/// <summary>
/// The main method of the engine that re-compute each vertex projection
/// during each frame
/// </summary>
/// <param name="camera"></param>
/// <param name="meshes"></param>
public void Render(Camera camera, params Mesh[] meshes)
{
// To understand this part, please read the prerequisites resources
var viewMatrix = Matrix.LookAtLH(camera.Position, camera.Target, Vector3.Up);
var projectionMatrix = Matrix.PerspectiveFovRH(0.78f,
(float)bmp.PixelWidth / bmp.PixelHeight,
0.01f, 1.0f);
for (var i = 0; i < meshes.Length; i++)
{
// Beware to apply rotation before translation
var worldMatrix = Matrix.RotationYawPitchRoll(meshes[i].Rotation.Y,
meshes[i].Rotation.X, meshes[i].Rotation.Z) *
Matrix.Translation(meshes[i].Position);
var transformMatrix = worldMatrix * viewMatrix * projectionMatrix;
//Iterate over the faces, get the vertices of each face and draw the lines between them
Parallel.For(0, meshes[i].Faces.Length, j =>
{
var pixelA = Project(meshes[i].Vertices[meshes[i].Faces[j].A], transformMatrix, worldMatrix);
var pixelB = Project(meshes[i].Vertices[meshes[i].Faces[j].B], transformMatrix, worldMatrix);
var pixelC = Project(meshes[i].Vertices[meshes[i].Faces[j].C], transformMatrix, worldMatrix);
var color = 0.25f + j % meshes[i].Faces.Length * 0.75f / meshes[i].Faces.Length;
DrawTriangle(pixelA, pixelB, pixelC, new Color
{
ScB = color,
ScG = color,
ScR = color,
ScA = 1f
}, meshes[i].Texture);
});
}
}
/// <summary>
/// Project takes some 3D coordinates and transform them
/// in 2D coordinates using the transformation matrix
/// </summary>
Vertex Project(Vertex vertex, Matrix transMat, Matrix world)
{
// transforming the coordinates
var point2D = Vector3.TransformCoordinates(vertex.Coordinates, transMat);
var point3D = Vector3.TransformCoordinates(vertex.Coordinates, world);
var normal3DWorld = Vector3.TransformCoordinates(vertex.Normal, world);
// The transformed coordinates will be based on coordinate system
// starting on the center of the screen. But drawing on screen normally starts
// from top left. We then need to transform them again to have x:0, y:0 on top left.
var x = point2D.X * renderWidth + renderWidth / 2.0f;
var y = -point2D.Y * renderHeight + renderHeight / 2.0f;
return(new Vertex
{
Coordinates = new Vector3(x, y, point3D.Z),
Normal = normal3DWorld,
WorldCoordinates = point3D,
TexCoord = vertex.TexCoord
});
}
