gate 0.6.3

A specialized 2D game library
Documentation 
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// Copyright 2017-2019 Matthew D. Michelotti
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::os::raw::c_char;
use std::{ptr, str};

use gl::types::*;
use gl;

pub fn compile_shader(src: *const c_char, ty: GLenum) -> GLuint {
    unsafe {
        let shader = gl::CreateShader(ty);

        gl::ShaderSource(shader, 1, &src, ptr::null());
        gl::CompileShader(shader);

        let mut status = gl::FALSE as GLint;
        gl::GetShaderiv(shader, gl::COMPILE_STATUS, &mut status);

        if status != (gl::TRUE as GLint) {
            let mut len = 0;
            gl::GetShaderiv(shader, gl::INFO_LOG_LENGTH, &mut len);
            let mut buf = Vec::with_capacity(len as usize - 1);
            buf.set_len(len as usize - 1); // subtract 1 to skip the trailing null character
            gl::GetShaderInfoLog(shader, len, ptr::null_mut(), buf.as_mut_ptr() as *mut GLchar);
            panic!("{}", str::from_utf8(&buf).ok().expect("glGetShaderInfoLog returned invalid utf8"));
        }
        shader
    }
}

pub fn link_program(vs: GLuint, fs: GLuint) -> GLuint {
    unsafe {
        let program = gl::CreateProgram();
        gl::AttachShader(program, vs);
        gl::AttachShader(program, fs);
        gl::LinkProgram(program);

        let mut status = gl::FALSE as GLint;
        gl::GetProgramiv(program, gl::LINK_STATUS, &mut status);

        if status != (gl::TRUE as GLint) {
            let mut len: GLint = 0;
            gl::GetProgramiv(program, gl::INFO_LOG_LENGTH, &mut len);
            let mut buf = Vec::with_capacity(len as usize - 1);
            buf.set_len(len as usize - 1); // subtract 1 to skip the trailing null character
            gl::GetProgramInfoLog(program, len, ptr::null_mut(), buf.as_mut_ptr() as *mut GLchar);
            panic!("{}", str::from_utf8(&buf).ok().expect("glGetProgramInfoLog returned invalid utf8"));
        }
        program
    }
}