Flat shading for basic shader

The purpose of the patch is to replace deprecated  glShadeModel.

To decrease glShadeModel calls I've set GL_SMOOTH by default

Reviewers: merwin, brecht

Reviewed By: brecht

Subscribers: blueprintrandom, Evgeny_Rodygin, AlexKowel, yurikovelenov

Differential Revision: https://developer.blender.org/D1958

22 files changed, 56 insertions, 129 deletions

diff --git a/source/blender/blenkernel/intern/DerivedMesh.c b/source/blender/blenkernel/intern/DerivedMesh.c
index 0de0e4d7797..d590a35bb57 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.c
+++ b/source/blender/blenkernel/intern/DerivedMesh.c
@@ -3881,7 +3881,6 @@ static void navmesh_drawColored(DerivedMesh *dm)
 	/* if (GPU_buffer_legacy(dm) ) */ /* TODO - VBO draw code, not high priority - campbell */
 	{
 		DEBUG_VBO("Using legacy code. drawNavMeshColored\n");
-		//glShadeModel(GL_SMOOTH);
 		glBegin(glmode = GL_QUADS);
 		for (a = 0; a < dm->numTessFaceData; a++, mface++) {
 			int new_glmode = mface->v4 ? GL_QUADS : GL_TRIANGLES;
diff --git a/source/blender/blenkernel/intern/cdderivedmesh.c b/source/blender/blenkernel/intern/cdderivedmesh.c
index 392a38773e7..267f7a65e00 100644
--- a/source/blender/blenkernel/intern/cdderivedmesh.c
+++ b/source/blender/blenkernel/intern/cdderivedmesh.c
@@ -464,7 +464,6 @@ static void cdDM_drawFacesSolid(
 
 			BKE_pbvh_draw(cddm->pbvh, partial_redraw_planes, face_nors,
 			              setMaterial, false, false);
-			glShadeModel(GL_FLAT);
 			return;
 		}
 	}
@@ -472,7 +471,6 @@ static void cdDM_drawFacesSolid(
 	GPU_vertex_setup(dm);
 	GPU_normal_setup(dm);
 	GPU_triangle_setup(dm);
-	glShadeModel(GL_SMOOTH);
 	for (a = 0; a < dm->drawObject->totmaterial; a++) {
 		if (!setMaterial || setMaterial(dm->drawObject->materials[a].mat_nr + 1, NULL)) {
 			GPU_buffer_draw_elements(
@@ -481,8 +479,6 @@ static void cdDM_drawFacesSolid(
 		}
 	}
 	GPU_buffers_unbind();
-
-	glShadeModel(GL_FLAT);
 }
 
 static void cdDM_drawFacesTex_common(
@@ -553,8 +549,7 @@ static void cdDM_drawFacesTex_common(
 	if (mloopcol) {
 		GPU_color_setup(dm, colType);
 	}
-		
-	glShadeModel(GL_SMOOTH);
+
 	/* lastFlag = 0; */ /* UNUSED */
 	for (mat_index = 0; mat_index < dm->drawObject->totmaterial; mat_index++) {
 		GPUBufferMaterial *bufmat = dm->drawObject->materials + mat_index;
@@ -633,7 +628,6 @@ static void cdDM_drawFacesTex_common(
 	}
 
 	GPU_buffers_unbind();
-	glShadeModel(GL_FLAT);
 	
 }
 
@@ -742,9 +736,6 @@ static void cdDM_drawMappedFaces(
 			}
 		}
 	}
-		
-
-	glShadeModel(GL_SMOOTH);
 
 	tot_tri_elem = dm->drawObject->tot_triangle_point;
 
@@ -841,7 +832,6 @@ static void cdDM_drawMappedFaces(
 	}
 
 	GPU_basic_shader_bind(GPU_SHADER_USE_COLOR);
-	glShadeModel(GL_FLAT);
 
 	GPU_buffers_unbind();
 
@@ -929,8 +919,6 @@ static void cdDM_drawMappedFacesGLSL(
 	matnr = -1;
 	do_draw = false;
 
