Avoid calling powf with integer exponent in more places

Move powX functions from particle code into math library and use them.

source/blender/blenkernel/intern/brush.c

@@ -1048,7 +1048,7 @@ struct ImBuf *BKE_brush_gen_radial_control_imbuf(Brush *br, bool secondary)
 
 	for (i = 0; i < side; ++i) {
 		for (j = 0; j < side; ++j) {
-			float magn = sqrtf(powf(i - half, 2) + powf(j - half, 2));
+			float magn = sqrtf(pow2f(i - half) + pow2f(j - half));
 			im->rect_float[i * side + j] = BKE_brush_curve_strength_clamp(br, magn, half);
 		}
 	}

source/blender/blenkernel/intern/cloth.c

@@ -789,7 +789,7 @@ static void cloth_apply_vgroup ( ClothModifierData *clmd, DerivedMesh *dm )
 						// Kicking goal factor to simplify things...who uses that anyway?
 						// ABS ( clmd->sim_parms->maxgoal - clmd->sim_parms->mingoal );
 						
-						verts->goal  = powf(verts->goal, 4.0f);
+						verts->goal  = pow4f(verts->goal);
 						if ( verts->goal >= SOFTGOALSNAP )
 							verts->flags |= CLOTH_VERT_FLAG_PINNED;
 					}

source/blender/blenkernel/intern/particle_system.c

@@ -2764,24 +2764,6 @@ static void sph_force_cb(void *sphdata_v, ParticleKey *state, float *force, floa
 	sphdata->pass++;
 }
 
-/* powf is really slow for raising to integer powers. */
-MINLINE float pow2(float x)
-{
-	return x * x;
-}
-MINLINE float pow3(float x)
-{
-	return pow2(x) * x;
-}
-MINLINE float pow4(float x)
-{
-	return pow2(pow2(x));
-}
-MINLINE float pow7(float x)
-{
-	return pow2(pow3(x)) * x;
-}
-
 static void sphclassical_density_accum_cb(void *userdata, int index, float UNUSED(squared_dist))
 {
 	SPHRangeData *pfr = (SPHRangeData *)userdata;
@@ -2803,7 +2785,7 @@ static void sphclassical_density_accum_cb(void *userdata, int index, float UNUSE
 	/* Smoothing factor. Utilise the Wendland kernel. gnuplot:
 	 *     q1(x) = (2.0 - x)**4 * ( 1.0 + 2.0 * x)
 	 *     plot [0:2] q1(x) */
-	q  = qfac / pow3(pfr->h) * pow4(2.0f - rij_h) * ( 1.0f + 2.0f * rij_h);
+	q  = qfac / pow3f(pfr->h) * pow4f(2.0f - rij_h) * ( 1.0f + 2.0f * rij_h);
 	q *= pfr->npsys->part->mass;
 
 	if (pfr->use_size)
@@ -2857,7 +2839,7 @@ static void sphclassical_force_cb(void *sphdata_v, ParticleKey *state, float *fo
 	float rest_density = fluid->rest_density * (fluid->flag & SPH_FAC_DENSITY ? 4.77f : 1.0f);
 
 	// Use speed of sound squared
-	float stiffness = pow2(fluid->stiffness_k);
+	float stiffness = pow2f(fluid->stiffness_k);
 
 	ParticleData *npa;
 	float vec[3];
@@ -2878,10 +2860,10 @@ static void sphclassical_force_cb(void *sphdata_v, ParticleKey *state, float *fo
 	pfr.pa = pa;
 
 	sph_evaluate_func(NULL, psys, state->co, &pfr, interaction_radius, sphclassical_neighbour_accum_cb);
-	pressure =  stiffness * (pow7(pa->sphdensity / rest_density) - 1.0f);
+	pressure =  stiffness * (pow7f(pa->sphdensity / rest_density) - 1.0f);
 
 	/* multiply by mass so that we return a force, not accel */
-	qfac2 *= sphdata->mass / pow3(pfr.h);
+	qfac2 *= sphdata->mass / pow3f(pfr.h);
 
 	pfn = pfr.neighbors;
 	for (i = 0; i < pfr.tot_neighbors; i++, pfn++) {
@@ -2902,19 +2884,19 @@ static void sphclassical_force_cb(void *sphdata_v, ParticleKey *state, float *fo
 		if (rij_h > 2.0f)
 			continue;
 
-		npressure = stiffness * (pow7(npa->sphdensity / rest_density) - 1.0f);
+		npressure = stiffness * (pow7f(npa->sphdensity / rest_density) - 1.0f);
 
 		/* First derivative of smoothing factor. Utilise the Wendland kernel.
 		 * gnuplot:
 		 *     q2(x) = 2.0 * (2.0 - x)**4 - 4.0 * (2.0 - x)**3 * (1.0 + 2.0 * x)
 		 *     plot [0:2] q2(x)
 		 * Particles > 2h away are excluded above. */
-		dq = qfac2 * (2.0f * pow4(2.0f - rij_h) - 4.0f * pow3(2.0f - rij_h) * (1.0f + 2.0f * rij_h)  );
+		dq = qfac2 * (2.0f * pow4f(2.0f - rij_h) - 4.0f * pow3f(2.0f - rij_h) * (1.0f + 2.0f * rij_h)  );
 
 		if (pfn->psys->part->flag & PART_SIZEMASS)
 			dq *= npa->size;
 
-		pressureTerm = pressure / pow2(pa->sphdensity) + npressure / pow2(npa->sphdensity);
+		pressureTerm = pressure / pow2f(pa->sphdensity) + npressure / pow2f(npa->sphdensity);
 
