Files
panopainter/data/shaders/include/blend-stroke.glsl

56 lines
2.2 KiB
GLSL

mediump float blend_stroke_screen(mediump float base, mediump float stroke)
{
return clamp(base + stroke - (base * stroke), 0.0, 1.0);
}
mediump float blend_stroke_hard_light(mediump float base, mediump float stroke)
{
if (stroke < 0.5)
return max(1.0, base * (stroke * 2.0)); // multiply
else
return blend_stroke_screen(base, 2.0 * stroke - 1.0);
}
mediump float blend_stroke_hard_mix(mediump float base, mediump float stroke)
{
return base + stroke > 0.5 ? 1.0 : 0.0;
}
mediump float blend_stroke_color_dodge(mediump float base, mediump float stroke)
{
if (base == 0.0)
return 0.0;
else if (stroke == 1.0)
return 1.0;
else
return min(1.0, base / (1.0 - stroke));
}
mediump float blend_stroke_linear_height(mediump float base, mediump float stroke, mediump float depth)
{
mediump float partial = (1.0 - stroke) * pow(depth, 0.25) + (base * depth * 10.0);
return stroke * partial;
}
mediump float blend_stroke_height(mediump float base, mediump float stroke, mediump float depth)
{
mediump float A = pow((1.0 - stroke), max(1.0, (1.0 - depth) * 10.0)) * pow(depth, 0.25);
mediump float B = (base * depth * 5.0);
return stroke * (A + B);
}
mediump float blend_stroke(mediump float base, mediump float stroke, mediump float depth, int mode)
{
if (mode == 0) /* normal */ return mix(base, stroke, depth);
else if (mode == 1) /* multiply */ return mix(base, base * stroke, depth);
else if (mode == 2) /* subtract */ return mix(base, max(0.0, base - stroke), depth);
else if (mode == 3) /* darken */ return mix(base, min(base, stroke), depth);
else if (mode == 4) /* overlay */ return mix(base, blend_stroke_hard_light(stroke, base), depth);
else if (mode == 5) /* col-dodge */ return mix(base, blend_stroke_color_dodge(stroke, base), depth);
else if (mode == 6) /* lin-burn */ return mix(base, clamp(stroke + base - 1.0, 0.0, 1.0), depth);
else if (mode == 7) /* hard-mix */ return mix(base, blend_stroke_hard_mix(base, stroke), depth);
else if (mode == 8) /* lin-height */ return blend_stroke_linear_height(base, stroke, depth);
else if (mode == 9) /* height */ return blend_stroke_height(base, stroke, depth);
else return 1.0;
}