-	glShadeModel(GL_SMOOTH);
-
 	if (setDrawOptions != NULL) {
 		DMVertexAttribs attribs;
 		DEBUG_VBO("Using legacy code. cdDM_drawMappedFacesGLSL\n");
@@ -1153,8 +1141,6 @@ static void cdDM_drawMappedFacesGLSL(
 		MEM_freeN(mat_orig_to_new);
 		MEM_freeN(matconv);
 	}
-	
-	glShadeModel(GL_FLAT);
 }
 
 static void cdDM_drawFacesGLSL(DerivedMesh *dm, DMSetMaterial setMaterial)
@@ -1203,8 +1189,6 @@ static void cdDM_drawMappedFacesMat(
 
 	matnr = -1;
 
-	glShadeModel(GL_SMOOTH);
-
 	memset(&attribs, 0, sizeof(attribs));
 
 	glBegin(GL_TRIANGLES);
@@ -1260,8 +1244,6 @@ static void cdDM_drawMappedFacesMat(
 		cddm_draw_attrib_vertex(&attribs, mvert, a, vtri[2], ltri[2], 2, ln3, smoothnormal);
 	}
 	glEnd();
-
-	glShadeModel(GL_FLAT);
 }
 
 static void cdDM_drawMappedEdges(DerivedMesh *dm, DMSetDrawOptions setDrawOptions, void *userData)
diff --git a/source/blender/blenkernel/intern/editderivedmesh.c b/source/blender/blenkernel/intern/editderivedmesh.c
index 8df07c5f3f4..6b81c47765b 100644
--- a/source/blender/blenkernel/intern/editderivedmesh.c
+++ b/source/blender/blenkernel/intern/editderivedmesh.c
@@ -1240,8 +1240,6 @@ static void emDM_drawFacesTex_common(
 	// dummylcol.r = dummylcol.g = dummylcol.b = dummylcol.a = 255;  /* UNUSED */
 
 	/* always use smooth shading even for flat faces, else vertex colors wont interpolate */
-	glShadeModel(GL_SMOOTH);
-
 	BM_mesh_elem_index_ensure(bm, BM_FACE);
 
 	/* call again below is ok */
@@ -1388,8 +1386,6 @@ static void emDM_drawFacesTex_common(
 			}
 		}
 	}
-
-	glShadeModel(GL_FLAT);
 }
 
 static void emDM_drawFacesTex(
@@ -1528,8 +1524,6 @@ static void emDM_drawMappedFacesGLSL(
 	vertexNos = bmdm->vertexNos;
 	polyNos = bmdm->polyNos;
 
-	/* always use smooth shading even for flat faces, else vertex colors wont interpolate */
-	glShadeModel(GL_SMOOTH);
 	BM_mesh_elem_index_ensure(bm, (BM_VERT | BM_FACE) | (lnors ? BM_LOOP : 0));
 
 	for (i = 0; i < em->tottri; i++) {
@@ -1640,8 +1634,6 @@ static void emDM_drawMappedFacesMat(
 	vertexNos = bmdm->vertexNos;
 	polyNos = bmdm->polyNos;
 
-	/* always use smooth shading even for flat faces, else vertex colors wont interpolate */
-	glShadeModel(GL_SMOOTH);
 	BM_mesh_elem_index_ensure(bm, (BM_VERT | BM_FACE) | (lnors ? BM_LOOP : 0));
 
 	for (i = 0; i < em->tottri; i++) {
diff --git a/source/blender/blenkernel/intern/subsurf_ccg.c b/source/blender/blenkernel/intern/subsurf_ccg.c
index 88bc3fb9854..b0d19320230 100644
--- a/source/blender/blenkernel/intern/subsurf_ccg.c
+++ b/source/blender/blenkernel/intern/subsurf_ccg.c
@@ -2619,7 +2619,6 @@ static void ccgDM_drawFacesSolid(DerivedMesh *dm, float (*partial_redraw_planes)
 		if (BKE_pbvh_has_faces(ccgdm->pbvh)) {
 			BKE_pbvh_draw(ccgdm->pbvh, partial_redraw_planes, NULL,
 			              setMaterial, false, fast);
-			glShadeModel(GL_FLAT);
 		}
 
 		return;
@@ -3164,7 +3163,7 @@ static void ccgDM_drawMappedFacesGLSL(DerivedMesh *dm,
 		MEM_freeN(matconv);
 	}
 
