use std::rc::Rc;
use gleam::gl::{self, Gl};
use image::RgbImage;
use log::trace;
use servo_geometry::FramebufferUintLength;
pub struct RenderTargetInfo {
gl: Rc<dyn Gl>,
framebuffer_ids: Vec<gl::GLuint>,
renderbuffer_ids: Vec<gl::GLuint>,
texture_ids: Vec<gl::GLuint>,
}
impl RenderTargetInfo {
pub fn new(
gl: Rc<dyn Gl>,
width: FramebufferUintLength,
height: FramebufferUintLength,
) -> Self {
let framebuffer_ids = gl.gen_framebuffers(1);
gl.bind_framebuffer(gl::FRAMEBUFFER, framebuffer_ids[0]);
trace!("Configuring fbo {}", framebuffer_ids[0]);
let texture_ids = gl.gen_textures(1);
gl.bind_texture(gl::TEXTURE_2D, texture_ids[0]);
gl.tex_image_2d(
gl::TEXTURE_2D,
0,
gl::RGB as gl::GLint,
width.get() as gl::GLsizei,
height.get() as gl::GLsizei,
0,
gl::RGB,
gl::UNSIGNED_BYTE,
None,
);
gl.tex_parameter_i(
gl::TEXTURE_2D,
gl::TEXTURE_MAG_FILTER,
gl::NEAREST as gl::GLint,
);
gl.tex_parameter_i(
gl::TEXTURE_2D,
gl::TEXTURE_MIN_FILTER,
gl::NEAREST as gl::GLint,
);
gl.framebuffer_texture_2d(
gl::FRAMEBUFFER,
gl::COLOR_ATTACHMENT0,
gl::TEXTURE_2D,
texture_ids[0],
0,
);
gl.bind_texture(gl::TEXTURE_2D, 0);
let renderbuffer_ids = gl.gen_renderbuffers(1);
let depth_rb = renderbuffer_ids[0];
gl.bind_renderbuffer(gl::RENDERBUFFER, depth_rb);
gl.renderbuffer_storage(
gl::RENDERBUFFER,
gl::DEPTH_COMPONENT24,
width.get() as gl::GLsizei,
height.get() as gl::GLsizei,
);
gl.framebuffer_renderbuffer(
gl::FRAMEBUFFER,
gl::DEPTH_ATTACHMENT,
gl::RENDERBUFFER,
depth_rb,
);
Self {
gl,
framebuffer_ids,
renderbuffer_ids,
texture_ids,
}
}
pub fn framebuffer_id(&self) -> gl::GLuint {
*self.framebuffer_ids.first().expect("Guaranteed by new")
}
pub fn bind(&self) {
trace!("Binding FBO {}", self.framebuffer_id());
self.gl
.bind_framebuffer(gl::FRAMEBUFFER, self.framebuffer_id());
}
pub fn unbind(&self) {
trace!("Unbinding FBO {}", self.framebuffer_id());
self.gl.bind_framebuffer(gl::FRAMEBUFFER, 0);
}
pub fn read_back_from_gpu(
self,
x: i32,
y: i32,
width: FramebufferUintLength,
height: FramebufferUintLength,
) -> RgbImage {
let width = width.get() as usize;
let height = height.get() as usize;
self.gl.bind_vertex_array(0);
let mut pixels = self.gl.read_pixels(
x,
y,
width as gl::GLsizei,
height as gl::GLsizei,
gl::RGB,
gl::UNSIGNED_BYTE,
);
let orig_pixels = pixels.clone();
let stride = width * 3;
for y in 0..height {
let dst_start = y * stride;
let src_start = (height - y - 1) * stride;
let src_slice = &orig_pixels[src_start..src_start + stride];
pixels[dst_start..dst_start + stride].clone_from_slice(&src_slice[..stride]);
}
RgbImage::from_raw(width as u32, height as u32, pixels).expect("Flipping image failed!")
}
}
impl Drop for RenderTargetInfo {
fn drop(&mut self) {
trace!("Dropping FBO {}", self.framebuffer_id());
self.unbind();
self.gl.delete_textures(&self.texture_ids);
self.gl.delete_renderbuffers(&self.renderbuffer_ids);
self.gl.delete_framebuffers(&self.framebuffer_ids);
}
}