[rmodels] Consistent `DrawBillboardPro` with `DrawTexturePro` (#4132)

* [rmodels] Re-implement `DrawBillboardPro`

* [rmodels] Add comments to `DrawBillboardPro`

* [rmodels] Make `DrawBillboardPro` consistent with `DrawTexturePro`

* Update raylib_api.* by CI

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/examples/models/models_billboard.c b/examples/models/models_billboard.c
index 237e1b69..7ad28513 100644
--- a/examples/models/models_billboard.c
+++ b/examples/models/models_billboard.c
@@ -44,10 +44,12 @@ int main(void)
     // NOTE: Billboard locked on axis-Y
     Vector3 billUp = { 0.0f, 1.0f, 0.0f };
 
+    // Set the height of the rotating billboard to 1.0 with the aspect ratio fixed
+    Vector2 size = { source.width / source.height, 1.0f };
+
     // Rotate around origin
     // Here we choose to rotate around the image center
-    // NOTE: (-1, 1) is the range where origin.x, origin.y is inside the texture
-    Vector2 rotateOrigin = { 0.0f };
+    Vector2 origin = Vector2Scale(size, 0.5f);
 
     // Distance is needed for the correct billboard draw order
     // Larger distance (further away from the camera) should be drawn prior to smaller distance.
@@ -84,11 +86,11 @@ int main(void)
                 if (distanceStatic > distanceRotating) 
                 {
                     DrawBillboard(camera, bill, billPositionStatic, 2.0f, WHITE);
-                    DrawBillboardPro(camera, bill, source, billPositionRotating, billUp, (Vector2) {1.0f, 1.0f}, rotateOrigin, rotation, WHITE);
+                    DrawBillboardPro(camera, bill, source, billPositionRotating, billUp, size, origin, rotation, WHITE);
                 } 
                 else
                 {
-                    DrawBillboardPro(camera, bill, source, billPositionRotating, billUp, (Vector2) {1.0f, 1.0f}, rotateOrigin, rotation, WHITE);
+                    DrawBillboardPro(camera, bill, source, billPositionRotating, billUp, size, origin, rotation, WHITE);
                     DrawBillboard(camera, bill, billPositionStatic, 2.0f, WHITE);
                 }
                 
@@ -108,4 +110,4 @@ int main(void)
     //--------------------------------------------------------------------------------------
 
     return 0;
-}
\ No newline at end of file
+}