LÖVE

Posted: **Fri Oct 30, 2015 9:11 am**

Hello!

I tried converting this shader I found to love2d, but I can't get it right.
This statement is the one in error:

vec3 grain = vec3(((mod(mod(int(x), 13) + 1)* (mod(int(x), 123) + 1), 0.01) - 0.005) * noiseStrength); // 0.01 and - 0.005

Unable to find compatible overloaded function "mod(float)". I get the error because mod is supposed to get 2 values, 2 floats, but it gets one. And I don't know how the dude that made this wants it to be.

Shader:

Code: Select all

//layout(location = 0) out vec3 out_color;

//uniform sampler2D colorMap; // This is the original image without noise
uniform float time; // Time since the start of the frame

const float noiseStrength = 30.0; // The strength of the noise effect -- default 30.0

vec4 effect(vec4 col, Image texture, vec2 texturePos, vec2 screenPos)
{
    vec3 color = texture2D(texture, texturePos).xyz;
    float x = (texturePos.x + 4) * (texturePos.y + 4) * (time * 10);

    int a = 13;
    int b = 123;

    vec3 grain = vec3(((mod(mod(int(x), 13) + 1)* (mod(int(x), 123) + 1), 0.01) - 0.005) * noiseStrength); // 0.01 and - 0.005

    // This one is optional, it makes a small "tear" every now and then
    //if(mod(time, 100) > 98 && mod(texcoord.y, 10) > 7) grain = vec3(-3.0, -3.0, -3.0);
    //vec3 grain = vec3(0,0,0);
    color += grain;
    vec4 finalColor = vec4(color, 1.0);
    return finalColor;
}

Link to reddit forum that made this originally:
https://m.reddit.com/r/opengl/comments/ ... ain_noise/

Posted: **Fri Oct 30, 2015 9:39 am**

Turns out that time was 0 all the time, so now I send time every frame.
I also deleted the error statement and replaced with this:

Code: Select all

float noise(vec2 seed)
{
  float x = (seed.x / 3.14159 + 4) * (seed.y / 13 + 4) * ((fract(time) + 1) * 10);
  return mod((mod(x, 13) + 1) * (mod(x, 123) + 1), 0.01) - 0.005;
}

Code: Select all

vec3 out_color = texture2D(texture, texturePos).xyz;

Code: Select all

vec2 seed = vec2(0.9,0.9);
    out_color += noise(seed);
    vec4 finalColor = vec4(out_color, 1.0);
    return finalColor;

Problem is.. Either the seed is so low that almost nothing happens, or it is so high that the screen flickers like crazy.

LÖVE

vec3 modulus error

vec3 modulus error

Re: vec3 modulus error