SoundFlix/FractalVisualizer/Rendering/FractalRenderer.cs

using System;
using System.Collections.Generic;
using FractalVisualizer.Models;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;

namespace FractalVisualizer.Rendering;

public sealed class FractalRenderer : IDisposable
{
    private readonly GraphicsDevice _graphicsDevice;
    private readonly SpriteBatch _spriteBatch;

    private int _internalWidth;
    private int _internalHeight;
    private Texture2D _fractalTexture;
    private Color[] _pixelBuffer;
    private Color[] _postBuffer;
    private Color[] _previousFrame;
    private readonly List<NoteParticle> _notes = [];
    private readonly List<FireworkRocket> _fireworkRockets = [];
    private readonly List<FireworkSpark> _fireworkSparks = [];
    private readonly Random _rng = new();

    private float _noteSpawnAccumulator;
    private float _fireworkSpawnAccumulator;
    private float _runtimePerformanceScale = 1f;
    private RenderQuality _quality = RenderQuality.Medium;
    private int _lastViewportWidth;
    private int _lastViewportHeight;

    private bool _disposed;

    public FractalRenderer(GraphicsDevice graphicsDevice, int internalWidth = 320, int internalHeight = 180)
    {
        _graphicsDevice = graphicsDevice ?? throw new ArgumentNullException(nameof(graphicsDevice));
        _spriteBatch = new SpriteBatch(_graphicsDevice);
        _internalWidth = Math.Max(32, internalWidth);
        _internalHeight = Math.Max(18, internalHeight);
        _fractalTexture = new Texture2D(_graphicsDevice, _internalWidth, _internalHeight, false, SurfaceFormat.Color);
        _pixelBuffer = new Color[_internalWidth * _internalHeight];
        _postBuffer = new Color[_internalWidth * _internalHeight];
        _previousFrame = new Color[_internalWidth * _internalHeight];
        _lastViewportWidth = _graphicsDevice.Viewport.Width;
        _lastViewportHeight = _graphicsDevice.Viewport.Height;
    }

    public RenderQuality Quality => _quality;

    public void SetQuality(RenderQuality quality)
    {
        if (_quality == quality)
        {
            return;
        }

        _quality = quality;
        ResizeForQuality();
    }

    public void UpdatePerformanceHint(int currentFps, int targetFps)
    {
        if (targetFps <= 0)
        {
            _runtimePerformanceScale = 1f;
            return;
        }

        float ratio = currentFps / (float)targetFps;
        _runtimePerformanceScale = Math.Clamp(ratio, 0.55f, 1.15f);
    }

    private void EnsureRenderSurface()
    {
        Viewport viewport = _graphicsDevice.Viewport;
        if (viewport.Width == _lastViewportWidth && viewport.Height == _lastViewportHeight)
        {
            return;
        }

        _lastViewportWidth = viewport.Width;
        _lastViewportHeight = viewport.Height;
        ResizeForQuality();
    }

    private void ResizeForQuality()
    {
        Viewport viewport = _graphicsDevice.Viewport;
        float scale = _quality switch
        {
            RenderQuality.Low => 0.35f,
            RenderQuality.Medium => 0.50f,
            RenderQuality.High => 0.75f,
            _ => 0.50f
        };

        int width = Math.Max(64, (int)(viewport.Width * scale));
        int height = Math.Max(36, (int)(viewport.Height * scale));
        ResizeBuffers(width, height);
    }

    private void ResizeBuffers(int width, int height)
    {
        if (_internalWidth == width && _internalHeight == height)
        {
            return;
        }

        _fractalTexture.Dispose();
        _internalWidth = width;
        _internalHeight = height;
        _fractalTexture = new Texture2D(_graphicsDevice, _internalWidth, _internalHeight, false, SurfaceFormat.Color);
        _pixelBuffer = new Color[_internalWidth * _internalHeight];
        _postBuffer = new Color[_internalWidth * _internalHeight];
        _previousFrame = new Color[_internalWidth * _internalHeight];
        _notes.Clear();
        _fireworkRockets.Clear();
        _fireworkSparks.Clear();
        _noteSpawnAccumulator = 0f;
        _fireworkSpawnAccumulator = 0f;
    }

    private int ScaleCount(int baseCount, int minCount = 1)
    {
        float qualityScale = _quality switch
        {
            RenderQuality.Low => 0.70f,
            RenderQuality.Medium => 1.0f,
            RenderQuality.High => 1.35f,
            _ => 1.0f
        };

        int scaled = (int)MathF.Round(baseCount * qualityScale * _runtimePerformanceScale);
        return Math.Max(minCount, scaled);
    }

    public void Draw(AudioFeatures features, float timeSeconds, int presetIndex)
    {
        ThrowIfDisposed();
        EnsureRenderSurface();

        switch (presetIndex)
        {
            case 0:
                RenderJulia(features, timeSeconds);
                break;
            case 1:
                RenderMandelbulbStyle(features, timeSeconds);
                break;
            case 2:
                RenderKaleidoscopeTunnel(features, timeSeconds);
                break;
            case 3:
                RenderFlame(features, timeSeconds);
                break;
            case 4:
                RenderPlasma(features, timeSeconds);
                break;
            case 5:
                RenderNebula(features, timeSeconds);
                break;
            case 6:
                RenderFlameGrill(features, timeSeconds);
                break;
            case 7:
                RenderFloatingNotes(features, timeSeconds);
                break;
            case 8:
                RenderFireworks(features, timeSeconds);
                break;
            case 9:
                RenderEqualizerCity(features, timeSeconds);
                break;
            case 10:
                RenderLiquidMetaballs(features, timeSeconds);
                break;
            case 11:
                RenderParticleGalaxy(features, timeSeconds);
                break;
            case 12:
                RenderAuroraCurtains(features, timeSeconds);
                break;
            case 13:
                RenderVortexPortal(features, timeSeconds);
                break;
            case 14:
                RenderLaserGrid(features, timeSeconds);
                break;
            case 15:
                RenderRainRipple(features, timeSeconds);
                break;
            case 16:
                RenderInkSmoke(features, timeSeconds);
                break;
            case 17:
                RenderMirrorMosaic(features, timeSeconds);
                break;
            case 18:
                RenderWaveformRibbon(features, timeSeconds);
                break;
            case 19:
                RenderGrainBars(features, timeSeconds);
                break;
            default:
                RenderJulia(features, timeSeconds);
                break;
        }

        ApplyFeedbackAndCrt(features, timeSeconds);
        _fractalTexture.SetData(_postBuffer);

