unity-asset-decode 0.2.0

Decode/export helpers for Unity assets (Texture/Audio/Sprite/Mesh) built on unity-asset-binary
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283

//! Basic texture format decoders
//!
//! This module handles uncompressed texture formats like RGBA32, RGB24, etc.

use super::{Decoder, create_rgba_image, validate_dimensions};
use crate::error::{BinaryError, Result};
use crate::texture::formats::TextureFormat;
use crate::texture::types::Texture2D;
use image::RgbaImage;

/// Decoder for basic uncompressed texture formats
pub struct BasicDecoder;

impl BasicDecoder {
    /// Create a new basic decoder
    pub fn new() -> Self {
        Self
    }

    /// Decode RGBA32 format (R8G8B8A8)
    fn decode_rgba32(&self, data: &[u8], width: u32, height: u32) -> Result<RgbaImage> {
        validate_dimensions(width, height)?;

        let expected_size = (width * height * 4) as usize;
        if data.len() < expected_size {
            return Err(BinaryError::invalid_data(format!(
                "Insufficient data for RGBA32: expected {}, got {}",
                expected_size,
                data.len()
            )));
        }

        // RGBA32 is already in the correct format
        create_rgba_image(data[..expected_size].to_vec(), width, height)
    }

    /// Decode RGB24 format (R8G8B8)
    fn decode_rgb24(&self, data: &[u8], width: u32, height: u32) -> Result<RgbaImage> {
        validate_dimensions(width, height)?;

        let expected_size = (width * height * 3) as usize;
        if data.len() < expected_size {
            return Err(BinaryError::invalid_data(format!(
                "Insufficient data for RGB24: expected {}, got {}",
                expected_size,
                data.len()
            )));
        }

        // Convert RGB24 to RGBA32 by adding alpha channel
        let mut rgba_data = Vec::with_capacity((width * height * 4) as usize);
        for chunk in data[..expected_size].chunks_exact(3) {
            rgba_data.push(chunk[0]); // R
            rgba_data.push(chunk[1]); // G
            rgba_data.push(chunk[2]); // B
            rgba_data.push(255); // A (fully opaque)
        }

        create_rgba_image(rgba_data, width, height)
    }

    /// Decode ARGB32 format (A8R8G8B8)
    fn decode_argb32(&self, data: &[u8], width: u32, height: u32) -> Result<RgbaImage> {
        validate_dimensions(width, height)?;

        let expected_size = (width * height * 4) as usize;
        if data.len() < expected_size {
            return Err(BinaryError::invalid_data(format!(
                "Insufficient data for ARGB32: expected {}, got {}",
                expected_size,
                data.len()
            )));
        }

        // Convert ARGB32 to RGBA32 by reordering channels
        let mut rgba_data = Vec::with_capacity(expected_size);
        for chunk in data[..expected_size].chunks_exact(4) {
            rgba_data.push(chunk[1]); // R (from position 1)
            rgba_data.push(chunk[2]); // G (from position 2)
            rgba_data.push(chunk[3]); // B (from position 3)
            rgba_data.push(chunk[0]); // A (from position 0)
        }

        create_rgba_image(rgba_data, width, height)
    }

    /// Decode BGRA32 format (B8G8R8A8)
    fn decode_bgra32(&self, data: &[u8], width: u32, height: u32) -> Result<RgbaImage> {
        validate_dimensions(width, height)?;

        let expected_size = (width * height * 4) as usize;
        if data.len() < expected_size {
            return Err(BinaryError::invalid_data(format!(
                "Insufficient data for BGRA32: expected {}, got {}",
                expected_size,
                data.len()
            )));
        }

        // Convert BGRA32 to RGBA32 by swapping R and B channels
        let mut rgba_data = Vec::with_capacity(expected_size);
        for chunk in data[..expected_size].chunks_exact(4) {
            rgba_data.push(chunk[2]); // R (from B position)
            rgba_data.push(chunk[1]); // G (unchanged)
            rgba_data.push(chunk[0]); // B (from R position)
            rgba_data.push(chunk[3]); // A (unchanged)
        }

        create_rgba_image(rgba_data, width, height)
    }

    /// Decode Alpha8 format (single channel alpha)
    fn decode_alpha8(&self, data: &[u8], width: u32, height: u32) -> Result<RgbaImage> {
        validate_dimensions(width, height)?;

        let expected_size = (width * height) as usize;
        if data.len() < expected_size {
            return Err(BinaryError::invalid_data(format!(
                "Insufficient data for Alpha8: expected {}, got {}",
                expected_size,
                data.len()
            )));
        }

        // Convert Alpha8 to RGBA32 (white with alpha)
        let mut rgba_data = Vec::with_capacity((width * height * 4) as usize);
        for &alpha in &data[..expected_size] {
            rgba_data.push(255); // R (white)
            rgba_data.push(255); // G (white)
            rgba_data.push(255); // B (white)
            rgba_data.push(alpha); // A (from source)
        }

        create_rgba_image(rgba_data, width, height)
    }

    /// Decode RGBA4444 format (4 bits per channel)
    fn decode_rgba4444(&self, data: &[u8], width: u32, height: u32) -> Result<RgbaImage> {
        validate_dimensions(width, height)?;

        let expected_size = (width * height * 2) as usize; // 2 bytes per pixel
        if data.len() < expected_size {
            return Err(BinaryError::invalid_data(format!(
                "Insufficient data for RGBA4444: expected {}, got {}",
                expected_size,
                data.len()
            )));
        }

