Chapter vertex processing mechanism
1 line: the data sequence and for processing element.
2. The rendering pipeline process comprising: a process vertex -> rasterization -> fragments process -> Output merge operation (wherein the programmable state comprises: vertex and fragment, called the vertex program and fragment program )
3. rasterization output merge operations and hardware dependent.
4. In the vertex processing stage, the model object space through a plurality of spaces, until it reaches the clip space.
5. Object Space - (World conversion) -> World Space - (viewport conversion) -> camera space - (projection conversion) -> clip space
2.1 Conversion world
1. World conversion and conversion depends on the view all the basic conversion: scaling transformation, rotation conversion, translation transducer
2. scaling transformation: a three-dimensional 3x3 matrix described scaling operation available:
3.sx, SY, SZ denotes the scaling along the major axis direction coefficients (coefficients are equal is called the uniform scaling)
4. the rotating operation (2D): [swirl angle required that a, b represents the rotated coordinates, x, y] represents the rotation of the former:
the rotating operation (3D): corresponding to three-dimensional coordinates, and the need to determine the rotation shaft, different transformation matrices corresponding to different rotational axes:
6. translational transformation: Matrix addition, adding the offset:
7. homogeneous coordinates: 3d Cartesian coordinates of a given vertex (x, y, z), may simply be (x, y, z, 1 ) considered homogeneous coordinate
8. The transform matrix corresponding to the four-dimensional :
9. homogeneous coordinates (x, y, z, w) corresponding to the Cartesian coordinates (x / w, y / w, z / w). W items are used to distinguish the vector vertex data and, if w = 0, represents the vector otherwise vertices.
2.1.2 world matrix
1. After completion of modeling, space objects belonging to the object itself whine that there are no other objects associated with space, primary pipelines will be defined in the model in its own space integrated into a single space, that world space.
2. "The World" can be regarded as the coordinate system for the entire game environment
3. "world matrix": corresponding matrix multiplication operations. The World matrix obtained by multiplying the original coordinates of white after the position in the world can change.
2.1.3 Euler conversion
1. Definitions: a continuous transition (along different axes using matrix multiplication), transformation angle x1, x2 along the x, y, z-axis, x3 Euler angles.
2.1.4 surface normal conversion
1. Standardization operation: changing operation of the series of vertices.
2. Let M polygon mesh transformation matrix, if M is a rotational operation, shift operation, a uniform scaling operation or a combination thereof, the available M on the object surface normals [not] non-uniform scaling is
3. conversion formula:
[T: transpose, -1: inverse]