golem 0.1.0-alpha1

use crate::*;

pub struct Surface {
    pub(crate) ctx: Context,
    pub(crate) id: GlFramebuffer,
    pub(crate) texture: Option<Texture>,
}

impl Surface {
    pub fn new(ctx: &Context) -> Result<Surface, GolemError> {
        let ctx = Context(ctx.0.clone());
        let id = unsafe { ctx.0.gl.create_framebuffer() }?;

        Ok(Surface {
            ctx,
            id,
            texture: None,
        })
    }

    pub fn bind(ctx: &Context, surface: Option<&Surface>) {
        unsafe {
            ctx.0
                .gl
                .bind_framebuffer(glow::FRAMEBUFFER, surface.map(|s| s.id));
        }
    }

    pub fn texture(&self) -> Option<&Texture> {
        self.texture.as_ref()
    }

    pub fn texture_mut(&mut self) -> Option<&mut Texture> {
        self.texture.as_mut()
    }

    pub fn set_texture(&mut self, texture: Option<Texture>) {
        let gl = &self.ctx.0.gl;
        self.texture = texture;
        unsafe {
            gl.bind_framebuffer(glow::FRAMEBUFFER, Some(self.id));
            gl.framebuffer_texture_2d(
                glow::FRAMEBUFFER,
                glow::COLOR_ATTACHMENT0,
                glow::TEXTURE_2D,
                self.texture.as_ref().map(|tex| tex.id),
                0,
            );
            gl.bind_framebuffer(glow::FRAMEBUFFER, None);
        }
    }

    pub fn get_pixel_data(
        &self,
        x: u32,
        y: u32,
        width: u32,
        height: u32,
        format: ColorFormat,
        data: &mut [u8],
    ) {
        let bytes_per_pixel = match format {
            ColorFormat::RGBA => 4,
            ColorFormat::RGB => 3,
        };
        let length = (width * height * bytes_per_pixel) as usize;
        assert!(data.len() >= length);
        let format = match format {
            ColorFormat::RGB => glow::RGB,
            ColorFormat::RGBA => glow::RGBA,
        };
        let gl = &self.ctx.0.gl;
        unsafe {
            gl.bind_framebuffer(glow::FRAMEBUFFER, Some(self.id));
            gl.read_pixels(
                x as i32,
                y as i32,
                width as i32,
                height as i32,
                format,
                glow::UNSIGNED_BYTE,
                data,
            );
            gl.bind_framebuffer(glow::FRAMEBUFFER, None);
        }
    }
}

impl Drop for Surface {
    fn drop(&mut self) {
        unsafe {
            self.ctx.0.gl.delete_framebuffer(self.id);
        }
    }
}