Learning_GTK4_tree/gsk/vulkan/resources/linear.frag

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2023-12-12 11:36:42 +01:00
#version 450
#include "common.frag.glsl"
#include "clip.frag.glsl"
#include "rect.frag.glsl"
layout(location = 0) in vec2 inPos;
layout(location = 1) in flat Rect inRect;
layout(location = 2) in float inGradientPos;
layout(location = 3) in flat int inRepeating;
layout(location = 4) in flat int inStopOffset;
layout(location = 5) in flat int inStopCount;
layout(location = 0) out vec4 color;
float
get_offset (int i)
{
return get_float (inStopOffset + i * 5);
}
vec4
get_color (int i)
{
i = clamp (i, 0, inStopCount - 1);
return color = vec4 (get_float (inStopOffset + i * 5 + 1),
get_float (inStopOffset + i * 5 + 2),
get_float (inStopOffset + i * 5 + 3),
get_float (inStopOffset + i * 5 + 4));
}
vec4
get_color_for_range_unscaled (float start,
float end)
{
vec4 result = vec4 (0);
float offset;
int i;
for (i = 0; i < inStopCount; i++)
{
offset = get_offset (i);
if (offset >= start)
break;
}
if (i == inStopCount)
offset = 1;
float last_offset = i > 0 ? get_offset (i - 1) : 0;
vec4 last_color = get_color (i - 1);
vec4 color = get_color (i);
if (last_offset < start)
{
last_color = mix (last_color, color, (start - last_offset) / (offset - last_offset));
last_offset = start;
}
if (end <= start)
return last_color;
for (; i < inStopCount; i++)
{
offset = get_offset (i);
color = get_color (i);
if (offset >= end)
break;
result += 0.5 * (color + last_color) * (offset - last_offset);
last_offset = offset;
last_color = color;
}
if (i == inStopCount)
{
offset = 1;
color = get_color (i);
}
if (offset > end)
{
color = mix (last_color, color, (end - last_offset) / (offset - last_offset));
offset = end;
}
result += 0.5 * (color + last_color) * (offset - last_offset);
return result;
}
vec4
get_color_for_range (float start,
float end)
{
return get_color_for_range_unscaled (start, end) / (end - start);
}
void main()
{
vec4 c;
float pos_start, pos_end;
float dPos = 0.5 * abs (fwidth (inGradientPos));
if (inRepeating != 0)
{
pos_start = inGradientPos - dPos;
pos_end = inGradientPos + dPos;
if (floor (pos_end) > floor (pos_start))
{
float fract_end = fract(pos_end);
float fract_start = fract(pos_start);
float n = floor (pos_end) - floor (pos_start);
if (fract_end > fract_start + 0.01)
c = get_color_for_range_unscaled (fract_start, fract_end);
else if (fract_start > fract_end + 0.01)
c = -get_color_for_range_unscaled (fract_end, fract_start);
c += get_color_for_range_unscaled (0.0, 1.0) * n;
c /= pos_end - pos_start;
}
else
{
c = get_color_for_range (fract (pos_start), fract (pos_end));
}
}
else
{
pos_start = clamp (inGradientPos - dPos, 0, 1);
pos_end = clamp (inGradientPos + dPos, 0, 1);
c = get_color_for_range (pos_start, pos_end);
}
float alpha = c.a * rect_coverage (inRect, inPos);
color = clip_scaled (inPos, vec4(c.rgb, 1) * alpha);
}