renpy-blend-modes

Photoshop-style blend mode shaders for Ren'Py.

This library adapts Jamie Owen's glsl-blend library to be used as Ren'Py shaders, allowing you to apply Photoshop-style image blending via a Ren'Py transform.

Installation

This project consists of a series of .rpy files. This means the best way to include it into your Ren'Py project is to download the files and place them into your game directory. You do not need to include the files for any shaders you don't plan to use, however you must include base.rpy.

To download an archive of this project, click the green Code button on GitHub and select "Download ZIP".

Prerequisites

You must have a version of Ren'Py which supports model-based rendering.

Blend modes

A few additional simple blend modes have been added to the config.gl_blend_func dictionary. If you add the appropriate source files to your project, you'll be able to use any of these blend functions with the blend transform property. The following blend modes have been added in this way:

• add
• linear_dodge (synonym for add)
• lighten
• darken

Blend shaders

More complex blend modes are implemented as GLSL shaders that will blend a texture image onto a base image using the specified blend mode. The easiest way to include any of these shaders is to use one of the included shader functions packaged with this library. Each shader function has the name cc_<blend_mode_name> (for example, cc_screen or cc_soft_light). They take the following arguments:

• base (Displayable): the base displayable, onto which other image data will be blended.
• tex (Displayable): the texture displayable, which will be blended onto the base displayable in the specified mode.
• fit (boolean, default True): if True, tex will be resized to be the same size as base. Weird stuff may happen if you pass False.

Here is an example of how shaders are used in transforms:

transform my_special_lighting(child=None):
  cc_soft_light(child, Solid("#ffffff7f"))

This transform applies a partially transparent pure white using the cc_soft_light displayable. Note that the transform takes the child=None argument: for the transform to work correctly, you must include this argument. Ren'Py will correctly set the value of child to be the base displayable the transform is applying to. cc_soft_light, and the other blend mode functions, return a displayable which will be the child displayable of your transform.

Once you've created the transform, you can use it the same way you'd use any other transform.

show protagonist_sprite at center, my_special_lighting

The following shaders are currently available:

• cc_color_burn
• cc_color_dodge
• cc_difference
• cc_exclusion
• cc_linear_burn
• cc_overlay
• cc_screen
• cc_soft_light
• cc_vivid_light

Limitations

Animating between the blend modes is not supported. You may get wacky results, or it may cause crashes, or nothing may happen. Shader-based transforms may not work with layered images.

Contributing

This project accepts pull requests. Please create a pull request if you would like to contribute. If you have any feature requests, please create a project issue and I will address it as soon as I can.

License

This project is made available under the MIT license. Please see LICENSE.md for more information.