rearranged previous patch to compile with C89

conversion to double probably not needed
better comments

source/blender/makesrna/intern/rna_brush.c

@@ -168,11 +168,14 @@ static void rna_Brush_set_size(PointerRNA *ptr, int value)
 {
 	Brush* me = (Brush*)(ptr->data);
 
-	// set unprojected radius, so they remain consistent
-	double size= (double)brush_size(me);
-	float unprojected_radius = 0.0f;
-	assert(size != 0); // paranoia: sanity checks during load and rna make sure we don't divide by zero here
-	unprojected_radius= (float)(brush_unprojected_radius(me) * (double)value / size);
+	float size= (float)brush_size(me);
+	float unprojected_radius;
+
+	// paranoia: previous checks should make sure we don't divide by zero
+	assert(size != 0);
+
+	// set unprojected radius, so it remains consistent with size
+	unprojected_radius= (float)(brush_unprojected_radius(me) * value / size);
 	brush_set_unprojected_radius(me, unprojected_radius);
 
 	brush_set_size(me, value);
@@ -224,11 +227,14 @@ static void rna_Brush_set_unprojected_radius(PointerRNA *ptr, float value)
 {
 	Brush* me = (Brush*)(ptr->data);
 
-	// set size, so they remain consistent
-	double unprojected_radius= (double)brush_unprojected_radius(me);
-	int size = 0;
-	assert(unprojected_radius != 0); // paranoia: sanity checks during load and rna make sure we don't divide by zero here
-	size= (int)((double)brush_size(me) * (double)value / unprojected_radius);
+	float unprojected_radius= brush_unprojected_radius(me);
+	int size;
+
+	// paranoia: previous checks should make sure we don't divide by zero
+	assert(unprojected_radius != 0.0f);
+
+	// set size, so that it is consistent with unprojected_radius
+	size= (int)((float)brush_size(me) * value / unprojected_radius);
 	brush_set_size(me, size);
 
 	brush_set_unprojected_radius(me, value);