Re: [AD] Additional opengl functions

[Edgar Reynaldo <edgarreynaldo@xxxxxxxxxx>]

On 10/29/2016 1:07 PM, SiegeLord wrote:
> I'm kind of leaning on not having these included, as they seem just 
> simple wrappers over the existing (rarely used) functions, but I can 
> be swayed. Style-wise, you'll want to add spaces around your 
> operators, and name the functions with '_f' rather than just 'f' (e.g. 
> following the 'al_map_rgb_f' example).
>
> -SL
>
> On 10/24/2016 11:44 AM, Edgar Reynaldo wrote:
> > Hey guys,
> >
> > I've been working with Allegro and OpenGL a bit lately, and I found that
> > the following additions to allegro/src/opengl/ogl_bitmap.c and
> > allegro/include/allegro5/allegro_opengl.h might be nice. Would you
> > consider them for addition, and let me know if they need to be modified,
> > or if they are suitable as is? If they're added, I will make a patch for
> > the docs to document them. The al_get_opengl_texture_positionf is to get
> > the u,v coordinates in fractional form, and the
> > al_get_opengl_texture_coordinates* functions would be to retrieve the
> > top left and bottom right coordinates, in pixels, and in fractional
> > parts of the parent texture.
> >
> > My patch is attached.
> >
> > Edgar

Hey SiegeLord,

I've updated the functions to use proper style and formatting. I've 
added a al_get_opengl_texture_size_f function to get the fractional 
width and height of a (sub) texture. I've changed 
al_get_opengl_texture_position_f and al_get_opengl_texture_coordinates_f 
to return bool because the underlying function call to 
al_get_opengl_texture_size could fail if it's not an OpenGL texture. 
Documentation has been added. The patch is attached below.

If there are any further changes or modifications you want me to make, 
just let me know.

Thanks,
Edgar







 docs/src/refman/opengl.txt        | 45 ++++++++++++++++++++-
 include/allegro5/allegro_opengl.h | 36 ++++++++++-------
 src/opengl/ogl_bitmap.c           | 84 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 149 insertions(+), 16 deletions(-)

diff --git a/docs/src/refman/opengl.txt b/docs/src/refman/opengl.txt
index ac968db..1fb779b 100644
--- a/docs/src/refman/opengl.txt
+++ b/docs/src/refman/opengl.txt
@@ -93,14 +93,55 @@ a sub-bitmap.
 Returns true on success, false on failure.
 Zero width and height are returned if the bitmap is not an OpenGL bitmap.
 
-See also: [al_get_opengl_texture_position]
+See also: [al_get_opengl_texture_position] [al_get_opengl_texture_size_f]
+
+## API: al_get_opengl_texture_size_f
+
+Retrieves the fractional size of the bitmap on its parent texture in the range
+[0.0 , 1.0]. The values may be less than 1.0 if it is a sub bitmap or the parent
+texture is larger than the bitmap.
+
+Returns true on success, or false on failure. If the function fails, w and h 
+remain unchanged.
+
+See also: [al_get_opengl_texture_size];
 
 ## API: al_get_opengl_texture_position
 
 Returns the u/v coordinates for the top/left corner of the bitmap within the
 used texture, in pixels.
 
-See also: [al_get_opengl_texture_size]
+See also: [al_get_opengl_texture_size] [al_get_opengl_texture_position_f]
+
+## API: al_get_opengl_texture_position_f
+
+Returns the u/v coordinates for the top left corner of the bitmap within the
+used texture, in fractional coordinates in the range [0.0 , 1.0].
+
+Returns true on success, false on failure. If the function fails, u and v
+are unchanged.
+
+See also : [al_get_opengl_texture_position]
+
+## API: al_get_opengl_texture_coordinates
+
+Returns the u/v coordinates for the top left and bottom right corners of the 
+bitmap within the used texture, in pixels.
+
+See also : [al_get_opengl_texture_size] [al_get_opengl_texture_coordinates_f]
+
+## API: al_get_opengl_texture_coordinates_f
+
+Returns the u/v coordinates for the top left and bottom right corners of the
+bitmap within the used texture, in fractional coordinates in the range
+[0.0 , 1.0]. These are not guaranteed to be 0.0 and 1.0, as may be in the case 
+of sub bitmaps and bitmaps smaller than the actual texture size, which may
+happen when bitmap sizes need to be powers of two.
+
+Returns true on success, false on failure. On failure, the data in the pointers
+passed into the function is unchanged.
+
+See also : [al_get_opengl_texture_coordinates]
 
