本文主要介绍如何使用Cython加速OpenGL，涉及到glad头文件的引入和编译，以及PyQt5或者PySide2中glad的初始化。glad下载步骤见CLion：OpenGL + GLAD配置.
测试环境：PySide2 + Cython + glad
-
新建项目，解压
glad.zip到项目根目录，最后项目结构为：项目结构 编写
pyx文件，比较重要的有两点：首先是cdef extern from "glad/glad.h" nogil:中添加nogil，主要是为了在使用OpenGL函数时释放GIL；其次是 glad初始化部分，如果在QOpenGLWidget的initializeGL函数里没有调用glad初始化函数，程序会闪退。例如：
def initializeGL(self):
print("gladLoadGL", demo.glad_init())
glEnable(GL_BLEND)
# glEnable(GL_POINT_SMOOTH)
# glEnable(GL_LINE_SMOOTH)
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
glClearColor(9 / 255, 28 / 255, 38 / 255, 1)
Cython示例代码如下：
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# cython: language_level = 3
# cython: boundscheck = False
# cython: wraparound = False
# cython: nonecheck = False
# cython: overflowcheck = False
# cython: cdivision = True
# cython: c_string_type = bytes
cdef extern from "glad/glad.h" nogil:
ctypedef int GLint
ctypedef unsigned int GLenum
ctypedef float GLfloat
ctypedef unsigned int GLbitfield
ctypedef void GLvoid
ctypedef unsigned int GLuint
ctypedef int GLsizei
ctypedef double GLdouble
int GL_LINE_STRIP
void glBegin(GLenum mode)
void glEnd()
void glVertex2f(GLfloat x, GLfloat y)
void glVertex3f(GLfloat x, GLfloat y, GLfloat z)
void glColor3f(GLfloat red, GLfloat green, GLfloat blue);
cdef extern from "glad/glad.h" nogil:
int GL_ARRAY_BUFFER
int GL_ELEMENT_ARRAY_BUFFER
int GL_STATIC_DRAW
int GL_DYNAMIC_DRAW
int GL_STREAM_DRAW
int GL_READ_ONLY
int GL_WRITE_ONLY
int GL_READ_WRITE
void *glMapBuffer(GLenum target, GLenum access)
void glUnmapBuffer(GLenum target)
int gladLoadGL()
# 初始化glad
cpdef int glad_init():
return gladLoadGL()
cpdef void draw(float[:] data, float dx, int length, int interval) nogil:
cdef int i
for i from 0 <= i <length by interval:
glVertex2f(i * dx, data[i])
cpdef int map_buffer(float[:,:] data, const int chs, int index, int block, int size) nogil:
cdef int i, j
cdef float *d
d = <float*>glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY)
for i in range(chs):
for j in range(block):
d[i * size + index + j] = data[i][j]
index = (index + block) % size
glUnmapBuffer(GL_ARRAY_BUFFER)
return index
- 编写编译脚本
编译时，需要指定头文件目录和添加glad.c源文件。完整setup.py为：
from distutils.core import setup
from Cython.Distutils import build_ext, Extension
# python setup.py build_ext --inplace
setup(
name="demo",
ext_modules=[Extension("demo", ["demo.pyx", "./src/glad.c"], include_dirs=["./include"])],
cmdclass={'build_ext': build_ext}
)
最后运行python setup.py build_ext --inplace即可。
总的来说，使用Cython加速OpenGL很简单，而且效果显著，使用时注意glad的初始化就行了。
若有不清楚地方，可联系我一起探讨探讨。
版权声明：本文为「txfly」的原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接及本声明。
原文链接：https://www.jianshu.com/p/418b49e3f285
