mirror of
https://github.com/pocketpy/pocketpy
synced 2025-10-30 16:30:16 +00:00
93 lines
2.3 KiB
Markdown
93 lines
2.3 KiB
Markdown
---
|
|
icon: dot
|
|
label: 'Complete example'
|
|
order: 0
|
|
---
|
|
|
|
In this example, we will create a `linalg` module
|
|
and implement a `vec2` type with some methods.
|
|
And make them available in python just like this.
|
|
|
|
```python
|
|
from linalg import vec2
|
|
|
|
# construct a vec2
|
|
a = vec2(1.0, 2.0)
|
|
b = vec2(0.0, -1.0)
|
|
|
|
# add two vec2
|
|
print(a + b) # vec2(1.0, 1.0)
|
|
|
|
# set x component
|
|
a.x = 8.0
|
|
print(a) # vec2(8.0, 2.0)
|
|
|
|
# use dot method
|
|
print(a.dot(b)) # -2.0
|
|
```
|
|
|
|
### Implement `Vec2` struct in cpp
|
|
|
|
```cpp
|
|
struct Vec2{
|
|
float x, y;
|
|
Vec2() : x(0.0f), y(0.0f) {}
|
|
Vec2(float x, float y) : x(x), y(y) {}
|
|
Vec2(const Vec2& v) : x(v.x), y(v.y) {}
|
|
Vec2 operator+(const Vec2& v) const { return Vec2(x + v.x, y + v.y); }
|
|
float dot(const Vec2& v) const { return x * v.x + y * v.y; }
|
|
};
|
|
```
|
|
|
|
### Create `PyVec2` wrapper
|
|
|
|
```cpp
|
|
struct PyVec2: Vec2 {
|
|
PY_CLASS(PyVec2, linalg, vec2)
|
|
|
|
PyVec2() : Vec2() {}
|
|
PyVec2(const Vec2& v) : Vec2(v) {}
|
|
PyVec2(const PyVec2& v) : Vec2(v) {}
|
|
|
|
static void _register(VM* vm, PyObject* mod, PyObject* type){
|
|
vm->bind_constructor<3>(type, [](VM* vm, ArgsView args){
|
|
float x = CAST_F(args[1]);
|
|
float y = CAST_F(args[2]);
|
|
return VAR(Vec2(x, y));
|
|
});
|
|
|
|
vm->bind__repr__(OBJ_GET(Type, type), [](VM* vm, PyObject* obj){
|
|
PyVec2& self = _CAST(PyVec2&, obj);
|
|
std::stringstream ss;
|
|
ss << "vec2(" << self.x << ", " << self.y << ")";
|
|
return VAR(ss.str());
|
|
});
|
|
|
|
vm->bind__add__(OBJ_GET(Type, type), [](VM* vm, PyObject* obj, PyObject* other){
|
|
PyVec2& self = _CAST(PyVec2&, obj);
|
|
PyVec2& other_ = CAST(PyVec2&, other);
|
|
return VAR_T(PyVec2, self + other_);
|
|
});
|
|
|
|
vm->bind_method<1>(type, "dot", [](VM* vm, ArgsView args){
|
|
PyVec2& self = _CAST(PyVec2&, args[0]);
|
|
PyVec2& other = CAST(PyVec2&, args[1]);
|
|
return VAR(self.dot(other));
|
|
});
|
|
}
|
|
};
|
|
```
|
|
|
|
### Create `linalg` module
|
|
|
|
```cpp
|
|
void add_module_linalg(VM* vm){
|
|
PyObject* linalg = vm->new_module("linalg");
|
|
// register PyVec2
|
|
PyVec2::register_class(vm, linalg);
|
|
}
|
|
```
|
|
|
|
### Further reading
|
|
|
|
See [linalg.h](https://github.com/blueloveTH/pocketpy/blob/main/src/linalg.h) for the complete implementation. |