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Yoann Berenguer edited this page Apr 4, 2022 · 24 revisions

Welcome to the PygameShader wiki!

Pygame Shaders Library

Pygame shader project is a 2D game library written in Python and Cython containing special effects for development of multimedia applications like video games, arcade game, video and camera image processing or to customize your sprites textures/surfaces.

This library is compatible with BMP, GIF (non - animated), JPEG, PNG image format.

pygame may not always be built to support all image formats. At minimum it will support 
uncompressed BMP. If pygame.image.get_extended() returns 'True', you should be able to
load most images (including PNG, JPG and GIF).

The shaders can be applied to the entire game display for a real time rendering @ 60 fps for games running in medium resolution such as 1024 x 768. Some algorithms are more demanding than others in terms of processing power ex : median filtering and predator vision (due to the fact that it is built with more than one shader to provide a composite effect). Consequently, not all shader will run at the same speed at medium resolutions. Feel free to experiment with higher display resolutions while the shader provides 60 fps or above.

If you are using the shader library for sprites texturing and special effects then the overall processing time should be extremely fast due to code optimization with cython. Nevertheless, to keep a good frame rate, it is advised to keep the sprites below the screen display resolution e,g 200x200 texture size.

rgb_to_bgr(object surface_) -> void:

    :param surface_    : Pygame surface or display surface compatible (image 24-32 bit with or 
                         without per-pixel transparency / alpha channel)
    :return             : void

This shader change a given pygame surface with RGB (red green, blue) pixel model to an equivalent BGR (blue, green, red) model instead. This method will also works with surface format different to RGB model, the shader will swap both channels (red & blue)
The argument surface_ represent a pygame surface object. The surface is either 24 - 32 bit with or without per-pixel transparency (Per pixel alphas are different because they store a transparency value for every pixel).

Surfaces with 8 - bit pixels are not compatible.

This "function" does not return any object (void) and the surface passed as an argument will be change inplace. Consequently, the surface will have the same attributes that the original surface/texture
The function will hold a pygame lock while processing the given surface If the surface is own by another process (locked), the function will raise an error message. Please refer to pygame documentation regarding the lock/unlock functionalities if necessary If the surface is already a BGR model then the output surface will revert to an RGB surface.

e.g:

rgb_to_bgr(surface_)

alt text alt text

rgb_to_brg(object surface_) -> void:

    :param surface_: Pygame surface or display surface compatible (image 24-32 bit with or without 
                     per-pixel transparency / alpha channel)
    :return: void

This shader change a given pygame surface with RGB (red green, blue) pixel model to an equivalent BRG (blue, red, green) model instead. This method will also works with surface format different to RGB model, the shader will swap the red channel for the green channel, the green channel swapped with the blue and finally the blue channel swapped with the red

The argument surface_ represent a pygame surface object. The surface is either 24 - 32 bit with or without per-pixel transparency (Per pixel alphas are different because they store a transparency value for every pixel). Surfaces with 8 - bit pixels are not compatible.

This function does not return any python object (void) and the surface_ passed as an argument will be change inplace. Consequently, the surface will have the same attributes that the original surface/texture

The function will hold a pygame lock while processing the given surface /texture. If the surface is own by another process (locked), the function will raise an error message. Please refer to pygame documentation regarding the lock/unlock functionalities if necessary

e.g:

rgb_to_brg(surface_)

alt text alt text

greyscale(object surface_) -> void:

    :param surface_  : Pygame surface or display surface compatible (image 24-32 bit with 
                       or without per-pixel transparency / alpha channel)
    :return          : void

This shader convert your game display or surface into a grayscale luminosity model. The grayscale mode can be used to change completely the style of your game by adding contrast between the colorfulness of your game and the greyscale equivalent format. When an image or display just seems overwhelmed by color a greyscale or sepia effect can calm down the whole image

It can be used for various effect:

  • to strain the sadness of an action or to display a sad story or special event.

  • to create a scene transition using the grey scale and the full range of color at the beginning of chapter or level.

The argument surface represent a pygame surface object. The surface is either 24 - 32 bit with or without per-pixel transparency (Per pixel alphas are different because they store a transparency value for every pixel). Surfaces with 8 - bit pixels are not compatible.

This function does not return any python object (void) and the surface passed as an argument will be change inplace. Consequently, the surface will have the same attributes that the original surface/texture

e.g:

greyscale(surface)

alt text alt text

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