3D rendering pipeline

What is rendering)

A simple understanding of rendering may be like this: it is to convert the description of a 3D object or a 3D scene into a two-dimensional image, and the generated two-dimensional image can well reflect a 3D object or a 3D scene (1):

What is a rendering pipeline?

A rendering pipeline, also known as a rendering pipeline, is a parallel processing unit that allows the display chip to process graphical signals independently of each other. A pipeline is a sequence of stages that can be performed in parallel and in a fixed order. Each stage receives input from the previous stage, and sends the output to the subsequent stage. Just like an assembly line made by different vehicles at different stages at the same time, the traditional graphic hardware assembly line processes a large number of vertices, geometric figures, and fragments in the form of water.

Figure 2 shows the graphic hardware pipeline used by today's graphics processors. 3D applicationsProgramThe vertices passed to the graphic processor form different geometric elements: Typical polygon, line segments, and points. As shown in figure 3, there are many ways to create geometric elements.

 

 

 

Local space --> World Space --> View space --> backface culling --> lighting --> clipping --> projection --> viewport space --> Rasterization

Local space: A local space is called a modeling space. This is the coordinate system that defines the triangle columns of an object.
World Space: World transformation is to set the positions, sizes, and directions of objects in the world.
View Space: The view space transformation is the same transformation of all objects in the world coordinate system with the camera transformation.
Backface culling: the front polygon blocks the back polygon behind the polygon. direct3d selects the polygon from the front polygon (that is, the redundant processing process is deleted) returns a polygon on the back to improve efficiency.
Lighting: the light source is defined in the world space, instead of being transformed to the view space through the view space.
Clipping: crop is the process of selecting geometric figures beyond the visible body range. Three cases are completely included, completely external, and partially included.
Projection: the process of converting from N-dimensional to n-1 dimension.
Viewport transform: This is a reliable transformation that converts a projection window to a rectangle on the screen.
Rasterization: the grating process is used to calculate the color value of each vertex in each triangle to be displayed.