rust/src/grain.rs

use crate::blood::handle_blood_grain;
use crate::bone::handle_bone_grain;
use crate::grid::{Grid, GridPosition};
use crate::utils::constants::{GAME_RESOLUTION_X, GAME_RESOLUTION_Y, WINDOW_SIZE};
use crate::utils::remap::remap_cursor_position;
use crate::utils::tick::TickCounter;
use bevy::prelude::*;
use bevy::sprite::Anchor;
use rand::Rng;

/*

    🦀 Components. Learn more: https://bevy-cheatbook.github.io/programming/res.html

*/

#[derive(Component)]
pub struct Grain {
    pub grain_type: GrainType,
    pub velocity: Vec2, // Physics-based movement
    pub mass: f32,
    pub is_simulated: bool,
}

#[derive(Component)]
pub struct Lifetime(pub u32);

#[derive(Component, Clone, Copy, Debug, PartialEq)]
pub enum GrainType {
    Bone,
    Blood,
}

#[derive(Component, PartialEq)]
pub enum Direction {
    Right,
    Left,
    None,
}

impl Default for Direction {
    fn default() -> Self {
        Direction::None
    }
}

#[derive(Bundle)]
pub struct GrainBundle {
    pub grain: Grain,
    pub lifetime: Lifetime,
    pub direction: Direction,
    pub grid_position: GridPosition,
    pub sprite_bundle: SpriteBundle,
}

impl GrainBundle {
    pub fn new(
        grain_type: GrainType,
        x: i32, 
        y: i32,
        color: Color,
        size: Vec2,
    ) -> Self {
        GrainBundle {
            grain: Grain {
                grain_type,
                velocity: Vec2::ZERO,
                mass: 1.0,
                is_simulated: true,
            },
            lifetime: Lifetime(0),
            direction: Direction::None,
            grid_position: GridPosition::new(x, y),
            sprite_bundle: SpriteBundle {
                sprite: Sprite {
                    color,
                    custom_size: Some(size),
                    anchor: Anchor::Center,
                    ..default()
                },
                transform: Transform::from_translation(Vec3::new(x as f32, y as f32, 0.0)),
                ..default()
            },
        }
    }
}

pub fn spawn_grain(
    mut commands: Commands,
    mouse_button_input: Res<Input<MouseButton>>,
    windows: Query<&Window>,
    camera: Query<(&Camera, &GlobalTransform)>,
) {
    if mouse_button_input.just_pressed(MouseButton::Left) {
        let window = windows.single();
        let (camera, camera_transform) = camera.single();
        
        if let Some(cursor_position) = window.cursor_position() {
            if let Some(world_position) = camera.viewport_to_world(camera_transform, cursor_position) {
                let grid_pos = remap_cursor_position(world_position.origin.truncate());
                
                commands.spawn(GrainBundle::new(
                    GrainType::Blood,
                    grid_pos.x,
                    grid_pos.y,
                    Color::RED,
                    Vec2::splat(1.0),
                ));
            }
        }
    }
    
    if mouse_button_input.just_pressed(MouseButton::Right) {
        let window = windows.single();
        let (camera, camera_transform) = camera.single();
        
        if let Some(cursor_position) = window.cursor_position() {
            if let Some(world_position) = camera.viewport_to_world(camera_transform, cursor_position) {
                let grid_pos = remap_cursor_position(world_position.origin.truncate());
                
                commands.spawn(GrainBundle::new(
                    GrainType::Bone,
                    grid_pos.x,
                    grid_pos.y,
                    Color::WHITE,
                    Vec2::splat(1.0),
                ));
            }
        }
    }
}

pub fn update_grains(
    mut query: Query<(&mut Transform, &mut GridPosition, &mut Grain, &mut Lifetime, &mut Direction)>,
    mut grid: ResMut<Grid>,
    time: Res<Time>,
) {
    // Process grains in reverse order for more realistic physics (bottom-up)
    let mut grains: Vec<_> = query.iter_mut().collect();
    grains.sort_by(|a, b| b.1.current_y.cmp(&a.1.current_y));
    
    for (mut transform, mut grid_position, mut grain, mut lifetime, mut direction) in grains {
        if !grain.is_simulated {
            continue;
        }
        
        // Update lifetime
        lifetime.0 += 1;
        
        // Apply gravity
        grain.velocity.y -= 9.8 * time.delta_seconds();
        
        // Apply air resistance
        grain.velocity *= 0.995;
        
        // Update position based on velocity
        let mut new_x = grid_position.current_x + (grain.velocity.x * time.delta_seconds()).round() as i32;
        let mut new_y = grid_position.current_y + (grain.velocity.y * time.delta_seconds()).round() as i32;
        
