一个简单的计算器，用于计算加减乘除，但不能进行脱式计算。-A simple calculator, but can not be used to calculate the add, subtract, multiply and divide and calculation

#version 130 in vec4 vPosition in vec4 vColor out vec4 color uniform int xsize uniform int ysize void main() { mat4 scale = mat4(2.0/xsize, 0.0, 0.0, 0.0, 0.0, 2.0/ysize, 0.0, 0.0, 0.0, 0.0, 1.0, 0

multiply matrices multiply matrices of given entities

根据编译器的基本原理，实现简单的加减乘除的计算(According to the basic principle of the compiler, the realization of a simple calculation of add, subtract, multiply and divide.)