The checkbox labeled draw per-pixel lighting toggles pixel shaders. Using pixel shaders allows X-Plane to add 3-D lighting on a per-pixel basis, to incredible effect. Rather than having the simulator tell the graphics card how to light an area, the graphics card determines it in real time, creating a very realistic image. If you have an older graphics card, this can have a large effect on frame rate.
I have this kind of problem too.After the last update of X-Plane 11 done on december 11th, the program does not start anymore and shows the following message:"There was a problem processing at GLSL pixel shader.You may need to rerun the installer or update your graphics drivers "."Resources / shaders / legacy.gls"; the latter repeated twice.
But if I start X-Plane 11 according to the normal procedure, it stops immediately and the message "There was a problem processing at GLSL pixel shader ... etc." and the related Log file, actually returns to register the X-Plane version 11.05. As if the update was not saved.
SV_PrimitiveID is an exception to this rule of only being input into the first active shader in the pipeline that can interpret the particular value; the hardware can provide the same ID value as input to the hull-shader stage, domain-shader stage, and after that whichever stage is the first enabled: geometry-shader stage or pixel-shader stage.
If tessellation is enabled, the hull-shader stage and domain-shader stage are present. For a given patch, the same PrimitiveID applies to the patch's hull-shader invocation, and all tessellated domain shader invocations. The same PrimitiveID also propagates to the next active stage; geometry-shader stage or pixel-shader stage if enabled.
If the geometry shader inputs SV_PrimitiveID and because it can output zero or one or more primitives per invocation, the shader must program its own choice of SV_PrimitiveID value for each output primitive if a subsequent pixel shader inputs SV_PrimtiveID.
The D3D10 semantic SV_Position provides similar functionality to the Direct3D 9 shader model 3 VPOS semantic. For instance, in Direct3D 9 the following syntax is used for a pixel shader using screen space coordinates:
In Direct3D 10 and later, the SV_Position semantic (when used in the context of a pixel shader) specifies screen space coordinates (offset by 0.5). Therefore, the Direct3D 9 shader would be roughly equivalent (without accounting for the 0.5 offset) to the following:
Starting with Windows 8, you can use the clipplanes function attribute in an HLSL function declaration rather than SV_ClipDistance to make your shader work on feature level 9_x as well as feature level 10 and higher. For more info, see User clip planes on feature level 9 hardware.
Please note the effects I've presented are mutually exclusive, but you can cascade effects, that is should you have a 'heat distortion' pixel shader effect, you can add it after post processing the colors like this:
This feature allows pixel shading to be independent of the geometric complexity of screen resolution and adds new texture level-of-detail methods to control the level of shading detail. These abilities are introduced to temporally decouple the shading pipeline from the traditional sample-, pixel-, or coarse-shading rates. Sampler feedback can provide sizable gains over traditional pixel-shader approaches, as shader complexity, geometry, or MSAA samples increases.
To support the rendering of mesh-shading output, the Xe rasterization pipeline is extended to support per-primitive pixel-shader attributes, in addition to the existing per-vertex attributes. Peak rates for mesh-shading function are provided in Table 2.
Additionally, the slice common also includes the pixel dispatch unit, which accumulates subspans/pixel information and dispatches threads to the XVEs. The block load balances across the multiple Xe-cores and ensures the order in which pixels retire from the shader units. It also includes support for variable rate shading (VRS), which reduces the pixel shader invocations, and in Xe-HPG has been enhanced from Tier 1 to Tier 2 support.
The process we have to follow, to calculate such a fractal in the GPU is verystraightforward. We will have to write a simple pixel (aka fragment) shader that willperforme the necessary calculations for each pixel of the fractal, and then makearrangements for this to be called for every pixel of the screen.
For a pixel shader to run, we have to render polygons after activating the shader,and for each pixel that needs to be drawn as a result of rendering any of thesepolygons, the shader is automatically run to calculate its final color.
Again, the shader is pretty simple, we have the texture with th palette, tex, theseed, c, and the number of iterations, iter, passed by the OpenGLprogram as uniforms. z starts from the current complex number (position of the pixel inthe plane), and we follow its orbit until it grows beyond 2, and thus isguaranteed to go to infinity, or we run out of iterations. Then we proceed to color itas usual, by using the number of iterations as an index in the palette texture.
Per vertex tangents are not stored from the Static Mesh when it is enabled for Nanite. Instead, tangent space is implicitly derived in the pixel shader. Tangent data is not stored in order to reduce data size. This difference in tangent space using this approach could cause discontinuities at edges. However, this particular issue has not shown to be significant, and there are plans to support vertex tangents in a future release.