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232 lines
10 KiB
232 lines
10 KiB
/*
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Shader from Godot Shaders - the free shader library.
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godotshaders.com/shader/VHS-and-CRT-monitor-effect
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This shader is under CC0 license. Feel free to use, improve and
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change this shader according to your needs and consider sharing
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the modified result to godotshaders.com.
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*/
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shader_type canvas_item;
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uniform sampler2D SCREEN_TEXTURE : hint_screen_texture, filter_linear_mipmap;
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//*** IMPORTANT! ***/
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// - If you are using this shader to affect the node it is applied to set 'overlay' to false (unchecked in the instepctor).
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// - If you are using this shader as an overlay, and want the shader to affect the nodes below in the Scene hierarchy,
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// set 'overlay' to true (checked in the inspector).
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// On Mac there is potentially a bug causing this to not work properly. If that is the case and you want to use the shader as an overlay
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// change all "overlay ? SCREEN_TEXTURE : TEXTURE" to only "SCREEN_TEXTURE" on lines 129-140, and "vec2 uv = overlay ? warp(SCREEN_UV) : warp(UV);"
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// to "vec2 uv = warp(SCREEN_UV);" on line 98.
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uniform bool overlay = false;
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uniform float scanlines_opacity : hint_range(0.0, 1.0) = 0.4;
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uniform float scanlines_width : hint_range(0.0, 0.5) = 0.25;
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uniform float grille_opacity : hint_range(0.0, 1.0) = 0.3;
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uniform vec2 resolution = vec2(640.0, 480.0); // Set the number of rows and columns the texture will be divided in. Scanlines and grille will make a square based on these values
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uniform bool pixelate = true; // Fill each square ("pixel") with a sampled color, creating a pixel look and a more accurate representation of how a CRT monitor would work.
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uniform bool roll = true;
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uniform float roll_speed = 8.0; // Positive values are down, negative are up
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uniform float roll_size : hint_range(0.0, 100.0) = 15.0;
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uniform float roll_variation : hint_range(0.1, 5.0) = 1.8; // This valie is not an exact science. You have to play around with the value to find a look you like. How this works is explained in the code below.
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uniform float distort_intensity : hint_range(0.0, 0.2) = 0.05; // The distortion created by the rolling effect.
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uniform float noise_opacity : hint_range(0.0, 1.0) = 0.4;
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uniform float noise_speed = 5.0; // There is a movement in the noise pattern that can be hard to see first. This sets the speed of that movement.
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uniform float static_noise_intensity : hint_range(0.0, 1.0) = 0.06;
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uniform float aberration : hint_range(-1.0, 1.0) = 0.03; // Chromatic aberration, a distortion on each color channel.
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uniform float brightness = 1.4; // When adding scanline gaps and grille the image can get very dark. Brightness tries to compensate for that.
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uniform bool discolor = true; // Add a discolor effect simulating a VHS
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uniform float warp_amount :hint_range(0.0, 5.0) = 1.0; // Warp the texture edges simulating the curved glass of a CRT monitor or old TV.
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uniform bool clip_warp = false;
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uniform float vignette_intensity = 0.4; // Size of the vignette, how far towards the middle it should go.
