gl_helpers 0.1.1

use alloc::vec::Vec;

use core::ops::Drop;

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

use super::{Attachment, GLTexture};


pub struct GLFramebuffer {
    id: GLuint,
}

impl GLFramebuffer {

    #[inline(always)]
    pub fn new(gl_texture: &GLTexture, buffers: &[Attachment], level: isize) -> Self {
        let framebuffer = GLFramebuffer {
            id: {
                let mut id = 0;
                unsafe { gl::GenFramebuffers(1, &mut id); }
                id
            },
        };

        framebuffer.set(gl_texture, buffers, level);
        framebuffer
    }

    #[inline(always)]
    pub fn id(&self) -> GLuint { self.id }

    #[inline]
    pub fn bind(&self) -> &Self {
        unsafe { gl::BindFramebuffer(gl::FRAMEBUFFER, self.id); }
        self
    }
    #[inline]
    pub fn unbind(&self) -> &Self {
        unsafe { gl::BindFramebuffer(gl::FRAMEBUFFER, 0); }
        self
    }

    #[inline]
    pub fn set(&self, gl_texture: &GLTexture, buffers: &[Attachment], level: isize) {
        let gl_texture_id = gl_texture.id();

        let mut gl_enums = Vec::with_capacity(buffers.len());
        for i in 0..buffers.len() {
            gl_enums.push(buffers[i].to_gl());
        }

        unsafe {
            gl::BindFramebuffer(gl::FRAMEBUFFER, self.id);
            gl::BindTexture(gl_texture.kind().to_gl(), gl_texture_id);

            for i in 0..gl_enums.len() {
                gl::FramebufferTexture(gl::FRAMEBUFFER, gl_enums[i], gl_texture_id, level as GLint);
            }
            gl::DrawBuffers(buffers.len() as GLint, gl_enums.as_ptr());

            if gl::CheckFramebufferStatus(gl::FRAMEBUFFER) != gl::FRAMEBUFFER_COMPLETE {
                panic!("Check framebuffer status failed");
            }
        }
    }
}

impl Drop for GLFramebuffer {
    #[inline]
    fn drop(&mut self) {
        if self.id != 0 {
            unsafe { gl::DeleteFramebuffers(1, &self.id); }
        }
    }
}