Flake

An Immediate-Mode game framework

Flake is an immediate-mode game framework and graphics library built on WGPU + Winit. (Inspired by macroquad). Designed to make creating apps and games easier. Supports all three main operating systems with known support for Windows.

Getting Started

Add flake-engine to your Cargo.toml using the following command:

cargo add flake-engine

In your main.rs add the following code to create a window

use flake::prelude::*;

#[flake]
async fn main() {
    loop {
        end_frame!()
    }
}

The #[flake] proc-macro is a shorthand to get you started. Use #[flake("my window")] if you want a window with a title.

Drawing with Flake

Flake has a global state which means you don't have to get the context for drawing. Just write your drawing functions directly:

loop {
// If you don't clear the background it will be transparent
clear_background(BLACK);

draw_rectangle(50.0, 50.0, 200.0, 50.0, BLUE);
draw_rectangle_lines(50.0, 50.0, 200.0, 50.0, 5.0, RED); // outline

end_frame ! () // Remember to end the frame to avoid crashing
}

Flake includes many drawing functions, the most important being:

clear_background(color);

draw_text(text, x, y, font_size, font, color);
draw_rich_text(position, size, color, spans);

draw_rectangle(x, y, w, h, color);
draw_rectangle_lines(x, y, w, h, thickness, color);

draw_circle(x, y, radius, color);
draw_circle_lines(x, y, radius, thickness, color);

draw_texture(texture, x, y, w, h, color);

draw_arrow(x1, y1, x2, y2, thickness, head_size, color);
draw_line(x1, y1, x2, y2, thickness, color);
draw_poly_line(points, thickness, color, closed);
draw_poly_line_rounded(points, thickness, color, closed);

draw_triangle(x1, y1, x2, y2, x3, y3, color);
draw_triangle_lines(x1, y1, x2, y2, x3, y3, thickness, color);
draw_polygon(points, color);
draw_polygon_concave(points, color);

Window Methods

Flake has many window methods:

get_window();
focus_window();

set_window_x(i32);
set_window_y(i32);
window_position() -> (f32, f32);
window_position_vec2() -> Vector2;
set_window_position(i32, i32);

window_width() -> f32;
window_height() -> f32;
window_size() -> Vector2;
set_window_width(u32);
set_window_height(u32);
set_window_size(u32, u32);

set_window_resizable(bool);
set_window_title( & str);
set_window_passthrough(passthrough); // whether you can click on the window
set_window_level(level); // WindowLevel::AlwaysOnTop
set_window_enabled_buttons(buttons); // WindowButtons::MAXIMIZE
set_skip_taskbar(bool);
set_window_transparent(bool); // may not work
set_window_decorations(bool);
set_window_visible(bool);
set_window_icon(path);
set_window_icon_bytes( & [u8]);

// Frames Per Second
get_fps() -> f32;
get_frames() -> usize;
get_frame_time() -> f32; // deltaTime
set_fps_capped(bool); // lets you uncap your FPS
set_target_fps(usize);

Input in Flake

Flake supports mouse and keyboard inputs as of now. Controller support may be added in the future.

Mouse Methods:

mouse_position() -> (f32, f32);
mouse_position_vec2() -> Vector2;
mouse_screen_position() -> (f32, f32);
mouse_screen_position_vec2() -> Vector2;

mouse_wheel() -> Vector2;
is_mouse_button_down(MouseButton) -> bool; // held
is_mouse_button_pressed(MouseButton) -> bool; // clicked this frame
is_mouse_button_released(MouseButton) -> bool; // released this frame

Keyboard Methods

is_key_down(KeyCode) -> bool; // held
is_key_pressed(KeyCode) -> bool; // held
is_key_released(KeyCode) -> bool; // held

// Returns -1 if left is held and 1 if right is held and 0 if both/none;
get_axis(left: KeyCode, right: KeyCode) -> f32;

// Returns a Vector2, similar to get_axis() but for 2 axes
get_vector(left, right, up, down) -> Vector2;

Text in Flake

By default, Flake is bundled with JetBrains Mono 💖. Text also supports using newlines like \n.

draw_text(text: &str, x: f32, y: f32, font_size: f32, font: Option<Font>, color: Color);

Loading Fonts

Load a font using the following:

let my_font = load_font_from_path("Arial.ttf");
// or
let my_font = load_font_from_bytes( & [u8]);

Please do NOT load fonts inside the loop {} to avoid lag. Fonts are expensive. They should be loaded before the loop;

You can use a font like this:

draw_text("This is using a Font", 20.0, 20.0, 16.0, Some( & my_font) RED);

Note: Fonts can be clone()'d without any overhead.

RichText

RichText is a section of multiple Spans of text which have their own properties (Text, Color, Font, Size). Useful for writing text with formatting or for dialog in games. It takes in an iterable of Spans to avoid allocation.

draw_richtext(vec2(10.0, 10.0), 16.0, WHITE, & [
span("Hello,\n    my name is "),
span("John Doe")
.with_font(Some( & my_font))
.with_size(30.0)
.with_color(RED)
]);

Measuring Text

If you need to get the width and height of some text before drawing (Such as for centering/aligning text) you can use the measure_text() function.

measure_text(text: & str, font_size: f32, font: Option<Font>) -> Vector2;

Where .x and .y give the width and height respectively.

Textures and Images

Flake supports loading, and writing to Images and drawing textures. Textures support FilterType::Nearest for pixelated and FilterType::Linear for smooth images. (default = Linear)

Example

// Before the `loop {}`
let my_texture = load_texture("src/Cupcake.png");

// Inside `loop {}`
draw_texture(my_texture, 50.0, 50.0, 100.0, 100.0, WHITE);

Loading a Texture

You can load a texture by using these methods:

load_texture(path);
load_texture_with_filter_type(path, FilterType);
// or
load_texture_from_bytes(&[u8]);
load_texture_from_bytes_with_filter_type(&[u8], FilterType);
// or
load_texture_from_data(width, height, &[f32]) // R, G, B, A pixel data from 0-1
load_texture_from_data_with_filter_type(width, height, &[f32], FilterType);
// or
load_texture_from_image(&Image);

Updating a Texture

You can update the data in a Texture using an Image by using the following:

update_texture(my_texture, &Image);
// or
my_texture.update(&Image);

Drawing a Texture

draw_texture(my_texture, x, y, w, h, color); // tint the texture using a Color
draw_texture_ex(my_texture, x, y, params);   // DrawTextureParams

Extra texture drawing parameters, called DrawTextureParams allow you to draw a part of the texture rather than the entire texture and even rotate or flip it.

pub struct DrawTextureParams {
    pub dest_size: Option<Vector2>,
    pub source: Option<Rect>, // x, y, w, h in pixels
    pub rotation: f32,        // radians
    pub pivot: Option<Vector2>, // world coords, default = center
    pub flip_x: bool,
    pub flip_y: bool,
    pub color: Color,
}

RenderTarget

A render target is a separate surface on which you can draw. Useful if you want to make a scrolling surface or for clipping some objects.

Instead of drawing to the screen, you can create a camera that uses the render target instead, then switch it back to the default screen camera afterward.

// Create a render target using a width and height
let target = render_target(100, 100, FilterType::Linear);
let cam = Camera2D {
    render_target: Some(target.clone()),
    ..Default::default()
};

It is advised that you create the target and the camera before the loop {} since creating targets infinitely at runtime will clog memory and speed.

// Draw the RenderTarget's texture at (0, 0) with size (100, 100)
draw_texture(target.texture, 0.0, 0.0, 100.0, 100.0, WHITE);