diff --git a/src/Makefile.cfg b/src/Makefile.cfg
index cdd4c3c7..1238050b 100644
--- a/src/Makefile.cfg
+++ b/src/Makefile.cfg
@@ -112,9 +112,7 @@ ifndef GCC295
  WFLAGS+=-Wno-div-by-zero
 endif
 #WFLAGS+=-Wsystem-headers
-ifndef ERRORMODE
-#WFLAGS+=-Wfloat-equal
-endif
+WFLAGS+=-Wfloat-equal
 #WFLAGS+=-Wtraditional
 ifdef VCHELP
  WFLAGS+=-Wdeclaration-after-statement
diff --git a/src/command.c b/src/command.c
index 16f18749..3183ba70 100644
--- a/src/command.c
+++ b/src/command.c
@@ -1102,7 +1102,7 @@ static void Setvalue(consvar_t *var, const char *valstr, boolean stealth)
 		if (var->flags & CV_FLOAT)
 		{
 			double d = atof(valstr);
-			if (!d && valstr[0] != '0')
+			if (fpclassify(d) == FP_ZERO && valstr[0] != '0')
 				v = INT32_MIN;
 			else
 				v = (INT32)(d * FRACUNIT);
diff --git a/src/hardware/hw_bsp.c b/src/hardware/hw_bsp.c
index 53602cc7..21fd85a3 100644
--- a/src/hardware/hw_bsp.c
+++ b/src/hardware/hw_bsp.c
@@ -193,7 +193,7 @@ static polyvertex_t *fracdivline(fdivline_t *bsp, polyvertex_t *v1,
 	v2dy = bsp->dy;
 
 	den = v2dy*v1dx - v2dx*v1dy;
-	if (fabs(den) < 1.0E-36f) // avoid checking exactly for 0.0
+	if (fabsf((float)den) < 1.0E-36f) // avoid checking exactly for 0.0
 		return NULL;       // parallel
 
 	// first check the frac along the polygon segment,
@@ -235,6 +235,11 @@ static boolean SameVertice (polyvertex_t *p1, polyvertex_t *p2)
 		return false;
 	if (p1->y != p2->y)
 		return false;
+#elif 0
+	if (fabsf( p2->x - p1->x ) > 1.0E-36f )
+		return false;
+	if (fabsf( p2->y - p1->y ) > 1.0E-36f )
+		return false;
 #else
 #define  DIVLINE_VERTEX_DIFF   0.45f
 	float ep = DIVLINE_VERTEX_DIFF;
diff --git a/src/hardware/hw_draw.c b/src/hardware/hw_draw.c
index 3963fd93..40d38d05 100644
--- a/src/hardware/hw_draw.c
+++ b/src/hardware/hw_draw.c
@@ -227,14 +227,14 @@ void HWR_DrawFixedPatch(GLPatch_t *gpatch, fixed_t x, fixed_t y, fixed_t pscale,
 				Z_Free(realpatch);
 			}
 			// centre screen
-			if ((float)vid.width != (float)BASEVIDWIDTH * dupx)
+			if (fabsf((float)vid.width - (float)BASEVIDWIDTH * dupx) > 1.0E-36f)
 			{
 				if (option & V_SNAPTORIGHT)
 					cx += ((float)vid.width - ((float)BASEVIDWIDTH * dupx));
 				else if (!(option & V_SNAPTOLEFT))
 					cx += ((float)vid.width - ((float)BASEVIDWIDTH * dupx))/2;
 			}
-			if ((float)vid.height != (float)BASEVIDHEIGHT * dupy)
+			if (fabsf((float)vid.height - (float)BASEVIDHEIGHT * dupy) > 1.0E-36f)
 			{
 				if ((option & (V_SPLITSCREEN|V_SNAPTOBOTTOM)) == (V_SPLITSCREEN|V_SNAPTOBOTTOM))
 					cy += ((float)vid.height/2 - ((float)BASEVIDHEIGHT/2 * dupy));
@@ -375,14 +375,14 @@ void HWR_DrawCroppedPatch(GLPatch_t *gpatch, fixed_t x, fixed_t y, fixed_t pscal
 				Z_Free(realpatch);
 			}
 			// centre screen
-			if ((float)vid.width != (float)BASEVIDWIDTH * dupx)
+			if (fabsf((float)vid.width - (float)BASEVIDWIDTH * dupx) > 1.0E-36f)
 			{
 				if (option & V_SNAPTORIGHT)
 					cx += ((float)vid.width - ((float)BASEVIDWIDTH * dupx));
 				else if (!(option & V_SNAPTOLEFT))
 					cx += ((float)vid.width - ((float)BASEVIDWIDTH * dupx))/2;
 			}
-			if ((float)vid.height != (float)BASEVIDHEIGHT * dupy)
+			if (fabsf((float)vid.height - (float)BASEVIDHEIGHT * dupy) > 1.0E-36f)
 			{
 				if ((option & (V_SPLITSCREEN|V_SNAPTOBOTTOM)) == (V_SPLITSCREEN|V_SNAPTOBOTTOM))
 					cy += ((float)vid.height/2 - ((float)BASEVIDHEIGHT/2 * dupy));
@@ -834,14 +834,14 @@ void HWR_DrawFill(INT32 x, INT32 y, INT32 w, INT32 h, INT32 color)
 		fw *= dupx;
 		fh *= dupy;
 
