69 lines
2.2 KiB
Markdown
69 lines
2.2 KiB
Markdown
# Basic Geomtric Computations
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[Русская версия / Russian version](intro-rus.md)
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## Naming
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C programming language does not have namespaces, thus prefixes often play role of namespaces in C code.
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The library uses prefixes in names of types, constants and functions to avoid name conflict with of othr libraries.
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### Library prefix (the main prefix)
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The main prefix is **BGC** which means **B**asic **G**eometric **C**omputations.
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The structure types and the contstans have prefix in the form **BGC_**.
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For example, structures:
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- BGC_FP64_Vector3
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- BGC_FP32_Quaternion
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- BGC_FP32_Matrix2x2
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Constants:
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- BGC_FP32_EPSILON
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- BGC_FP64_TWO_PI
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The functions have prefix in the form **bgc_**, for example:
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- bgc_fp32_turn3_combine
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- bgc_fp64_matrix3x3_subtract
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### Basic type prefix (the secondary prefix)
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Prefixs of type ends the names of constats, types and functions of the library.
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The library uses two types of floating point numbers: **float** and **double** (**binary32** and **binary64** types of the **IEEE 754** standard).
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Thus there are two prefixes of types:
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- **FP32** - means **F**loating **P**oint, **32** bit, which corresponds to the **float** type of the C programming language.
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- **FP64** - means **F**loating **P**oint, **64** bit, which corresponds to the **double** type of the C programming language.
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The constants and the types of structures which are based in the **float** type have **FP32_** as the type prefix:
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- BGC_FP32_Vector3
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- BGC_FP32_Matrix3x2
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- BGC_FP32_Quaternion
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- BGC_FP32_PI
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- BGC_FP32_EPSILON
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The constants and the types of structures which are based in the **double** type have **FP64_** as the type prefix:
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- BGC_FP64_Vector2
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- BGC_FP64_Matrix2x3
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- BGC_FP64_Turn3
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- BGC_FP64_HALF_PI
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- BGC_FP64_ONE_THIRD
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The functions which works with data of the **float** type have **fp32_** as the type prefix:
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- bcg_fp32_vector2_get_length
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- bgc_fp32_radians_to_degrees
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The functions which works with data of the **double** type have **fp64_** as the type prefix:
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- bgc_fp64_vector3_reset
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- bgc_fp64_normalize_radians.
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Using of such prefixes of a basic type allows to enhance the library with new basic types in future.
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### Data types
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- [2D-vectors](vector2-eng.md)
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- [3D-vectors](vector3-eng.md)
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- [Quaternions](quaternion-rus.md)
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