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uniform float vignette_opacity : hint_range(0.0, 1.0) = 0.5;
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// Used by the noise functin to generate a pseudo random value between 0.0 and 1.0
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vec2 random(vec2 uv){
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uv = vec2( dot(uv, vec2(127.1,311.7) ),
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dot(uv, vec2(269.5,183.3) ) );
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return -1.0 + 2.0 * fract(sin(uv) * 43758.5453123);
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}
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// Generate a Perlin noise used by the distortion effects
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float noise(vec2 uv) {
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vec2 uv_index = floor(uv);
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vec2 uv_fract = fract(uv);
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vec2 blur = smoothstep(0.0, 1.0, uv_fract);
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return mix( mix( dot( random(uv_index + vec2(0.0,0.0) ), uv_fract - vec2(0.0,0.0) ),
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dot( random(uv_index + vec2(1.0,0.0) ), uv_fract - vec2(1.0,0.0) ), blur.x),
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mix( dot( random(uv_index + vec2(0.0,1.0) ), uv_fract - vec2(0.0,1.0) ),
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dot( random(uv_index + vec2(1.0,1.0) ), uv_fract - vec2(1.0,1.0) ), blur.x), blur.y) * 0.5 + 0.5;
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}
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// Takes in the UV and warps the edges, creating the spherized effect
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vec2 warp(vec2 uv){
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vec2 delta = uv - 0.5;
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float delta2 = dot(delta.xy, delta.xy);
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float delta4 = delta2 * delta2;
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float delta_offset = delta4 * warp_amount;
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return uv + delta * delta_offset;
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}
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// Adds a black border to hide stretched pixel created by the warp effect
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float border (vec2 uv){
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float radius = min(warp_amount, 0.08);
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radius = max(min(min(abs(radius * 2.0), abs(1.0)), abs(1.0)), 1e-5);
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vec2 abs_uv = abs(uv * 2.0 - 1.0) - vec2(1.0, 1.0) + radius;
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float dist = length(max(vec2(0.0), abs_uv)) / radius;
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float square = smoothstep(0.96, 1.0, dist);
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return clamp(1.0 - square, 0.0, 1.0);
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}
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// Adds a vignette shadow to the edges of the image
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float vignette(vec2 uv){
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uv *= 1.0 - uv.xy;
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float vignette = uv.x * uv.y * 15.0;
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return pow(vignette, vignette_intensity * vignette_opacity);
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}
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void fragment()
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{
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vec2 uv = overlay ? warp(SCREEN_UV) : warp(UV); // Warp the uv. uv will be used in most cases instead of UV to keep the warping
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vec2 text_uv = uv;
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vec2 roll_uv = vec2(0.0);
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float time = roll ? TIME : 0.0;
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// Pixelate the texture based on the given resolution.
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if (pixelate)
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{
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text_uv = ceil(uv * resolution) / resolution;
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}
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// Create the rolling effect. We need roll_line a bit later to make the noise effect.
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// That is why this runs if roll is true OR noise_opacity is over 0.
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float roll_line = 0.0;
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if (roll || noise_opacity > 0.0)
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{
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// Create the areas/lines where the texture will be distorted.
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roll_line = smoothstep(0.3, 0.9, sin(uv.y * roll_size - (time * roll_speed) ) );
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// Create more lines of a different size and apply to the first set of lines. This creates a bit of variation.
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roll_line *= roll_line * smoothstep(0.3, 0.9, sin(uv.y * roll_size * roll_variation - (time * roll_speed * roll_variation) ) );
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// Distort the UV where where the lines are
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roll_uv = vec2(( roll_line * distort_intensity * (1.-UV.x)), 0.0);
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}
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vec4 text;
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if (roll)
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{
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// If roll is true distort the texture with roll_uv. The texture is split up into RGB to
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// make some chromatic aberration. We apply the aberration to the red and green channels accorging to the aberration parameter
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// and intensify it a bit in the roll distortion.
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text.r = texture(SCREEN_TEXTURE, text_uv + roll_uv * 0.8 + vec2(aberration, 0.0) * .1).r;
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text.g = texture(SCREEN_TEXTURE, text_uv + roll_uv * 1.2 - vec2(aberration, 0.0) * .1 ).g;
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text.b = texture(SCREEN_TEXTURE, text_uv + roll_uv).b;
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text.a = 1.0;
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}
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else
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{
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// If roll is false only apply the aberration without any distorion. The aberration values are very small so the .1 is only
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// to make the slider in the Inspector less sensitive.
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text.r = texture(SCREEN_TEXTURE, text_uv + vec2(aberration, 0.0) * .1).r;
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text.g = texture(SCREEN_TEXTURE, text_uv - vec2(aberration, 0.0) * .1).g;
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text.b = texture(SCREEN_TEXTURE, text_uv).b;
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text.a = 1.0;
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}
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float r = text.r;
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float g = text.g;
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float b = text.b;
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uv = warp(UV);
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// CRT monitors don't have pixels but groups of red, green and blue dots or lines, called grille. We isolate the texture's color channels
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// and divide it up in 3 offsetted lines to show the red, green and blue colors next to each other, with a small black gap between.
