added flicker CRT effect, including preferences

gui/crt/preferences.go

@@ -33,6 +33,7 @@ type Preferences struct {
 	Scanlines      prefs.Bool
 	Interference   prefs.Bool
 	Noise          prefs.Bool
+	Flicker        prefs.Bool
 	Fringing       prefs.Bool
 	Ghosting       prefs.Bool
 	Phosphor       prefs.Bool
@@ -45,6 +46,7 @@ type Preferences struct {
 	ScanlinesFine        prefs.Float
 	InterferenceLevel    prefs.Float
 	NoiseLevel           prefs.Float
+	FlickerLevel         prefs.Float
 	FringingAmount       prefs.Float
 	GhostingAmount       prefs.Float
 	PhosphorLatency      prefs.Float
@@ -75,6 +77,7 @@ const (
 	scanlines            = true
 	interference         = true
 	noise                = true
+	flicker              = false
 	fringing             = true
 	ghosting             = true
 	phosphor             = true
@@ -86,6 +89,7 @@ const (
 	scanlinesFine        = 1.80
 	interferenceLevel    = 0.15
 	noiseLevel           = 0.19
+	flickerLevel         = 0.025
 	fringingAmount       = 0.15
 	ghostingAmount       = 2.9
 	phosphorLatency      = 0.5
@@ -150,6 +154,10 @@ func NewPreferences() (*Preferences, error) {
 	if err != nil {
 		return nil, err
 	}
+	err = p.dsk.Add("crt.flicker", &p.Flicker)
+	if err != nil {
+		return nil, err
+	}
 	err = p.dsk.Add("crt.fringing", &p.Fringing)
 	if err != nil {
 		return nil, err
@@ -194,6 +202,10 @@ func NewPreferences() (*Preferences, error) {
 	if err != nil {
 		return nil, err
 	}
+	err = p.dsk.Add("crt.flickerLevel", &p.FlickerLevel)
+	if err != nil {
+		return nil, err
+	}
 	err = p.dsk.Add("crt.fringingAmount", &p.FringingAmount)
 	if err != nil {
 		return nil, err
@@ -258,6 +270,7 @@ func (p *Preferences) SetDefaults() {
 	p.Scanlines.Set(scanlines)
 	p.Interference.Set(interference)
 	p.Noise.Set(noise)
+	p.Flicker.Set(flicker)
 	p.Fringing.Set(fringing)
 	p.Ghosting.Set(ghosting)
 	p.Phosphor.Set(phosphor)
@@ -269,6 +282,7 @@ func (p *Preferences) SetDefaults() {
 	p.ScanlinesFine.Set(scanlinesFine)
 	p.InterferenceLevel.Set(interferenceLevel)
 	p.NoiseLevel.Set(noiseLevel)
+	p.FlickerLevel.Set(flickerLevel)
 	p.FringingAmount.Set(fringingAmount)
 	p.GhostingAmount.Set(ghostingAmount)
 	p.PhosphorLatency.Set(phosphorLatency)