-		if ((float)vid.width != (float)BASEVIDWIDTH * dupx)
+		if (fabsf((float)vid.width - (float)BASEVIDWIDTH * dupx) > 1.0E-36f)
 		{
 			if (color & V_SNAPTORIGHT)
 				fx += ((float)vid.width - ((float)BASEVIDWIDTH * dupx));
 			else if (!(color & V_SNAPTOLEFT))
 				fx += ((float)vid.width - ((float)BASEVIDWIDTH * dupx)) / 2;
 		}
-		if ((float)vid.height != (float)BASEVIDHEIGHT * dupy)
+		if (fabsf((float)vid.height - (float)BASEVIDHEIGHT * dupy) > 1.0E-36f)
 		{
 			// same thing here
 			if (color & V_SNAPTOBOTTOM)
diff --git a/src/hardware/hw_main.c b/src/hardware/hw_main.c
index db679223..efecac52 100644
--- a/src/hardware/hw_main.c
+++ b/src/hardware/hw_main.c
@@ -4137,7 +4137,7 @@ static void HWR_DrawSpriteShadow(gr_vissprite_t *spr, GLPatch_t *gpatch, float t
 	swallVerts[0].z = swallVerts[3].z = spr->z1;
 	swallVerts[2].z = swallVerts[1].z = spr->z2;
 
-	if (spr->mobj && this_scale != 1.0f)
+	if (spr->mobj && fabsf(this_scale - 1.0f) > 1.0E-36f)
 	{
 		// Always a pixel above the floor, perfectly flat.
 		swallVerts[0].y = swallVerts[1].y = swallVerts[2].y = swallVerts[3].y = spr->ty - gpatch->topoffset * this_scale - (floorheight+3);
@@ -4305,7 +4305,7 @@ static void HWR_SplitSprite(gr_vissprite_t *spr)
 	wallVerts[1].z = wallVerts[2].z = spr->z2;
 
 	wallVerts[2].y = wallVerts[3].y = spr->ty;
-	if (spr->mobj && this_scale != 1.0f)
+	if (spr->mobj && fabsf(this_scale - 1.0f) > 1.0E-36f)
 		wallVerts[0].y = wallVerts[1].y = spr->ty - gpatch->height * this_scale;
 	else
 		wallVerts[0].y = wallVerts[1].y = spr->ty - gpatch->height;
@@ -4595,7 +4595,7 @@ static void HWR_DrawSprite(gr_vissprite_t *spr)
 	wallVerts[0].x = wallVerts[3].x = spr->x1;
 	wallVerts[2].x = wallVerts[1].x = spr->x2;
 	wallVerts[2].y = wallVerts[3].y = spr->ty;
-	if (spr->mobj && this_scale != 1.0f)
+	if (spr->mobj && fabsf(this_scale - 1.0f) > 1.0E-36f)
 		wallVerts[0].y = wallVerts[1].y = spr->ty - gpatch->height * this_scale;
 	else
 		wallVerts[0].y = wallVerts[1].y = spr->ty - gpatch->height;
@@ -4851,7 +4851,7 @@ static void HWR_SortVisSprites(void)
 				best = ds;
 			}
 			// order visprites of same scale by dispoffset, smallest first
-			else if (ds->tz == bestdist && ds->dispoffset < bestdispoffset)
+			else if (fabsf(ds->tz - bestdist) < 1.0E-36f && ds->dispoffset < bestdispoffset)
 			{
 				bestdispoffset = ds->dispoffset;
 				best = ds;
@@ -5772,7 +5772,7 @@ void HWR_SetViewSize(void)
 
 	gr_viewwindowx = (vid.width - gr_viewwidth) / 2;
 	gr_windowcenterx = (float)(vid.width / 2);
-	if (gr_viewwidth == vid.width)
+	if (fabsf(gr_viewwidth - vid.width) < 1.0E-36f)
 	{
 		gr_baseviewwindowy = 0;
 		gr_basewindowcentery = gr_viewheight / 2;               // window top left corner at 0,0
diff --git a/src/hardware/r_opengl/r_opengl.c b/src/hardware/r_opengl/r_opengl.c
index 2d9f4219..b324fced 100644
--- a/src/hardware/r_opengl/r_opengl.c
+++ b/src/hardware/r_opengl/r_opengl.c
@@ -602,7 +602,8 @@ static void GLPerspective(GLdouble fovy, GLdouble aspect)
 	const GLdouble deltaZ = zFar - zNear;
 	GLdouble cotangent;
 