        Viewport viewport = _graphicsDevice.Viewport;
        Rectangle destination = new(0, 0, viewport.Width, viewport.Height);
        _spriteBatch.Begin(samplerState: SamplerState.LinearClamp, blendState: BlendState.Opaque);
        _spriteBatch.Draw(_fractalTexture, destination, Color.White);
        _spriteBatch.End();
    }

    private void ApplyFeedbackAndCrt(AudioFeatures features, float timeSeconds)
    {
        float bass = Clamp01(features.Bass * 0.012f);
        float high = Clamp01(features.High * 0.003f);
        float beat = Clamp01(features.Beat);
        float lowSpec = GetSpectrumBand(features, 0.00f, 0.20f);
        float midSpec = GetSpectrumBand(features, 0.20f, 0.60f);
        float highSpec = GetSpectrumBand(features, 0.60f, 1.00f);
        float fullSpec = Clamp01((lowSpec + midSpec + highSpec) / 3f);

        int shiftPixels = 1 + (int)MathF.Round((high * 2f) + (highSpec * 3f) + (beat * 2f));
        float trailStrength = Clamp01(0.14f + (bass * 0.20f) + (lowSpec * 0.20f) + (beat * 0.26f));
        float glowBoost = (high * 0.05f) + (highSpec * 0.08f) + (midSpec * 0.05f) + (beat * 0.05f);

        for (int y = 0; y < _internalHeight; y++)
        {
            float ny = (y / (_internalHeight - 1f)) * 2f - 1f;
            float scanline = 0.90f + (0.10f * MathF.Sin(((y * 0.42f) + (timeSeconds * 22f)) * MathF.PI));

            for (int x = 0; x < _internalWidth; x++)
            {
                int index = (y * _internalWidth) + x;
                Vector3 raw = _pixelBuffer[index].ToVector3();
                Vector3 previous = _previousFrame[index].ToVector3();

                Vector3 trailed = Vector3.Lerp(raw, previous, trailStrength);

                int xr = Math.Min(_internalWidth - 1, x + shiftPixels);
                int xb = Math.Max(0, x - shiftPixels);
                int rightIndex = (y * _internalWidth) + xr;
                int leftIndex = (y * _internalWidth) + xb;

                float r = _pixelBuffer[rightIndex].R / 255f;
                float g = trailed.Y;
                float b = _pixelBuffer[leftIndex].B / 255f;
                Vector3 crt = new(r, g, b);

                float nx = (x / (_internalWidth - 1f)) * 2f - 1f;
                float vignette = Clamp01(1f - ((nx * nx + ny * ny) * 0.42f));
                float spectralIndex = ((x / (float)_internalWidth) * 63f) + (timeSeconds * 6f) + (y * 0.03f);
                float spectralPulse = GetSpectrumSample(features, spectralIndex);
                float hueWarpR = 1f + (lowSpec * 0.20f) + spectralPulse * 0.12f;
                float hueWarpG = 1f + (midSpec * 0.24f) + spectralPulse * 0.08f;
                float hueWarpB = 1f + (highSpec * 0.28f) + spectralPulse * 0.14f;
                crt *= scanline;
                crt *= 0.5f + (vignette * 0.5f);
                crt += raw * glowBoost;
                crt.X *= hueWarpR;
                crt.Y *= hueWarpG;
                crt.Z *= hueWarpB;
                crt += new Vector3(spectralPulse * 0.03f, spectralPulse * 0.02f, spectralPulse * 0.035f) * (0.3f + fullSpec);

                crt.X = Clamp01(crt.X);
                crt.Y = Clamp01(crt.Y);
                crt.Z = Clamp01(crt.Z);

                Color finalColor = new(crt.X, crt.Y, crt.Z, 1f);
                _postBuffer[index] = finalColor;
                _previousFrame[index] = finalColor;
            }
        }
    }

    private float GetSpectrumBand(AudioFeatures features, float normalizedStart, float normalizedEnd)
    {
        if (features.Spectrum is null || features.Spectrum.Length == 0)
        {
            return 0f;
        }

        int length = features.Spectrum.Length;
        int start = Math.Clamp((int)(normalizedStart * length), 0, length - 1);
        int end = Math.Clamp((int)(normalizedEnd * length), start + 1, length);
        float sum = 0f;
        int count = 0;
        for (int i = start; i < end; i++)
        {
            sum += features.Spectrum[i];
            count++;
        }

        if (count == 0)
        {
            return 0f;
        }

        return Clamp01((sum / count) * 0.08f);
    }

    private void RenderMandelbulbStyle(AudioFeatures features, float timeSeconds)
    {
        float bass = Clamp01(features.Bass * 0.012f);
        float mid = Clamp01(features.Mid * 0.003f);
        float high = Clamp01(features.High * 0.0025f);
        float beat = Clamp01(features.Beat);

        float power = 6f + (bass * 4f);
        float detail = 28f + (high * 22f);
        float rotation = timeSeconds * (0.25f + mid * 0.8f);
        float aspect = _internalWidth / (float)_internalHeight;

        float cosR = MathF.Cos(rotation);
        float sinR = MathF.Sin(rotation);

        for (int y = 0; y < _internalHeight; y++)
        {
            float sy = (y / (float)_internalHeight) * 2f - 1f;
            for (int x = 0; x < _internalWidth; x++)
            {
                float sx = ((x / (float)_internalWidth) * 2f - 1f) * aspect;

                float rayX = sx;
                float rayY = sy;
                float rayZ = 1.65f - beat * 0.25f;

                float march = 0f;
                float glow = 0f;
                float minDist = 10f;

                int steps = ScaleCount((int)detail, 14);
                for (int step = 0; step < steps; step++)
                {
                    float px = rayX * march;
                    float py = rayY * march;
                    float pz = rayZ - march;

                    float rpx = (px * cosR) - (pz * sinR);
                    float rpz = (px * sinR) + (pz * cosR);

                    float d = MandelbulbDistance(rpx, py, rpz, power);
                    minDist = MathF.Min(minDist, d);
                    glow += MathF.Exp(-20f * d) * (0.015f + high * 0.03f);
                    march += d * 0.95f;

                    if (d < 0.002f || march > 3.2f)
                    {
                        break;
                    }
                }

                float hit = Clamp01(1f - (minDist * 110f));
                float fog = Clamp01(1f - (march / 3.2f));
                float pulse = beat * 0.45f;

                float r = Clamp01(hit * (0.35f + bass * 1.2f + pulse) + glow * 1.3f);
                float g = Clamp01(hit * (0.22f + mid * 1.1f) + glow * 0.6f);
                float b = Clamp01(hit * (0.45f + high * 1.5f) + glow * 1.5f + fog * 0.08f);

                _pixelBuffer[(y * _internalWidth) + x] = new Color(r, g, b, 1f);
            }
        }
    }

    private void RenderKaleidoscopeTunnel(AudioFeatures features, float timeSeconds)
    {
        float bass = Clamp01(features.Bass * 0.01f);
        float mid = Clamp01(features.Mid * 0.0035f);
        float high = Clamp01(features.High * 0.0035f);
        float beat = Clamp01(features.Beat);
        float level = Clamp01(features.Level * 3f);

        float aspect = _internalWidth / (float)_internalHeight;
        float tunnelSpeed = 0.45f + bass * 1.35f;
        float spin = timeSeconds * (0.25f + mid * 1.1f);
        float slices = 6f + MathF.Floor(high * 8f);

        for (int y = 0; y < _internalHeight; y++)
        {
            float py = (y / (float)_internalHeight) * 2f - 1f;
            for (int x = 0; x < _internalWidth; x++)
            {
                float px = ((x / (float)_internalWidth) * 2f - 1f) * aspect;
                float radius = MathF.Sqrt((px * px) + (py * py)) + 1e-5f;
                float angle = MathF.Atan2(py, px) + spin;

                float wedge = MathF.PI / slices;
                angle = MathF.Abs((angle % (2f * wedge)) - wedge);

                float spectrumDrive = GetSpectrumSample(features, radius * 8f + beat * 10f);
                float distortion = spectrumDrive * (0.55f + high * 0.7f);
                float tunnel = MathF.Sin((1f / radius) * 9f - timeSeconds * tunnelSpeed * 7f + distortion * 8f);
                float rings = MathF.Sin(radius * 35f - timeSeconds * (2f + mid * 4f));
                float edge = MathF.Exp(-10f * MathF.Abs(angle - wedge * 0.5f));

                float pulse = beat * 0.6f;
                float brightness = Clamp01((tunnel * 0.5f + 0.5f) * (0.4f + level) + edge * 0.5f + pulse * 0.3f);
                float hueShift = (timeSeconds * 0.15f) + (beat * 0.25f);

                float r = Clamp01(brightness * (0.5f + 0.5f * MathF.Sin(hueShift + 0.0f)) + rings * 0.08f + bass * 0.25f);
                float g = Clamp01(brightness * (0.5f + 0.5f * MathF.Sin(hueShift + 2.09f)) + rings * 0.06f + mid * 0.25f);
                float b = Clamp01(brightness * (0.5f + 0.5f * MathF.Sin(hueShift + 4.18f)) + rings * 0.10f + high * 0.35f);

