embedded_3dgfx/draw/
effects.rs

1//! Post-processing and environment effect configurations (fog and dithering).
2
3use core::fmt::Debug;
4use embedded_graphics_core::pixelcolor::{Rgb565, RgbColor};
5
6/// Configuration for depth-based fog effect.
7#[derive(Debug, Clone, Copy)]
8pub struct FogConfig {
9    /// Fog color to blend towards.
10    pub color: Rgb565,
11    /// Near plane distance (fixed-point 16.16 format).
12    pub near: u32,
13    /// Far plane distance (fixed-point 16.16 format).
14    pub far: u32,
15}
16
17impl FogConfig {
18    /// Create a new fog configuration.
19    pub fn new(color: Rgb565, near: f32, far: f32) -> Self {
20        Self {
21            color,
22            near: (near * 65536.0) as u32,
23            far: (far * 65536.0) as u32,
24        }
25    }
26
27    /// Apply fog effect to a color based on depth.
28    #[inline]
29    pub fn apply(&self, base_color: Rgb565, depth: u32) -> Rgb565 {
30        let fog_factor = if depth <= self.near {
31            0u32
32        } else if depth >= self.far {
33            65536u32
34        } else {
35            let numerator = (depth - self.near) as u64;
36            let denominator = (self.far - self.near) as u64;
37            ((numerator * 65536) / denominator) as u32
38        };
39
40        let base_r = base_color.r() as u32;
41        let base_g = base_color.g() as u32;
42        let base_b = base_color.b() as u32;
43
44        let fog_r = self.color.r() as u32;
45        let fog_g = self.color.g() as u32;
46        let fog_b = self.color.b() as u32;
47
48        let r = ((base_r * (65536 - fog_factor) + fog_r * fog_factor) / 65536) as u8;
49        let g = ((base_g * (65536 - fog_factor) + fog_g * fog_factor) / 65536) as u8;
50        let b = ((base_b * (65536 - fog_factor) + fog_b * fog_factor) / 65536) as u8;
51
52        Rgb565::new(r, g, b)
53    }
54}
55
56/// Configuration for ordered dithering effect.
57#[derive(Debug, Clone, Copy)]
58pub struct DitherConfig {
59    /// Dithering intensity (0-255, where 0 is no dithering).
60    pub intensity: u8,
61}
62
63impl DitherConfig {
64    /// 4x4 Bayer matrix for ordered dithering.
65    const BAYER_MATRIX: [[u8; 4]; 4] =
66        [[0, 8, 2, 10], [12, 4, 14, 6], [3, 11, 1, 9], [15, 7, 13, 5]];
67
68    /// Create a new dither configuration.
69    pub fn new(intensity: u8) -> Self {
70        Self { intensity }
71    }
72
73    /// Apply dithering effect to a color based on screen position.
74    #[inline]
75    pub fn apply(&self, color: Rgb565, x: i32, y: i32) -> Rgb565 {
76        if self.intensity == 0 {
77            return color;
78        }
79
80        let matrix_x = (x & 3) as usize;
81        let matrix_y = (y & 3) as usize;
82        let threshold = Self::BAYER_MATRIX[matrix_y][matrix_x];
83
84        let scaled_threshold = ((threshold as u16 * self.intensity as u16) / 15) as u8;
85
86        let r = color.r();
87        let g = color.g();
88        let b = color.b();
89
90        let r = if r > scaled_threshold {
91            r.saturating_sub(scaled_threshold / 2)
92        } else {
93            r.saturating_add(scaled_threshold / 2)
94        };
95
96        let g = if g > scaled_threshold {
97            g.saturating_sub(scaled_threshold / 2)
98        } else {
99            g.saturating_add(scaled_threshold / 2)
100        };
101
102        let b = if b > scaled_threshold {
103            b.saturating_sub(scaled_threshold / 2)
104        } else {
105            b.saturating_add(scaled_threshold / 2)
106        };
107
108        Rgb565::new(r, g, b)
109    }
110}
embedded_3dgfx/draw/effects.rs

embedded_3dgfx/draw/
effects.rs
