated Oriented Bounding Box that contains the set of points</returns>
private static OrientedBoundingBox ComputeFromPointsRecursive(Vector3[] points, Vector3 initValues, Vector3 endValues,
float step)
{
var minObb = new OrientedBoundingBox();
var minimumVolume = float.MaxValue;
var minInitValues = Vector3.Zero;
var minEndValues = Vector3.Zero;
var transformedPoints = new Vector3[points.Length];
float y, z;
var x = initValues.X;
while (x <= endValues.X)
{
y = initValues.Y;
var rotationX = MathHelper.ToRadians(x);
while (y <= endValues.Y)
{
z = initValues.Z;
var rotationY = MathHelper.ToRadians(y);
while (z <= endValues.Z)
{
// Rotation matrix
var rotationZ = MathHelper.ToRadians(z);
var rotationMatrix = Matrix.CreateFromYawPitchRoll(rotationY, rotationX, rotationZ);
// Transform every point to OBB-Space
for (var index = 0; index < transformedPoints.Length; index++)
{
transformedPoints[index] = Vector3.Transform(points[index], rotationMatrix);
}
// Obtain an AABB enclosing every transformed point
var aabb = BoundingBox.CreateFromPoints(transformedPoints);
// Calculate the volume of the AABB
var volume = BoundingVolumesExtensions.GetVolume(aabb);
// Find lesser volume
if (volume < minimumVolume)
{
minimumVolume = volume;
minInitValues = new Vector3(x, y, z);
minEndValues = new Vector3(x + step, y + step, z + step);
// Restore the AABB center in World-Space
var center = BoundingVolumesExtensions.GetCenter(aabb);
center = Vector3.Transform(center, rotationMatrix);
// Create OBB
minObb = new OrientedBoundingBox(center, BoundingVolumesExtensions.GetExtents(aabb));
minObb.Orientation = rotationMatrix;
}
z += step;
}
y += step;
}
x += step;
}
// Loop again if the step is higher than a given acceptance threshold
if (step > 0.01f)
{
minObb = ComputeFromPointsRecursive(points, minInitValues, minEndValues, step / 10f);
}
return(minObb);
}