public void GenerateMesh(Vector2 trailTipPosition, Vector2 trailTipNormal, int startFromIndex, out VertexPositionColorTexture[] vertices, out short[] indices, TrailWidthFunction trailWidthFunction, TrailColorFunction trailColorFunction)
{
/* C---D
* / \ / \
* B---A---E
*
* This tip attempts to approximate a semicircle as shown.
* Consists of a fan of triangles which share a common center (A).
* The higher the accuracy, the more points there are.
*/
// We want an array of vertices the size of the accuracy amount plus the center.
vertices = new VertexPositionColorTexture[accuracy + 1];
Vector2 fanCenterTexCoord = new Vector2(1, 0.5f);
vertices[0] = new VertexPositionColorTexture(trailTipPosition.Vec3(), trailColorFunction?.Invoke(fanCenterTexCoord) ?? Color.White, fanCenterTexCoord);
List <short> indicesTemp = new List <short>();
for (int k = 0; k < accuracy; k++)
{
// Referring to the illustration: 0 is point B, 1 is point E, any other value represent the rotation factor of points in between.
float rotationFactor = k / (float)(accuracy - 1);
// Rotates by pi/2 - (factor * pi) so that when the factor is 0 we get A and when it is 1 we get E.
float angle = MathHelper.PiOver2 - (rotationFactor * MathHelper.Pi);
Vector2 circlePoint = trailTipPosition + (trailTipNormal.RotatedBy(angle) * (trailWidthFunction?.Invoke(1) ?? 1));
// Handily, the rotation factor can also be used as a texture coordinate because it is a measure of how far around the tip a point is.
Vector2 circleTexCoord = new Vector2(1, rotationFactor);
Color circlePointColor = trailColorFunction?.Invoke(circleTexCoord) ?? Color.White;
vertices[k + 1] = new VertexPositionColorTexture(circlePoint.Vec3(), circlePointColor, circleTexCoord);
// Skip last point, since there is no point to pair with it.
if (k == accuracy - 1)
{
continue;
}
short[] tri = new short[]
{
/* Because this is a fan, we want all triangles to share a common point. This is represented by index 0 offset to the next available index.
* The other indices are just pairs of points around the fan. The vertex k points along the circle is just index k + 1, followed by k + 2 at the next one along.
* The reason these are offset by 1 is because index 0 is taken by the fan center.
*/
(short)startFromIndex,
(short)(startFromIndex + k + 1),
(short)(startFromIndex + k + 2)
};
indicesTemp.AddRange(tri);
}
indices = indicesTemp.ToArray();
}
public void GenerateMesh(Vector2 trailTipPosition, Vector2 trailTipNormal, int startFromIndex, out VertexPositionColorTexture[] vertices, out short[] indices, TrailWidthFunction trailWidthFunction, TrailColorFunction trailColorFunction)
{
vertices = new VertexPositionColorTexture[0];
indices = new short[0];
}
public void GenerateMesh(Vector2 trailTipPosition, Vector2 trailTipNormal, int startFromIndex, out VertexPositionColorTexture[] vertices, out short[] indices, TrailWidthFunction trailWidthFunction, TrailColorFunction trailColorFunction)
{
/* C
* / \
* / \
* / \
* A-------B
*
* This tip is arranged as the above shows.
* Consists of a single triangle with indices (0, 1, 2) offset by the next available index.
*/
Vector2 normalPerp = trailTipNormal.RotatedBy(MathHelper.PiOver2);
Vector2 a = trailTipPosition + (normalPerp * (trailWidthFunction?.Invoke(1) ?? 1));
Vector2 b = trailTipPosition - (normalPerp * (trailWidthFunction?.Invoke(1) ?? 1));
Vector2 c = trailTipPosition + (trailTipNormal * length);
Vector2 texCoordA = Vector2.UnitX;
Vector2 texCoordB = Vector2.One;
Vector2 texCoordC = Vector2.One;
Color colorA = trailColorFunction?.Invoke(texCoordA) ?? Color.White;
Color colorB = trailColorFunction?.Invoke(texCoordB) ?? Color.White;
Color colorC = trailColorFunction?.Invoke(texCoordC) ?? Color.White;
vertices = new VertexPositionColorTexture[]
{
new VertexPositionColorTexture(a.Vec3(), colorA, texCoordA),
new VertexPositionColorTexture(b.Vec3(), colorB, texCoordB),
new VertexPositionColorTexture(c.Vec3(), colorC, texCoordC)
};
indices = new short[]
{
(short)startFromIndex,
(short)(startFromIndex + 1),
(short)(startFromIndex + 2)
};
}
public void GenerateMesh(Vector2 trailTipPosition, Vector2 trailTipNormal, int startFromIndex, out VertexPositionColorTexture[] vertices, out short[] indices, TrailWidthFunction trailWidthFunction, TrailColorFunction trailColorFunction)
{
/* C---D
* / \ / \
* B---A---E (first layer)
*
* H---G
* / \ / \
* I---A---F (second layer)
*
* This tip attempts to approximate a semicircle as shown.
