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// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
//! [1]
#version 440
layout(location = 0) in vec2 vTexCoord;
layout(location = 0) out vec4 fragColor;
//! [2]
// uniform block: 84 bytes
layout(std140, binding = 0) uniform buf {
mat4 qt_Matrix; // offset 0
float qt_Opacity; // offset 64
float zoom; // offset 68
vec2 center; // offset 72
int limit; // offset 80
} ubuf;
//! [2]
void main()
{
vec4 color1 = vec4(1.0, 0.85, 0.55, 1);
vec4 color2 = vec4(0.226, 0.0, 0.615, 1);
float aspect_ratio = -ubuf.qt_Matrix[0][0]/ubuf.qt_Matrix[1][1];
vec2 z, c;
c.x = (vTexCoord.x - 0.5) / ubuf.zoom + ubuf.center.x;
c.y = aspect_ratio * (vTexCoord.y - 0.5) / ubuf.zoom + ubuf.center.y;
int iLast;
z = c;
for (int i = 0; i < 1000000; i++) {
if (i >= ubuf.limit)
{
iLast = i;
break;
}
float x = (z.x * z.x - z.y * z.y) + c.x;
float y = (z.y * z.x + z.x * z.y) + c.y;
if ((x * x + y * y) > 4.0)
{
iLast = i;
break;
}
z.x = x;
z.y = y;
}
if (iLast == ubuf.limit) {
fragColor = vec4(0.0, 0.0, 0.0, 1.0);
} else {
float f = (iLast * 1.0) / ubuf.limit;
fragColor = mix(color1, color2, sqrt(f));
}
}
//! [1]
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