/// <summary>
/// This function generates normals for every vertex.
/// </summary>
/// <param name="parent">The parent polygon.</param>
public void GenerateNormals(Polygon parent)
{
if (Indices.Count >= 3)
{
foreach (Index index in Indices)
{
// Do we have enough vertices for a normal?
if (Indices.Count >= 3)
{
// Create a normal.
Vertex vNormal = GetSurfaceNormal(parent);
vNormal.UnitLength();
// Add it to the normals, setting the index for next time.
if (index.Normal != -1)
{
parent.Normals.RemoveAt(index.Normal);
}
index.Normal = parent.Normals.Add(new Normal(vNormal));
}
}
}
}
/// <summary>
/// Render to the provided instance of OpenGL.
/// </summary>
/// <param name="gl">The OpenGL instance.</param>
/// <param name="renderMode">The render mode.</param>
public virtual void Render(OpenGL gl, RenderMode renderMode)
{
// If we're frozen, use the helper.
if (freezableHelper.IsFrozen)
{
freezableHelper.Render(gl);
return;
}
// Go through each face.
foreach (Face face in faces)
{
// If the face has its own material, push it.
if (face.Material != null)
{
face.Material.Push(gl);
}
// Begin drawing a polygon.
if (face.Indices.Count == 2)
{
gl.Begin(OpenGL.GL_LINES);
}
else
{
gl.Begin(OpenGL.GL_POLYGON);
}
foreach (Index index in face.Indices)
{
// Set a texture coord (if any).
if (index.UV != -1)
{
gl.TexCoord(uvs[index.UV]);
}
// Set a normal, or generate one.
if (index.Normal != -1)
{
gl.Normal(normals[index.Normal]);
}
else
{
// Do we have enough vertices for a normal?
if (face.Indices.Count >= 3)
{
// Create a normal.
Vertex vNormal = face.GetSurfaceNormal(this);
vNormal.UnitLength();
// todo use auto smoothing instead
// Add it to the normals, setting the index for next time.
normals.Add(vNormal);
index.Normal = normals.Count - 1;
gl.Normal(vNormal);
}
}
// Set the vertex.
gl.Vertex(vertices[index.Vertex]);
}
gl.End();
// If the face has its own material, pop it.
if (face.Material != null)
{
face.Material.Pop(gl);
}
}
// Draw normals if we have to.
if (drawNormals)
{
// Set the colour to red.
gl.PushAttrib(OpenGL.GL_ALL_ATTRIB_BITS);
gl.Color(1, 0, 0, 1);
gl.Disable(OpenGL.GL_LIGHTING);
// Go through each face.
foreach (Face face in faces)
{
// Go though each index.
foreach (Index index in face.Indices)
{
// Make sure it's got a normal, and a vertex.
if (index.Normal != -1 && index.Vertex != -1)
{
// Get the vertex.
Vertex vertex = vertices[index.Vertex];
// Get the normal vertex.
Vertex normal = normals[index.Normal];
Vertex vertex2 = vertex + normal;
gl.Begin(OpenGL.GL_LINES);
gl.Vertex(vertex);
gl.Vertex(vertex2);
gl.End();
}
}
}
// Restore the attributes.
gl.PopAttrib();
}
}