 ## API: al_get_opengl_program_object
 
diff --git a/include/allegro5/allegro_opengl.h b/include/allegro5/allegro_opengl.h
index 0f86a67..17b7081 100644
--- a/include/allegro5/allegro_opengl.h
+++ b/include/allegro5/allegro_opengl.h
@@ -164,20 +164,28 @@ typedef enum ALLEGRO_OPENGL_VARIANT {
    ALLEGRO_OPENGL_ES
 } ALLEGRO_OPENGL_VARIANT;
 
-AL_FUNC(uint32_t,              al_get_opengl_version,            (void));
-AL_FUNC(bool,                  al_have_opengl_extension,         (const char *extension));
-AL_FUNC(void*,                 al_get_opengl_proc_address,       (const char *name));
-AL_FUNC(ALLEGRO_OGL_EXT_LIST*, al_get_opengl_extension_list,     (void));
-AL_FUNC(GLuint,                al_get_opengl_texture,            (ALLEGRO_BITMAP *bitmap));
-AL_FUNC(void,                  al_remove_opengl_fbo,             (ALLEGRO_BITMAP *bitmap));
-AL_FUNC(GLuint,                al_get_opengl_fbo,                (ALLEGRO_BITMAP *bitmap));
-AL_FUNC(bool,                  al_get_opengl_texture_size,       (ALLEGRO_BITMAP *bitmap,
-                                                                  int *w, int *h));
-AL_FUNC(void,                  al_get_opengl_texture_position,   (ALLEGRO_BITMAP *bitmap,
-                                                                  int *u, int *v));
-AL_FUNC(GLuint,                al_get_opengl_program_object,     (ALLEGRO_SHADER *shader));
-AL_FUNC(void,                  al_set_current_opengl_context,    (ALLEGRO_DISPLAY *display));
-AL_FUNC(int,                   al_get_opengl_variant,            (void));
+AL_FUNC(uint32_t,              al_get_opengl_version,              (void));
+AL_FUNC(bool,                  al_have_opengl_extension,           (const char *extension));
+AL_FUNC(void*,                 al_get_opengl_proc_address,         (const char *name));
+AL_FUNC(ALLEGRO_OGL_EXT_LIST*, al_get_opengl_extension_list,       (void));
+AL_FUNC(GLuint,                al_get_opengl_texture,              (ALLEGRO_BITMAP *bitmap));
+AL_FUNC(void,                  al_remove_opengl_fbo,               (ALLEGRO_BITMAP *bitmap));
+AL_FUNC(GLuint,                al_get_opengl_fbo,                  (ALLEGRO_BITMAP *bitmap));
+AL_FUNC(bool,                  al_get_opengl_texture_size,         (ALLEGRO_BITMAP *bitmap,
+                                                                    int *w, int *h));
+AL_FUNC(bool,                  al_get_opengl_texture_size_f,       (ALLEGRO_BITMAP *bitmap,
+                                                                    float *w, float *h));
+AL_FUNC(void,                  al_get_opengl_texture_position,     (ALLEGRO_BITMAP *bitmap,
+                                                                    int *u, int *v));
+AL_FUNC(bool,                  al_get_opengl_texture_position_f,   (ALLEGRO_BITMAP* bitmap,
+                                                                    float* u , float* v));
+AL_FUNC(void,                  al_get_opengl_texture_coordinates,  (ALLEGRO_BITMAP* bitmap,
+                                                                    int* lx , int* ty , int* rx , int* by));
+AL_FUNC(bool,                  al_get_opengl_texture_coordinates_f,(ALLEGRO_BITMAP* bitmap,
+                                                                    float* lx , float* ty , float* rx , float* by));
+AL_FUNC(GLuint,                al_get_opengl_program_object,       (ALLEGRO_SHADER *shader));
+AL_FUNC(void,                  al_set_current_opengl_context,      (ALLEGRO_DISPLAY *display));
+AL_FUNC(int,                   al_get_opengl_variant,              (void));
 
