Optimized Rect multi-collision methods (#2786)

* optimized rect multi-collision methods

* fix

* Addressed reviews, added more comments, swapped Py_BuildValue for PyTuple_Pack.

* addressed review

* addressed reviews

Author: itzpr3d4t0r

src_c/rect_impl.h

@@ -1292,17 +1292,47 @@ RectExport_colliderect(RectObject *self, PyObject *const *args,
     return PyBool_FromLong(_pg_do_rects_intersect(&self->r, argrect));
 }
 
+#ifndef OPTIMIZED_COLLIDERECT_SETUP
+/* This macro is used to optimize the colliderect function. It calculates
+ * the left, top, right and bottom values of the calling rect only once
+ * and uses them in the OPTIMIZED_COLLIDERECT macro. */
+#define OPTIMIZED_COLLIDERECT_SETUP                                 \
+    const PrimitiveType left = MIN(srect->x, srect->x + srect->w);  \
+    const PrimitiveType top = MIN(srect->y, srect->y + srect->h);   \
+    const PrimitiveType right = MAX(srect->x, srect->x + srect->w); \
+    const PrimitiveType bottom = MAX(srect->y, srect->y + srect->h);
+#endif
+
+#ifndef OPTIMIZED_COLLIDERECT
+/* This macro is used to optimize the colliderect function. Makes use of
+ * precalculated values to avoid unnecessary calculations. It also checks
+ * whether the other rect has 0 width or height, in which case we don't
+ * collide. */
+#define OPTIMIZED_COLLIDERECT(r)                                       \
+    (r->w && r->h && left < MAX(r->x, r->x + r->w) &&                  \
+     top < MAX(r->y, r->y + r->h) && right > MIN(r->x, r->x + r->w) && \
+     bottom > MIN(r->y, r->y + r->h))
+#endif
+
 static PyObject *
 RectExport_collidelist(RectObject *self, PyObject *arg)
 {
     InnerRect *argrect, *srect = &self->r, temp;
     int loop;
 
+    /* If the calling rect has 0 width or height, it cannot collide with
+     * anything, hence return -1 directly. */
+    if (srect->w == 0 || srect->h == 0) {
+        return PyLong_FromLong(-1);
+    }
+
     if (!PySequence_Check(arg)) {
         return RAISE(PyExc_TypeError,
                      "Argument must be a sequence of rectstyle objects.");
     }
 
+    OPTIMIZED_COLLIDERECT_SETUP;
+
     /* If the sequence is a fast sequence, we can use the faster
      * PySequence_Fast_ITEMS() function to get the items. */
     if (pgSequenceFast_Check(arg)) {
@@ -1313,16 +1343,17 @@ RectExport_collidelist(RectObject *self, PyObject *arg)
                     PyExc_TypeError,
                     "Argument must be a sequence of rectstyle objects.");
             }
-            if (_pg_do_rects_intersect(srect, argrect)) {
+
+            if (OPTIMIZED_COLLIDERECT(argrect)) {
                 return PyLong_FromLong(loop);
             }
         }
     }
     /* If the sequence is not a fast sequence, we have to use the slower
-     * PySequence_GetItem() function to get the items. */
+     * PySequence_ITEM() function to get the items. */
     else {
         for (loop = 0; loop < PySequence_Length(arg); loop++) {
-            PyObject *obj = PySequence_GetItem(arg, loop);
+            PyObject *obj = PySequence_ITEM(arg, loop);
 
             if (!obj || !(argrect = RectFromObject(obj, &temp))) {
                 Py_XDECREF(obj);
@@ -1333,7 +1364,7 @@ RectExport_collidelist(RectObject *self, PyObject *arg)
 
             Py_DECREF(obj);
 
-            if (_pg_do_rects_intersect(srect, argrect)) {
+            if (OPTIMIZED_COLLIDERECT(argrect)) {
                 return PyLong_FromLong(loop);
             }
         }
@@ -1358,6 +1389,14 @@ RectExport_collidelistall(RectObject *self, PyObject *arg)
         return NULL;
     }
 
