private static void DrawTriangle(Vertex v1, Vertex v2, Vertex v3)
{
__ShaderName__ shader = new __ShaderName__();
//调用顶点着色shader
__CreateVSInputStruct1__
__VSOutputType__ p1 = shader.__VertexShaderName__(vi1);
__CreateVSInputStruct2__
__VSOutputType__ p2 = shader.__VertexShaderName__(vi2);
__CreateVSInputStruct3__
__VSOutputType__ p3 = shader.__VertexShaderName__(vi3);
p1 = ToScreen(p1);
p2 = ToScreen(p2);
p3 = ToScreen(p3);
//Console.WriteLine($"{p1.Position} {p2.Position} {p3.Position}");
//Console.WriteLine((p1.Position.Y - p2.Position.Y));
//排序，并调用填充函数
Sort(ref p1, ref p2, ref p3);
if (p2.Position.Y == p3.Position.Y)
{
FillFlatTriangle(p1, p2, p3, shader, false);
}
else if (p1.Position.Y == p2.Position.Y)
{
FillFlatTriangle(p3, p1, p2, shader, true);
}
else
{
float t = (p2.Position.Y - p1.Position.Y) / (p3.Position.Y - p1.Position.Y);
__VSOutputType__ p4 = Lerp(p1, p3, t);
FillFlatTriangle(p1, p2, p4, shader, false);
FillFlatTriangle(p3, p2, p4, shader, true);
}
}
private static void DrawFlatLine(__VSOutputType__ v1, __VSOutputType__ v2, __ShaderName__ shader)
{
if (v1.Position.X > v2.Position.X)
{
Swap(ref v1, ref v2);
}
float x0 = v1.Position.X;
float x1 = v2.Position.X;
//if (x0 > x1) Swap(ref x0, ref x1);
float dx = x1 - x0 + 0.01f;
//Console.WriteLine($"dx: {dx}");
for (int i = (int)x0; i <= x1; i++)
{
__FSOutputType__ o = shader.__FragmentShaderName__(Lerp(v1, v2, (i - x0) / dx));
Canvas.SetPixel(i, (int)(v1.Position.Y /*+ 0.5f*/), o.Color);
}
}
private static void FillFlatTriangle(__VSOutputType__ v1, __VSOutputType__ v2, __VSOutputType__ v3, __ShaderName__ shader, bool isFlatBottom)
{
if (isFlatBottom)
{
for (float scanlineY = v2.Position.Y; scanlineY <= v1.Position.Y; scanlineY++)
{
float t = (scanlineY - v2.Position.Y) / (v1.Position.Y - v2.Position.Y);
DrawFlatLine(Lerp(v1, v2, t), Lerp(v1, v3, t), shader);
}
}
else
{
for (float scanlineY = v1.Position.Y; scanlineY <= v2.Position.Y; scanlineY++)
{
float t = (scanlineY - v1.Position.Y) / (v2.Position.Y - v1.Position.Y);
DrawFlatLine(Lerp(v1, v2, t), Lerp(v1, v3, t), shader);
}
}
}
public static void SetShader(object shader) => Shader = (__ShaderName__)shader;
