public static void WireTriangle(
TransformedTriangle triangle,
RendererContext context)
{
Line(triangle.V0, triangle.V1, context);
Line(triangle.V0, triangle.V2, context);
Line(triangle.V1, triangle.V2, context);
}
public static void Triangle(
TransformedTriangle triangle,
RendererContext context,
float light, Material material)
{
int IL = (int)(255 * light);
IL = IL << 16 | IL << 8 | IL;
float triangleYHeight = triangle.V2.Y - triangle.V0.Y + 1;
float firstSegmentHeight = triangle.V1.Y - triangle.V0.Y + 1;
float secondSegmentHeight = triangle.V2.Y - triangle.V1.Y + 1;
for (int y = (int)triangle.V0.Y; y <= triangle.V2.Y; y++)
{
if (y < 0 | y >= context.Height)
{
continue;
}
bool isFirstSegment = y < triangle.V1.Y;
float segmentStartY = isFirstSegment ? triangle.V0.Y : triangle.V1.Y;
float alpha = (y - triangle.V0.Y) / triangleYHeight;
float beta = (y - segmentStartY) / (isFirstSegment ? firstSegmentHeight : secondSegmentHeight);
if (beta < 0)
{
beta = 0f;
}
if (alpha < 0)
{
alpha = 0f;
}
Vector3 A = Vector3.Lerp(triangle.V0, triangle.V2, alpha);
Vector3 B = Vector3.Lerp(isFirstSegment ? triangle.V0 : triangle.V1, isFirstSegment ? triangle.V1 : triangle.V2, beta);
Vector2 uvA = Vector2.Lerp(triangle.UV0, triangle.UV2, alpha);
Vector2 uvB = Vector2.Lerp(isFirstSegment ? triangle.UV0 : triangle.UV1, isFirstSegment ? triangle.UV1 : triangle.UV2, beta);
if (A.X > B.X)
{
Vector3.Swap(ref A, ref B);
}
for (int x = (int)(A.X); x <= B.X; x++)
{
if (x < 0 | x >= context.Width)
{
continue;
}
float delta = (x - A.X) / (B.X - A.X);
if (A.X == B.X)
{
delta = 1f;
}
if (delta < 0)
{
delta = 0f;
}
Vector3 C = Vector3.Lerp(A, B, delta);
Vector2 uvC = Vector2.Lerp(uvA, uvB, delta);
int bufferIndex = x + y * context.Width;
if (context.depthBuffer[bufferIndex] <= C.Z)
{
context.depthBuffer[bufferIndex] = C.Z;
context.Buffer[bufferIndex] = IL;
}
}
}
}
