/// <summary>
/// 画一条直线
/// </summary>
/// <param name="point0"></param>
/// <param name="point1"></param>
/// <param name="scene"></param>
/// <param name="v1"></param>
/// <param name="v2"></param>
public void DrawLine(Vector4 point0, Vector4 point1, Scene scene, Vertex v1, Vertex v2)
{
int x0 = (int)point0.X;
int y0 = (int)point0.Y;
int x1 = (int)point1.X;
int y1 = (int)point1.Y;
int dx = x1 - x0;
int dy = y1 - y0;
int steps = Math.Max(Math.Abs(dx), Math.Abs(dy));
if (steps == 0)
{
return;
}
float offsetX = (float)dx / (float)steps;
float offsetY = (float)dy / (float)steps;
float x = x0;
float y = y0;
Color vColor = new Color(128, 128, 128);
for (int i = 1; i <= steps; i++)
{
float dt = (float)(i) / (float)steps;
vColor = MathUntily.Lerp(v1.Color, v2.Color, dt);
float z = MathUntily.Lerp(point0.Z, point1.Z, dt);
if (float.IsNaN(z))
{
return;
}
DrawPoint(new Vector4((int)x, (int)y, z, 0), vColor);
x += offsetX;
y += offsetY;
}
}
/// <summary>
/// 求交点, 返回的pos是裁剪空间下坐标
/// </summary>
/// <param name="v1"></param>
/// <param name="v2"></param>
/// <param name="face"></param>
/// <param name="wMin"></param>
/// <param name="wMax"></param>
/// <returns></returns>
Vertex Intersect(Vertex v1, Vertex v2, FaceTypes face, Vector4 wMin, Vector4 wMax)
{
Vertex vertex = new Vertex();
float k1 = 0, k2 = 0, k3 = 0, k4 = 0, k5 = 0, k6 = 0;
Vector4 p1 = v1.ClipPosition;
Vector4 p2 = v2.ClipPosition;
if (p1.X != p2.X)
{
k1 = (wMin.X - p1.X) / (p2.X - p1.X); k2 = (wMax.X - p1.X) / (p2.X - p1.X);
}
else
{
k1 = k2 = 1;
}
if (p1.Y != p2.Y)
{
k3 = (wMin.Y - p1.Y) / (p2.Y - p1.Y); k4 = (wMax.Y - p1.Y) / (p2.Y - p1.Y);
}
else
{
k3 = k4 = 1;
}
if (p1.Z != p2.Z)
{
k5 = (wMin.Z - p1.Z) / (p2.Z - p1.Z); k6 = (wMax.Z - p1.Z) / (p2.Z - p1.Z);
}
else
{
k5 = k6 = 1;
}
Vector4 clipPos = new Vector4();
Vector4 pos = new Vector4();
Color col = new Color(0, 0, 0);
Vector4 normal = new Vector4();
Vector2 uv = new Vector2();
switch (face)
{
case FaceTypes.LEFT:
clipPos.X = wMin.X;
clipPos.Y = p1.Y + (p2.Y - p1.Y) * k1;
clipPos.Z = p1.Z + (p2.Z - p1.Z) * k1;
clipPos.W = p1.W + (p2.W - p1.W) * k1;
col = MathUntily.Lerp(v1.Color, v2.Color, k1);
normal = MathUntily.Lerp(v1.Normal, v2.Normal, k1);
pos = MathUntily.Lerp(v1.Position, v2.Position, k1);
uv = MathUntily.Lerp(v1.UV, v2.UV, k1);
break;
case FaceTypes.RIGHT:
clipPos.X = wMax.X;
clipPos.Y = p1.Y + (p2.Y - p1.Y) * k2;
clipPos.Z = p1.Z + (p2.Z - p1.Z) * k2;
clipPos.W = p1.W + (p2.W - p1.W) * k2;
col = MathUntily.Lerp(v1.Color, v2.Color, k2);
normal = MathUntily.Lerp(v1.Normal, v2.Normal, k2);
pos = MathUntily.Lerp(v1.Position, v2.Position, k2);
uv = MathUntily.Lerp(v1.UV, v2.UV, k2);
break;
case FaceTypes.BUTTOM:
clipPos.Y = wMin.Y;
clipPos.X = p1.X + (p2.X - p1.X) * k3;
clipPos.Z = p1.Z + (p2.Z - p1.Z) * k3;
clipPos.W = p1.W + (p2.W - p1.W) * k3;
col = MathUntily.Lerp(v1.Color, v2.Color, k3);
normal = MathUntily.Lerp(v1.Normal, v2.Normal, k3);
pos = MathUntily.Lerp(v1.Position, v2.Position, k3);
uv = MathUntily.Lerp(v1.UV, v2.UV, k3);
break;
case FaceTypes.TOP:
clipPos.Y = wMax.Y;
clipPos.X = p1.X + (p2.X - p1.X) * k4;
clipPos.Z = p1.Z + (p2.Z - p1.Z) * k4;
clipPos.W = p1.W + (p2.W - p1.W) * k4;
col = MathUntily.Lerp(v1.Color, v2.Color, k4);
normal = MathUntily.Lerp(v1.Normal, v2.Normal, k4);
pos = MathUntily.Lerp(v1.Position, v2.Position, k4);
uv = MathUntily.Lerp(v1.UV, v2.UV, k4);
break;
case FaceTypes.NEAR:
clipPos.Z = wMin.Z;
clipPos.X = p1.X + (p2.X - p1.X) * k5;
clipPos.Y = p1.Y + (p2.Y - p1.Y) * k5;
clipPos.W = p1.W + (p2.W - p1.W) * k5;
col = MathUntily.Lerp(v1.Color, v2.Color, k5);
normal = MathUntily.Lerp(v1.Normal, v2.Normal, k5);
pos = MathUntily.Lerp(v1.Position, v2.Position, k5);
uv = MathUntily.Lerp(v1.UV, v2.UV, k5);
break;
case FaceTypes.FAR:
clipPos.Z = wMax.Z;
clipPos.X = p1.X + (p2.X - p1.X) * k6;
clipPos.Y = p1.Y + (p2.Y - p1.Y) * k6;
clipPos.W = p1.W + (p2.W - p1.W) * k6;
col = MathUntily.Lerp(v1.Color, v2.Color, k6);
normal = MathUntily.Lerp(v1.Normal, v2.Normal, k6);
pos = MathUntily.Lerp(v1.Position, v2.Position, k6);
uv = MathUntily.Lerp(v1.UV, v2.UV, k6);
break;
}
vertex.Position = pos;
vertex.ClipPosition = clipPos;
vertex.ScreenPosition = this.mDevice.ViewPort(clipPos);
vertex.Normal = normal;
vertex.UV = uv;
vertex.Color = col;
return(vertex);
}