+    /* If the calling rect has 0 width or height, it cannot collide with
+     * anything, hence return an empty list directly. */
+    if (srect->w == 0 || srect->h == 0) {
+        return ret;
+    }
+
+    OPTIMIZED_COLLIDERECT_SETUP;
+
     /* If the sequence is a fast sequence, we can use the faster
      * PySequence_Fast_ITEMS() function to get the items. */
     if (pgSequenceFast_Check(arg)) {
@@ -1370,7 +1409,7 @@ RectExport_collidelistall(RectObject *self, PyObject *arg)
                     "Argument must be a sequence of rectstyle objects.");
             }
 
-            if (_pg_do_rects_intersect(srect, argrect)) {
+            if (OPTIMIZED_COLLIDERECT(argrect)) {
                 PyObject *num = PyLong_FromLong(loop);
                 if (!num) {
                     Py_DECREF(ret);
@@ -1400,7 +1439,7 @@ RectExport_collidelistall(RectObject *self, PyObject *arg)
 
             Py_DECREF(obj);
 
-            if (_pg_do_rects_intersect(srect, argrect)) {
+            if (OPTIMIZED_COLLIDERECT(argrect)) {
                 PyObject *num = PyLong_FromLong(loop);
                 if (!num) {
                     Py_DECREF(ret);
@@ -1452,7 +1491,7 @@ static PyObject *
 RectExport_collideobjectsall(RectObject *self, PyObject *args,
                              PyObject *kwargs)
 {
-    InnerRect *argrect;
+    InnerRect *argrect, *srect = &self->r;
     InnerRect temp;
     Py_ssize_t size;
     int loop;
@@ -1485,14 +1524,22 @@ RectExport_collideobjectsall(RectObject *self, PyObject *args,
         return NULL;
     }
 
+    /* If the calling rect has 0 width or height, it cannot collide with
+     * anything, hence return an empty list directly. */
+    if (srect->w == 0 || srect->h == 0) {
+        return ret;
+    }
+
+    OPTIMIZED_COLLIDERECT_SETUP;
+
     size = PySequence_Length(list);
     if (size == -1) {
         Py_DECREF(ret);
         return NULL;
     }
 
     for (loop = 0; loop < size; ++loop) {
-        obj = PySequence_GetItem(list, loop);
+        obj = PySequence_ITEM(list, loop);
 
         if (!obj) {
             Py_DECREF(ret);
@@ -1506,7 +1553,7 @@ RectExport_collideobjectsall(RectObject *self, PyObject *args,
             return NULL;
         }
 
-        if (_pg_do_rects_intersect(&self->r, argrect)) {
+        if (OPTIMIZED_COLLIDERECT(argrect)) {
             if (0 != PyList_Append(ret, obj)) {
                 Py_DECREF(ret);
                 Py_DECREF(obj);
@@ -1522,7 +1569,7 @@ RectExport_collideobjectsall(RectObject *self, PyObject *args,
 static PyObject *
 RectExport_collideobjects(RectObject *self, PyObject *args, PyObject *kwargs)
 {
-    InnerRect *argrect;
+    InnerRect *argrect, *srect = &self->r;
     InnerRect temp;
     Py_ssize_t size;
     int loop;
@@ -1549,13 +1596,21 @@ RectExport_collideobjects(RectObject *self, PyObject *args, PyObject *kwargs)
                      "Key function must be callable with one argument.");
     }
 
