// CHANNEL CONTRAST — the classic contrast/gain/lift ladder, but each of
// red, green and blue carries its own fixed weighting, so pushing the
// dials bends the picture's colour balance instead of just its punch.
{
    name: "Channel Contrast"
    engine: "screen"
    seed: 202
    input0: "test"

    speed: 1.0
    beat_pulse: 0.4
    beat_rate: 1.0
    bar_beats: 4
    glow: 1.0
    // PERFORMANCE DIALS — mid-knob = the stock look, exact.
    p0: 0.5  p1: 0.5  p2: 0.5
    dials: [
        {name: "CONTRAST", bind: "p0", default: 0.5},
        {name: "GAIN", bind: "p1", default: 0.5},
        {name: "ADD", bind: "p2", default: 0.5}
    ]

    color_bg: #x03040a
    color_a: #x30ffd0
    color_b: #xff3a86
    color_c: #xfff0d0

    stages: [
        {kind: "bloom", threshold: 0.62, strength: 1.0, levels: 2}
    ]

    // THE LOOK LIVES HERE: the whole frame is this function. A fixed
    // per-channel weight vector makes CONTRAST/GAIN/ADD bend red, green
    // and blue by different amounts instead of moving them together.
    // Inputs: uv, content = input0 at uv, cmix = pre-gated content
    // strength. Signals: self.time_beat (time, beat, phase, pulse),
    // self.sig (bar, bpm, energy, dt), self.user (p0..p3),
    // self.col_a/b/c/bg, self.fog (density, glow, content, -).
    shader: draw.DrawVjFxScreen {
        fx_color: fn(uv: vec2, content: vec4, cmix: float) -> vec4 {
            let wc = vec3(1.15, 1.0, 0.82)
            let wg = vec3(1.05, 1.0, 0.92)
            let wa = vec3(1.0, 0.55, -0.4)
            let contrast = 1.0 + (self.user.x - 0.5) * 2.0
            let gain = 0.25 + 1.5 * self.user.y
            let add = (self.user.z - 0.5) * 0.5
            let half = vec3(0.5, 0.5, 0.5)
            let one = vec3(1.0, 1.0, 1.0)
            let cmul = one + (contrast - 1.0) * wc
            let gmul = one + (gain - 1.0) * wg
            let stretched = (content.xyz - half) * cmul + half
            let gained = stretched * gmul
            let out = gained + add * wa
            return vec4(clamp(out, vec3(0.0, 0.0, 0.0), vec3(1.0, 1.0, 1.0)), 1.0)
        }
    }
}