public static mat4x4 LookAtRH(vec3 position, vec3 target, vec3 normal)
{
vec3 zaxis = (position - target).Normalized;
vec3 xaxis = vec3.cross(normal, zaxis).Normalized;
vec3 yaxis = vec3.cross(zaxis, xaxis);
return new mat4x4(
xaxis.X, yaxis.X, zaxis.X, 0,
xaxis.Y, yaxis.Y, zaxis.Y, 0,
xaxis.Z, yaxis.Z, zaxis.Z, 0,
-vec3.dot(xaxis, position), -vec3.dot(yaxis, position), -vec3.dot(zaxis, position), 1
);
}
public static mat4x4 Rotation(float radians, vec3 axis)
{
//se lleva el eje que se quiere rotar al eje de las X, se rota el eje de las X y se vira para atras
mat4x4 t = I4;
float alpha = (float)Math.Atan2(axis.Z, axis.X);
t = t * RotationY(-alpha);
float beta = (float)Math.Atan2(axis.Y, axis.X);
t = t * RotationZ(-beta);
return t.Inverse * RotationX(radians) * t;
}
private static vec2 SphereTextureCoordenates(vec3 position)
{
return new vec2(position.X / 2 + 0.5f, position.Y);
}
private static vec2 PlaneTextureCoordenates(vec3 position)
{
return new vec2(position.X + 0.5f, position.Z + 0.5f);
}
private static vec2 DiskTextureCoordenates(vec3 position)
{
return new vec2(position.X / 2 + 0.5f, position.Z / 2 + 0.5f);
}
private static vec2 CylinderTextureCoordenates(vec3 position)
{
//tapa superior
if (position.Y.AproxEqual(1) || position.Y.AproxEqual(0))
return DiskTextureCoordenates(position);
return new vec2(position.X / 2 + 0.5f, position.Y);
}
public static vec2 TextureCoordenates(this Model model, vec3 position)
{
switch (model)
{
case Model.Cube: return CubeTextureCoordenates(position);
case Model.Disk: return DiskTextureCoordenates(position);
case Model.Sphere: return SphereTextureCoordenates(position);
case Model.Cylinder: return CylinderTextureCoordenates(position);
case Model.Cone: return ConeTextureCoordenates(position);
case Model.Plane: return PlaneTextureCoordenates(position);
default: throw new NotImplementedException();
}
}
public static Ray FromDirection(vec3 position, vec3 direction)
{
return new Ray(position, direction.Normalized);
}
public vec4(vec3 v, float w)
: this(v.X, v.Y, v.Z, w)
{
}
//modificado
public LightSource(vec3 position, vec4 intensity, ModelGraphic modelGraphicLight)
{
Position = position;
Intensity = intensity;
ModelGraphic = modelGraphicLight;
}
public static vec3 normalize(vec3 v)
{
float length = v.Length;
if (length == 0)
throw new InvalidOperationException();
return new vec3(v.X / length, v.Y / length, v.Z / length);
}
public static float dot(vec3 v1, vec3 v2)
{
return v1.X * v2.X + v1.Y * v2.Y + v1.Z * v2.Z;
}
public static vec3 cross(vec3 v1, vec3 v2)
{
return new vec3(
v1.Y * v2.Z - v1.Z * v2.Y,
v1.Z * v2.X - v1.X * v2.Z,
v1.X * v2.Y - v1.Y * v2.X);
}
public static Graphic Rotated(this Graphic graphic, float radians, vec3 axis)
{
return new TransformedGraphic(graphic, Matrices.Rotation(radians, axis));
}
private static vec2 ConeTextureCoordenates(vec3 position)
{
return DiskTextureCoordenates(position);
}
private Ray(vec3 from, vec3 direction)
{
this.From = from;
this.Direction = direction;
}
private static vec2 CubeTextureCoordenates(vec3 position)
{
// Front Intersection
if (position.Z.AproxEqual(0))
return new vec2(position.X, position.Y);
// Back Intersection
if (position.Z.AproxEqual(1))
return new vec2(1 - position.X, position.Y);
// Left Intersection
if (position.X.AproxEqual(0))
return new vec2(1 - position.Z, position.Y);
// Right Intersection
if (position.X.AproxEqual(1))
return new vec2(position.Z, position.Y);
// Top Intersection
if (position.Y.AproxEqual(1))
return new vec2(position.X, position.Z);
// Bottom Intersection
if (position.Y.AproxEqual(0))
return new vec2(position.X, position.Z);
throw new Exception("Una de las componentes X,Y,Z tiene que ser aproximadamente 1 o 0}");
}
public static Ray FromTo(vec3 position, vec3 target)
{
return new Ray(position, (target - position).Normalized);
}
/// <summary>
/// Crea un rayo que parte del observador y atraviesa un punto en la pantalla.
/// </summary>
private Ray ConstructRay(int px, int py)
{
/// Soportada por el momento camaras perspectivas
if (Scene.Camera is PerspectiveCamera)
{
var projectionCamera = Scene.Camera as PerspectiveCamera;
/// Determinar el alto y ancho de la pantalla en el mundo.
float height = (float)Math.Tan(projectionCamera.FieldOfView/2);
float width = height * frameBuffer.Width / frameBuffer.Height;
/// Punto de la pantalla en coordenadas de proyeccion
vec3 projected = new vec3(width * (px / (float)frameBuffer.Width * 2 - 1), height * (1 - 2 * py / (float)frameBuffer.Height), 0);
/// Punto de la pantalla en coordenadas del observador.
vec3 viewed = projected + new vec3(0, 0, 1);
/// Vectores de la camara.
vec3 cameraRight = vec3.cross(projectionCamera.Normal, projectionCamera.Direction).Normalized;
vec3 cameraNormal = vec3.cross(projectionCamera.Direction, cameraRight).Normalized;
vec3 cameraDirection = projectionCamera.Direction.Normalized;
/// Rayo.
return Ray.FromDirection(projectionCamera.Position,
viewed.X * cameraRight + viewed.Y * cameraNormal + viewed.Z * cameraDirection);
}
throw new NotSupportedException();
}