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if (grille_opacity > 0.0){
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float g_r = smoothstep(0.85, 0.95, abs(sin(uv.x * (resolution.x * 3.14159265))));
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r = mix(r, r * g_r, grille_opacity);
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float g_g = smoothstep(0.85, 0.95, abs(sin(1.05 + uv.x * (resolution.x * 3.14159265))));
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g = mix(g, g * g_g, grille_opacity);
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float b_b = smoothstep(0.85, 0.95, abs(sin(2.1 + uv.x * (resolution.x * 3.14159265))));
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b = mix(b, b * b_b, grille_opacity);
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}
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// Apply the grille to the texture's color channels and apply Brightness. Since the grille and the scanlines (below) make the image very dark you
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// can compensate by increasing the brightness.
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text.r = clamp(r * brightness, 0.0, 1.0);
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text.g = clamp(g * brightness, 0.0, 1.0);
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text.b = clamp(b * brightness, 0.0, 1.0);
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// Scanlines are the horizontal lines that make up the image on a CRT monitor.
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// Here we are actual setting the black gap between each line, which I guess is not the right definition of the word, but you get the idea
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float scanlines = 0.5;
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if (scanlines_opacity > 0.0)
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{
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// Same technique as above, create lines with sine and applying it to the texture. Smoothstep to allow setting the line size.
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scanlines = smoothstep(scanlines_width, scanlines_width + 0.5, abs(sin(uv.y * (resolution.y * 3.14159265))));
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text.rgb = mix(text.rgb, text.rgb * vec3(scanlines), scanlines_opacity);
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}
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// Apply the banded noise.
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if (noise_opacity > 0.0)
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{
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// Generate a noise pattern that is very stretched horizontally, and animate it with noise_speed
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float noise = smoothstep(0.4, 0.5, noise(uv * vec2(2.0, 200.0) + vec2(10.0, (TIME * (noise_speed))) ) );
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// We use roll_line (set above) to define how big the noise should be vertically (multiplying cuts off all black parts).
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// We also add in some basic noise with random() to break up the noise pattern above. The noise is sized according to
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// the resolution value set in the inspector. If you don't like this look you can
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// change "ceil(uv * resolution) / resolution" to only "uv" to make it less pixelated. Or multiply resolution with som value
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// greater than 1.0 to make them smaller.
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roll_line *= noise * scanlines * clamp(random((ceil(uv * resolution) / resolution) + vec2(TIME * 0.8, 0.0)).x + 0.8, 0.0, 1.0);
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// Add it to the texture based on noise_opacity
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text.rgb = clamp(mix(text.rgb, text.rgb + roll_line, noise_opacity), vec3(0.0), vec3(1.0));
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}
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// Apply static noise by generating it over the whole screen in the same way as above
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if (static_noise_intensity > 0.0)
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{
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text.rgb += clamp(random((ceil(uv * resolution) / resolution) + fract(TIME)).x, 0.0, 1.0) * static_noise_intensity;
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}
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// Apply a black border to hide imperfections caused by the warping.
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// Also apply the vignette
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text.rgb *= border(uv);
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text.rgb *= vignette(uv);
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// Hides the black border and make that area transparent. Good if you want to add the the texture on top an image of a TV or monitor.
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if (clip_warp)
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{
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text.a = border(uv);
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}
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// Apply discoloration to get a VHS look (lower saturation and higher contrast)
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// You can play with the values below or expose them in the Inspector.
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float saturation = 0.5;
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float contrast = 1.2;
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if (discolor)
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{
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// Saturation
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vec3 greyscale = vec3(text.r + text.g + text.b) / 3.;
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text.rgb = mix(text.rgb, greyscale, saturation);
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// Contrast
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float midpoint = pow(0.5, 2.2);
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text.rgb = (text.rgb - vec3(midpoint)) * contrast + midpoint;
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}
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COLOR = text;
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}
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