+    /* If the calling rect has 0 width or height, it cannot collide with
+     * anything, hence return None directly. */
+    if (srect->w == 0 || srect->h == 0) {
+        Py_RETURN_NONE;
+    }
+
+    OPTIMIZED_COLLIDERECT_SETUP;
+
     size = PySequence_Length(list);
     if (size == -1) {
         return NULL;
     }
 
     for (loop = 0; loop < size; ++loop) {
-        obj = PySequence_GetItem(list, loop);
+        obj = PySequence_ITEM(list, loop);
 
         if (!obj) {
             return NULL;
@@ -1567,7 +1622,7 @@ RectExport_collideobjects(RectObject *self, PyObject *args, PyObject *kwargs)
             return NULL;
         }
 
-        if (_pg_do_rects_intersect(&self->r, argrect)) {
+        if (OPTIMIZED_COLLIDERECT(argrect)) {
             return obj;
         }
         Py_DECREF(obj);
@@ -1579,7 +1634,7 @@ RectExport_collideobjects(RectObject *self, PyObject *args, PyObject *kwargs)
 static PyObject *
 RectExport_collidedict(RectObject *self, PyObject *args, PyObject *kwargs)
 {
-    InnerRect *argrect, temp;
+    InnerRect *argrect, temp, *srect = &self->r;
     Py_ssize_t loop = 0;
     Py_ssize_t values = 0; /* Defaults to expecting keys as rects. */
     PyObject *dict, *key, *val;
@@ -1596,6 +1651,14 @@ RectExport_collidedict(RectObject *self, PyObject *args, PyObject *kwargs)
         return RAISE(PyExc_TypeError, "first argument must be a dict");
     }
 
+    /* If the calling rect has 0 width or height, it cannot collide with
+     * anything, hence return None directly. */
+    if (srect->w == 0 || srect->h == 0) {
+        Py_RETURN_NONE;
+    }
+
+    OPTIMIZED_COLLIDERECT_SETUP;
+
     while (PyDict_Next(dict, &loop, &key, &val)) {
         if (values) {
             if (!(argrect = RectFromObject(val, &temp))) {
@@ -1609,8 +1672,8 @@ RectExport_collidedict(RectObject *self, PyObject *args, PyObject *kwargs)
             }
         }
 
-        if (_pg_do_rects_intersect(&self->r, argrect)) {
-            ret = Py_BuildValue("(OO)", key, val);
+        if (OPTIMIZED_COLLIDERECT(argrect)) {
+            ret = PyTuple_Pack(2, key, val);
             break;
         }
     }
@@ -1624,7 +1687,7 @@ RectExport_collidedict(RectObject *self, PyObject *args, PyObject *kwargs)
 static PyObject *
 RectExport_collidedictall(RectObject *self, PyObject *args, PyObject *kwargs)
 {
-    InnerRect *argrect, temp;
+    InnerRect *argrect, temp, *srect = &self->r;
     Py_ssize_t loop = 0;
     Py_ssize_t values = 0; /* Defaults to expecting keys as rects. */
     PyObject *dict, *key, *val;
@@ -1645,6 +1708,14 @@ RectExport_collidedictall(RectObject *self, PyObject *args, PyObject *kwargs)
     if (!ret)
         return NULL;
 
+    /* If the calling rect has 0 width or height, it cannot collide with
+     * anything, hence return an empty list directly. */
+    if (srect->w == 0 || srect->h == 0) {
+        return ret;
+    }
+
+    OPTIMIZED_COLLIDERECT_SETUP;
+
     while (PyDict_Next(dict, &loop, &key, &val)) {
         if (values) {
             if (!(argrect = RectFromObject(val, &temp))) {
@@ -1660,8 +1731,8 @@ RectExport_collidedictall(RectObject *self, PyObject *args, PyObject *kwargs)
             }
         }
 
-        if (_pg_do_rects_intersect(&self->r, argrect)) {
-            PyObject *num = Py_BuildValue("(OO)", key, val);
+        if (OPTIMIZED_COLLIDERECT(argrect)) {
+            PyObject *num = PyTuple_Pack(2, key, val);
             if (!num) {
                 Py_DECREF(ret);
                 return NULL;