gui/sdlimgui/glsl_crtseq.go

@@ -33,6 +33,7 @@ type crtSeqPrefs struct {
 	Scanlines      bool
 	Interference   bool
 	Noise          bool
+	Flicker        bool
 	Fringing       bool
 	Ghosting       bool
 	Phosphor       bool
@@ -45,6 +46,7 @@ type crtSeqPrefs struct {
 	ScanlinesFine        float64
 	InterferenceLevel    float64
 	NoiseLevel           float64
+	FlickerLevel         float64
 	FringingAmount       float64
 	GhostingAmount       float64
 	PhosphorLatency      float64
@@ -65,6 +67,7 @@ func newCrtSeqPrefs(prefs *crt.Preferences) crtSeqPrefs {
 		Scanlines:            prefs.Scanlines.Get().(bool),
 		Interference:         prefs.Interference.Get().(bool),
 		Noise:                prefs.Noise.Get().(bool),
+		Flicker:              prefs.Flicker.Get().(bool),
 		Fringing:             prefs.Fringing.Get().(bool),
 		Ghosting:             prefs.Ghosting.Get().(bool),
 		Phosphor:             prefs.Phosphor.Get().(bool),
@@ -76,6 +79,7 @@ func newCrtSeqPrefs(prefs *crt.Preferences) crtSeqPrefs {
 		ScanlinesFine:        prefs.ScanlinesFine.Get().(float64),
 		InterferenceLevel:    prefs.InterferenceLevel.Get().(float64),
 		NoiseLevel:           prefs.NoiseLevel.Get().(float64),
+		FlickerLevel:         prefs.FlickerLevel.Get().(float64),
 		FringingAmount:       prefs.FringingAmount.Get().(float64),
 		GhostingAmount:       prefs.GhostingAmount.Get().(float64),
 		PhosphorLatency:      prefs.PhosphorLatency.Get().(float64),

gui/sdlimgui/glsl_crtseq_effects.go

@@ -37,6 +37,7 @@ type crtSeqEffectsShader struct {
 	scanlines            int32
 	interference         int32
 	noise                int32
+	flicker              int32
 	fringing             int32
 	curveAmount          int32
 	roundedCornersAmount int32
@@ -46,6 +47,7 @@ type crtSeqEffectsShader struct {
 	scanlinesFine        int32
 	interferenceLevel    int32
 	noiseLevel           int32
+	flickerLevel         int32
 	fringingAmount       int32
 	time                 int32
 	rotation             int32
@@ -70,6 +72,7 @@ func newCrtSeqEffectsShader(yflip bool) shaderProgram {
 	sh.scanlines = gl.GetUniformLocation(sh.handle, gl.Str("Scanlines"+"\x00"))
 	sh.interference = gl.GetUniformLocation(sh.handle, gl.Str("Interference"+"\x00"))
 	sh.noise = gl.GetUniformLocation(sh.handle, gl.Str("Noise"+"\x00"))
+	sh.flicker = gl.GetUniformLocation(sh.handle, gl.Str("Flicker"+"\x00"))
 	sh.fringing = gl.GetUniformLocation(sh.handle, gl.Str("Fringing"+"\x00"))
 	sh.curveAmount = gl.GetUniformLocation(sh.handle, gl.Str("CurveAmount"+"\x00"))
 	sh.roundedCornersAmount = gl.GetUniformLocation(sh.handle, gl.Str("RoundedCornersAmount"+"\x00"))
@@ -79,6 +82,7 @@ func newCrtSeqEffectsShader(yflip bool) shaderProgram {
 	sh.scanlinesFine = gl.GetUniformLocation(sh.handle, gl.Str("ScanlinesFine"+"\x00"))
 	sh.interferenceLevel = gl.GetUniformLocation(sh.handle, gl.Str("InterferenceLevel"+"\x00"))
 	sh.noiseLevel = gl.GetUniformLocation(sh.handle, gl.Str("NoiseLevel"+"\x00"))
+	sh.flickerLevel = gl.GetUniformLocation(sh.handle, gl.Str("FlickerLevel"+"\x00"))
 	sh.fringingAmount = gl.GetUniformLocation(sh.handle, gl.Str("FringingAmount"+"\x00"))
 	sh.time = gl.GetUniformLocation(sh.handle, gl.Str("Time"+"\x00"))
 	sh.rotation = gl.GetUniformLocation(sh.handle, gl.Str("Rotation"+"\x00"))
@@ -104,6 +108,7 @@ func (sh *crtSeqEffectsShader) setAttributesArgs(env shaderEnvironment,
 	gl.Uniform1i(sh.scanlines, boolToInt32(prefs.Scanlines))
 	gl.Uniform1i(sh.interference, boolToInt32(prefs.Interference))
 	gl.Uniform1i(sh.noise, boolToInt32(prefs.Noise))
+	gl.Uniform1i(sh.flicker, boolToInt32(prefs.Flicker))
 	gl.Uniform1i(sh.fringing, boolToInt32(prefs.Fringing))
 	gl.Uniform1f(sh.curveAmount, float32(prefs.CurveAmount))
 	gl.Uniform1f(sh.roundedCornersAmount, float32(prefs.RoundedCornersAmount))
@@ -113,6 +118,7 @@ func (sh *crtSeqEffectsShader) setAttributesArgs(env shaderEnvironment,
 	gl.Uniform1f(sh.scanlinesFine, float32(prefs.ScanlinesFine))
 	gl.Uniform1f(sh.interferenceLevel, float32(prefs.InterferenceLevel))
 	gl.Uniform1f(sh.noiseLevel, float32(prefs.NoiseLevel))
+	gl.Uniform1f(sh.flickerLevel, float32(prefs.FlickerLevel))
 	gl.Uniform1f(sh.fringingAmount, float32(prefs.FringingAmount))
 	gl.Uniform1f(sh.time, float32(time.Now().Nanosecond())/100000000.0)
 	gl.Uniform1i(sh.rotation, int32(rotation))

