Your way

[osozero]

tinyrenderer/main.cpp

Line 38 in 68a5ae3

Vec3f barycentric(Vec3f A, Vec3f B, Vec3f C, Vec3f P) {

I do not understand your barycentric method's way. When i implement lesson 2 with my own barycentric method (finding cross products of edges and check point is inside with dot product, x and y are in screen coordinates format, but z is world coordinate) the final image is not same as yours. this is my method, if you can give me the point it would be glad.

Vec3f barycentric(Vec3f A, Vec3f B, Vec3f C, Vec3f P)
{
	float u;
	float v;
	float w;

	Vec3f AB(B - A);
	Vec3f AP(P - A);

	Vec3f BC(C - B);
	Vec3f BP(P - B);

	Vec3f CA(A - C);
	Vec3f CP(P - C);

	//for plane normal calculation
	Vec3f AC(C - A);

	Vec3f normal = cross(AB, AC);

	float denom = normal.dot(normal);

	Vec3f crossABAP = cross(AB, AP);

	if (normal.dot(crossABAP) < 0)
	{
		return Vec3f(-1, -1, -1);
	}

	Vec3f crossBCBP = cross(BC, BP);

	if ((u = normal.dot(crossBCBP)) < 0)
	{
		return Vec3f(-1, -1, -1);
	}

	Vec3f crossCACP = cross(CA, CP);

	if ((v = normal.dot(crossCACP) < 0))
	{
		return Vec3f(-1, -1, -1);
	}

	u /= denom;
	v /= denom;
	w = 1 - u - v;

	return Vec3f(w, u, v);
}

[ssloy]

Check this link:
https://github.com/ssloy/tinyrenderer/wiki/Lesson-2:-Triangle-rasterization-and-back-face-culling

Start reading from here:

Okay, let us start: first of all we need to know what the barycentric coordinates are. Given a 2D