librashader-runtime-gl 0.11.4

RetroArch shaders for all.
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

use crate::filter_chain::GLCaps;
use glow::HasContext;

macro_rules! backup_gl_int_state {
    (let $var:ident as $glenum:expr; $gl:ident) => {
        // GL object names and enums are non-negative; store them as u32 so the
        // restore path needs no casts.
        let $var = $gl.get_parameter_i32($glenum) as u32;
    };
    (let $var:ident as $glenum:expr; if $if:expr; $gl:ident) => {
        let $var = if $if {
            $gl.get_parameter_i32($glenum) as u32
        } else {
            0
        };
    };
    (let $var:ident[$num:literal] as $glenum:expr; $gl:ident) => {
        let mut $var = [0; $num];
        $gl.get_parameter_i32_slice($glenum, &mut $var);
    };
    (let $var:ident[$num:literal] as $glenum:expr; if $if:expr; $gl:ident) => {
        let mut $var = [0; $num];
        if $if {
            $gl.get_parameter_i32_slice($glenum, &mut $var);
        }
    };
    (let enabled $var:ident as $glenum:expr; $gl:ident) => {
        let $var = $gl.is_enabled($glenum);
    };
    (let enabled $var:ident as $glenum:expr; if $if:expr; $gl:ident) => {
        let $var = if $if { $gl.is_enabled($glenum) } else { false };
    };
}

/// Guard to prepare the fixed function state for librashader rendering
pub struct EnterFixedFunctionState<'gl> {
    gl: &'gl glow::Context,
    last_enable_blend: bool,
    last_enable_cull_face: bool,
    last_enable_depth_test: bool,
    last_enable_stencil_test: bool,
    last_enable_scissor_test: bool,
    last_enable_primitive_restart: bool,
    last_enable_framebuffer_srgb: bool,

    has_primitive_restart: bool,
    has_framebuffer_srgb: bool,
}

impl<'gl> EnterFixedFunctionState<'gl> {
    /// Backs up fixed function state, then
    /// disables SCISSOR_TEST/CULL_FACE/BLEND/DEPTH_TEST/STENCIL_TEST
    /// to prepare the frame for rendering.
    pub fn new(gl: &'gl glow::Context, caps: &GLCaps) -> Self {
        unsafe {
            backup_gl_int_state!(let enabled last_enable_blend as glow::BLEND; gl);
            backup_gl_int_state!(let enabled last_enable_cull_face as glow::CULL_FACE; gl);
            backup_gl_int_state!(let enabled last_enable_depth_test as glow::DEPTH_TEST; gl);
            backup_gl_int_state!(let enabled last_enable_stencil_test as glow::STENCIL_TEST; gl);
            backup_gl_int_state!(let enabled last_enable_scissor_test as glow::SCISSOR_TEST; gl);

            backup_gl_int_state!(let enabled last_enable_primitive_restart as glow::PRIMITIVE_RESTART;
                    if caps.primitive_restart; gl);
            backup_gl_int_state!(let enabled last_enable_framebuffer_srgb as glow::FRAMEBUFFER_SRGB;
                    if caps.framebuffer_srgb; gl);

            gl.disable(glow::SCISSOR_TEST);
            gl.disable(glow::CULL_FACE);
            gl.disable(glow::BLEND);
            gl.disable(glow::DEPTH_TEST);
            gl.disable(glow::STENCIL_TEST);

            EnterFixedFunctionState {
                gl,
                last_enable_blend,
                last_enable_cull_face,
                last_enable_depth_test,
                last_enable_stencil_test,
                last_enable_scissor_test,
                last_enable_primitive_restart,
                last_enable_framebuffer_srgb,
                has_primitive_restart: caps.primitive_restart,
                has_framebuffer_srgb: caps.framebuffer_srgb,
            }
        }
    }
}

impl Drop for EnterFixedFunctionState<'_> {
    fn drop(&mut self) {
        let gl = self.gl;

        unsafe {
            if self.last_enable_blend {
                gl.enable(glow::BLEND)
            } else {
                gl.disable(glow::BLEND)
            }

            if self.last_enable_cull_face {
                gl.enable(glow::CULL_FACE)
            } else {
                gl.disable(glow::CULL_FACE)
            }

            if self.last_enable_depth_test {
                gl.enable(glow::DEPTH_TEST)
            } else {
                gl.disable(glow::DEPTH_TEST)
            }

            if self.last_enable_stencil_test {
                gl.enable(glow::STENCIL_TEST)
            } else {
                gl.disable(glow::STENCIL_TEST)
            }

            if self.last_enable_scissor_test {
                gl.enable(glow::SCISSOR_TEST)
            } else {
                gl.disable(glow::SCISSOR_TEST)
            }

            if self.has_primitive_restart {
                if self.last_enable_primitive_restart {
                    gl.enable(glow::PRIMITIVE_RESTART)
                } else {
                    gl.disable(glow::PRIMITIVE_RESTART)
                }
            }

            if self.has_framebuffer_srgb {
                if self.last_enable_framebuffer_srgb {
                    gl.enable(glow::FRAMEBUFFER_SRGB)
                } else {
                    gl.disable(glow::FRAMEBUFFER_SRGB)
                }
            }
        }
    }
}