Fire.glsl

#include "Uniforms.glsl"
#include "Samplers.glsl"
#include "Transform.glsl"
#include "ScreenPos.glsl"
#include "Lighting.glsl"

varying vec2 vScreenPos;

precision mediump float;
uniform vec2 resolution = vec2(1366.0,768.0);

#ifdef COMPILEPS
uniform float cElapsedTime;
uniform vec2  cSpeed;
#endif

uniform float shift;

float rand(vec2 n) {
    return fract(cos(dot(n, vec2(12.9898, 4.1414))) * 43758.5453);
}

float noise(vec2 n) {
    const vec2 d = vec2(0.0, 1.0);
    vec2 b = floor(n), f = smoothstep(vec2(0.0), vec2(1.0), fract(n));
    return mix(mix(rand(b), rand(b + d.yx), f.x), mix(rand(b + d.xy), rand(b + d.yy), f.x), f.y);
}

float fbm(vec2 n) {
    float total = 0.0, amplitude = 1.0;
    for (int i = 0; i < 4; i++) {
        total += noise(n) * amplitude;
        n += n;
        amplitude *= 0.5;
    }
    return total;
}

void VS()
{
    mat4 modelMatrix = iModelMatrix;
    vec3 worldPos = GetWorldPos(modelMatrix);
    gl_Position = GetClipPos(worldPos);
    vScreenPos = GetScreenPosPreDiv(gl_Position);
}

void PS() {

    const vec3 c1 = vec3(12.0/255.0, 10.0/212.0, 71.0/255.0);
    const vec3 c2 = vec3(218.0/255.0, 220.0/255.0, 11.4/755.0);
    const vec3 c3 = vec3(0.2, 0.0, 0.0);
    const vec3 c4 = vec3(162.0/255.0, 1.0/255.0, 4.4/955.0);
    const vec3 c5 = vec3(3.1);
    const vec3 c6 = vec3(1.151);

    vec2 p = gl_FragCoord.xy * 8.0 / resolution.xx;
    float q = fbm(p - cElapsedTime * 0.1);
    vec2 r = vec2(fbm(p + q + cElapsedTime * cSpeed.x - p.x - p.y), fbm(p + q - cElapsedTime * cSpeed.y));
    vec3 c = mix(c1, c2, fbm(p + r)) + mix(c3, c4, r.x) - mix(c5, c6, r.y);
    float grad = gl_FragCoord.y / resolution.y;
    gl_FragColor = vec4(c * cos(shift * gl_FragCoord.y / resolution.y), 1.0);
    gl_FragColor.xyz *= 1.0-grad;
}