如何在glShaderSource中将String作为GLchar**(char**)参数传递？

Question

我有一个存储在String值中的着色器:

    var myShader = 
    "    attribute vec4 a_position;" +
    "    void main() {" +
    "    gl_Position = a_position;" +
    "    }"

    glShaderSource(shader, GLsizei(1), myShader, nil)

函数glShaderSource具有绑定签名:

    func glShaderSource(shader: GLuint, count: GLsizei, string: UnsafePointer<UnsafePointer<GLchar>>, length: UnsafePointer<GLint>)

当我尝试直接将着色器String传递给glShaderSource时,我收到错误消息:

    'String' is not convertible to 'UnsafePointer<UnsafePointer<GLchar>>'

如何正确传递String？(xCode版本6.1(6A1052d))

Answer 1

经过半天的搜索,我找到了没有编译错误的工作解决方案,错误的内存访问失败了:

var cStringSource = (code as NSString).UTF8String
glShaderSource(shader, GLsizei(1), &cStringSource, nil)

Answer 2

斯威夫特3：

let shaderStringUTF8 = shaderString.cString(using: String.defaultCStringEncoding)
var shaderStringUTF8Pointer = UnsafePointer<GLchar>(shaderStringUTF8)

glShaderSource(shaderHandle, GLsizei(1), &shaderStringUTF8Pointer, nil)