Ngon

This example is meant to show off a simple shader using the sin of time to offset the y values of a regular n-gon. This is shows off how you can easily render regular n-gons with Bottomless-Pit.

main.rs:

use std::f32::consts::PI;

use bottomless_pit::colour::Colour;
use bottomless_pit::engine_handle::{Engine, EngineBuilder};
use bottomless_pit::material::{Material, MaterialBuilder};
use bottomless_pit::render::RenderInformation;
use bottomless_pit::shader::Shader;
use bottomless_pit::shader::UniformData;
use bottomless_pit::vectors::Vec2;
use bottomless_pit::Game;
use encase::ShaderType;

fn main() {
    let mut engine = EngineBuilder::new()
        .with_resolution((500, 500))
        .remove_vsync()
        .set_clear_colour(Colour::BLACK)
        .build()
        .unwrap();

    let data = Time {
        time: 0.0,
        _pading: 0.0,
        _padding2: 0.0,
        _padding4: 0.0,
    };

    let uniform_data = UniformData::new(&engine, &data);

    let mouse_shader = Shader::new("examples/sinewaves.wgsl", true, &mut engine);

    let regular_material = MaterialBuilder::new()
        .set_uniform(&uniform_data)
        .set_shader(mouse_shader)
        .build(&mut engine);

    let pos = Position {
        regular_material,
        time: 0.0,
    };

    engine.run(pos);
}

#[derive(ShaderType)]
struct Time {
    time: f32,
    _pading: f32,
    _padding2: f32,
    _padding4: f32,
}

struct Position {
    regular_material: Material,
    time: f32,
}

impl Game for Position {
    fn render<'pass, 'others>(
        &'others mut self,
        mut render_handle: RenderInformation<'pass, 'others>,
    ) where
        'others: 'pass,
    {
        self.regular_material.add_regular_n_gon(
            120,
            200.0,
            Vec2 { x: 250.0, y: 250.0 },
            Colour::BLUE,
            &render_handle,
        );

        self.regular_material.draw(&mut render_handle);
    }

    fn update(&mut self, engine_handle: &mut Engine) {
        let dt = engine_handle.get_frame_delta_time();
        self.time = (self.time + dt) % (32.0 * PI);
        self.regular_material
            .update_uniform_data(&self.time, &engine_handle);
    }
}

sinewaves.wgsl

struct EngineUniforms {
    camera: mat3x3<f32>,
    screen_size: vec2<f32>,
}

@group(1) @binding(0)
var<uniform> engine: EngineUniforms;

// now why does this struct look like this?
// its becuase we need 16bit alignment on web
struct Time {
    time: f32,
    _junk: f32,
    _junk1: f32,
    _junk4: f32,
}

@group(2) @binding(0)
var<uniform> time: Time;

@group(1) @binding(0)
var<uniform> camera: CameraUniform;

@group(2) @binding(0)
var<uniform> time: Time;

struct VertexInput {
    @location(0) position: vec3<f32>,
    @location(1) tex_coords: vec2<f32>,
    @location(2) colour: vec4<f32>
}

struct VertexOutput {
    @builtin(position) clip_position: vec4<f32>,
    @location(0) tex_coords: vec2<f32>,
    @location(1) colour: vec4<f32>,
}

// vertex shader
@vertex
fn vs_main(model: VertexInput) -> VertexOutput {
    var out: VertexOutput;
    out.tex_coords = model.tex_coords;
    var pos: vec3<f32> = engine.camera * vec3<f32>(
        model.position.x,
        model.position.y,
        1.0
    ); // the vectors on the right the matrices go on the left in order of importance

    pos = pos / pos.z;
    pos.x = 2.0 * pos.x / engine.screen_size.x - 1.0;
    pos.y = (((2.0 * pos.y / engine.screen_size.y) - 1.0) * -1.0) + sin(time.time + pos.x * 12.0) / 12.0;
    out.clip_position = vec4(pos.xy, 0.0, 1.0);

    out.colour = model.colour;
    return out;
}


// Fragment shader

@fragment
fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
    var r: f32 = (sin((in.clip_position.x + time.time * 16.0)/16.0) + 1.0) / 2.0;
    var b: f32 = (sin((in.clip_position.y + time.time * 16.0)/16.0) + 1.0) / 2.0;
    var g: f32 = (r + b) / 2.0;
    return vec4(r, g, b, 1.0);
}