-	glShadeModel(GL_FLAT);
+	glShadeModel(GL_SMOOTH);
 }
 
 static void ccgDM_drawFacesGLSL(DerivedMesh *dm, DMSetMaterial setMaterial)
diff --git a/source/blender/editors/gpencil/drawgpencil.c b/source/blender/editors/gpencil/drawgpencil.c
index 0329598d711..79a2c494239 100644
--- a/source/blender/editors/gpencil/drawgpencil.c
+++ b/source/blender/editors/gpencil/drawgpencil.c
@@ -763,6 +763,7 @@ static void gp_draw_stroke_2d(bGPDspoint *points, int totpoints, short thickness
 		}
 		
 		glEnd();
+		glShadeModel(GL_SMOOTH);
 	}
 	
 	/* draw debug points of curve on top? (original stroke points) */
diff --git a/source/blender/editors/interface/interface_draw.c b/source/blender/editors/interface/interface_draw.c
index 8fbc545cb77..d78b41820b4 100644
--- a/source/blender/editors/interface/interface_draw.c
+++ b/source/blender/editors/interface/interface_draw.c
@@ -181,7 +181,6 @@ void UI_draw_roundbox_shade_x(
 	coldown[1] = max_ff(0.0f, color[1] + shadedown);
 	coldown[2] = max_ff(0.0f, color[2] + shadedown);
 
-	glShadeModel(GL_SMOOTH);
 	glBegin(mode);
 
 	/* start with corner right-bottom */
@@ -260,7 +259,6 @@ void UI_draw_roundbox_shade_x(
 	}
 	
 	glEnd();
-	glShadeModel(GL_FLAT);
 }
 
 /* linear vertical shade within button or in outline */
@@ -291,7 +289,6 @@ void UI_draw_roundbox_shade_y(
 	colRight[1] = max_ff(0.0f, color[1] + shadeRight);
 	colRight[2] = max_ff(0.0f, color[2] + shadeRight);
 
-	glShadeModel(GL_SMOOTH);
 	glBegin(mode);
 
 	/* start with corner right-bottom */
@@ -367,7 +364,6 @@ void UI_draw_roundbox_shade_y(
 	}
 	
 	glEnd();
-	glShadeModel(GL_FLAT);
 }
 
 /* plain antialiased unfilled rectangle */
@@ -531,7 +527,6 @@ static void histogram_draw_one(
 	}
 	else {
 		/* under the curve */
-		glShadeModel(GL_FLAT);
 		glBegin(GL_TRIANGLE_STRIP);
 		glVertex2f(x, y);
 		glVertex2f(x, y + (data[0] * h));
@@ -1087,7 +1082,6 @@ void ui_draw_but_COLORBAND(uiBut *but, uiWidgetColors *UNUSED(wcol), const rcti
 	GPU_basic_shader_bind(GPU_SHADER_USE_COLOR);
 
 	/* layer: color ramp */
-	glShadeModel(GL_FLAT);
 	glEnable(GL_BLEND);
 
 	CBData *cbd = coba->data;
@@ -1133,7 +1127,6 @@ void ui_draw_but_COLORBAND(uiBut *but, uiWidgetColors *UNUSED(wcol), const rcti
 	glEnd();
 
 	glDisable(GL_BLEND);
-	glShadeModel(GL_SMOOTH);
 
