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Pixelorama/src/Shaders/MarchingAntsOutline.shader
2022-04-18 15:32:14 +03:00

49 lines
1.7 KiB
GLSL

// Taken and modified from https://godotshaders.com/shader/2d-outline-inline/
// Also thanks to https://andreashackel.de/tech-art/stripes-shader-1/ for the stripe tutorial
shader_type canvas_item;
uniform vec4 first_color : hint_color = vec4(1.0);
uniform vec4 second_color : hint_color = vec4(0.0, 0.0, 0.0, 1.0);
uniform bool animated = true;
uniform float width : hint_range(0, 2) = 0.05;
uniform float frequency = 50.0;
uniform float stripe_direction : hint_range(0, 1) = 0.5;
bool has_contrary_neighbour(vec2 uv, vec2 texture_pixel_size, sampler2D tex) {
float i = -ceil(width);
float j = ceil(width);
float x1 = abs(i) > width ? width * sign(i) : i;
float x2 = abs(j) > width ? width * sign(j) : j;
float y1 = abs(i) > width ? width * sign(i) : i;
float y2 = abs(j) > width ? width * sign(j) : j;
vec2 xy1 = uv + texture_pixel_size * vec2(x1, y1);
vec2 xy2 = uv + texture_pixel_size * vec2(x2, y2);
if (xy1 != clamp(xy1, vec2(0.0), vec2(1.0)) || texture(tex, xy1).a == 0.0 || xy2 != clamp(xy2, vec2(0.0), vec2(1.0)) || texture(tex, xy2).a == 0.0) {
return true;
}
return false;
}
void fragment() {
COLOR = texture(TEXTURE, UV);
vec2 ts = TEXTURE_PIXEL_SIZE;
if (COLOR.a > 0.0 && has_contrary_neighbour(UV, ts, TEXTURE)) {
vec2 ratio = (ts.x > ts.y) ? vec2(ts.y / ts.x, 1) : vec2(1, ts.x / ts.y);
vec2 uv = UV * ratio;
if(animated)
uv -= TIME / frequency;
// Generate diagonal stripes
float pos = mix(uv.x, uv.y, stripe_direction) * frequency;
float value = floor(fract(pos) + 0.5);
COLOR = mix(first_color, second_color, step(1.0, mod(value, 2.0)));
}
else {
// Erase the texture's pixels in order to only keep the outline visible
COLOR.a = 0.0;
}
}