feat: add particles

config/config.go

@@ -29,6 +29,12 @@ type ConfigS struct {
 	LineBrightness                   float64
 	LineThickness                    float32
 	LineInvSqrtOpacityControl        bool
+	Particles                        bool
+	ParticleGenPerFrameEveryXSamples int
+	ParticleMaxCount                 int
+	ParticleMinSize                  float32
+	ParticleMaxSize                  float32
+	ParticleAcceleration             float32
 }
 
 var DefaultConfig = ConfigS{
@@ -47,6 +53,12 @@ var DefaultConfig = ConfigS{
 	LineBrightness:                   1,
 	LineThickness:                    3,
 	LineInvSqrtOpacityControl:        false,
+	Particles:                        true,
+	ParticleGenPerFrameEveryXSamples: 9600,
+	ParticleMaxCount:                 3000,
+	ParticleMinSize:                  0.2,
+	ParticleMaxSize:                  2.0,
+	ParticleAcceleration:             0.01,
 }
 
 var Config ConfigS

go.mod

@@ -3,6 +3,7 @@ module xyosc
 go 1.23.2
 
 require (
+	github.com/chewxy/math32 v1.11.1
 	github.com/flopp/go-findfont v0.1.0
 	github.com/fsnotify/fsnotify v1.8.0
 	github.com/gen2brain/malgo v0.11.22

go.sum

@@ -1,3 +1,5 @@
+github.com/chewxy/math32 v1.11.1 h1:b7PGHlp8KjylDoU8RrcEsRuGZhJuz8haxnKfuMMRqy8=
+github.com/chewxy/math32 v1.11.1/go.mod h1:dOB2rcuFrCn6UHrze36WSLVPKtzPMRAQvBvUwkSsLqs=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/ebitengine/gomobile v0.0.0-20240911145611-4856209ac325 h1:Gk1XUEttOk0/hb6Tq3WkmutWa0ZLhNn/6fc6XZpM7tM=

main.go

@@ -5,15 +5,18 @@ import (
 	"image"
 	"image/color"
 	"log"
+	"math/rand/v2"
 	"xyosc/audio"
 	"xyosc/config"
 	"xyosc/fastsqrt"
 	"xyosc/fonts"
 	"xyosc/icons"
 	"xyosc/media"
+	"xyosc/particles"
 
 	"fmt"
 
+	"github.com/chewxy/math32"
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
 	"github.com/hajimehoshi/ebiten/v2/text/v2"
@@ -35,6 +38,7 @@ func (g *Game) Draw(screen *ebiten.Image) {
 	var BY float32
 	binary.Read(audio.SampleRingBuffer, binary.NativeEndian, &AX)
 	binary.Read(audio.SampleRingBuffer, binary.NativeEndian, &AY)
+	S := float32(0)
 	for i := uint32(0); i < config.Config.ReadBufferSize/audio.SampleSizeInBytes/2; i++ {
 		binary.Read(audio.SampleRingBuffer, binary.NativeEndian, &BX)
 		binary.Read(audio.SampleRingBuffer, binary.NativeEndian, &BY)
@@ -43,17 +47,41 @@ func (g *Game) Draw(screen *ebiten.Image) {
 		fBX := float32(BX) * config.Config.Gain * float32(scale)
 		fBY := -float32(BY) * config.Config.Gain * float32(scale)
 		if config.Config.LineInvSqrtOpacityControl {
-
 			inv := fastsqrt.FastInvSqrt32((fBX-fAX)*(fBX-fAX) + (fBY-fBY)*(fBY-fBY))
 			colorAdjusted := color.RGBA{config.ThirdColor.R, config.ThirdColor.G, config.ThirdColor.B, uint8(float32(config.Config.LineOpacity) * inv)}
-			vector.StrokeLine(screen, float32(config.Config.WindowWidth/2)+fAX, float32(config.Config.WindowWidth/2)+fAY, float32(config.Config.WindowWidth/2)+fBX, float32(config.Config.WindowWidth/2)+fBY, config.Config.LineThickness, colorAdjusted, true)
+			vector.StrokeLine(screen, float32(config.Config.WindowWidth/2)+fAX, float32(config.Config.WindowHeight/2)+fAY, float32(config.Config.WindowWidth/2)+fBX, float32(config.Config.WindowHeight/2)+fBY, config.Config.LineThickness, colorAdjusted, true)
 		} else {
-			vector.StrokeLine(screen, float32(config.Config.WindowWidth/2)+fAX, float32(config.Config.WindowWidth/2)+fAY, float32(config.Config.WindowWidth/2)+fBX, float32(config.Config.WindowWidth/2)+fBY, config.Config.LineThickness, config.ThirdColorAdj, true)
+			vector.StrokeLine(screen, float32(config.Config.WindowWidth/2)+fAX, float32(config.Config.WindowHeight/2)+fAY, float32(config.Config.WindowWidth/2)+fBX, float32(config.Config.WindowHeight/2)+fBY, config.Config.LineThickness, config.ThirdColorAdj, true)
-
 		}
+		S += float32(AX)*float32(AX) + float32(AY)*float32(AY)
+		if config.Config.Particles {
+			if rand.IntN(config.Config.ParticleGenPerFrameEveryXSamples) == 0 {
+				if len(particles.Particles) >= config.Config.ParticleMaxCount {
+					particles.Particles = particles.Particles[1:]
+				}
+				particles.Particles = append(particles.Particles, particles.Particle{
+					X:    float32(AX) * config.Config.Gain,
+					Y:    float32(AY) * config.Config.Gain,
+					VX:   0,
+					VY:   0,
+					Size: rand.Float32()*(config.Config.ParticleMaxSize-config.Config.ParticleMinSize) + config.Config.ParticleMinSize,
+				})
+			}
+		}
+
 		AX = BX
 		AY = BY
 	}
+
+	for i, particle := range particles.Particles {
+		vector.DrawFilledCircle(screen, float32(config.Config.WindowWidth/2)+particle.X*float32(scale), float32(config.Config.WindowHeight/2)+particle.Y*float32(scale), particle.Size, config.ThirdColor, true)
+		norm := math32.Sqrt(particles.Particles[i].X*particles.Particles[i].X + particles.Particles[i].Y*particles.Particles[i].Y)
+		particles.Particles[i].X += particle.VX / float32(ebiten.ActualTPS())
+		particles.Particles[i].Y += particle.VY / float32(ebiten.ActualTPS())
+		particles.Particles[i].VX += config.Config.ParticleAcceleration * particle.X / norm * S / float32(ebiten.ActualTPS())
+		particles.Particles[i].VY += config.Config.ParticleAcceleration * particle.Y / norm * S / float32(ebiten.ActualTPS())
+	}
+
 	//audio.SampleRingBuffer.Reset()
 	if config.Config.FPSCounter {
 		ebitenutil.DebugPrint(screen, fmt.Sprintf("TPS: %0.2f", ebiten.ActualTPS()))

particles/particles.go

@@ -0,0 +1,11 @@
+package particles
+
+type Particle struct {
+	X    float32
+	Y    float32
+	VX   float32
+	VY   float32
+	Size float32
+}
+
+var Particles = []Particle{}