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++ // Copyright (C) 2025 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
++ #version 440
++
++ layout(location = 0) in vec2 texCoord;
++ layout(location = 1) in vec2 fragCoord;
++ layout(location = 0) out vec4 fragColor;
++
++ layout(std140, binding = 0) uniform buf {
++ mat4 qt_Matrix;
++ float qt_Opacity;
++ vec3 iResolution;
++ int origo;
++ vec4 gridVisibility;
++ float gridWidth;
++ float gridHeight;
++ vec2 gridMovement;
++ vec4 subGridColor;
++ vec4 gridColor;
++ float subGridLineWidth;
++ float gridLineWidth;
++ float smoothing;
++ float verticalSubGridScale;
++ float horizontalSubGridScale;
++ vec4 plotAreaBackgroundColor;
++ bool verticalLogarithmic;
++ bool horizontalLogarithmic;
++ float verticalBase;
++ float horizontalBase;
++ };
++
++
++ float createBars(float coord, float spacing, float strokeWidth) {
++ float sbar = 1.0 / spacing;// * 0.5;
++ float barWidth = strokeWidth / spacing;// * 0.5;
++ float firstPos = -((gridLineWidth / spacing) * 0.5);
++ float p = firstPos + coord * sbar;
++ //float p = (coord - 0.5) * sbar;
++ float bar = abs(2.0 * fract(p) - 1.0);
++ float barSmoothness = smoothing / spacing;
++ bar = smoothstep(1.0 - barWidth - barSmoothness, 1.0 - barWidth + barSmoothness, bar);
++ return bar;
++ }
++
++ float createLogBars(float coord, float base, int numTicks, float spacing) {
++
++ float pos = fract(coord / spacing);
++ const float logBase = log(base);
++ float logSpacePos = exp(pos * logBase) ;
++
++ float adjustedPos = (logSpacePos - 1) * numTicks / (base - 1);
++ float nearestMinorDecade = floor((adjustedPos) + 0.5);
++
++ float unadjustedDecade = ((nearestMinorDecade * (base - 1)) / numTicks) + 1;
++ float linearDecade = log(unadjustedDecade) / logBase;
++
++ float barWidth = subGridLineWidth / spacing;
++ float c = smoothstep(barWidth, 0.0, abs(linearDecade - pos));
++ return c;
++ }
++
++
++ void main() {
++ {
++ // sublines
++ float subLines = 0.0;
++
++ if (gridVisibility.z > 0) {
++
++ if (horizontalLogarithmic)
++ subLines += createLogBars(fragCoord.x, horizontalBase, int(1 / horizontalSubGridScale), gridWidth);
++ else
++ subLines += createBars(fragCoord.x, gridWidth * horizontalSubGridScale, subGridLineWidth);
++
++ }
++ if (gridVisibility.w > 0) {
++ if (verticalLogarithmic)
++ subLines += createLogBars(fragCoord.y, verticalBase, int(1 / verticalSubGridScale), gridHeight);
++ else
++ subLines += createBars(fragCoord.y, gridHeight * verticalSubGridScale, subGridLineWidth) * (1.0 - subLines);
++ }
++ // Major lines
++ float lines = 0.0;
++ if (gridVisibility.x > 0)
++ lines += createBars(fragCoord.x, gridWidth, gridLineWidth);
++ if (gridVisibility.y > 0)
++ lines += createBars(fragCoord.y, gridHeight, gridLineWidth) * (1.0 - lines);
++ // Combine lines, sublines below
++ vec3 barColor = plotAreaBackgroundColor.rgb;
++ float gridColorAlpha = lines * gridColor.a;
++ float subGridColorAlpha = subLines * subGridColor.a;
++ barColor = mix(barColor, subGridColor.rgb, subGridColorAlpha);
++ barColor = mix(barColor, gridColor.rgb, gridColorAlpha);
++ fragColor = vec4(barColor, min(1.0, subGridColorAlpha + gridColorAlpha + plotAreaBackgroundColor.a));
++ }
++ fragColor = fragColor * qt_Opacity;
++ }