alacritty/res/text.f.glsl


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

#version 330 core
in vec2 TexCoords;
flat in vec4 fg;
flat in vec4 bg;
uniform int backgroundPass;

layout(location = 0, index = 0) out vec4 color;
layout(location = 0, index = 1) out vec4 alphaMask;

uniform sampler2D mask;

void main()
{
    if (backgroundPass != 0) {
        if (bg.a == 0.0)
            discard;

        alphaMask = vec4(1.0);
        color = vec4(bg.rgb, 1.0);
    } else {
        if (fg.a != 0.0) {
            // Color glyphs, like emojis.
            vec4 glyphColor = texture(mask, TexCoords);
            alphaMask = vec4(glyphColor.a);

            // Revert alpha premultiplication.
            if (glyphColor.a != 0) {
                glyphColor.rgb = vec3(glyphColor.rgb / glyphColor.a);
            }

            color = vec4(glyphColor.rgb, 1.0);
        } else {
            // Regular text glyphs.
            vec3 textColor = texture(mask, TexCoords).rgb;
            alphaMask = vec4(textColor, textColor.r);
            color = vec4(fg.rgb, 1.0);
        }
    }
}