                _pixelBuffer[(y * _internalWidth) + x] = new Color(r, g, b, 1f);
            }
        }
    }

    private float GetSpectrumSample(AudioFeatures features, float virtualIndex)
    {
        if (features.Spectrum is null || features.Spectrum.Length == 0)
        {
            return 0f;
        }

        int i0 = ((int)virtualIndex) % features.Spectrum.Length;
        if (i0 < 0)
        {
            i0 += features.Spectrum.Length;
        }

        int i1 = (i0 + 1) % features.Spectrum.Length;
        float t = virtualIndex - MathF.Floor(virtualIndex);
        float sample = features.Spectrum[i0] + ((features.Spectrum[i1] - features.Spectrum[i0]) * t);
        return Clamp01(sample * 0.06f);
    }

    private static float MandelbulbDistance(float x, float y, float z, float power)
    {
        float zx = x;
        float zy = y;
        float zz = z;
        float dr = 1f;
        float r = 0f;

        for (int i = 0; i < 7; i++)
        {
            r = MathF.Sqrt((zx * zx) + (zy * zy) + (zz * zz));
            if (r > 2f)
            {
                break;
            }

            float theta = MathF.Acos(zz / (r + 1e-6f));
            float phi = MathF.Atan2(zy, zx);
            float zr = MathF.Pow(r, power);

            dr = MathF.Pow(r, power - 1f) * power * dr + 1f;

            float sinTheta = MathF.Sin(theta * power);
            zx = zr * sinTheta * MathF.Cos(phi * power) + x;
            zy = zr * sinTheta * MathF.Sin(phi * power) + y;
            zz = zr * MathF.Cos(theta * power) + z;
        }

        return 0.5f * MathF.Log(r + 1e-6f) * r / dr;
    }

    private static float Frac(float v)
    {
        return v - MathF.Floor(v);
    }

    private static float Hash01(int x, int y, int seed)
    {
        unchecked
        {
            int h = x * 374761393 + y * 668265263 + seed * 2147483647;
            h = (h ^ (h >> 13)) * 1274126177;
            h ^= h >> 16;
            return (h & 0x7fffffff) / (float)int.MaxValue;
        }
    }

    private void RenderFlame(AudioFeatures features, float timeSeconds)
    {
        float bass = Clamp01(features.Bass * 0.012f);
        float high = Clamp01(features.High * 0.003f);
        float beat = Clamp01(features.Beat);
        float level = Clamp01(features.Level * 3f);

        float aspect = _internalWidth / (float)_internalHeight;
        float flowSpeed = 0.65f + (bass * 1.8f);
        float turbulence = 1.2f + (high * 3.0f);
        float pulse = 0.2f + (beat * 0.8f);

        for (int y = 0; y < _internalHeight; y++)
        {
            float y01 = y / (float)(_internalHeight - 1);
            float fy = 1f - y01;

            for (int x = 0; x < _internalWidth; x++)
            {
                float x01 = x / (float)(_internalWidth - 1);
                float fx = (x01 * 2f - 1f) * aspect;

                float t = timeSeconds * flowSpeed;
                float n1 = MathF.Sin((fx * 6.0f) + (fy * 7.5f) - t * 5.0f);
                float n2 = MathF.Sin((fx * 12.0f - t * 2.1f) + MathF.Cos(fy * 10.0f + t * 3.3f));
                float n3 = MathF.Sin((fx * 22.0f + t * 1.4f) + MathF.Sin(fy * 18.0f - t * 2.7f));
                float noise = ((n1 * 0.55f) + (n2 * 0.30f) + (n3 * 0.15f)) * turbulence;
                noise = noise * 0.5f + 0.5f;

                float cone = 1f - MathF.Abs(fx) * (0.55f + fy * 0.65f);
                cone = Clamp01(cone);

                float baseIntensity = MathF.Pow(fy, 1.8f);
                float flame = Clamp01(baseIntensity * cone * (0.6f + noise * 0.9f + pulse * 0.25f));
                flame *= 0.65f + level * 0.75f;

                float ember = MathF.Sin((fx * 45f) + (fy * 14f) - t * 18f);
                float sparks = ember > 0.985f ? 0.35f + beat * 0.45f : 0f;

                float r = Clamp01(flame * 2.1f + sparks);
                float g = Clamp01(MathF.Pow(flame, 1.35f) * (0.95f + high * 0.45f) + sparks * 0.7f);
                float b = Clamp01(MathF.Pow(flame, 3.2f) * (0.25f + beat * 0.25f));

                _pixelBuffer[(y * _internalWidth) + x] = new Color(r, g, b, 1f);
            }
        }
    }

    private void RenderPlasma(AudioFeatures features, float timeSeconds)
    {
        float bass = Clamp01(features.Bass * 0.01f);
        float mid = Clamp01(features.Mid * 0.003f);
        float high = Clamp01(features.High * 0.003f);
        float beat = Clamp01(features.Beat);
        float level = Clamp01(features.Level * 3f);

        float aspect = _internalWidth / (float)_internalHeight;
        float speed = 0.8f + bass * 1.6f;

        for (int y = 0; y < _internalHeight; y++)
        {
            float py = (y / (float)_internalHeight) * 2f - 1f;
            for (int x = 0; x < _internalWidth; x++)
            {
                float px = ((x / (float)_internalWidth) * 2f - 1f) * aspect;
                float t = timeSeconds * speed;

                float v1 = MathF.Sin((px * 4.5f) + t * 1.9f);
                float v2 = MathF.Sin((py * 5.0f) - t * 1.3f);
                float v3 = MathF.Sin((px + py) * 4.0f + t * (2.2f + mid * 2f));
                float v4 = MathF.Sin(MathF.Sqrt(px * px + py * py) * 10f - t * (3f + high * 3f));
                float plasma = (v1 + v2 + v3 + v4) * 0.25f;
                float p = plasma * 0.5f + 0.5f;

                float pulse = beat * 0.35f;
                float spec = GetSpectrumSample(features, (x * 0.08f) + (y * 0.03f));

                float r = Clamp01((0.35f + 0.65f * MathF.Sin((p + pulse) * 6.28f)) * (0.6f + level * 0.6f));
                float g = Clamp01((0.35f + 0.65f * MathF.Sin((p + 0.33f) * 6.28f + spec * 2f)) * (0.55f + mid * 0.8f));
                float b = Clamp01((0.35f + 0.65f * MathF.Sin((p + 0.66f) * 6.28f + spec * 3f)) * (0.55f + high * 0.9f + pulse));

