drm-gfx

A 3D graphics rendering library for the Linux Direct Rendering Manager (DRM). This library provides a lightweight 3D rendering engine that works directly with the DRM interface, without requiring a full graphics stack or window manager.

Or to put it more bluntly: I stitched together https://github.com/Kezii/embedded-gfx/tree/master with https://github.com/Smithay/drm-rs/tree/develop without any care and threw it into https://gitlab.com/FLimburg/drm-gfx .

Features

• 3D mesh rendering with multiple render modes (Points, Lines, Solid, Directional Lighting)
• Camera with configurable position, target, and field of view
• Support for transformations and model matrices
• Backface culling
• Simple lighting model
• Direct rendering to DRM framebuffers
• Double buffering support
• Performance counters for optimization

Usage

Add this to your Cargo.toml:

[dependencies]
drm-gfx = "0.1.0"

features

use feature tokio-thread to use drm-gfx in a tokio based application

Basic Example

use drm_gfx::mesh::K3dMesh;
use drm_gfx::{
    draw::draw,
    mesh::Geometry,
    perfcounter::PerformanceCounter,
    K3dengine,
    doublebuffer::DoubleBuffer,
    drm_render_target::RenderTarget,
};
use embedded_graphics::Drawable;
use embedded_graphics::{
    geometry::Point,
    mono_font::{ascii::FONT_6X10, MonoTextStyle},
    text::Text,
};
use embedded_graphics_core::pixelcolor::{Bgr888, WebColors};
use nalgebra::Point3;
use std::f32::consts::PI;
use std::ffi::c_void;

mod locs;
// TODO: make this run time
// this needs to fit with the output from display creation
const WIDTH: usize = 1024;
const HEIGHT: usize = 600;


#[tokio::main]
async fn main() {
    println!("Hello, world!");
    let locs = Vec![[-1,0,0],[1,0,0],[0,1,0]];
    // card1 is used for the rasperry pi hdmi port
    let display = RenderTarget::new("/dev/dri/card1");

    let mut locations = K3dMesh::new(Geometry{
        vertices: &locs,
        faces: &[],
        colors: &[],
        lines: &[],
        normals: &[],
    });
    locations.set_color(Bgr888::CSS_GREEN);

    let mut raw_framebuffer_0 = Box::new([0u32; WIDTH * HEIGHT]);
    let mut raw_framebuffer_1 = Box::new([0u32; WIDTH * HEIGHT]);

    let mut buffers = DoubleBuffer::<WIDTH, HEIGHT>::new(
        raw_framebuffer_0.as_mut_ptr() as *mut c_void,
        raw_framebuffer_1.as_mut_ptr() as *mut c_void,
    );

    buffers.start_thread(display);

    let text_style = MonoTextStyle::new(&FONT_6X10, Bgr888::CSS_WHITE);

    let mut engine = K3dengine::new(WIDTH as u16, HEIGHT as u16);
    engine.camera.set_position(Point3::new(0.0, 0.0, -4.0));
    engine.camera.set_target(Point3::new(0.0, 0.0, 0.0));
    engine.camera.set_fovy(PI / 4.0);

    let mut perf = PerformanceCounter::new();
    // perf.only_fps(true);

    // TODO: get Render loop and framebuffer into lib
    println!("Starting render loop ... ");
    loop {
        let fbuf = buffers.swap_framebuffer();

        perf.start_of_frame();

        engine.render([&locations], |p| draw(p, fbuf));
        perf.add_measurement("render");

        Text::new(perf.get_text(), Point::new(20, 20), text_style)
            .draw(fbuf)
            .unwrap();

        buffers.send_framebuffer();
        perf.add_measurement("draw");

        perf.print();
    }

    println!("all done. Last perf: {}", perf.get_text());
}

Supported Render Modes

• Points: Renders just the vertices as points
• Lines: Renders edges of the mesh as lines
• Solid: Renders filled triangles with backface culling
• SolidLightDir: Adds directional lighting to solid rendering

Dependencies

• embedded-graphics-core: For pixel color representation
• nalgebra: For matrix math and transformations
• line_drawing: For line rasterization
• drm: For interfacing with the Direct Rendering Manager

Performance

The library includes performance counters that can be used to measure rendering time and optimize your application.

use drm_gfx::perfcounter::PerfCounter;

let mut perf = PerfCounter::new();
perf.start();
// Perform rendering
perf.end();
println!("Rendering took {} ms", perf.elapsed_ms());

Framebuffer Optimization

For improved performance, the library supports double buffering:

use drm_gfx::doublebuffer::DoubleBuffer;

let mut buffer = DoubleBuffer::new(width, height);

// In your render loop:
buffer.swap();
let framebuffer = buffer.get_front();

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you shall be dual licensed as above, without any additional terms or conditions.

unit test disclaimer

All unit tests are autogenerated by some ai.