Shaders have access to a number of variables that are available from everywhere. They are defined per-view, meaning that some data will vary depending on current viewport. Compute shader can access this data as well, as long as they are being dispatched from render context.
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I don't love these names but they're not going to go anywhere, so you're free to use them. In all likelihood in the future we'll get together and create a bunch of nicer #define's for them, so g_flTime will be accessible viaTime.Now, or just time etc.
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:::info
This page only includes variables that are actually used by the engine and have useful purpose for shaders. You can look up a full list of all global per-view variables, including unused ones, here: game/core/shaders/common.fxc
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Type
Name
Description
float
g_flTime
Current time
These projection matrices are used for conversions between various coordinate spaces.
Type
Name
Description
Helper Functions
float4x4
g_matWorldToProjection
Converts world-space coordinates to projection-space. In vertex shaders, it is common to convert world-space vertex position back to projection space before finalizing vertex manipulations
Position4WsToPs, Position3WsToPs
float4x4
g_matProjectionToWorld
Converts projection-space coordinates to world-space. Used in Depth::GetWorldPosition to reconstruct world-space position of ray from depth buffer
...
float4x4
g_matWorldToView
Converts world-space coordinates to view-space. This coordinate system is built relative to the camera, with it as the origin
Position4WsToVs, Position3WsToVs
float4x4
g_matViewToProjection
Converts view-space coordinates to projection-space
Position4VsToPs, Position3VsToPs
float4x4
g_matProjectionToView
Converts projection-space coordinates to view space
...
float4x4
g_matCurrFrameViewToPrevFrameProj
Converts view-space coordinates of current frame to projection-space coordinates of previous frame
ReprojectFromLastFrameSs
float4
g_vInvProjRow3
Row 3 of the inverse projection matrix
...
Type
Name
Description
float3
g_vCameraPositionWs
Camera position in world space
float3
g_vCameraDirWs
Camera direction in world space
float3
g_vCameraUpDirWs
Camera up direction in world space
float4
g_vCameraAngles
Camera raw pitch/yaw/roll in radians, unused
float
g_flCameraFOV
Camera FOV in radians
float
g_flNearPlane
Camera's near plane
float
g_flFarPlane
Camera's far plane
Type
Name
Description
float
g_flViewportMinZ
Depth buffer min range for current viewport
float
g_flViewportMaxZ
Depth buffer max range for current viewport
float2
g_vViewportSize
Viewport width (X) and height (Y)
float2
g_vViewportOffset
Viewport top left XY coords for offset if it's on a shared render target
float2
g_vRenderTargetSize
Render target width (X) and height (Y)
float2
g_vInvViewportSize
Reciprocal of original viewport size (1.0 / g_vViewportSize)
float4
g_vFrameBufferCopyInvSizeAndUvScale
Reciprocal of frame buffer size. X and Y are 1.0f / viewport size, Z and W are always 1.0. This property is considered unused, but you still may see it in some older shaders
Type
Name
Description
float4
g_vRandomFloats
Random floats in each component, values change every frame