 #ifdef __cplusplus
    }
diff --git a/src/opengl/ogl_bitmap.c b/src/opengl/ogl_bitmap.c
index cf76a1c..e9e270f 100644
--- a/src/opengl/ogl_bitmap.c
+++ b/src/opengl/ogl_bitmap.c
@@ -1212,6 +1212,25 @@ bool al_get_opengl_texture_size(ALLEGRO_BITMAP *bitmap, int *w, int *h)
    return true;
 }
 
+/* Function: al_get_opengl_texture_size_f
+ */
+bool al_get_opengl_texture_size_f(ALLEGRO_BITMAP *bitmap, float *w, float *h)
+{
+   /* The designers of OpenGL ES 1.0 forgot to add a function to query
+    * texture sizes, so this will be the only way there to get the texture
+    * size. On normal OpenGL also glGetTexLevelParameter could be used.
+    */
+   int iw = 0;
+   int ih = 0;
+   
+   if (!al_get_opengl_texture_size(&iw , &ih)) {
+      return false;
+   }
+   *w = al_get_bitmap_width(bitmap) / (float)iw;
+   *h = al_get_bitmap_height(bitmap) / (float)ih;
+   return true;
+}
+
 /* Function: al_get_opengl_texture_position
  */
 void al_get_opengl_texture_position(ALLEGRO_BITMAP *bitmap, int *u, int *v)
@@ -1224,4 +1243,69 @@ void al_get_opengl_texture_position(ALLEGRO_BITMAP *bitmap, int *u, int *v)
    *v = bitmap->yofs;
 }
 
+/* Function: al_get_opengl_texture_position_f
+ */
+bool al_get_opengl_texture_position_f(ALLEGRO_BITMAP* bitmap , float* u , float* v)
+{
+   int iu = 0;
+   int iv = 0;
+   int tw = 0;
+   int th = 0;
+
+   ASSERT(bitmap);
+   ASSERT(u);
+   ASSERT(v);
+   
+   al_get_opengl_texture_position(bitmap , &iu , &iv);
+   if (!al_get_opengl_texture_size(bitmap , &tw , &th)) {
+      return false;
+   }
+   *u = (float)iu / tw;
+   *v = (float)iv / th;
+   return true;
+}
+
+/* Function: al_get_opengl_texture_coordinates
+ */
+void al_get_opengl_texture_coordinates(ALLEGRO_BITMAP* bitmap , int* lx , int* ty , int* rx , int* by)
+{
+   ASSERT(bitmap);
+   ASSERT(lx);
+   ASSERT(ty);
+   ASSERT(rx);
+   ASSERT(by);
+   
+   al_get_opengl_texture_position(bitmap , lx , ty);
+   *rx = *lx + al_get_bitmap_width(bitmap);
+   *by = *ty + al_get_bitmap_height(bitmap);
+}
+
+/* Function: al_get_opengl_texture_coordinates_f
+ */
+bool al_get_opengl_texture_coordinates_f(ALLEGRO_BITMAP* bitmap , float* lx , float* ty , float* rx , float* by)
+{
+   int ilx = 0;
+   int ity = 0;
+   int irx = 0;
+   int iby = 0;
+   int tw = 0;
+   int th = 0;
+   
+   ASSERT(bitmap);
+   ASSERT(lx);
+   ASSERT(ty);
+   ASSERT(rx);
+   ASSERT(by);
+   
+   al_get_opengl_texture_coordinates(bitmap , &ilx , &ity , &irx , &iby);
+   if (!al_get_opengl_texture_size(bitmap , &tw , &th)) {
+      return false;
+   }
+   *lx = (float)ilx / tw;
+   *ty = (float)ity / th;
+   *rx = (float)irx / tw;
+   *by = (float)iby / th;
+   return true;
+}
+
 /* vim: set sts=3 sw=3 et: */