                _pixelBuffer[(y * _internalWidth) + x] = new Color(r, g, b, 1f);
            }
        }
    }

    private void RenderNebula(AudioFeatures features, float timeSeconds)
    {
        float bass = Clamp01(features.Bass * 0.01f);
        float mid = Clamp01(features.Mid * 0.003f);
        float high = Clamp01(features.High * 0.003f);
        float beat = Clamp01(features.Beat);
        float level = Clamp01(features.Level * 3f);

        float aspect = _internalWidth / (float)_internalHeight;
        float zoom = 1.6f - bass * 0.5f;
        float driftX = MathF.Sin(timeSeconds * (0.16f + mid * 0.4f)) * 0.45f;
        float driftY = MathF.Cos(timeSeconds * (0.12f + high * 0.5f)) * 0.45f;

        for (int y = 0; y < _internalHeight; y++)
        {
            float py = ((y / (float)_internalHeight) * 2f - 1f) * zoom;
            for (int x = 0; x < _internalWidth; x++)
            {
                float px = (((x / (float)_internalWidth) * 2f - 1f) * aspect) * zoom;
                float fx = px + driftX;
                float fy = py + driftY;

                float density = 0f;
                float amp = 0.55f;
                float freq = 1.1f;
                for (int o = 0; o < 5; o++)
                {
                    float n = MathF.Sin((fx * freq + timeSeconds * 0.15f) * 2.1f)
                            * MathF.Cos((fy * freq - timeSeconds * 0.19f) * 2.3f);
                    density += (n * 0.5f + 0.5f) * amp;
                    freq *= 1.9f;
                    amp *= 0.55f;
                }

                float rad = MathF.Sqrt(fx * fx + fy * fy);
                float core = MathF.Exp(-rad * (1.6f + bass * 1.2f));
                float stars = GetSpectrumSample(features, rad * 24f + timeSeconds * 8f);
                float pulse = beat * 0.45f;

                float cloud = Clamp01(density * (0.6f + level * 0.5f));
                float r = Clamp01(cloud * (0.25f + mid * 0.8f) + core * (0.8f + pulse));
                float g = Clamp01(cloud * (0.35f + high * 0.9f) + core * 0.55f + stars * 0.35f);
                float b = Clamp01(cloud * (0.55f + bass * 0.8f) + core * 0.75f + stars * 0.5f + pulse * 0.2f);

                _pixelBuffer[(y * _internalWidth) + x] = new Color(r, g, b, 1f);
            }
        }
    }

    private void RenderFlameGrill(AudioFeatures features, float timeSeconds)
    {
        float level = Clamp01(features.Level * 3f);
        float bass = Clamp01(features.Bass * 0.012f);
        float high = Clamp01(features.High * 0.003f);
        float beat = Clamp01(features.Beat);

        float intensity = Clamp01(0.25f + level * 0.45f + bass * 0.35f + beat * 0.35f);
        float flameHeight = 0.22f + intensity * 0.68f;
        float flickerSpeed = 2.2f + bass * 4.0f;
        int grillTop = (int)(_internalHeight * 0.86f);
        float barSpacing = 14f;
        float barThickness = 3.5f;

        for (int y = 0; y < _internalHeight; y++)
        {
            float y01 = y / (float)(_internalHeight - 1);
            float fromBottom = 1f - y01;

            for (int x = 0; x < _internalWidth; x++)
            {
                int idx = (y * _internalWidth) + x;

                float x01 = x / (float)(_internalWidth - 1);
                float wave1 = MathF.Sin((x01 * 18f) + timeSeconds * flickerSpeed);
                float wave2 = MathF.Sin((x01 * 36f) - timeSeconds * (flickerSpeed * 0.65f));
                float wave3 = MathF.Sin((x01 * 72f) + timeSeconds * (flickerSpeed * 1.35f));
                float turbulence = (wave1 * 0.45f + wave2 * 0.35f + wave3 * 0.20f) * (0.22f + high * 0.55f);

                float localHeight = flameHeight + turbulence;
                float flameMask = Clamp01((fromBottom - 0.02f) / MathF.Max(0.05f, localHeight));
                float taper = Clamp01(1f - MathF.Pow(fromBottom / MathF.Max(0.05f, localHeight), 1.35f));
                float flameCore = flameMask * taper;

                float tongues = MathF.Sin((x01 * 110f) + timeSeconds * (6f + high * 8f) - fromBottom * 22f);
                float tongueMask = Clamp01(tongues * 0.5f + 0.5f);
                float flame = flameCore * (0.72f + tongueMask * 0.45f);
                flame *= 0.65f + intensity * 0.7f;

                float emberNoise = MathF.Sin((x01 * 180f) + (fromBottom * 90f) - timeSeconds * 18f);
                float sparks = emberNoise > 0.992f && fromBottom < localHeight ? 0.55f + beat * 0.35f : 0f;

                float r = Clamp01(flame * 2.4f + sparks);
                float g = Clamp01(MathF.Pow(flame, 1.4f) * (1.05f + high * 0.35f) + sparks * 0.55f);
                float b = Clamp01(MathF.Pow(flame, 3.1f) * (0.22f + beat * 0.18f));

                if (y >= grillTop)
                {
                    float line = MathF.Abs(((x % barSpacing) - barSpacing * 0.5f));
                    float barMask = Clamp01(1f - (line / barThickness));
                    float hot = 0.25f + intensity * 0.55f;
                    float metal = 0.08f;
                    float grillR = Clamp01(metal + barMask * hot);
                    float grillG = Clamp01(metal * 0.7f + barMask * hot * 0.45f);
                    float grillB = Clamp01(metal * 0.6f + barMask * hot * 0.18f);

                    r = MathF.Max(r * 0.45f, grillR);
                    g = MathF.Max(g * 0.45f, grillG);
                    b = MathF.Max(b * 0.45f, grillB);
                }

                _pixelBuffer[idx] = new Color(r, g, b, 1f);
            }
        }
    }

    private void RenderFloatingNotes(AudioFeatures features, float timeSeconds)
    {
        float level = Clamp01(features.Level * 3f);
        float bass = Clamp01(features.Bass * 0.012f);
        float high = Clamp01(features.High * 0.003f);
        float beat = Clamp01(features.Beat);
        float intensity = Clamp01(level * 0.6f + bass * 0.25f + beat * 0.35f);

        for (int y = 0; y < _internalHeight; y++)
        {
            float t = y / (float)(_internalHeight - 1);
            float r = 0.03f + 0.08f * (1f - t);
            float g = 0.02f + 0.05f * (1f - t);
            float b = 0.08f + 0.20f * (1f - t);
            Color bg = new(r, g, b, 1f);
            int row = y * _internalWidth;
            for (int x = 0; x < _internalWidth; x++)
            {
                _pixelBuffer[row + x] = bg;
            }
        }

        float spawnRate = (0.08f + intensity * 1.8f + high * 0.7f) * _runtimePerformanceScale;
        _noteSpawnAccumulator += spawnRate;
        while (_noteSpawnAccumulator >= 1f)
        {
            SpawnNote(intensity);
            _noteSpawnAccumulator -= 1f;
        }

        for (int i = _notes.Count - 1; i >= 0; i--)
        {
            NoteParticle note = _notes[i];
            note.Y += note.Vy;
            note.X += note.Vx + MathF.Sin(timeSeconds * 2.8f + note.Phase) * 0.0012f;
            note.Life -= 0.012f + (1f - intensity) * 0.004f;

            if (note.Life <= 0f || note.Y < -0.12f || note.X < -0.2f || note.X > 1.2f)
            {
                _notes.RemoveAt(i);
                continue;
            }

