rustbatch 0.4.0

purely game dewelopment crate that offers simple but powerfull 2D rendering and some fast solutions for game world bottle necks
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

use crate::render::program::Program;
use crate::render::texture::Texture;
use crate::render::buffer::Buffer;

pub trait Target {
    fn append(&mut self, data: &[f32], pattern: &[u32], vertex_size: u32, program: Option<&Program>, texture: Option<&Texture>, buffer: Option<&Buffer>);
}

pub struct VertexData {
    pub(crate) vertices: Vec<f32>,
    pub(crate) indices: Vec<u32>,
    pub(crate) vertex_size: u32,
}

impl VertexData {
    pub fn new() -> Self {
        Self{ vertices: vec![], indices: vec![], vertex_size: 8 }
    }

    pub fn no_texture() -> Self {
        Self{ vertices: vec![], indices: vec![], vertex_size: 6 }
    }

    pub fn custom(vertex_size: u32) -> Self {
        Self{ vertices: vec![], indices: vec![], vertex_size }
    }

    fn error_check(&self, vertex_size: u32) {
        if self.vertex_size != vertex_size {
            panic!("incorrect vertex size, this vertex data accepts only vertex size {}, but \
               you inputted vertex data with vertex size {}", self.vertex_size, vertex_size);
        }
    }

    pub fn draw<T: Target>(&self, target: &mut T) {
        target.append(&self.vertices, &self.indices, self.vertex_size, None, None, None);
    }

    pub fn clear(&mut self) {
        self.indices.clear();
        self.vertices.clear();
    }
}

impl Target for VertexData {
    #[inline]
    fn append(&mut self, data: &[f32], pattern: &[u32], vertex_size: u32, _: Option<&Program>, _: Option<&Texture>, _: Option<&Buffer>) {
        self.error_check(vertex_size);

        let offset = self.vertices.len() as u32/ vertex_size;

        self.vertices.extend(data);

        for i in pattern {
            self.indices.push(*i + offset);
        }
    }
}

/// Batch is a core drawing method. You can append vertex data to it and then draw it to window.
/// I made sure you can customize batch however you like. You can for example use custom fragment and
/// vertex shader along with custom buffer and make your own rendering model so 3D is totally possible
/// if you kow how.
pub struct Batch {
    pub data: VertexData,
    pub(crate) texture: Texture,
    pub(crate) program: Program,
    pub(crate) buffer: Option<Buffer>,
}

impl Batch {
    pub fn no_texture() -> Batch {
        Self::customized(Texture::NONE, Program::no_texture(), Some(Buffer::no_texture()))
    }

    /// new returns batch from texture.
    pub fn new(texture: Texture) -> Batch {
        Self::customized(texture, Program::default(), None)
    }

    /// from_program creates batch with custom rendering program
    /// # Example
    /// ```should_fail
    /// use rustbatch::render::program::Program;
    /// use rustbatch::render::shader::Shader;
    /// use rustbatch::{Batch, Texture};
    ///
    /// let texture = Texture::new("your_texture.png", gl::NEAREST, gl::RGBA).unwrap();
    /// let program = Program::from_shaders(&[Shader::default_vertex(), Shader::new("your_shader.frag")]).unwrap();
    /// let batch = Batch::customized(texture, program, none);
    /// ```
    pub fn customized(texture: Texture, program: Program, buffer: Option<Buffer>) -> Batch {
        program.set_texture_size(texture.size());
        let data = match &buffer {
            Some(b) => {
                VertexData::custom(b.data_size as u32)
            }
            None => VertexData::new()
        };
        Batch{texture, program, data, buffer}
    }

    pub fn draw<T: Target>(&self, target: &mut T) {
        let buffer = match &self.buffer {
            Some(b) => Some(b),
            None => None,
        };
        target.append(&self.data.vertices, &self.data.indices, self.data.vertex_size, Some(&self.program), Some(&self.texture), buffer)
    }

    /// clear clears batch
    #[inline]
    pub fn clear(&mut self) {
        self.data.clear();
    }
}

impl Target for Batch {
    /// append appends vertex data to texture.
    /// pattern specifies how data is used. If you for example provide 4 vertexes you can make
    /// rectangle from it with pattern [0, 2, 3, 1, 2, 3]. If you don't know what i mean try to
    /// draw four points on paper, index them from 0 to 3 and connect them with lines in specified
    /// order.
    ///
    /// # Panics
    ///
    /// If batch has custom buffer and buffers size do not corresponds to `vertex_size` you will get
    /// panic. This is mainly to prevent confusion in case of providing incorrect vertex data
    /// structure.
    #[inline]
    fn append(&mut self, data: &[f32], pattern: &[u32], vertex_size: u32, _: Option<&Program>, _: Option<&Texture>, _: Option<&Buffer>) {
        self.data.append(data, pattern, vertex_size, None, None, None);
    }
}