Common software rendering algorithms include scanline, ray tracing, and
radiosity
Scan-line algorithm
scan-line
: The scan-line algorithm is very simple, and its basic idea is to convert the 3D scene into
Perform two-dimensional projection, then divide the projection into small blocks, and perform calculations step by step. The biggest advantage of this algorithm is the speed
Fast, almost all renderers support the scanline algorithm. First, the object in the 3D scene along the direction of the camera vector
The direction is projected, and the
z
channel is calculated, and the color information of the sampling point. Then use this information to finally find the rendered image
The color value of each pixel in . Representative software
renderman
Ray tracing algorithm
raytracing
: The calculation method of ray tracing is very similar to the imaging principle in real life.
Count the light emitted by the light source as an infinitely long ray that changes direction when it encounters reflection or refraction, and when it encounters diffuse reflection
It ends when the shooting surface or no object is blocked, and the actual calculation is actually a reverse solution. The advantage of this algorithm is that it can truly reproduce
Refraction and reflection between objects makes it easy to render photo-quality pictures. Represents the software
mentalray.
Radiosity
algorithm for radiosity transfer
: it is an algorithm based on the real thermal radiation transfer formula, which divides the scene into many different sizes
Different surfaces, calculate the value of light radiation on each surface one by one, after attenuation, and then pass to the surface in the corresponding direction, as follows
Go until the energy of the light is lower than the value we set. Since this algorithm is completely modeled on the principles of physics, the effect
Very realistic, but very slow, generally only used for still frames. Representative software
maxwell
Hardware rendering: the picture is completely calculated by the graphics card, mostly used for particle rendering, game picture production and
wed3d
. rendering
The effect depends on the graphics card. Representative software
CgFX
The understanding of rendering algorithms and renderers is crucial to improving work efficiency.