 	/* layer: box outline */
 	glColor4f(0.0, 0.0, 0.0, 1.0);
@@ -1212,9 +1205,9 @@ void ui_draw_but_UNITVEC(uiBut *but, uiWidgetColors *wcol, const rcti *rect)
 		
 		qobj = gluNewQuadric();
 		gluQuadricDrawStyle(qobj, GLU_FILL);
-		glShadeModel(GL_SMOOTH);
+		int bound_options = GPU_basic_shader_bound_options();
+		GPU_basic_shader_bind(bound_options);
 		gluSphere(qobj, 100.0, 32, 24);
-		glShadeModel(GL_FLAT);
 		gluDeleteQuadric(qobj);
 		
 		glEndList();
@@ -1677,7 +1670,6 @@ static void ui_shadowbox(float minx, float miny, float maxx, float maxy, float s
 void UI_draw_box_shadow(unsigned char alpha, float minx, float miny, float maxx, float maxy)
 {
 	glEnable(GL_BLEND);
-	glShadeModel(GL_SMOOTH);
 	
 	glBegin(GL_QUADS);
 
@@ -1689,7 +1681,6 @@ void UI_draw_box_shadow(unsigned char alpha, float minx, float miny, float maxx,
 	glEnd();
 	
 	glDisable(GL_BLEND);
-	glShadeModel(GL_FLAT);
 }
 
 
diff --git a/source/blender/editors/interface/interface_icons.c b/source/blender/editors/interface/interface_icons.c
index 222b0366791..6dc60f1d70b 100644
--- a/source/blender/editors/interface/interface_icons.c
+++ b/source/blender/editors/interface/interface_icons.c
@@ -368,7 +368,6 @@ static void vicon_disclosure_tri_right_draw(int x, int y, int w, int UNUSED(h),
 	viconutil_set_point(pts[1], cx - d2, cy - d);
 	viconutil_set_point(pts[2], cx + d2, cy);
 
-	glShadeModel(GL_SMOOTH);
 	glBegin(GL_TRIANGLES);
 	glColor4f(0.8f, 0.8f, 0.8f, alpha);
 	glVertex2iv(pts[0]);
@@ -376,7 +375,6 @@ static void vicon_disclosure_tri_right_draw(int x, int y, int w, int UNUSED(h),
 	glColor4f(0.3f, 0.3f, 0.3f, alpha);
 	glVertex2iv(pts[2]);
 	glEnd();
-	glShadeModel(GL_FLAT);
 
 	glColor4f(0.0f, 0.0f, 0.0f, 1);
 	viconutil_draw_lineloop_smooth(pts, 3);
@@ -395,13 +393,11 @@ static void vicon_small_tri_right_draw(int x, int y, int w, int UNUSED(h), float
 
 	glColor4f(0.2f, 0.2f, 0.2f, alpha);
 
-	glShadeModel(GL_SMOOTH);
 	glBegin(GL_TRIANGLES);
 	glVertex2iv(pts[0]);
 	glVertex2iv(pts[1]);
 	glVertex2iv(pts[2]);
 	glEnd();
-	glShadeModel(GL_FLAT);
 }
 
 static void vicon_disclosure_tri_down_draw(int x, int y, int w, int UNUSED(h), float alpha)
@@ -415,7 +411,6 @@ static void vicon_disclosure_tri_down_draw(int x, int y, int w, int UNUSED(h), f
 	viconutil_set_point(pts[1], cx - d, cy + d2);
 	viconutil_set_point(pts[2], cx, cy - d2);
 
-	glShadeModel(GL_SMOOTH);
 	glBegin(GL_TRIANGLES);
 	glColor4f(0.8f, 0.8f, 0.8f, alpha);
 	glVertex2iv(pts[0]);
@@ -423,7 +418,6 @@ static void vicon_disclosure_tri_down_draw(int x, int y, int w, int UNUSED(h), f
 	glColor4f(0.3f, 0.3f, 0.3f, alpha);
 	glVertex2iv(pts[2]);
 	glEnd();
-	glShadeModel(GL_FLAT);
 
