hal/shader/analytic.lisp

system luv · 5 definitions · on GitHub

Small analytic GUI primitives evaluated directly in the fragment shader.

in-package#:luv.analytic

/1.065536.0

Negative values are inside. RADIUS is clamped to the shape's shorter half-extent, so rectangles, roundrects, capsules, and circles share one definition.

arith-lisp:define-lisp-arithmetic-functionroundrect-signed-distance

half-width

half-height

radius

let*

safe-radius

min

maxradius0.0

minhalf-widthhalf-height

absx

-half-widthsafe-radius

absy

-half-heightsafe-radius

outside-x

maxqx0.0

outside-y

maxqy0.0

outside

sqrt

*outside-xoutside-x

*outside-youtside-y

inside

min

maxqxqy

0.0

+outsideinside

safe-radius

shader:define-shader-functionroundrect-coverage

coordinatehalf-size-radius

"Evaluate an analytic roundrect and turn its screen gradient into coverage."

let*

distance

roundrect-signed-distance

shader:swizzlecoordinate:x

shader:swizzlecoordinate:y

shader:swizzlehalf-size-radius:x

shader:swizzlehalf-size-radius:y

shader:swizzlehalf-size-radius:z

distance-dx

shader:derivative-xdistance

distance-dy

shader:derivative-ydistance

pixel-span

max

sqrt

*distance-dxdistance-dx

*distance-dydistance-dy

+analytic-coverage-epsilon+

shader:clamp

-0.5

/distancepixel-span

0.01.0

shader:define-shaderroundrect-vertex-specification

:stage:vertex:inputs

position:vec3:location0

local-coordinate:vec3:location1

half-size-radius:vec3:location2

color:vec3:location3

:outputs

clip-position:vec4:built-in:position

render-coordinate:vec2:location0

render-half-size-radius:vec3:location1

render-color:vec4:location2

let*

alpha

shader:swizzleposition:z

shader:set-outputclip-position

shader:vec4

shader:swizzleposition:xy

0.01.0

shader:set-outputrender-coordinate

shader:swizzlelocal-coordinate:xy

shader:set-outputrender-half-size-radiushalf-size-radius

shader:set-outputrender-color

shader:vec4

*coloralpha

alpha

shader:define-shaderroundrect-fragment-specification

:stage:fragment:inputs

render-coordinate:vec2:location0

half-size-radius:vec3:location1

color:vec4:location2

:outputs

color-output:vec4:location0

let*

coverage

roundrect-coveragerender-coordinatehalf-size-radius

shader:set-outputcolor-output

*colorcoverage