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

use Api;
use ContextError;
use CreationError;
use GlAttributes;
use GlContext;
use GlProfile;
use GlRequest;
use PixelFormat;
use PixelFormatRequirements;
use Robustness;

use platform;

/// Object that allows you to build headless contexts.
#[derive(Clone)]
pub struct HeadlessRendererBuilder<'a> {
    /// The dimensions to use.
    pub dimensions: (u32, u32),

    /// The OpenGL attributes to build the context with.
    pub opengl: GlAttributes<&'a platform::HeadlessContext>,

    // Should be made public once it's stabilized.
    pf_reqs: PixelFormatRequirements,

    /// Platform-specific configuration.
    platform_specific: platform::PlatformSpecificHeadlessBuilderAttributes,
}

impl<'a> HeadlessRendererBuilder<'a> {
    /// Initializes a new `HeadlessRendererBuilder` with default values.
    #[inline]
    pub fn new(width: u32, height: u32) -> HeadlessRendererBuilder<'a> {
        HeadlessRendererBuilder {
            dimensions: (width, height),
            pf_reqs: PixelFormatRequirements {
                hardware_accelerated: None,
                .. Default::default()
            },
            opengl: Default::default(),
            platform_specific: Default::default(),
        }
    }

    /// Sets how the backend should choose the OpenGL API and version.
    #[inline]
    pub fn with_gl(mut self, request: GlRequest) -> HeadlessRendererBuilder<'a> {
        self.opengl.version = request;
        self
    }

    /// Sets the desired OpenGL context profile.
    #[inline]
    pub fn with_gl_profile(mut self, profile: GlProfile) -> HeadlessRendererBuilder<'a> {
        self.opengl.profile = Some(profile);
        self
    }

    /// Sets the *debug* flag for the OpenGL context.
    ///
    /// The default value for this flag is `cfg!(ndebug)`, which means that it's enabled
    /// when you run `cargo build` and disabled when you run `cargo build --release`.
    #[inline]
    pub fn with_gl_debug_flag(mut self, flag: bool) -> HeadlessRendererBuilder<'a> {
        self.opengl.debug = flag;
        self
    }

    /// Sets the robustness of the OpenGL context. See the docs of `Robustness`.
    #[inline]
    pub fn with_gl_robustness(mut self, robustness: Robustness) -> HeadlessRendererBuilder<'a> {
        self.opengl.robustness = robustness;
        self
    }

    /// Builds the headless context.
    ///
    /// Error should be very rare and only occur in case of permission denied, incompatible system,
    ///  out of memory, etc.
    #[inline]
    pub fn build(self) -> Result<HeadlessContext, CreationError> {
        platform::HeadlessContext::new(self.dimensions, &self.pf_reqs, &self.opengl,
                                       &self.platform_specific)
                .map(|w| HeadlessContext { context: w })
    }

    /// Builds the headless context.
    ///
    /// The context is build in a *strict* way. That means that if the backend couldn't give
    /// you what you requested, an `Err` will be returned.
    #[inline]
    pub fn build_strict(self) -> Result<HeadlessContext, CreationError> {
        self.build()
    }
}

/// Represents a headless OpenGL context.
pub struct HeadlessContext {
    pub(crate) context: platform::HeadlessContext,
}

impl GlContext for HeadlessContext {
    /// Creates a new OpenGL context
    /// Sets the context as the current context.
    #[inline]
    unsafe fn make_current(&self) -> Result<(), ContextError> {
        self.context.make_current()
    }

    /// Returns true if this context is the current one in this thread.
    #[inline]
    fn is_current(&self) -> bool {
        self.context.is_current()
    }

    /// Returns the address of an OpenGL function.
    ///
    /// Contrary to `wglGetProcAddress`, all available OpenGL functions return an address.
    #[inline]
    fn get_proc_address(&self, addr: &str) -> *const () {
        self.context.get_proc_address(addr)
    }

    /// Returns the API that is currently provided by this window.
    ///
    /// See `Window::get_api` for more infos.
    #[inline]
    fn get_api(&self) -> Api {
        self.context.get_api()
    }

    #[inline]
    fn swap_buffers(&self) -> Result<(), ContextError> {
        self.context.swap_buffers()
    }

    #[inline]
    fn get_pixel_format(&self) -> PixelFormat {
        self.context.get_pixel_format()
    }

    #[inline]
    fn resize(&self, _width: u32, _height: u32) {
        // This method does not mean anything for a HeadlessContext.
        unimplemented!()
    }
}