        // Convert RGBA4444 to RGBA32
        let mut rgba_data = Vec::with_capacity((width * height * 4) as usize);
        for chunk in data[..expected_size].chunks_exact(2) {
            let pixel = u16::from_le_bytes([chunk[0], chunk[1]]);

            // Extract 4-bit channels and expand to 8-bit
            let r = ((pixel >> 12) & 0xF) as u8;
            let g = ((pixel >> 8) & 0xF) as u8;
            let b = ((pixel >> 4) & 0xF) as u8;
            let a = (pixel & 0xF) as u8;

            // Expand 4-bit to 8-bit by duplicating bits
            rgba_data.push(r << 4 | r);
            rgba_data.push(g << 4 | g);
            rgba_data.push(b << 4 | b);
            rgba_data.push(a << 4 | a);
        }

        create_rgba_image(rgba_data, width, height)
    }

    /// Decode ARGB4444 format (4 bits per channel, ARGB order)
    fn decode_argb4444(&self, data: &[u8], width: u32, height: u32) -> Result<RgbaImage> {
        validate_dimensions(width, height)?;

        let expected_size = (width * height * 2) as usize; // 2 bytes per pixel
        if data.len() < expected_size {
            return Err(BinaryError::invalid_data(format!(
                "Insufficient data for ARGB4444: expected {}, got {}",
                expected_size,
                data.len()
            )));
        }

        // Convert ARGB4444 to RGBA32
        let mut rgba_data = Vec::with_capacity((width * height * 4) as usize);
        for chunk in data[..expected_size].chunks_exact(2) {
            let pixel = u16::from_le_bytes([chunk[0], chunk[1]]);

            // Extract 4-bit channels (ARGB order)
            let a = ((pixel >> 12) & 0xF) as u8;
            let r = ((pixel >> 8) & 0xF) as u8;
            let g = ((pixel >> 4) & 0xF) as u8;
            let b = (pixel & 0xF) as u8;

            // Expand 4-bit to 8-bit by duplicating bits
            rgba_data.push(r << 4 | r); // R
            rgba_data.push(g << 4 | g); // G
            rgba_data.push(b << 4 | b); // B
            rgba_data.push(a << 4 | a); // A
        }

        create_rgba_image(rgba_data, width, height)
    }

    /// Decode RGB565 format (5-6-5 bits per channel)
    fn decode_rgb565(&self, data: &[u8], width: u32, height: u32) -> Result<RgbaImage> {
        validate_dimensions(width, height)?;

        let expected_size = (width * height * 2) as usize; // 2 bytes per pixel
        if data.len() < expected_size {
            return Err(BinaryError::invalid_data(format!(
                "Insufficient data for RGB565: expected {}, got {}",
                expected_size,
                data.len()
            )));
        }

        // Convert RGB565 to RGBA32
        let mut rgba_data = Vec::with_capacity((width * height * 4) as usize);
        for chunk in data[..expected_size].chunks_exact(2) {
            let pixel = u16::from_le_bytes([chunk[0], chunk[1]]);

            // Extract RGB channels
            let r = ((pixel >> 11) & 0x1F) as u8;
            let g = ((pixel >> 5) & 0x3F) as u8;
            let b = (pixel & 0x1F) as u8;

            // Expand to 8-bit
            rgba_data.push((r << 3) | (r >> 2)); // 5-bit to 8-bit
            rgba_data.push((g << 2) | (g >> 4)); // 6-bit to 8-bit
            rgba_data.push((b << 3) | (b >> 2)); // 5-bit to 8-bit
            rgba_data.push(255); // Alpha (fully opaque)
        }

        create_rgba_image(rgba_data, width, height)
    }
}

impl Decoder for BasicDecoder {
    fn decode(&self, texture: &Texture2D) -> Result<RgbaImage> {
        let width = texture.width as u32;
        let height = texture.height as u32;
        let data = &texture.image_data;

        match texture.format {
            TextureFormat::RGBA32 => self.decode_rgba32(data, width, height),
            TextureFormat::RGB24 => self.decode_rgb24(data, width, height),
            TextureFormat::ARGB32 => self.decode_argb32(data, width, height),
            TextureFormat::BGRA32 => self.decode_bgra32(data, width, height),
            TextureFormat::Alpha8 => self.decode_alpha8(data, width, height),
            TextureFormat::RGBA4444 => self.decode_rgba4444(data, width, height),
            TextureFormat::ARGB4444 => self.decode_argb4444(data, width, height),
            TextureFormat::RGB565 => self.decode_rgb565(data, width, height),
            _ => Err(BinaryError::unsupported(format!(
                "Format {:?} is not a basic format",
                texture.format
            ))),
        }
    }

    fn can_decode(&self, format: TextureFormat) -> bool {
        format.is_basic_format()
    }

    fn supported_formats(&self) -> Vec<TextureFormat> {
        vec![
            TextureFormat::Alpha8,
            TextureFormat::RGB24,
            TextureFormat::RGBA32,
            TextureFormat::ARGB32,
            TextureFormat::BGRA32,
            TextureFormat::RGBA4444,
            TextureFormat::ARGB4444,
            TextureFormat::RGB565,
        ]
    }
}

impl Default for BasicDecoder {
    fn default() -> Self {
        Self::new()
    }
}