FragCoord
FragCoord
Decorating a variable with the FragCoord built-in decoration will make
that variable contain the coordinates (x,y,z,1/w) of the fragment
being processed.
The (x,y) values are the framebuffer coordinates (xf,yf) of the fragment.
When Sample Shading is enabled, the x and
y components of FragCoord reflect the location of one of the
samples corresponding to the shader invocation.
Otherwise, the x and y components of FragCoord reflect the
location of the center of the fragment.
The z component of FragCoord is the interpolated depth value of
the primitive.
The w component is the interpolated .
The Centroid interpolation decoration is ignored, but allowed, on
FragCoord.
Valid Usage
VUID-FragCoord-FragCoord-04210
The FragCoord decoration must be used only within the
Fragment Execution Model
VUID-FragCoord-FragCoord-04211
The variable decorated with FragCoord must be declared using the
Input Storage Class
VUID-FragCoord-FragCoord-04212
The variable decorated with FragCoord must be declared as a
four-component vector of 32-bit floating-point values