Restructure find_center()

* return bool for success/failure
* use an out-vector to store the result
* fix tests

src/gl_draw.c

@@ -96,9 +96,12 @@ static void draw_obj(uint32_t const myxrot,
 	static uint32_t xrot = 0,
 					yrot = 0,
 					zrot = 0;
-	HE_vert *center_vert = find_center(obj);
+	vector center_vert;
 	float scalefactor = get_normalized_scale_factor(obj) * VISIBILITY_FACTOR;
 
+	if (!find_center(obj, &center_vert))
+		return; /* TODO: better error handling */
+
 	xrot += myxrot;
 	yrot += myyrot;
 	zrot += myzrot;
@@ -116,9 +119,9 @@ static void draw_obj(uint32_t const myxrot,
 	glTranslatef(0.0f, 0.0f, SYSTEM_POS_Z_BACK);
 
 	/* pull into middle of universe */
-	glTranslatef(-center_vert->x,
-			-center_vert->y,
-			-center_vert->z + SYSTEM_POS_Z);
+	glTranslatef(-center_vert.x,
+			-center_vert.y,
+			-center_vert.z + SYSTEM_POS_Z);
 
 	glBegin(GL_POLYGON);
 	glColor3f(0.0f, 1.0f, 0.0f);
@@ -126,8 +129,6 @@ static void draw_obj(uint32_t const myxrot,
 	glEnd();
 
 	glPopMatrix();
-
-	free(center_vert);
 }
 
 /**

src/half_edge.c

@@ -27,7 +27,9 @@
 #include "err.h"
 #include "filereader.h"
 #include "half_edge.h"
+#include "vector.h"
 
+#include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -50,21 +52,19 @@ HE_edge **get_all_emanating_edges(HE_vert *vertice)
  * in a HE_vert struct.
  *
  * @param obj the object we want to find the center of
- * @return newly allocated HE_vert with empty edge member
- * and coordinates which represent the middle of the object
+ * @param vec the vector to store the result in [out]
+ * @return true/false for success/failure
  */
-HE_vert *find_center(HE_obj const * const obj)
+bool find_center(HE_obj const * const obj, vector *vec)
 {
 	float x = 0,
 		  y = 0,
 		  z = 0;
 	uint32_t i;
-	HE_vert *newvert;
 
-	if (!obj)
-		return NULL;
+	if (!obj || !vec)
+		return false;
 
-	newvert = malloc(sizeof(HE_vert));
 
 	for (i = 0; i < obj->vc; i++) {
 		x += obj->vertices[i].x;
@@ -72,12 +72,11 @@ HE_vert *find_center(HE_obj const * const obj)
 		z += obj->vertices[i].z;
 	}
 
-	newvert->x = x / i;
-	newvert->y = y / i;
-	newvert->z = z / i;
-	newvert->edge = NULL;
+	vec->x = x / i;
+	vec->y = y / i;
+	vec->z = z / i;
 
-	return newvert;
+	return true;
 }
 
 /**

src/half_edge.h

@@ -28,6 +28,9 @@
 #define _DROW_ENGINE_HE_OPERATIONS_H
 
 
+#include "vector.h"
+
+#include <stdbool.h>
 #include <stdint.h>
 
 
@@ -124,7 +127,7 @@ struct HE_obj {
 
 
 HE_edge **get_all_emanating_edges(HE_vert *vertice);
-HE_vert *find_center(HE_obj const * const obj);
+bool find_center(HE_obj const * const obj, vector *vec);
 float get_normalized_scale_factor(HE_obj const * const obj);
 HE_obj *parse_obj(char const * const filename);
 

src/test/cunit.c

@@ -106,6 +106,8 @@ int main(void)
 							 test_find_center1)) ||
 		(NULL == CU_add_test(pSuite, "test2 finding center ob obj",
 							 test_find_center2)) ||
+		(NULL == CU_add_test(pSuite, "test3 finding center ob obj",
+							 test_find_center3)) ||
 		(NULL == CU_add_test(pSuite, "test1 getting normalized scale factor",
 							 test_get_normalized_scale_factor1)) ||
 		(NULL == CU_add_test(pSuite, "test2 getting normalized scale factor",

src/test/cunit.h

@@ -45,6 +45,7 @@ void test_parse_obj4(void);
 
 void test_find_center1(void);
 void test_find_center2(void);
+void test_find_center3(void);
 
 void test_get_normalized_scale_factor1(void);
 void test_get_normalized_scale_factor2(void);

src/test/cunit_half_edge.c

@@ -457,13 +457,15 @@ void test_find_center1(void)
 		"f 7 1 3 5\n";
 
 	HE_obj *obj = parse_obj(string);
-	HE_vert *newvert = find_center(obj);
+	vector newvec;
+	bool retval = find_center(obj, &newvec);
 
 	CU_ASSERT_PTR_NOT_NULL(obj);
+	CU_ASSERT_EQUAL(retval, true);
 
-	CU_ASSERT_EQUAL(newvert->x, 10.0);
-	CU_ASSERT_EQUAL(newvert->y, 10.5);
-	CU_ASSERT_EQUAL(newvert->z, 10.0);
+	CU_ASSERT_EQUAL(newvec.x, 10.0);
+	CU_ASSERT_EQUAL(newvec.y, 10.5);
+	CU_ASSERT_EQUAL(newvec.z, 10.0);
 }
 
 /**
@@ -471,9 +473,37 @@ void test_find_center1(void)
  */
 void test_find_center2(void)
 {
-	HE_vert *newvert = find_center(NULL);
+	vector newvec;
+	bool retval = find_center(NULL, &newvec);
 
-	CU_ASSERT_PTR_NULL(newvert);
+	CU_ASSERT_EQUAL(retval, false);
+}
+
+/**
+ * Test error handling by passing a NULL pointer.
+ */
+void test_find_center3(void)
+{
+	char const * const string = ""
+		"v 9.0 10.0 11.0\n"
+		"v 11.0 10.0 11.0\n"
+		"v 9.0 11.0 11.0\n"
+		"v 11.0 11.0 11.0\n"
+		"v 9.0 11.0 9.0\n"
+		"v 11.0 11.0 9.0\n"
+		"v 9.0 10.0 9.0\n"
+		"v 11.0 10.0 9.0\n"
+		"f 1 2 4 3\n"
+		"f 3 4 6 5\n"
+		"f 5 6 8 7\n"
+		"f 7 8 2 1\n"
+		"f 2 8 6 4\n"
+		"f 7 1 3 5\n";
+
+	HE_obj *obj = parse_obj(string);
+	bool retval = find_center(obj, NULL);
+
+	CU_ASSERT_EQUAL(retval, false);
 }
 
 /**
@@ -499,7 +529,6 @@ void test_get_normalized_scale_factor1(void)
 		"f 7 1 3 5\n";
 
 	HE_obj *obj = parse_obj(string);
-	HE_vert *newvert = find_center(obj);
 	float factor = get_normalized_scale_factor(obj);
 
 	CU_ASSERT_PTR_NOT_NULL(obj);