How to tell if a point is inside a triangle
Assuming that the point that needs to be judged is X, and the vertices of the triangle line are ABC according to the clockwise order, then
If X is inside the triangle, AB×AX, BC×BX, CA×CX should have the same sign (they are all vector cross products), otherwise X is not inside the triangle.
Frequency domain interpretation of aliasing
Rasterized sampling can be regarded as the product of the time domain information and the impulse function, and the multiplication in the time domain is equal to the convolution in the frequency domain, as shown in the figure below.
The aliasing phenomenon is the aliasing of high-frequency information after frequency domain convolution.
Therefore, blurring the image, removing some high-frequency signals and then sampling may have the effect of anti-aliasing
