fn create_opengl_program()

in native/desktop-linux-sample/src/sample_linux.rs [161:200]

• 36 lines of code
• 3 McCabe index (conditional complexity)

fn create_opengl_program(gl: &OpenGlFuncs) -> Option<GLuint> {
    const V_SHADER_STR: &CStr = c"attribute vec4 vPosition;
void main()
{
  gl_Position = vPosition;
}
";
    const F_SHADER_STR: &CStr = c"precision mediump float;
void main()
{
  gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
}
";
    // Load the vertex/fragment shaders
    let vertex_shader = load_shader(gl, GL_VERTEX_SHADER, V_SHADER_STR.as_ptr()).unwrap();
    let fragment_shader = load_shader(gl, GL_FRAGMENT_SHADER, F_SHADER_STR.as_ptr()).unwrap();
    // Create the program object
    unsafe {
        let program = (gl.glCreateProgram)();
        if program == 0 {
            return None;
        }
        (gl.glAttachShader)(program, vertex_shader);
        (gl.glAttachShader)(program, fragment_shader);
        // Bind vPosition to attribute 0
        (gl.glBindAttribLocation)(program, V_POSITION, c"vPosition".as_ptr());
        (gl.glLinkProgram)(program);
        // Check the link status
        {
            let mut linked: GLint = 0;
            (gl.glGetProgramiv)(program, GL_LINK_STATUS, &raw mut linked);
            if linked == 0 {
                (gl.glDeleteProgram)(program);
                return None;
            }
        }
        (gl.glClearColor)(0.0, 1.0, 0.0, 1.0);
        Some(program)
    }
}