gui/sdlimgui/shaders/crt_effects.frag

@@ -24,6 +24,7 @@ uniform int ShadowMask;
 uniform int Scanlines;
 uniform int Interference;
 uniform int Noise;
+uniform int Flicker;
 uniform int Fringing;
 uniform float CurveAmount;
 uniform float RoundedCornersAmount;
@@ -33,6 +34,7 @@ uniform float ScanlinesIntensity;
 uniform float ScanlinesFine;
 uniform float InterferenceLevel;
 uniform float NoiseLevel;
+uniform float FlickerLevel;
 uniform float FringingAmount;
 uniform float Time;
 
@@ -191,9 +193,11 @@ void main() {
 			Crt_Color.b *= max(1.0-NoiseLevel, n);
 		}
 
-		// flicker
-		float level = 0.025;
-		Crt_Color *= (1.0-level*(sin(50.0*Time+uv.y*2.0)*0.5+0.5));
+	}
+
+	// flicker
+	if (Flicker == 1) {
+		Crt_Color *= (1.0-FlickerLevel*(sin(50.0*Time+uv.y*2.0)*0.5+0.5));
 	}
 
 	// fringing (chromatic aberration)

gui/sdlimgui/win_prefs_crt.go

@@ -64,6 +64,8 @@ func (win *winPrefs) drawCRT() {
 		imgui.Spacing()
 		win.drawNoise()
 		imgui.Spacing()
+		win.drawFlicker()
+		imgui.Spacing()
 		win.drawFringing()
 		imgui.Spacing()
 		win.drawGhosting()
@@ -251,6 +253,31 @@ func (win *winPrefs) drawNoise() {
 	}
 }
 
+func (win *winPrefs) drawFlicker() {
+	b := win.img.crtPrefs.Flicker.Get().(bool)
+	if imgui.Checkbox("Flicker##flicker", &b) {
+		win.img.crtPrefs.Flicker.Set(b)
+	}
+
+	f := float32(win.img.crtPrefs.FlickerLevel.Get().(float64))
+
+	var label string
+
+	if f >= 0.06 {
+		label = "very high"
+	} else if f >= 0.04 {
+		label = "high"
+	} else if f >= 0.03 {
+		label = "low"
+	} else {
+		label = "very low"
+	}
+
+	if imgui.SliderFloatV("##flickerlevel", &f, 0.01, 0.06, label, 1.0) {
+		win.img.crtPrefs.FlickerLevel.Set(f)
+	}
+}
+
 func (win *winPrefs) drawFringing() {
 	b := win.img.crtPrefs.Fringing.Get().(bool)
 	if imgui.Checkbox("Colour Fringing##fringing", &b) {