Add al_get_current_shader

Requested on Discord.

Author: TRDario

docs/src/refman/shader.txt

@@ -264,7 +264,15 @@ Since: 5.1.6
 
 See also: [al_destroy_shader], [al_set_shader_sampler], [al_set_shader_matrix],
 [al_set_shader_int], [al_set_shader_float], [al_set_shader_bool],
-[al_set_shader_int_vector], [al_set_shader_float_vector]
+[al_set_shader_int_vector], [al_set_shader_float_vector], [al_get_current_shader]
+
+## API: al_get_current_shader
+
+Return the shader of the target bitmap, or NULL if one isn't being used.
+
+Since: 5.2.9
+
+See also: [al_use_shader]
 
 ## API: al_destroy_shader
 

include/allegro5/shader.h

@@ -59,6 +59,7 @@ AL_FUNC(bool, al_build_shader, (ALLEGRO_SHADER *shader));
 AL_FUNC(const char *, al_get_shader_log, (ALLEGRO_SHADER *shader));
 AL_FUNC(ALLEGRO_SHADER_PLATFORM, al_get_shader_platform, (ALLEGRO_SHADER *shader));
 AL_FUNC(bool, al_use_shader, (ALLEGRO_SHADER *shader));
+AL_FUNC(ALLEGRO_SHADER *, al_get_current_shader, (void));
 AL_FUNC(void, al_destroy_shader, (ALLEGRO_SHADER *shader));
 
 AL_FUNC(bool, al_set_shader_sampler, (const char *name, ALLEGRO_BITMAP *bitmap,

src/shader.c

@@ -211,6 +211,20 @@ bool al_use_shader(ALLEGRO_SHADER *shader)
    }
 }
 
+/* Function: al_get_current_shader
+*/
+ALLEGRO_SHADER *al_get_current_shader()
+{
+   ALLEGRO_BITMAP* bmp = al_get_target_bitmap();
+
+   if (bmp != NULL) {
+      return bmp->shader;
+   }
+   else {
+      return NULL;
+   }
+}
+
 /* Function: al_destroy_shader
  */
 void al_destroy_shader(ALLEGRO_SHADER *shader)