-	if ((deltaZ == 0.0f) || (sine == 0.0f) || (aspect == 0.0f)) {
+	if ((fabsf((float)deltaZ) < 1.0E-36f) || fpclassify(sine) == FP_ZERO || fpclassify(aspect) == FP_ZERO)
+	{
 		return;
 	}
 	cotangent = cos(radians) / sine;
@@ -641,7 +642,7 @@ static void GLProject(GLdouble objX, GLdouble objY, GLdouble objZ,
 			out[2] * projMatrix[2*4+i] +
 			out[3] * projMatrix[3*4+i];
 	}
-	if (in[3] == 0.0f) return;
+	if (fpclassify(in[3]) == FP_ZERO) return;
 	in[0] /= in[3];
 	in[1] /= in[3];
 	in[2] /= in[3];
@@ -1986,7 +1987,7 @@ static  void DrawMD2Ex(INT32 *gl_cmd_buffer, md2_frame_t *frame, INT32 duration,
 
 			pglTexCoord2f(s, t);
 
-			if (!nextframe || pol == 0.0f)
+			if (!nextframe || fpclassify(pol) == FP_ZERO)
 			{
 				pglNormal3f(frame->vertices[pindex].normal[0],
 				            frame->vertices[pindex].normal[1],
@@ -2055,6 +2056,7 @@ EXPORT void HWRAPI(SetTransform) (FTransform *stransform)
 	pglLoadIdentity();
 	if (stransform)
 	{
+		boolean fovx90;
 		// keep a trace of the transformation for md2
 		memcpy(&md2_transform, stransform, sizeof (md2_transform));
 
@@ -2069,7 +2071,8 @@ EXPORT void HWRAPI(SetTransform) (FTransform *stransform)
 
 		pglMatrixMode(GL_PROJECTION);
 		pglLoadIdentity();
-		special_splitscreen = (stransform->splitscreen && stransform->fovxangle == 90.0f);
+		fovx90 = stransform->fovxangle > 0.0f && fabsf(stransform->fovxangle - 90.0f) < 0.5f;
+		special_splitscreen = (stransform->splitscreen && fovx90);
 		if (special_splitscreen)
 			GLPerspective(53.13l, 2*ASPECT_RATIO);  // 53.13 = 2*atan(0.5)
 		else
diff --git a/src/r_data.c b/src/r_data.c
index 453ef69e..e0b9a814 100644
--- a/src/r_data.c
+++ b/src/r_data.c
@@ -1220,7 +1220,7 @@ INT32 R_CreateColormap(char *p1, char *p2, char *p3)
 			continue;
 		if (maskcolor == extra_colormaps[i].maskcolor
 			&& fadecolor == extra_colormaps[i].fadecolor
-			&& (float)maskamt == (float)extra_colormaps[i].maskamt
+			&& fabsf((float)(maskamt - extra_colormaps[i].maskamt)) < 1.0E-36f
 			&& fadestart == extra_colormaps[i].fadestart
 			&& fadeend == extra_colormaps[i].fadeend
 			&& fog == extra_colormaps[i].fog)
diff --git a/src/sdl/mixer_sound.c b/src/sdl/mixer_sound.c
index 083ef005..6e90a6e0 100644
--- a/src/sdl/mixer_sound.c
+++ b/src/sdl/mixer_sound.c
@@ -765,6 +765,7 @@ void I_UnloadSong(void)
 
 boolean I_PlaySong(boolean looping)
 {
+	boolean lpz = fpclassify(loop_point) == FP_ZERO;
 #ifdef HAVE_LIBGME
 	if (gme)
 	{
@@ -778,14 +779,15 @@ boolean I_PlaySong(boolean looping)
 	if (!music)
 		return false;
 
-	if (Mix_PlayMusic(music, looping && loop_point == 0.0f ? -1 : 0) == -1)
+
+	if (Mix_PlayMusic(music, looping && lpz ? -1 : 0) == -1)
 	{
 		CONS_Alert(CONS_ERROR, "Mix_PlayMusic: %s\n", Mix_GetError());
 		return false;
 	}
 	Mix_VolumeMusic((UINT32)music_volume*128/31);
 
-	if (loop_point != 0.0f)
+	if (!lpz)
 		Mix_HookMusicFinished(music_loop);
 	return true;
 }
diff --git a/src/win32/win_vid.c b/src/win32/win_vid.c
index a9dd097b..cca7810b 100644
--- a/src/win32/win_vid.c
+++ b/src/win32/win_vid.c
@@ -996,7 +996,7 @@ static INT32 WINAPI VID_SetDirectDrawMode(viddef_t *lvid, vmode_t *currentmode)
 	// but rather render to memory bitmap buffer
 	lvid->direct = NULL;
 
-	if (!cv_stretch.value && (float)vid.width/vid.height != ((float)BASEVIDWIDTH/BASEVIDHEIGHT))
+	if (!cv_stretch.value && fabsf((float)vid.width/vid.height - ((float)BASEVIDWIDTH/BASEVIDHEIGHT)) > 1.0E-36f)
 		vid.height = (int)(vid.width * ((float)BASEVIDHEIGHT/BASEVIDWIDTH));// Adjust the height to match
 
 	return 1;