diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/api.texi | 101 |
1 files changed, 82 insertions, 19 deletions
diff --git a/doc/api.texi b/doc/api.texi index 07005a6..5fa18b3 100644 --- a/doc/api.texi +++ b/doc/api.texi @@ -1965,7 +1965,7 @@ interface for working with sprites. Bitmaps are stored in textures @code{draw-sprite} procedure. @deffn {Procedure} draw-sprite texture position @ - [#:tint white] [#:origin] [#:scale] [#:rotation] [#:blend-mode alpha] @ + [#:tint white] [#:origin] [#:scale] [#:rotation] [#:blend-mode] @ [#:rect] Draw @var{texture} at @var{position}. @@ -2036,7 +2036,7 @@ See @code{draw-sprite} for information about the other arguments. Reset size of @var{batch} to 0. @end deffn -@deffn {Procedure} draw-sprite-batch batch [#:blend-mode @code{alpha}] +@deffn {Procedure} draw-sprite-batch batch [#:blend-mode] Render @var{batch} using @var{blend-mode}. Alpha blending is used by default. @end deffn @@ -2071,7 +2071,7 @@ artifacts. @deffn {Procedure} draw-nine-patch texture rect @ [#:margin 0] [#:top-margin margin] [#:bottom-margin margin] @ [#:left-margin margin] [#:right-margin margin] @ - [#:origin] [#:scale] [#:rotation] [#:blend-mode alpha] @ + [#:origin] [#:scale] [#:rotation] [#:blend-mode] @ [#:tint white] Draw a nine patch sprite. A nine patch sprite renders @var{texture} @@ -2410,7 +2410,7 @@ at the coordinates @code{(320, 240)}: To see all of the tweakable knobs and switches, read on! -@deffn {Procedure} make-particles capacity [#:blend-mode @code{alpha}] @ +@deffn {Procedure} make-particles capacity [#:blend-mode] @ [#:color white] [#:end-color transparent] [#:texture] @ [#:animation-rows 1] [#:animation-columns 1] [#:width] [#:height] @ [#:speed-range (vec2 0.1 1.0)] [#:acceleration-range (vec2 0.0 0.1)] @ @@ -2420,7 +2420,7 @@ Return a new particle system that may contain up to @var{capacity} particles. Achieving the desired particle effect involves tweaking the following keyword arguments as needed: -- @var{blend-mode}: Pixel blending mode. @code{alpha} by default. +- @var{blend-mode}: Pixel blending mode. Alpha blending is used by default. (@pxref{Blending} for more about blend modes). - @var{start-color}: The tint color of the particle at the beginning of its @@ -2789,36 +2789,99 @@ and @var{view-matrix} applied. Rendering a scene often involves drawing layers of objects that overlap each other. Blending determines how two overlapping pixels are combined in the final image that is rendered to the screen. -Chickadee provides the following blend modes: - -@itemize -@item @code{replace} -Use the latest color, ignoring all others. +Chickadee provides the following blend modes: -@item @code{alpha} +@defvar blend:alpha Blend pixels according to the values of their alpha channels. This is -the most commonly used blend mode and thus is Chickadee's default -mode. +the most commonly used blend mode. +@end defvar -@item @code{add} +@defvar blend:replace +Overwrite the output pixel color with the color being drawn. +@end defvar + +@defvar blend:add Add all pixel color values together. The more colors blended together, the more white the final color becomes. +@end defvar -@item @code{subtract} +@defvar blend:subtract Subtract all pixel color values. The more colors blended together, the more black the final color becomes. +@end defvar + +@defvar blend:multiply +@end defvar -@item @code{multiply} +@defvar blend:darken +@end defvar -@item @code{darken} +@defvar blend:lighten +@end defvar -@item @code{lighten} +@defvar blend:screen +@end defvar -@item @code{screen} +Custom blend modes can be created using the @code{make-blend-mode} procedure: +@deffn {Procedure} make-blend-mode equation source-function destination-function +Return a new custom blend mode that applies @var{source-function} to +the source color, @var{destination-function} to the destination color, +and finally applies @var{equation} to the transformed +source/destination color values. These arguments are @emph{not} +procedures, but symbolic representations of the functions that OpenGL +supports. + +Valid values for @var{equation} are: + +@itemize +@item @code{add} +@item @code{subtract} +@item @code{reverse-subtract} +@item @code{min} +@item @code{max} +@item @code{alpha-min} +@item @code{alpha-max} @end itemize +Valid values for @var{source-function} are: + +@itemize +@item @code{zero} +@item @code{one} +@item @code{destination-color} +@item @code{one-minus-destination-color} +@item @code{source-alpha-saturate} +@item @code{source-alpha} +@item @code{one-minus-source-alpha} +@item @code{destination-alpha} +@item @code{one-minus-destination-alpha} +@item @code{constant-color} +@item @code{one-minus-constant-color} +@item @code{constant-alpha} +@item @code{one-minus-constant-alpha} +@end itemize + +Valid values for @var{destination-function} are: + +@itemize +@item @code{zero} +@item @code{one} +@item @code{source-color} +@item @code{one-minus-source-color} +@item @code{source-alpha} +@item @code{one-minus-source-alpha} +@item @code{destination-alpha} +@item @code{one-minus-destination-alpha} +@item @code{constant-color} +@item @code{one-minus-constant-color} +@item @code{constant-alpha} +@item @code{one-minus-constant-alpha} +@end itemize + +@end deffn + @node Framebuffers @subsection Framebuffers |