            _notes[i] = note;
            DrawNote(note);
        }
    }

    private void RenderFireworks(AudioFeatures features, float timeSeconds)
    {
        float level = Clamp01(features.Level * 3f);
        float bass = Clamp01(features.Bass * 0.012f);
        float high = Clamp01(features.High * 0.003f);
        float beat = Clamp01(features.Beat);
        float intensity = Clamp01(level * 0.55f + bass * 0.30f + beat * 0.45f);

        for (int y = 0; y < _internalHeight; y++)
        {
            float t = y / (float)(_internalHeight - 1);
            float r = 0.01f + 0.05f * (1f - t);
            float g = 0.01f + 0.04f * (1f - t);
            float b = 0.04f + 0.16f * (1f - t);
            Color bg = new(r, g, b, 1f);
            int row = y * _internalWidth;
            for (int x = 0; x < _internalWidth; x++)
            {
                _pixelBuffer[row + x] = bg;
            }
        }

        float spawnRate = (0.02f + intensity * 0.45f + high * 0.15f) * _runtimePerformanceScale;
        _fireworkSpawnAccumulator += spawnRate;
        while (_fireworkSpawnAccumulator >= 1f)
        {
            SpawnFireworkRocket(intensity);
            _fireworkSpawnAccumulator -= 1f;
        }

        for (int i = _fireworkRockets.Count - 1; i >= 0; i--)
        {
            FireworkRocket rocket = _fireworkRockets[i];
            rocket.Y += rocket.Vy;
            rocket.X += rocket.Vx;
            rocket.Age += 0.016f;

            DrawFilledCircle(
                (int)(rocket.X * _internalWidth),
                (int)(rocket.Y * _internalHeight),
                1 + (int)(rocket.Size * 0.6f),
                rocket.Color,
                0.95f);

            bool explode = rocket.Y <= rocket.TargetY || rocket.Age >= rocket.MaxAge;
            if (explode)
            {
                ExplodeFirework(rocket, intensity);
                _fireworkRockets.RemoveAt(i);
            }
            else
            {
                _fireworkRockets[i] = rocket;
            }
        }

        for (int i = _fireworkSparks.Count - 1; i >= 0; i--)
        {
            FireworkSpark spark = _fireworkSparks[i];
            spark.X += spark.Vx;
            spark.Y += spark.Vy;
            spark.Vy += 0.00022f;
            spark.Vx *= 0.995f;
            spark.Life -= 0.012f;

            if (spark.Life <= 0f || spark.Y > 1.1f || spark.X < -0.2f || spark.X > 1.2f)
            {
                _fireworkSparks.RemoveAt(i);
                continue;
            }

            _fireworkSparks[i] = spark;
            int sx = (int)(spark.X * _internalWidth);
            int sy = (int)(spark.Y * _internalHeight);
            DrawFilledCircle(sx, sy, spark.Size, spark.Color, spark.Life);
        }
    }

    private void RenderEqualizerCity(AudioFeatures features, float timeSeconds)
    {
        for (int y = 0; y < _internalHeight; y++)
        {
            float t = y / (float)(_internalHeight - 1);
            Color bg = new(0.01f, 0.02f + 0.08f * (1f - t), 0.08f + 0.18f * (1f - t), 1f);
            int row = y * _internalWidth;
            for (int x = 0; x < _internalWidth; x++)
            {
                _pixelBuffer[row + x] = bg;
            }
        }

        int buildings = 48;
        float beat = Clamp01(features.Beat);
        for (int i = 0; i < buildings; i++)
        {
            float bin = GetSpectrumSample(features, i * (64f / buildings));
            int bw = Math.Max(2, _internalWidth / buildings);
            int x0 = i * bw;
            int h = (int)((_internalHeight * 0.15f) + bin * _internalHeight * 0.75f);
            int y0 = _internalHeight - h;
            Vector3 c = new(0.08f + bin * 0.9f, 0.2f + bin * 0.6f + beat * 0.2f, 0.4f + bin * 0.5f);
            DrawRect(x0, y0, bw - 1, h, c, 0.95f);

            for (int wy = y0 + 4; wy < _internalHeight - 2; wy += 6)
            {
                for (int wx = x0 + 1; wx < x0 + bw - 1; wx += 4)
                {
                    if (Hash01(wx, wy, i) > 0.55f - beat * 0.25f)
                    {
                        DrawRect(wx, wy, 2, 2, new Vector3(1f, 0.85f, 0.4f), 0.75f);
                    }
                }
            }
        }
    }

    private void RenderLiquidMetaballs(AudioFeatures features, float timeSeconds)
    {
        float bass = Clamp01(features.Bass * 0.012f);
        float high = Clamp01(features.High * 0.003f);
        for (int y = 0; y < _internalHeight; y++)
        {
            float py = y / (float)_internalHeight;
            for (int x = 0; x < _internalWidth; x++)
            {
                float px = x / (float)_internalWidth;
                float field = 0f;
                for (int i = 0; i < 6; i++)
                {
                    float ax = 0.5f + MathF.Sin(timeSeconds * (0.4f + i * 0.13f) + i) * (0.2f + bass * 0.1f);
                    float ay = 0.5f + MathF.Cos(timeSeconds * (0.35f + i * 0.11f) + i * 1.7f) * (0.25f + bass * 0.12f);
                    float dx = px - ax;
                    float dy = py - ay;
                    field += 0.02f / (dx * dx + dy * dy + 0.002f);
                }

                float m = Clamp01((field - 0.35f) * 0.8f);
                float edge = Clamp01((field - 0.5f) * 2.5f);
                float r = Clamp01(m * 0.2f + edge * (0.5f + high));
                float g = Clamp01(m * 0.45f + edge * 0.3f);
                float b = Clamp01(m * 0.75f + edge * (0.2f + high));
                _pixelBuffer[y * _internalWidth + x] = new Color(r, g, b, 1f);
            }
        }
    }

    private void RenderParticleGalaxy(AudioFeatures features, float timeSeconds)
    {
        for (int i = 0; i < _pixelBuffer.Length; i++)
        {
            _pixelBuffer[i] = new Color(0.01f, 0.01f, 0.04f, 1f);
        }

        float beat = Clamp01(features.Beat);
        int particles = ScaleCount(2200, 600);
        float arms = 4f + Clamp01(features.Mid * 0.002f) * 3f;
        for (int i = 0; i < particles; i++)
        {
            float fi = i / (float)particles;
            float radius = MathF.Pow(fi, 0.65f) * 0.48f * (1f + beat * 0.2f);
            float arm = (i % (int)arms) / arms;
            float angle = arm * MathF.Tau + radius * 14f + timeSeconds * (0.15f + beat * 0.8f);
            float x = 0.5f + MathF.Cos(angle) * radius;
            float y = 0.5f + MathF.Sin(angle) * radius;
            int px = (int)(x * _internalWidth);
            int py = (int)(y * _internalHeight);
            if (px < 0 || py < 0 || px >= _internalWidth || py >= _internalHeight)
            {
                continue;
            }

            float hue = fi * 0.7f + beat * 0.2f;
            Vector3 c = new(
                0.5f + 0.5f * MathF.Sin(hue * 6.28f),
                0.5f + 0.5f * MathF.Sin(hue * 6.28f + 2.1f),
                0.5f + 0.5f * MathF.Sin(hue * 6.28f + 4.2f));
            DrawFilledCircle(px, py, 1, c, 0.85f);
        }

