59 lines
2.1 KiB
GLSL
59 lines
2.1 KiB
GLSL
/*
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* SPDX-FileCopyrightText: 2020 Arjen Hiemstra <ahiemstra@heimr.nl>
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*
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* SPDX-License-Identifier: LGPL-2.0-or-later
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*/
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// See sdf.glsl for the SDF related functions.
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// This shader renders a rectangle with rounded corners and a shadow below it.
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uniform lowp float opacity;
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uniform lowp float size;
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uniform lowp vec4 radius;
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uniform lowp vec4 color;
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uniform lowp vec4 shadowColor;
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uniform lowp vec2 offset;
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uniform lowp vec2 aspect;
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#ifdef CORE_PROFILE
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in lowp vec2 uv;
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out lowp vec4 out_color;
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#else
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varying lowp vec2 uv;
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#define out_color gl_FragColor
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#endif
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const lowp float minimum_shadow_radius = 0.05;
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void main()
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{
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// Scaling factor that is the inverse of the amount of scaling applied to the geometry.
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lowp float inverse_scale = 1.0 / (1.0 + size + length(offset) * 2.0);
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// Correction factor to round the corners of a larger shadow.
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// We want to account for size in regards to shadow radius, so that a larger shadow is
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// more rounded, but only if we are not already rounding the corners due to corner radius.
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lowp vec4 size_factor = 0.5 * (minimum_shadow_radius / max(radius, minimum_shadow_radius));
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lowp vec4 shadow_radius = radius + size * size_factor;
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lowp vec4 col = vec4(0.0);
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// Calculate the shadow's distance field.
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lowp float shadow = sdf_rounded_rectangle(uv - offset * 2.0 * inverse_scale, aspect * inverse_scale, shadow_radius * inverse_scale);
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// Render it, interpolating the color over the distance.
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col = mix(col, shadowColor * sign(size), 1.0 - smoothstep(-size * 0.5, size * 0.5, shadow));
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// Calculate the main rectangle distance field.
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lowp float rect = sdf_rounded_rectangle(uv, aspect * inverse_scale, radius * inverse_scale);
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// First, remove anything that was rendered by the shadow if it is inside the rectangle.
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// This allows us to use colors with alpha without rendering artifacts.
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col = sdf_render(rect, col, vec4(0.0));
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// Then, render it again but this time with the proper color and properly alpha blended.
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col = sdf_render(rect, col, color);
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out_color = col * opacity;
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}
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