```
public interface MTLRasterizationRateMap
```
[@protocol] MTLRasterizationRateMap Compiled read-only object that determines how variable rasterization rate is applied when rendering. A variable rasterization rate map is compiled by MTLDevice from a MTLRasterizationRateMapDescriptor containing one or more MTLRasterizationRateLayerDescriptor. During compilation, the quality samples provided in the MTLRasterizationRateLayerDescriptor may be rounded up to the nearest supported value or granularity, depending on hardware support. However, the compilation will never round values down, so the actual rasterization will always happen at a quality level matching or exceeding the provided quality samples. During rasterization using the MTLRasterizationRateMap the screen space rendering is stored in a smaller area of the framebuffer, such that lower quality regions will not occupy as many texels as higher quality regions. The quality will never exceed 1:1 in any region of screen space. Because a smaller area of the framebuffer is populated, less fragment shader invocations are required to render content, and less bandwidth is consumed to store the shaded values. Use a rasterization rate map to reduce rendering quality in less-important or less-sampled regions of the framebuffer, such as the periphery of a VR/AR display or a far-away cascade of a shadow map.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`copyParameterDataToBufferOffset(MTLBuffer buffer, long offset)`	copyParameterDataToBuffer:offset: Copy the parameter data into the provided buffer at the provided offset.
`MTLDevice`	`device()`	[@property] device
`java.lang.String`	`label()`	[@property] label A string to help identify this object.
`long`	`layerCount()`	[@property] layerCount Different render-target layers may target different variable rasterization configurations.
`MTLSamplePosition`	`mapPhysicalToScreenCoordinatesForLayer(MTLSamplePosition physicalCoordinates, long layerIndex)`	mapPhysicalToScreenCoordinates:forLayer: Computes where an offset relative to the top-left of the framebuffer, in physical pixels, would end up in screen space, in screen space pixels.
`MTLSamplePosition`	`mapScreenToPhysicalCoordinatesForLayer(MTLSamplePosition screenCoordinates, long layerIndex)`	mapScreenToPhysicalCoordinates:forLayer: Computes where an offset relative to the top-left of screen space, in screen space pixels, would end up in the framebuffer, in physical fragments.
`MTLSizeAndAlign`	`parameterBufferSizeAndAlign()`	[@property] parameterBufferSizeAndAlign Returns the size and alignment requirements of the parameter buffer for this rate map.
`MTLSize`	`physicalGranularity()`	[@property] physicalGranularity Rendering algorithms that use binning or tiling in screen space may want to determine the screen space bin size using this value.
`MTLSize`	`physicalSizeForLayer(long layerIndex)`	getPhysicalSizeForLayer: The dimensions, in physical fragments, of the area in the render target where variable rasterization is applied Different configured layers may have a different rasterization rate and may have different size after rendering.
`MTLSize`	`screenSize()`	[@property] screenSize The region always has its origin at [0, 0].

- Method Detail
  - copyParameterDataToBufferOffset
```
void copyParameterDataToBufferOffset(MTLBuffer buffer,
                                     long offset)
```
    copyParameterDataToBuffer:offset: Copy the parameter data into the provided buffer at the provided offset. The buffer must have storageMode MTLStorageModeShared, and a size of at least parameterBufferSizeAndAlign.size + offset. The specified offset must be a multiple of parameterBufferSize.align. The buffer can be bound to a shader stage to map screen space to physical fragment space, or vice versa.
  - device
```
MTLDevice device()
```
    [@property] device
    
    Returns:
    
    The device on which the rasterization rate map was created
  - label
```
java.lang.String label()
```
    [@property] label A string to help identify this object.
  - layerCount
```
long layerCount()
```
    [@property] layerCount Different render-target layers may target different variable rasterization configurations. The rasterization rate layer for a primitive is selected on the [[render_target_layer_index]].
    
    Returns:
    
    The number of different configured layers in the rasterization map.
  - mapPhysicalToScreenCoordinatesForLayer
```
MTLSamplePosition mapPhysicalToScreenCoordinatesForLayer(MTLSamplePosition physicalCoordinates,
                                                         long layerIndex)
```
    mapPhysicalToScreenCoordinates:forLayer: Computes where an offset relative to the top-left of the framebuffer, in physical pixels, would end up in screen space, in screen space pixels. The returned value is greater-or-equal the input value because the rasterization quality never exceeds 1:1 in any region.
  - mapScreenToPhysicalCoordinatesForLayer
```
MTLSamplePosition mapScreenToPhysicalCoordinatesForLayer(MTLSamplePosition screenCoordinates,
                                                         long layerIndex)
```
    mapScreenToPhysicalCoordinates:forLayer: Computes where an offset relative to the top-left of screen space, in screen space pixels, would end up in the framebuffer, in physical fragments. The returned value is less-or-equal the input value because the rasterization quality never exceeds 1:1 in any region.
  - parameterBufferSizeAndAlign
```
MTLSizeAndAlign parameterBufferSizeAndAlign()
```
    [@property] parameterBufferSizeAndAlign Returns the size and alignment requirements of the parameter buffer for this rate map. The parameter data can be copied into a buffer with this size and alignment using copyParameterDataToBuffer:offset:
  - physicalGranularity
```
MTLSize physicalGranularity()
```
    [@property] physicalGranularity Rendering algorithms that use binning or tiling in screen space may want to determine the screen space bin size using this value. The depth component of the returned MTLSize is always 0.
    
    Returns:
    
    The granularity, in physical pixels, at which variable rasterization rate varies.
  - physicalSizeForLayer
```
MTLSize physicalSizeForLayer(long layerIndex)
```
    getPhysicalSizeForLayer: The dimensions, in physical fragments, of the area in the render target where variable rasterization is applied Different configured layers may have a different rasterization rate and may have different size after rendering. The rasterization rate layer for a primitive is selected on the [[render_target_layer_index]].
  - screenSize
```
MTLSize screenSize()
```
    [@property] screenSize The region always has its origin at [0, 0]. The depth component of the returned MTLSize is always 0.
    
    Returns:
    
    The dimensions, in screen space pixels, of the region where variable rasterization is applied.

Interface MTLRasterizationRateMap

Method Summary

Method Detail

copyParameterDataToBufferOffset

device

label

layerCount

mapPhysicalToScreenCoordinatesForLayer

mapScreenToPhysicalCoordinatesForLayer

parameterBufferSizeAndAlign

physicalGranularity

physicalSizeForLayer

screenSize