        // Handle grain-specific behavior
        match grain.grain_type {
            GrainType::Blood => {
                handle_blood_grain(
                    &mut transform,
                    &mut grid_position,
                    &mut grid,
                    &mut direction,
                    &mut grain,
                    lifetime.0,
                    &mut new_x,
                    &mut new_y,
                );
            }
            GrainType::Bone => {
                handle_bone_grain(
                    &mut transform,
                    &mut grid_position,
                    &mut grid,
                    &mut direction,
                    &mut grain,
                    lifetime.0,
                    &mut new_x,
                    &mut new_y,
                );
            }
        }
        
        // Update transform position
        transform.translation.x = grid_position.current_x as f32;
        transform.translation.y = grid_position.current_y as f32;
        
        // Reset previous position tracking
        grid_position.reset_prev();
    }
}    🦀 Systems. Learn more: https://bevy-cheatbook.github.io/programming/systems.html

*/

pub fn add_grain(
    mut commands: Commands,
    query: Query<&Window>,
    asset_server: Res<AssetServer>,
    input: Res<Input<MouseButton>>,
) {
    if let Some(position) = query.single().cursor_position() {
        let remaped_cursor_pos = remap_cursor_position(position, WINDOW_SIZE, [GAME_RESOLUTION_X, GAME_RESOLUTION_Y]);
        let mut rng = rand::thread_rng();

        if input.pressed(MouseButton::Left) {
            // Create a bone sprite texture
            let bone_textures: [&str; 3] = ["bone_1.png", "bone_2.png", "bone_3.png"];
            let random_index = rng.gen_range(0..bone_textures.len());

            let bone_sprite_bundle = SpriteBundle {
                sprite: Sprite {
                    custom_size: Some(Vec2::new(1.0, 1.0)),
                    anchor: Anchor::TopLeft,
                    ..default()
                },
                texture: asset_server.load(bone_textures[random_index]),
                ..default()
            };

            // Add a data row (entity) with it's set of components
            commands
                .spawn((
                    Grain,
                    bone_sprite_bundle,
                    GrainType::Bone,
                    GridPosition {
                        current_x: remaped_cursor_pos.x.round() as i32,
                        current_y: remaped_cursor_pos.y.round() as i32,
                        prev_x: None,
                        prev_y: None,
                    },
                ))
                .insert(Transform {
                    translation: Vec3::new(
                        remaped_cursor_pos.x.round() - (GAME_RESOLUTION_X as f32 / 2.0),
                        -(remaped_cursor_pos.y.round() - (GAME_RESOLUTION_Y as f32 / 2.0)),
                        0.0,
                    ),
                    ..default()
                });
        }

        if input.pressed(MouseButton::Right) {
            // Creat a blood sprite texture
            let blood_sprite_bundle = SpriteBundle {
                sprite: Sprite {
                    custom_size: Some(Vec2::new(1.0, 1.0)),
                    anchor: Anchor::TopLeft,
                    ..default()
                },
                texture: asset_server.load("blood_2.png"),
                ..default()
            };

            // Pick a random direction to slide toward
            let random_number = rng.gen::<f32>();

            let random_direction = if random_number < 0.5 {
                Direction::Left
            } else {
                Direction::Right
            };

            // Add a data row (entity) with it's set of components
            commands
                .spawn((
                    Grain,
                    Lifetime(0),
                    blood_sprite_bundle,
                    GrainType::Blood,
                    random_direction,
                    GridPosition {
                        current_x: remaped_cursor_pos.x.round() as i32,
                        current_y: remaped_cursor_pos.y.round() as i32,
                        prev_x: None,
                        prev_y: None,
                    },
                ))
                .insert(Transform {
                    translation: Vec3::new(
                        remaped_cursor_pos.x.round() - (GAME_RESOLUTION_X as f32 / 2.0),
                        -(remaped_cursor_pos.y.round() - (GAME_RESOLUTION_Y as f32 / 2.0)),
                        0.0,
                    ),
                    ..default()
                });
        }
    }
}

pub fn update_grain(
    grid_data: Res<Grid>,
    mut query: Query<(
        &mut Transform,
        &mut GridPosition,
        &GrainType,
        &mut Lifetime,
        Option<&mut Direction>,
    )>,
    mut tick_counter: ResMut<TickCounter>,
) {
    tick_counter.count += 1;
    if tick_counter.count >= tick_counter.tick_rate {
        tick_counter.count = 0;
        for (mut transform, mut grid_position, grain_type, mut lifetime, direction) in query.iter_mut() {
            lifetime.0 += 1;
            match grain_type {
                GrainType::Bone => handle_bone_grain(&grid_position, &grid_data),
                GrainType::Blood => {
                    if let Some(mut dir) = direction {
                        handle_blood_grain(&mut transform, &mut grid_position, &grid_data, &mut dir, lifetime.0);
                    }
                }
            }
        }
    }
}