 		/* Note that 'minus' is removed, because vec = vecBA, not vecAB.
 		 * This applies to the viscosity calculation below, too. */

source/blender/blenkernel/intern/smoke.c

@@ -2020,7 +2020,7 @@ BLI_INLINE void apply_inflow_fields(SmokeFlowSettings *sfs, float emission_value
 	if (fuel && fuel[index] > FLT_EPSILON) {
 		/* instead of using 1.0 for all new fuel add slight falloff
 		 * to reduce flow blockiness */
-		float value = 1.0f - powf(1.0f - emission_value, 2.0f);
+		float value = 1.0f - pow2f(1.0f - emission_value);
 
 		if (value > react[index]) {
 			float f = fuel_flow / fuel[index];

source/blender/blenlib/BLI_math_base.h

@@ -157,6 +157,11 @@ static const int NAN_INT = 0x7FC00000;
 
 /******************************* Float ******************************/
 
+MINLINE float pow2f(float x);
+MINLINE float pow3f(float x);
+MINLINE float pow4f(float x);
+MINLINE float pow7f(float x);
+
 MINLINE float sqrt3f(float f);
 MINLINE double sqrt3d(double d);
 

source/blender/blenlib/intern/math_base_inline.c

@@ -44,6 +44,24 @@
 #  define UNLIKELY(x)     (x)
 #endif
 
+/* powf is really slow for raising to integer powers. */
+MINLINE float pow2f(float x)
+{
+	return x * x;
+}
+MINLINE float pow3f(float x)
+{
+	return pow2f(x) * x;
+}
+MINLINE float pow4f(float x)
+{
+	return pow2f(pow2f(x));
+}
+MINLINE float pow7f(float x)
+{
+	return pow2f(pow3f(x)) * x;
+}
+
 MINLINE float sqrt3f(float f)
 {
 	if      (UNLIKELY(f == 0.0f)) return 0.0f;

source/blender/editors/interface/interface_handlers.c

@@ -5381,7 +5381,7 @@ static bool ui_numedit_but_HISTOGRAM(uiBut *but, uiHandleButtonData *data, int m
 	float dy = my - data->draglasty;
 
 	/* scale histogram values (dy / 10 for better control) */
-	const float yfac = min_ff(powf(hist->ymax, 2.0f), 1.0f) * 0.5f;
+	const float yfac = min_ff(pow2f(hist->ymax), 1.0f) * 0.5f;
 	hist->ymax += (dy * 0.1f) * yfac;
 
 	/* 0.1 allows us to see HDR colors up to 10 */

source/blender/editors/interface/interface_widgets.c

@@ -2119,7 +2119,7 @@ void ui_hsvcircle_pos_from_vals(uiBut *but, const rcti *rect, float *hsv, float
 	ang = 2.0f * (float)M_PI * hsv[0] + 0.5f * (float)M_PI;
 	
 	if ((but->flag & UI_BUT_COLOR_CUBIC) && (U.color_picker_type == USER_CP_CIRCLE_HSV))
-		radius_t = (1.0f - powf(1.0f - hsv[1], 3.0f));
+		radius_t = (1.0f - pow3f(1.0f - hsv[1]));
 	else
 		radius_t = hsv[1];
 	

source/blender/editors/space_view3d/drawobject.c

@@ -1331,7 +1331,7 @@ static void drawlamp(View3D *v3d, RegionView3D *rv3d, Base *base,
 
 		/* draw the circle/square representing spotbl */
 		if (la->type == LA_SPOT) {
-			float spotblcirc = fabsf(z) * (1.0f - powf(la->spotblend, 2));
+			float spotblcirc = fabsf(z) * (1.0f - pow2f(la->spotblend));
 			/* hide line if it is zero size or overlaps with outer border,
 			 * previously it adjusted to always to show it but that seems
 			 * confusing because it doesn't show the actual blend size */

source/blender/editors/uvedit/uvedit_draw.c

@@ -325,7 +325,7 @@ static void draw_uvs_stretch(SpaceImage *sima, Scene *scene, BMEditMesh *em, MTe
 					BM_ITER_ELEM_INDEX (l, &liter, efa, BM_LOOPS_OF_FACE, i) {
 						luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
 						a = fabsf(uvang[i] - ang[i]) / (float)M_PI;
-						weight_to_rgb(col, 1.0f - powf((1.0f - a), 2.0f));
+						weight_to_rgb(col, 1.0f - pow2f(1.0f - a));
 						glColor3fv(col);
 						glVertex2fv(luv->uv);
 					}

source/blender/render/intern/source/rayshade.c

@@ -1299,7 +1299,7 @@ static void trace_refract(float col[4], ShadeInput *shi, ShadeResult *shr)
 	float v_refract[3], v_refract_new[3];
 	float sampcol[4], colsq[4];
 	
-	float blur = powf(1.0f - shi->mat->gloss_tra, 3);
+	float blur = pow3f(1.0f - shi->mat->gloss_tra);
 	short max_samples = shi->mat->samp_gloss_tra;
 	float adapt_thresh = shi->mat->adapt_thresh_tra;
 	
@@ -1400,7 +1400,7 @@ static void trace_reflect(float col[3], ShadeInput *shi, ShadeResult *shr, float
 	float v_nor_new[3], v_reflect[3];
 	float sampcol[4], colsq[4];
 		
-	float blur = powf(1.0f - shi->mat->gloss_mir, 3);
+	float blur = pow3f(1.0f - shi->mat->gloss_mir);
 	short max_samples = shi->mat->samp_gloss_mir;
 	float adapt_thresh = shi->mat->adapt_thresh_mir;
 	float aniso = 1.0f - shi->mat->aniso_gloss_mir;