Differential D28222 Diff 78987 src/scenegraph/shaders/shadowedrectangle.frag

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src/scenegraph/shaders/shadowedrectangle.frag

  • This file was moved from src/scenegraph/shadowedrectangle_core.frag.
1/* 1​/*
2 * SPDX-FileCopyrightText: 2020 Arjen Hiemstra <ahiemstra@heimr.nl> 2​ * SPDX-FileCopyrightText: 2020 Arjen Hiemstra <ahiemstra@heimr.nl>
3 * 3​ *
4 * SPDX-License-Identifier: LGPL-2.0-or-later 4​ * SPDX-License-Identifier: LGPL-2.0-or-later
5 */ 5​ */
6 6​
7// This is based on the 2D SDF functions provided by Inigo Quilez: 7​// See sdf.glsl for the SDF related functions.
8// https://iquilezles.org/www/articles/distfunctions2d/distfunctions2d.htm ​
9 8​
10// This shader renders a rectangle with rounded corners and a shadow below it. 9​// This shader renders a rectangle with rounded corners and a shadow below it.
11 10​
12uniform lowp float opacity; 11​uniform lowp float opacity;
13uniform lowp float size; 12​uniform lowp float size;
14uniform lowp float radius; 13​uniform lowp float radius;
15uniform lowp vec4 color; 14​uniform lowp vec4 color;
16uniform lowp vec4 shadowColor; 15​uniform lowp vec4 shadowColor;
17uniform lowp vec2 offset; 16​uniform lowp vec2 offset;
18uniform lowp vec2 aspect; 17​uniform lowp vec2 aspect;
19 18​
19​#ifdef CORE_PROFILE
20in lowp vec2 uv; 20​in lowp vec2 uv;
21 ​
22out lowp vec4 out_color; 21​out lowp vec4 out_color;
22​#else
23​varying lowp vec2 uv;
24​#endif
23 25​
24const lowp float minimum_shadow_radius = 0.05; 26​const lowp float minimum_shadow_radius = 0.05;
25 27​
26// Calculate the distance to a rectangle with rounded corners. ​
27// \param point The point to calculate the distance of. ​
28// \param rect The rectangle to calculate the distance of. ​
29// \param translation The amount of translation to apply to the rectangle. ​
30// \param radius A vec4 with the radius of each corner. Order is top right, bottom right, top left, bottom left. ​
31lowp float sdf_rounded_rectangle(in lowp vec2 point, in lowp vec2 rect, in lowp vec2 translation, in lowp vec4 radius) ​
32{ ​
33 radius.xy = (point.x > 0.0) ? radius.xy : radius.zw; ​
34 radius.x = (point.y > 0.0) ? radius.x : radius.y; ​
35 lowp vec2 d = abs(point - translation) - rect + radius.x; ​
36 return min(max(d.x, d.y), 0.0) + length(max(d, 0.0)) - radius.x; ​
37} ​
38 ​
39void main() 28​void main()
40{ 29​{
41 // Scaling factor that is the inverse of the amount of scaling applied to the geometry. 30​ // Scaling factor that is the inverse of the amount of scaling applied to the geometry.
42 lowp float inverse_scale = 1.0 / (1.0 + size + length(offset) * 2.0); 31​ lowp float inverse_scale = 1.0 / (1.0 + size + length(offset) * 2.0);
43 32​
44 // Correction factor to round the corners of a larger shadow. 33​ // Correction factor to round the corners of a larger shadow.
45 // We want to account for size in regards to shadow radius, so that a larger shadow is 34​ // We want to account for size in regards to shadow radius, so that a larger shadow is
46 // more rounded, but only if we are not already rounding the corners due to corner radius. 35​ // more rounded, but only if we are not already rounding the corners due to corner radius.
47 lowp float size_factor = 0.5 * (minimum_shadow_radius / max(radius, minimum_shadow_radius)); 36​ lowp float size_factor = 0.5 * (minimum_shadow_radius / max(radius, minimum_shadow_radius));
48 37​ lowp float shadow_radius = radius + size * size_factor;
49 lowp float shadowRadius = radius + size * size_factor; ​
50 38​
51 lowp vec4 col = vec4(0.0); 39​ lowp vec4 col = vec4(0.0);
52 40​
53 // Calculate the shadow's distance field. 41​ // Calculate the shadow's distance field.
54 lowp float shadow = sdf_rounded_rectangle(uv, aspect * inverse_scale, offset * 2.0 * inverse_scale, vec4(shadowRadius * inverse_scale)); 42​ lowp float shadow = sdf_rounded_rectangle(uv - offset * 2.0 * inverse_scale, aspect * inverse_scale, vec4(shadow_radius * inverse_scale));
55 // Render it, interpolating the color over the distance. 43​ // Render it, interpolating the color over the distance.
56 col = mix(col, shadowColor * sign(size), 1.0 - smoothstep(-size * 0.5, size * 0.5, shadow)); 44​ col = mix(col, shadowColor * sign(size), 1.0 - smoothstep(-size * 0.5, size * 0.5, shadow));
57 45​
58 // Calculate the main rectangle distance field. 46​ // Calculate the main rectangle distance field.
59 lowp float rect = sdf_rounded_rectangle(uv, aspect * inverse_scale, vec2(0.0), vec4(radius * inverse_scale)); 47​ lowp float rect = sdf_rounded_rectangle(uv, aspect * inverse_scale, vec4(radius * inverse_scale));
60 ​
61 lowp float g = fwidth(rect); ​
62 48​
63 // First, remove anything that was rendered by the shadow if it is inside the rectangle. 49​ // First, remove anything that was rendered by the shadow if it is inside the rectangle.
64 // This allows us to use colors with alpha without rendering artifacts. 50​ // This allows us to use colors with alpha without rendering artifacts.
65 col = mix(col, vec4(0.0), 1.0 - smoothstep(0.001 - g, 0.001 + g, rect)); 51​ col = sdf_render(rect, col, vec4(0.0));
66 52​
67 // Then, render it again but this time with the proper color and properly alpha blended. 53​ // Then, render it again but this time with the proper color and properly alpha blended.
68 col = mix(col, color, 1.0 - smoothstep(0.001 - g, 0.001 + g, rect)); 54​ col = sdf_render(rect, col, color);
69 55​
56​#ifdef CORE_PROFILE
70 out_color = col * opacity; 57​ out_color = col * opacity;
58​#else
59​ gl_FragColor = col * opacity;
60​#endif
71} 61​}