use tetra::graphics::text::{Font, Text};
use tetra::graphics::{self, Canvas, Color, DrawParams, Shader, Texture};
use tetra::math::Vec2;
use tetra::{Context, ContextBuilder, State};
struct GameState {
canvas: Canvas,
texture: Texture,
shader: Shader,
text: Text,
timer: f32,
red: f32,
green: f32,
blue: f32,
}
impl GameState {
fn new(ctx: &mut Context) -> tetra::Result<GameState> {
Ok(GameState {
canvas: Canvas::new(ctx, 1280, 720)?,
texture: Texture::new(ctx, "./examples/resources/player.png")?,
shader: Shader::from_fragment_file(ctx, "./examples/resources/disco.frag")?,
text: Text::new(
"",
Font::vector(ctx, "./examples/resources/DejaVuSansMono.ttf", 32.0)?,
),
timer: 0.0,
red: 0.0,
green: 0.0,
blue: 0.0,
})
}
}
impl State for GameState {
fn update(&mut self, _ctx: &mut Context) -> tetra::Result {
self.timer += 1.0;
self.red = ((self.timer / 10.0).sin() + 1.0) / 2.0;
self.green = ((self.timer / 100.0).sin() + 1.0) / 2.0;
self.blue = ((self.timer / 1000.0).sin() + 1.0) / 2.0;
self.text.set_content(format!(
"Red: {:.2}\nGreen: {:.2}\nBlue: {:.2}",
self.red, self.green, self.blue
));
Ok(())
}
fn draw(&mut self, ctx: &mut Context) -> tetra::Result {
graphics::set_canvas(ctx, &self.canvas);
graphics::clear(ctx, Color::rgb(0.392, 0.584, 0.929));
self.texture.draw(
ctx,
DrawParams::new()
.position(Vec2::new(640.0, 360.0))
.origin(Vec2::new(8.0, 8.0))
.scale(Vec2::new(24.0, 24.0)),
);
graphics::reset_canvas(ctx);
graphics::set_shader(ctx, &self.shader);
self.shader.set_uniform(ctx, "u_red", self.red);
self.shader.set_uniform(ctx, "u_green", self.green);
self.shader.set_uniform(ctx, "u_blue", self.blue);
self.canvas.draw(ctx, Vec2::zero());
graphics::reset_shader(ctx);
self.text.draw(ctx, Vec2::new(16.0, 16.0));
Ok(())
}
}
fn main() -> tetra::Result {
ContextBuilder::new("Canvas Rendering", 1280, 720)
.quit_on_escape(true)
.build()?
.run(GameState::new)
}