godot-visual-effects/camera-effects/under-water.gdshader
2023-12-18 19:03:51 +01:00

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shader_type canvas_item;
uniform sampler2D SCREEN_TEXTURE : hint_screen_texture, filter_linear_mipmap;
uniform float speed : hint_range(0.0, 5.0) = .5;
uniform float strength : hint_range(0.0, 1.0) = .5;
uniform float intensity : hint_range(0.0, 1.0) = .5;
uniform float distortionStrength : hint_range(0.0, 20.0) = 5.0;
uniform int maximumIterations : hint_range(0, 10) = 5;
uniform bool showTiling = false;
uniform bool showYellowLine = false;
// based on: https://www.shadertoy.com/view/MdlXz8
#define TAU 6.28318530718
void fragment() {
float time = TIME * speed + 23.0;
// uv should be the 0-1 uv of texture...
vec2 iResolution = 1.0 / SCREEN_PIXEL_SIZE;
vec2 uv = FRAGCOORD.xy / iResolution.xy;
vec2 p;
if (showTiling) {
p = mod(uv*TAU*2.0, TAU) - 250.0;
} else {
p = mod(uv*TAU, TAU) - 250.0;
}
vec2 i = vec2(p);
float c = 1.0;
float inten = intensity / 100.0;
for (int n = 0; n < maximumIterations; n++)
{
float t = time * (1.0 - (3.5 / float(n+1)));
i = p + vec2(cos(t - i.x) + sin(t + i.y), sin(t - i.y) + cos(t + i.x));
c += 1.0/length(vec2(p.x / (sin(i.x+t)/inten),p.y / (cos(i.y+t)/inten)));
}
c /= float(maximumIterations);
c = 1.17-pow(c, 1.4);
vec3 colorBase = vec3(pow(abs(c), 8.0));
vec3 colour = clamp(colorBase + vec3(0.0, 0.35, 0.5), 0.0, 1.0);
if (showTiling) {
// Flash tile borders...
vec2 pixel = 2.0 / iResolution.xy;
uv *= 2.0;
float f = floor(mod(TIME * speed, 2.0)); // Flash value.
vec2 first = step(pixel, uv) * f; // Rule out first screen pixels and flash.
uv = step(fract(uv), pixel); // Add one line of pixels per tile.
if (showYellowLine)
colour = mix(colour, vec3(1.0, 1.0, 0.0), (uv.x + uv.y) * first.x * first.y); // Yellow line
}
vec4 pixelColor = textureLod(SCREEN_TEXTURE, UV, colorBase.r * distortionStrength);
vec3 appliedColor = mix(pixelColor.rgb, colour, strength);
COLOR = vec4(appliedColor, 1.0);
}