* Consists of a fan of triangles which share a common center (A).
* The higher the tri count, the more points there are.
* Point E and F are ontop of eachother to prevent a visual seam.
*/
/// We want an array of vertices the size of the accuracy amount plus the center.
vertices = new VertexPositionColorTexture[ExtraVertices];
Vector2 fanCenterTexCoord = new Vector2(1, 0.5f);
vertices[0] = new VertexPositionColorTexture(trailTipPosition.Vec3(), (trailColorFunction?.Invoke(fanCenterTexCoord) ?? Color.White) * 0.75f, fanCenterTexCoord);
List <short> indicesTemp = new List <short>();
for (int k = 0; k <= triCount; k++)
{
// Referring to the illustration: 0 is point B, 1 is point E, any other value represent the rotation factor of points in between.
float rotationFactor = k / (float)(triCount);
// Rotates by pi/2 - (factor * pi) so that when the factor is 0 we get B and when it is 1 we get E.
float angle = MathHelper.PiOver2 - (rotationFactor * MathHelper.Pi);
Vector2 circlePoint = trailTipPosition + (trailTipNormal.RotatedBy(angle) * (trailWidthFunction?.Invoke(1) ?? 1));
// Handily, the rotation factor can also be used as a texture coordinate because it is a measure of how far around the tip a point is.
Vector2 circleTexCoord = new Vector2(rotationFactor, 1);
// The transparency must be changed a bit so it looks right when overlapped
Color circlePointColor = (trailColorFunction?.Invoke(new Vector2(1, 0)) ?? Color.White) * rotationFactor * 0.85f;
vertices[k + 1] = new VertexPositionColorTexture(circlePoint.Vec3(), circlePointColor, circleTexCoord);
//if (k == triCount)//leftover and not needed
//{
// continue;
//}
short[] tri = new short[]
{
/* Because this is a fan, we want all triangles to share a common point. This is represented by index 0 offset to the next available index.
* The other indices are just pairs of points around the fan. The vertex k points along the circle is just index k + 1, followed by k + 2 at the next one along.
* The reason these are offset by 1 is because index 0 is taken by the fan center.
*/
//before the fix, I believe these being in the wrong order was what prevented it from drawing
(short)startFromIndex,
(short)(startFromIndex + k + 2),
(short)(startFromIndex + k + 1)
};
indicesTemp.AddRange(tri);
}
// These 2 forloops overlap so that 2 points share the same location, this hidden point hides a tri that acts as a transition from one UV to another
for (int k = triCount + 1; k <= triCount * 2 + 1; k++)
{
// Referring to the illustration: triCount + 1 is point F, 1 is point I, any other value represent the rotation factor of points in between.
float rotationFactor = ((k - 1) / (float)(triCount)) - 1;
// Rotates by pi/2 - (factor * pi) so that when the factor is 0 we get B and when it is 1 we get E.
float angle = MathHelper.PiOver2 - (rotationFactor * MathHelper.Pi);
Vector2 circlePoint = trailTipPosition + (trailTipNormal.RotatedBy(-angle) * (trailWidthFunction?.Invoke(1) ?? 1));
// Handily, the rotation factor can also be used as a texture coordinate because it is a measure of how far around the tip a point is.
Vector2 circleTexCoord = new Vector2(rotationFactor, 0);
// The transparency must be changed a bit so it looks right when overlapped
Color circlePointColor = ((trailColorFunction?.Invoke(new Vector2(1, 0)) ?? Color.White) * rotationFactor * 0.75f);
vertices[k + 1] = new VertexPositionColorTexture(circlePoint.Vec3(), circlePointColor, circleTexCoord);
// Skip last point, since there is no point to pair with it.
if (k == triCount * 2 + 1)
{
continue;
}
short[] tri = new short[]
{
/* Because this is a fan, we want all triangles to share a common point. This is represented by index 0 offset to the next available index.
* The other indices are just pairs of points around the fan. The vertex k points along the circle is just index k + 1, followed by k + 2 at the next one along.
* The reason these are offset by 1 is because index 0 is taken by the fan center.
*/
//The order of the indices is reversed since the direction is backwards
(short)startFromIndex,
(short)(startFromIndex + k + 1),
(short)(startFromIndex + k + 2)
};
indicesTemp.AddRange(tri);
}
indices = indicesTemp.ToArray();
}
