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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
use gleam::gl;
use image::RgbImage;
use servo_geometry::FramebufferUintLength;
#[derive(Default)]
pub struct RenderTargetInfo {
framebuffer_ids: Vec<gl::GLuint>,
renderbuffer_ids: Vec<gl::GLuint>,
texture_ids: Vec<gl::GLuint>,
}
pub fn initialize_png(
gl: &dyn gl::Gl,
width: FramebufferUintLength,
height: FramebufferUintLength,
) -> RenderTargetInfo {
let framebuffer_ids = gl.gen_framebuffers(1);
gl.bind_framebuffer(gl::FRAMEBUFFER, 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,
);
RenderTargetInfo {
framebuffer_ids,
renderbuffer_ids,
texture_ids,
}
}
pub fn draw_img(
gl: &dyn gl::Gl,
render_target_info: RenderTargetInfo,
x: i32,
y: i32,
width: FramebufferUintLength,
height: FramebufferUintLength,
) -> RgbImage {
let width = width.get() as usize;
let height = height.get() as usize;
// For some reason, OSMesa fails to render on the 3rd
// attempt in headless mode, under some conditions.
// I think this can only be some kind of synchronization
// bug in OSMesa, but explicitly un-binding any vertex
// array here seems to work around that bug.
// See https://github.com/servo/servo/issues/18606.
gl.bind_vertex_array(0);
let mut pixels = gl.read_pixels(
x,
y,
width as gl::GLsizei,
height as gl::GLsizei,
gl::RGB,
gl::UNSIGNED_BYTE,
);
gl.bind_framebuffer(gl::FRAMEBUFFER, 0);
gl.delete_textures(&render_target_info.texture_ids);
gl.delete_renderbuffers(&render_target_info.renderbuffer_ids);
gl.delete_framebuffers(&render_target_info.framebuffer_ids);
// flip image vertically (texture is upside down)
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];
(&mut 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!")
}
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