Class CRTBeamClock
Counts display refreshes for the beam simulator and tells where the beam is: which CRT frame is showing and which part of it the current refresh covers.
Inherited Members
Namespace: Scylla.TextMode.CRT
Assembly: ScyllaTextMode.CRT.dll
Syntax
public sealed class CRTBeamClockRemarks
The beam must advance once per display refresh, not per game frame. With vSync on, every Unity frame is one refresh. A frame that took longer than a refresh advances the count by the refreshes it spanned, so a missed refresh moves the beam on instead of stalling it.
The clock does not read the display or the configuration; the caller sets the rates with SetRates(double, double, bool) and advances it once per frame with Advance(float).
The count only ever grows until Reset(). CycleIndex and Window are worked out from it, so the beam position follows from the count alone. TextModeCRTBeam owns the shared instance that every CRT picture reads; the class is public so tests can drive their own.
Properties
AntiRetention
Gets whether an even number of refreshes per CRT frame drifts slowly, for LCDs.
Declaration
public bool AntiRetention { get; }Property Value
| Type | Description |
|---|---|
| bool |
CRTRate
Gets the simulated CRT's refresh rate in hertz.
Declaration
public double CRTRate { get; }Property Value
| Type | Description |
|---|---|
| double |
CanRun
Gets whether the simulator can run: at least MIN_FRAMES refreshes per CRT frame.
Declaration
public bool CanRun { get; }Property Value
| Type | Description |
|---|---|
| bool |
CycleIndex
Gets the index of the CRT frame showing now. It changes when a new source frame is due. While the clock cannot run it equals Refreshes.
Declaration
public long CycleIndex { get; }Property Value
| Type | Description |
|---|---|
| long |
DisplayRate
Gets the display refresh rate in hertz the clock counts with.
Declaration
public double DisplayRate { get; }Property Value
| Type | Description |
|---|---|
| double |
Frames
Gets the display refreshes per CRT frame, including the anti-retention drift, or 0 when the simulator cannot run at the set rates.
Declaration
public float Frames { get; }Property Value
| Type | Description |
|---|---|
| float |
MissedRefreshes
Gets the number of refreshes that passed without a frame, counted since the clock started or was reset. A steady rise means the game does not keep up with the display.
Declaration
public long MissedRefreshes { get; }Property Value
| Type | Description |
|---|---|
| long |
Refreshes
Gets the number of display refreshes counted since the clock started or was reset.
Declaration
public long Refreshes { get; }Property Value
| Type | Description |
|---|---|
| long |
SlowMotionDivisor
Gets or sets how many frames each refresh step lasts, for watching the sweep on a slow display. 1, the default, runs at the real rate. A development aid only. Values below 1 are raised to 1.
Declaration
public int SlowMotionDivisor { get; set; }Property Value
| Type | Description |
|---|---|
| int |
Window
Gets where the current refresh starts within the CRT frame, in refreshes, from 0 up to but not including Frames. 0 while the clock cannot run.
Declaration
public float Window { get; }Property Value
| Type | Description |
|---|---|
| float |
Methods
Advance(float)
Advances the clock by one frame.
Declaration
public int Advance(float deltaTime)Parameters
| Type | Name | Description |
|---|---|---|
| float | deltaTime | The unscaled time the frame took, in seconds. |
Returns
| Type | Description |
|---|---|
| int | The number of refreshes the frame advanced by, 0 while slow motion holds. |
Remarks
A frame that spans more than one refresh adds the extra refreshes to MissedRefreshes. With slow motion on, the frame time is ignored and the clock steps one refresh every SlowMotionDivisor frames, without counting missed refreshes. Nothing happens while CanRun is false.
Reset()
Starts counting from zero again, with the rates kept.
Declaration
public void Reset()SetRates(double, double, bool)
Sets the rates the clock counts with. The count keeps running, so the beam does not jump when the rates are set again with the same values.
Declaration
public void SetRates(double displayRate, double crtRate, bool antiRetention)Parameters
| Type | Name | Description |
|---|---|---|
| double | displayRate | The display's refresh rate in hertz. |
| double | crtRate | The simulated CRT's refresh rate in hertz, such as 60. |
| bool | antiRetention | Whether an even number of refreshes per CRT frame drifts, for LCDs. |
ShaderVector(float, CRTBeamScanDirection)
Returns the shader vector for the composite's beam stage at the current refresh.
Declaration
public Vector4 ShaderVector(float gain, CRTBeamScanDirection direction)Parameters
| Type | Name | Description |
|---|---|---|
| float | gain | The share of the value emitted on average. |
| CRTBeamScanDirection | direction | The scan direction. |
Returns
| Type | Description |
|---|---|
| Vector4 | The vector for |