        DrawFilledCircle(_internalWidth / 2, _internalHeight / 2, 6, new Vector3(1f, 0.9f, 0.7f), 0.9f);
    }

    private void RenderAuroraCurtains(AudioFeatures features, float timeSeconds)
    {
        float mid = Clamp01(features.Mid * 0.003f);
        float high = Clamp01(features.High * 0.003f);
        for (int y = 0; y < _internalHeight; y++)
        {
            float ny = y / (float)(_internalHeight - 1);
            for (int x = 0; x < _internalWidth; x++)
            {
                float nx = x / (float)(_internalWidth - 1);
                float wave = MathF.Sin(nx * 8f + timeSeconds * (0.3f + mid * 1.2f) + MathF.Sin(nx * 3f + timeSeconds));
                float layer = MathF.Exp(-MathF.Abs(ny - (0.35f + wave * 0.18f)) * (6f + high * 12f));
                float layer2 = MathF.Exp(-MathF.Abs(ny - (0.55f + MathF.Sin(nx * 5f - timeSeconds * 0.4f) * 0.12f)) * 9f);
                float a = Clamp01(layer + layer2 * 0.7f);
                float r = a * 0.15f;
                float g = a * (0.6f + high * 0.5f);
                float b = a * (0.45f + mid * 0.5f);
                _pixelBuffer[y * _internalWidth + x] = new Color(r, g, b, 1f);
            }
        }
    }

    private void RenderVortexPortal(AudioFeatures features, float timeSeconds)
    {
        float bass = Clamp01(features.Bass * 0.012f);
        float aspect = _internalWidth / (float)_internalHeight;
        for (int y = 0; y < _internalHeight; y++)
        {
            float py = (y / (float)_internalHeight) * 2f - 1f;
            for (int x = 0; x < _internalWidth; x++)
            {
                float px = ((x / (float)_internalWidth) * 2f - 1f) * aspect;
                float r = MathF.Sqrt(px * px + py * py) + 1e-5f;
                float a = MathF.Atan2(py, px) + timeSeconds * (0.5f + bass * 2f);
                float spiral = MathF.Sin(14f * r - a * 5f - timeSeconds * 3f);
                float glow = MathF.Exp(-r * (2.5f - bass));
                float v = Clamp01((spiral * 0.5f + 0.5f) * glow * 2f);
                _pixelBuffer[y * _internalWidth + x] = new Color(v * 0.7f, v * 0.4f, v, 1f);
            }
        }
    }

    private void RenderLaserGrid(AudioFeatures features, float timeSeconds)
    {
        float beat = Clamp01(features.Beat);
        float bass = Clamp01(features.Bass * 0.012f);
        for (int y = 0; y < _internalHeight; y++)
        {
            float fy = y / (float)(_internalHeight - 1);
            for (int x = 0; x < _internalWidth; x++)
            {
                float fx = x / (float)(_internalWidth - 1);
                float perspective = 1f / (0.2f + fy * (1.8f - bass * 0.6f));
                float gx = MathF.Abs(((fx * perspective * 20f + timeSeconds) % 1f) - 0.5f);
                float gy = MathF.Abs(((fy * perspective * 20f) % 1f) - 0.5f);
                float line = Clamp01(0.08f / (gx + 0.02f) + 0.08f / (gy + 0.02f));
                float sweep = MathF.Exp(-MathF.Abs(fy - ((timeSeconds * 0.25f + beat * 0.2f) % 1f)) * 60f);
                float v = Clamp01(line * 0.6f + sweep);
                _pixelBuffer[y * _internalWidth + x] = new Color(v * 0.1f, v * 0.9f, v, 1f);
            }
        }
    }

    private void RenderRainRipple(AudioFeatures features, float timeSeconds)
    {
        float level = Clamp01(features.Level * 3f);
        float density = 70f + level * 220f;
        for (int y = 0; y < _internalHeight; y++)
        {
            for (int x = 0; x < _internalWidth; x++)
            {
                _pixelBuffer[y * _internalWidth + x] = new Color(0.02f, 0.04f, 0.08f, 1f);
            }
        }

        int drops = ScaleCount((int)density, 20);
        for (int i = 0; i < drops; i++)
        {
            float seed = i * 13.37f;
            float x = Frac(seed * 0.731f);
            float phase = Frac(seed * 0.379f + timeSeconds * (0.4f + level * 1.2f));
            float y = phase;
            int px = (int)(x * _internalWidth);
            int py = (int)(y * _internalHeight);
            DrawRect(px, py, 1, 6, new Vector3(0.6f, 0.8f, 1f), 0.7f);

            if (py > _internalHeight * 0.8f)
            {
                float rr = (phase - 0.8f) * 80f;
                DrawRing(px, (int)(_internalHeight * 0.82f), rr, new Vector3(0.7f, 0.9f, 1f), 0.35f);
            }
        }
    }

    private void RenderInkSmoke(AudioFeatures features, float timeSeconds)
    {
        float bass = Clamp01(features.Bass * 0.012f);
        float high = Clamp01(features.High * 0.003f);
        for (int y = 0; y < _internalHeight; y++)
        {
            float ny = y / (float)(_internalHeight - 1);
            for (int x = 0; x < _internalWidth; x++)
            {
                float nx = (x / (float)(_internalWidth - 1)) * 2f - 1f;
                float basePlume = MathF.Exp(-MathF.Abs(nx) * (2.5f - bass));
                float turbulence = MathF.Sin(nx * 12f + ny * 9f - timeSeconds * (1.5f + high * 5f))
                                 + MathF.Sin(nx * 21f - ny * 14f + timeSeconds * 2.2f);
                turbulence = turbulence * 0.25f + 0.5f;
                float rise = Clamp01((1f - ny) * (0.7f + bass * 0.7f));
                float d = Clamp01(basePlume * rise * turbulence);
                _pixelBuffer[y * _internalWidth + x] = new Color(d * 0.18f, d * 0.2f, d * 0.24f, 1f);
            }
        }
    }

    private void RenderMirrorMosaic(AudioFeatures features, float timeSeconds)
    {
        int tiles = 3 + (int)(Clamp01(features.Beat + features.Level * 2f) * 5f);
        float t = timeSeconds * 0.6f;
        for (int y = 0; y < _internalHeight; y++)
        {
            float v = y / (float)_internalHeight;
            for (int x = 0; x < _internalWidth; x++)
            {
                float u = x / (float)_internalWidth;
                float mu = Frac(u * tiles);
                float mv = Frac(v * tiles);
                if (((int)(u * tiles) & 1) == 1) mu = 1f - mu;
                if (((int)(v * tiles) & 1) == 1) mv = 1f - mv;
                float pattern = MathF.Sin((mu * 10f + t) * MathF.Tau) * MathF.Cos((mv * 10f - t) * MathF.Tau);
                float p = pattern * 0.5f + 0.5f;
                _pixelBuffer[y * _internalWidth + x] = new Color(
                    Clamp01(0.2f + p * 0.9f),
                    Clamp01(0.2f + (1f - p) * 0.8f),
                    Clamp01(0.35f + p * 0.7f),
                    1f);
            }
        }
    }

