ALLEGRO_SHADER_TYPE - Allegro 5 API
typedef enum ALLEGRO_SHADER_TYPE ALLEGRO_SHADER_TYPE;
Used with al_attach_shader_source(3alleg5) and
al_attach_shader_source_file(3alleg5) to specify how to interpret the attached
- A vertex shader is executed for each vertex it is used
with. The program will output exactly one vertex at a time.
When Allegro's graphics are being used then in addition to all vertices of
primitives from the primitives addon, each drawn bitmap also consists of four
- A pixel shader is executed for each pixel it is used with.
The program will output exactly one pixel at a time - either in the
backbuffer or in the current target bitmap.
With Allegro's builtin graphics this means the shader is for example called for
each destination pixel of the output of an al_draw_bitmap(3alleg5) call.
A more accurate term for pixel shader would be fragment shader since one final
pixel in the target bitmap is not necessarily composed of only a single output
but of multiple fragments (for example when multi-sampling is being