RFR: 8217853: Cleanup in the D3D native pipeline [v5]

[Nir Lisker]

On Tue, 2 Aug 2022 18:01:06 GMT, Ambarish Rapte <arapte at openjdk.org> wrote:

>> Nir Lisker has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Renamed method
>
> modules/javafx.graphics/src/main/native-prism-d3d/hlsl/vs2ps.h line 38:
> 
>> 36:     float3 worldVecToEye               : texcoord2;
>> 37:     float3 worldVecsToLights[nLights]  : texcoord3; // 3, 4, 5
>> 38:     float3 worldNormLightDirs[nLights] : texcoord6; // 6, 7, 8
> 
> This is an existing behavior, and I just want to open it for discussion and bring it to your consideration for future changes.
> These are per vertex attributes and they may cause un-required processing/overhead during rasterization.
> In a regular scenario where only one light i.e. default light is set, the other two values in these arrays are reset and are unused in pixel shader. But rasterizer interpolates these values for all pixel and pass them as input to pixel shader.
> May be in future we can find a way to avoid this.

I think that when the strict limit of 3 lights is removed then we will touch this as well.

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PR: https://git.openjdk.org/jfx/pull/789