    private void RenderWaveformRibbon(AudioFeatures features, float timeSeconds)
    {
        for (int i = 0; i < _pixelBuffer.Length; i++)
        {
            _pixelBuffer[i] = new Color(0.01f, 0.01f, 0.03f, 1f);
        }

        if (features.Spectrum is null || features.Spectrum.Length == 0)
        {
            return;
        }

        int points = _internalWidth;
        float beat = Clamp01(features.Beat);
        for (int x = 0; x < points; x++)
        {
            float tx = x / (float)(points - 1);
            float idx = tx * (features.Spectrum.Length - 1);
            int i0 = (int)idx;
            int i1 = Math.Min(features.Spectrum.Length - 1, i0 + 1);
            float f = idx - i0;
            float amp = (features.Spectrum[i0] + (features.Spectrum[i1] - features.Spectrum[i0]) * f) * 0.18f;
            amp = Clamp01(amp);
            float center = 0.5f + MathF.Sin(tx * 8f + timeSeconds * 0.9f) * 0.08f;
            float yNorm = center - amp * (0.35f + beat * 0.2f);
            int y = (int)(yNorm * _internalHeight);
            int thickness = 2 + (int)(amp * 9f);
            for (int k = -thickness; k <= thickness; k++)
            {
                int yy = y + k;
                if (yy < 0 || yy >= _internalHeight)
                {
                    continue;
                }

                float w = 1f - MathF.Abs(k) / (float)(thickness + 1);
                Vector3 c = new(0.2f + amp * 1.0f, 0.3f + w * 0.7f, 0.7f + beat * 0.3f);
                BlendPixel(x, yy, c, w * 0.8f);
            }
        }
    }

    private void RenderGrainBars(AudioFeatures features, float timeSeconds)
    {
        float bass = Clamp01(features.Bass * 0.012f);
        float mid = Clamp01(features.Mid * 0.0035f);
        float high = Clamp01(features.High * 0.0035f);
        float beat = Clamp01(features.Beat);
        float level = Clamp01(features.Level * 3f);

        for (int y = 0; y < _internalHeight; y++)
        {
            float t = y / (float)(_internalHeight - 1);
            Color bg = new(0.015f, 0.02f + 0.04f * (1f - t), 0.03f + 0.07f * (1f - t), 1f);
            int row = y * _internalWidth;
            for (int x = 0; x < _internalWidth; x++)
            {
                _pixelBuffer[row + x] = bg;
            }
        }

        int totalBars = ScaleCount(Math.Max(120, _internalWidth / 2), 60);
        float bandWidth = _internalWidth / 3f;
        float maxHeight = _internalHeight * (0.22f + 0.62f * (0.35f + level * 0.65f));

        for (int i = 0; i < totalBars; i++)
        {
            float xNorm = i / (float)(totalBars - 1);
            int x = (int)(xNorm * (_internalWidth - 1));
            int region = x < bandWidth ? 0 : (x < bandWidth * 2f ? 1 : 2);

            float band = region switch
            {
                0 => bass,
                1 => mid,
                _ => high
            };

            float grain = Hash01(i, (int)(timeSeconds * 60f), region) * 2f - 1f;
            float wobble = MathF.Sin(timeSeconds * (6.0f + region * 2.0f) + i * 0.21f) * 0.22f;
            float spectrum = GetSpectrumSample(features, i * 0.43f + region * 7f) * 1.8f;

            float amp = Clamp01(band * 0.8f + spectrum * 0.45f + beat * 0.3f + grain * 0.13f + wobble * 0.1f);
            int h = Math.Max(2, (int)(amp * maxHeight));

            Vector3 color = region switch
            {
                0 => new Vector3(1f, 0.35f + amp * 0.4f, 0.2f),
                1 => new Vector3(0.2f, 0.9f, 0.35f + amp * 0.5f),
                _ => new Vector3(0.25f + amp * 0.4f, 0.5f, 1f)
            };

            int barW = 1;
            int y0 = _internalHeight - h;
            DrawRect(x, y0, barW, h, color, 0.95f);

            if (Hash01(i, region, (int)(timeSeconds * 100f)) > 0.68f)
            {
                int gritCount = 2 + (int)(amp * 8f);
                for (int g = 0; g < gritCount; g++)
                {
                    int gy = _internalHeight - 1 - (int)(Hash01(g, i, region) * h);
                    DrawRect(x, gy, 1, 1, Vector3.One, 0.3f + amp * 0.5f);
                }
            }
        }
    }

    private void SpawnFireworkRocket(float intensity)
    {
        if (_fireworkRockets.Count >= ScaleCount(42, 12))
        {
            return;
        }

        float x = 0.1f + (float)_rng.NextDouble() * 0.8f;
        float y = 1.02f;
        float vy = -(0.0065f + (float)_rng.NextDouble() * (0.0025f + intensity * 0.0025f));
        float vx = ((float)_rng.NextDouble() - 0.5f) * 0.0018f;
        float targetY = 0.2f + (float)_rng.NextDouble() * 0.42f;
        float maxAge = 0.7f + (float)_rng.NextDouble() * 0.45f;

        Vector3 color = new(
            0.55f + (float)_rng.NextDouble() * 0.45f,
            0.45f + (float)_rng.NextDouble() * 0.55f,
            0.45f + (float)_rng.NextDouble() * 0.55f);

        _fireworkRockets.Add(new FireworkRocket
        {
            X = x,
            Y = y,
            Vx = vx,
            Vy = vy,
            TargetY = targetY,
            Age = 0f,
            MaxAge = maxAge,
            Size = 1.4f + (float)_rng.NextDouble() * 1.4f,
            Color = color
        });
    }

    private void ExplodeFirework(FireworkRocket rocket, float intensity)
    {
        int count = ScaleCount(22 + (int)(intensity * 38f), 10);
        float speedBase = 0.0018f + intensity * 0.0034f;

        for (int i = 0; i < count; i++)
        {
            if (_fireworkSparks.Count >= ScaleCount(4500, 800))
            {
                break;
            }

            float a = (float)(i * (Math.PI * 2.0 / count));
            float speed = speedBase + (float)_rng.NextDouble() * speedBase;
            float vx = MathF.Cos(a) * speed;
            float vy = MathF.Sin(a) * speed;

            _fireworkSparks.Add(new FireworkSpark
            {
                X = rocket.X,
                Y = rocket.Y,
                Vx = vx,
                Vy = vy,
                Life = 0.65f + (float)_rng.NextDouble() * 0.35f,
                Size = 1 + _rng.Next(0, 2),
                Color = rocket.Color
            });
        }
    }

    private void SpawnNote(float intensity)
    {
        if (_notes.Count >= ScaleCount(320, 80))
        {
            return;
        }

        float x = 0.08f + (float)_rng.NextDouble() * 0.84f;
        float y = 0.94f + (float)_rng.NextDouble() * 0.08f;
        float vy = -(0.0025f + (float)_rng.NextDouble() * (0.0035f + intensity * 0.004f));
        float vx = ((float)_rng.NextDouble() - 0.5f) * (0.0018f + intensity * 0.0015f);
        float size = 0.75f + (float)_rng.NextDouble() * (1.6f + intensity * 1.2f);
        bool flagged = _rng.NextDouble() > 0.42;

