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

use std::{
    collections::HashMap,
    io::Read,
    str,
};

use byteorder::{ByteOrder, LittleEndian};

// TODO: Need to check if the math is correct
pub fn get_box_size(matrix: &[[f32; 4]; 4]) -> (usize, usize, usize) {
    let mut result = [0.0; 3];
    let mut values = [
        [1.0, 0.0, 0.0, 0.0],
        [0.0, 1.0, 0.0, 0.0],
        [0.0, 0.0, 1.0, 0.0],
    ];

    for (i, value) in values.iter_mut().enumerate() {
        let vector = mat4_mul_vec4(&matrix, value);
        result[i] = vec3_norm(&vector);
    }

    // FIXME: For some reason the size is half of the supposed value, so for now I just multiply by 2 to get the proper size
    ((result[0] * 2.0) as usize, (result[1] * 2.0) as usize, (result[2] * 2.0) as usize)
}

pub fn get_value(dict: &HashMap<String, Vec<u8>>, key: &str) -> Vec<u8> {
    if let Some(value) = dict.get(key) {
        value.to_vec()
    } else {
        Default::default()
    }
}

pub fn get_value_string(dict: &HashMap<String, Vec<u8>>, key: &str) -> String {
    let value = get_value(dict, &key);
    if value.len() > 0 {
        str::from_utf8(&value).unwrap().to_string()
    } else {
        "".to_string()
    }
}

pub fn get_value_int(dict: &HashMap<String, Vec<u8>>, key: &str) -> i32 {
    let value = get_value(dict, &key);

    if value.len() > 0 {
        ((value[0] as i32) <<  0) +
            ((value[1] as i32) <<  8) +
            ((value[2] as i32) << 16) +
            ((value[3] as i32) << 24)
    } else {
        0
    }
}

fn mat4_mul_vec4(matrix: &[[f32; 4]; 4], vector: &[f32; 4]) -> [f32; 4] {
    let mut result = [0.0; 4];

    for i in 0..4 {
        for j in 0..4 {
            result[i] += matrix[i][j] * vector[j];
        }
    }

    result
}

pub fn parse_float(byte_array: &[u8; 4]) -> f32 {
    LittleEndian::read_f32(byte_array)
}

pub fn read(stream: &mut dyn Read, bytes: i32) -> Vec<u8> {
    let mut result = vec![];

    for _ in 0..bytes {
        result.push(read_u8(stream));
    }

    result
}

pub fn read_dict(stream: &mut dyn Read, max_bytes: i32) -> HashMap<String, Vec<u8>> {
    let mut result = HashMap::new();
    let mut bytes_read = 0;

    if max_bytes == 0 {
        return result;
    }

    while let Some((key, value, key_value_length)) = read_dict_key_value(stream) {
        result.insert(key, value);
        bytes_read += key_value_length;

        if bytes_read >= max_bytes {
            break;
        }
    }

    result
}

pub fn read_dict_key_value(stream: &mut dyn Read) -> Option<(String, Vec<u8>, i32)> {
    let key_size = read_int(stream);
    if key_size > 0 {
        let key = read_str(stream, key_size);
        let value_size = read_int(stream);

        let value = read(stream, value_size);
        Some((key.to_string(), value, key_size + value_size + 8))
    } else {
        None
    }
}

pub fn read_int(stream: &mut dyn Read) -> i32 {
    let mut buffer = [0; 4];
    let _result = stream.read(&mut buffer);

    ((buffer[0] as i32) <<  0) +
        ((buffer[1] as i32) <<  8) +
        ((buffer[2] as i32) << 16) +
        ((buffer[3] as i32) << 24)
}

pub fn read_str(stream: &mut dyn Read, bytes: i32) -> String {
    let result = read(stream, bytes);
    match str::from_utf8(&result) {
        Ok(string) => string.to_string(),
        _ => "".to_string()
    }
}

pub fn read_u8(stream: &mut dyn Read) -> u8 {
    let mut buffer = [0; 1];
    let _result = stream.read(&mut buffer);

    (buffer[0] << 0)
}

fn vec3_dot(lhs: &[f32; 4], rhs: &[f32; 4]) -> f32 {
    lhs[0] * rhs[0] + lhs[1] * rhs[1] + lhs[2] * rhs[2]
}

fn vec3_norm(vector: &[f32; 4])  -> f32 {
    let dot = vec3_dot(vector, vector);
    dot.sqrt()
}