        Vector3 color = new(
            0.7f + (float)_rng.NextDouble() * 0.3f,
            0.55f + (float)_rng.NextDouble() * 0.45f,
            0.4f + (float)_rng.NextDouble() * 0.6f);

        _notes.Add(new NoteParticle
        {
            X = x,
            Y = y,
            Vx = vx,
            Vy = vy,
            Life = 1f,
            Size = size,
            Phase = (float)_rng.NextDouble() * MathF.PI * 2f,
            Color = color,
            HasFlag = flagged
        });
    }

    private void DrawNote(NoteParticle note)
    {
        int px = (int)(note.X * _internalWidth);
        int py = (int)(note.Y * _internalHeight);
        int s = Math.Max(1, (int)MathF.Round(note.Size));

        float alpha = Clamp01(note.Life);
        Vector3 color = note.Color;

        int headX = px;
        int headY = py;
        DrawFilledCircle(headX, headY, s + 1, color, alpha * 0.75f);
        DrawFilledCircle(headX, headY, s, color, alpha);

        int stemHeight = 6 + s * 4;
        DrawRect(headX + s, headY - stemHeight, 2, stemHeight, color, alpha);

        if (note.HasFlag)
        {
            for (int i = 0; i < 6 + s; i++)
            {
                int fx = headX + s + 1 + i;
                int fy = headY - stemHeight + (int)(MathF.Sin(i * 0.55f) * (2f + s * 0.25f));
                DrawRect(fx, fy, 2, 2, color, alpha * 0.95f);
            }
        }
    }

    private void DrawFilledCircle(int cx, int cy, int radius, Vector3 color, float alpha)
    {
        int r2 = radius * radius;
        for (int oy = -radius; oy <= radius; oy++)
        {
            int yy = cy + oy;
            if (yy < 0 || yy >= _internalHeight)
            {
                continue;
            }

            int oy2 = oy * oy;
            for (int ox = -radius; ox <= radius; ox++)
            {
                if (ox * ox + oy2 > r2)
                {
                    continue;
                }

                int xx = cx + ox;
                if (xx < 0 || xx >= _internalWidth)
                {
                    continue;
                }

                BlendPixel(xx, yy, color, alpha);
            }
        }
    }

    private void DrawRect(int x, int y, int width, int height, Vector3 color, float alpha)
    {
        for (int yy = y; yy < y + height; yy++)
        {
            if (yy < 0 || yy >= _internalHeight)
            {
                continue;
            }

            for (int xx = x; xx < x + width; xx++)
            {
                if (xx < 0 || xx >= _internalWidth)
                {
                    continue;
                }

                BlendPixel(xx, yy, color, alpha);
            }
        }
    }

    private void DrawRing(int cx, int cy, float radius, Vector3 color, float alpha)
    {
        int r = Math.Max(1, (int)radius);
        int minX = Math.Max(0, cx - r - 1);
        int maxX = Math.Min(_internalWidth - 1, cx + r + 1);
        int minY = Math.Max(0, cy - r - 1);
        int maxY = Math.Min(_internalHeight - 1, cy + r + 1);
        float r0 = MathF.Max(0f, radius - 1.25f);
        float r1 = radius + 1.25f;
        float r0s = r0 * r0;
        float r1s = r1 * r1;

        for (int y = minY; y <= maxY; y++)
        {
            float dy = y - cy;
            for (int x = minX; x <= maxX; x++)
            {
                float dx = x - cx;
                float d2 = dx * dx + dy * dy;
                if (d2 < r0s || d2 > r1s)
                {
                    continue;
                }

                BlendPixel(x, y, color, alpha);
            }
        }
    }

    private void BlendPixel(int x, int y, Vector3 color, float alpha)
    {
        int idx = y * _internalWidth + x;
        Vector3 baseColor = _pixelBuffer[idx].ToVector3();
        Vector3 mixed = Vector3.Lerp(baseColor, color, Clamp01(alpha));
        _pixelBuffer[idx] = new Color(Clamp01(mixed.X), Clamp01(mixed.Y), Clamp01(mixed.Z), 1f);
    }

    private void RenderJulia(AudioFeatures features, float timeSeconds)
    {
        float level = Clamp01(features.Level * 3f);
        float bass = Clamp01(features.Bass * 0.015f);
        float mid = Clamp01(features.Mid * 0.004f);
        float high = Clamp01(features.High * 0.003f);
        float beat = Clamp01(features.Beat);

        float zoom = 1.1f - (bass * 0.45f) - (beat * 0.15f);
        if (zoom < 0.45f)
        {
            zoom = 0.45f;
        }

        float cRe = -0.8f + (mid * 1.6f) + (MathF.Sin(timeSeconds * 0.31f) * 0.06f);
        float cIm = 0.156f + ((high - 0.5f) * 1.0f) + (MathF.Cos(timeSeconds * 0.23f) * 0.04f);

        int maxIterations = 42 + (int)(level * 54f);
        float aspect = _internalWidth / (float)_internalHeight;

        for (int y = 0; y < _internalHeight; y++)
        {
            float ny = ((y / (float)_internalHeight) * 2f - 1f) * zoom;
            for (int x = 0; x < _internalWidth; x++)
            {
                float nx = (((x / (float)_internalWidth) * 2f - 1f) * aspect) * zoom;

                float zr = nx;
                float zi = ny;
                int iter = 0;
                while (iter < maxIterations)
                {
                    float zr2 = zr * zr;
                    float zi2 = zi * zi;
                    if (zr2 + zi2 > 4f)
                    {
                        break;
                    }

                    zi = (2f * zr * zi) + cIm;
                    zr = zr2 - zi2 + cRe;
                    iter++;
                }

                float t = iter / (float)maxIterations;
                float pulse = beat * 0.35f;

                float r = MathF.Pow(t, 0.65f) * (0.35f + high * 1.2f + pulse);
                float g = MathF.Pow(t, 1.2f) * (0.28f + mid * 1.1f);
                float b = MathF.Pow(t, 0.85f) * (0.45f + bass * 1.5f + pulse);

                _pixelBuffer[(y * _internalWidth) + x] = new Color(
                    Clamp01(r),
                    Clamp01(g),
                    Clamp01(b),
                    1f);
            }
        }
    }

    private static float Clamp01(float value)
    {
        if (value < 0f)
        {
            return 0f;
        }

        if (value > 1f)
        {
            return 1f;
        }

        return value;
    }

    private void ThrowIfDisposed()
    {
        if (_disposed)
        {
            throw new ObjectDisposedException(nameof(FractalRenderer));
        }
    }

    public void Dispose()
    {
        if (_disposed)
        {
            return;
        }

        _fractalTexture.Dispose();
        _spriteBatch.Dispose();
        _disposed = true;
    }

    private struct NoteParticle
    {
        public float X;
        public float Y;
        public float Vx;
        public float Vy;
        public float Life;
        public float Size;
        public float Phase;
        public Vector3 Color;
        public bool HasFlag;
    }

    private struct FireworkRocket
    {
        public float X;
        public float Y;
        public float Vx;
        public float Vy;
        public float TargetY;
        public float Age;
        public float MaxAge;
        public float Size;
        public Vector3 Color;
    }

    private struct FireworkSpark
    {
        public float X;
        public float Y;
        public float Vx;
        public float Vy;
        public float Life;
        public int Size;
        public Vector3 Color;
    }
}