 	glColor4f(0.0f, 0.0f, 0.0f, 1);
 	viconutil_draw_lineloop_smooth(pts, 3);
diff --git a/source/blender/editors/interface/interface_panel.c b/source/blender/editors/interface/interface_panel.c
index 62b373c58c8..85e32144bcd 100644
--- a/source/blender/editors/interface/interface_panel.c
+++ b/source/blender/editors/interface/interface_panel.c
@@ -1763,12 +1763,10 @@ void UI_panel_category_draw_all(ARegion *ar, const char *category_id_active)
 			ui_panel_category_draw_tab(GL_LINE_STRIP, rct->xmin - px, rct->ymin - px, rct->xmax - px, rct->ymax + px,
 			                           tab_curve_radius, roundboxtype, true, true, NULL);
 			/* tab highlight (3d look) */
-			glShadeModel(GL_SMOOTH);
 			glColor3ubv(is_active ? theme_col_tab_highlight : theme_col_tab_highlight_inactive);
 			ui_panel_category_draw_tab(GL_LINE_STRIP, rct->xmin, rct->ymin, rct->xmax, rct->ymax,
-			                           tab_curve_radius, roundboxtype, true, false,
-			                           is_active ? theme_col_back : theme_col_tab_inactive);
-			glShadeModel(GL_FLAT);
+									   tab_curve_radius, roundboxtype, true, false,
+									   is_active ? theme_col_back : theme_col_tab_inactive);
 		}
 
 		/* tab blackline */
diff --git a/source/blender/editors/interface/interface_widgets.c b/source/blender/editors/interface/interface_widgets.c
index 19e0b55374e..5098e701638 100644
--- a/source/blender/editors/interface/interface_widgets.c
+++ b/source/blender/editors/interface/interface_widgets.c
@@ -712,8 +712,7 @@ static void widgetbase_draw(uiWidgetBase *wtb, uiWidgetColors *wcol)
 			unsigned char *col_pt = col_array;
 			
 			shadecolors4(col1, col2, wcol->inner, wcol->shadetop, wcol->shadedown);
-			
-			glShadeModel(GL_SMOOTH);
+
 			for (a = 0; a < wtb->totvert; a++, col_pt += 4) {
 				round_box_shade_col4_r(col_pt, col1, col2, wtb->inner_uv[a][wtb->draw_shadedir ? 1 : 0]);
 			}
@@ -725,8 +724,6 @@ static void widgetbase_draw(uiWidgetBase *wtb, uiWidgetColors *wcol)
 			glDrawArrays(GL_POLYGON, 0, wtb->totvert);
 			glDisableClientState(GL_VERTEX_ARRAY);
 			glDisableClientState(GL_COLOR_ARRAY);
-
-			glShadeModel(GL_FLAT);
 		}
 	}
 	
@@ -2311,8 +2308,6 @@ static void ui_draw_but_HSVCIRCLE(uiBut *but, uiWidgetColors *wcol, const rcti *
 	
 	ui_color_picker_to_rgb(0.0f, 0.0f, hsv[2], colcent, colcent + 1, colcent + 2);
 
-	glShadeModel(GL_SMOOTH);
-
 	glBegin(GL_TRIANGLE_FAN);
 	glColor3fv(colcent);
 	glVertex2f(centx, centy);
@@ -2330,8 +2325,6 @@ static void ui_draw_but_HSVCIRCLE(uiBut *but, uiWidgetColors *wcol, const rcti *
 	}
 	glEnd();
 	
-	glShadeModel(GL_FLAT);
-	
 	/* fully rounded outline */
 	glPushMatrix();
 	glTranslatef(centx, centy, 0.0f);
@@ -2363,7 +2356,6 @@ void ui_draw_gradient(const rcti *rect, const float hsv[3], const int type, cons
 	float col1[4][3];   /* right half, rect bottom to top */
 
 	/* draw series of gouraud rects */
-	glShadeModel(GL_SMOOTH);
 	
 	switch (type) {
 		case UI_GRAD_SV:
@@ -2486,8 +2478,6 @@ void ui_draw_gradient(const rcti *rect, const float hsv[3], const int type, cons
 		}
 		glEnd();
 	}
-
-	glShadeModel(GL_FLAT);
 }
 
 bool ui_but_is_colorpicker_display_space(uiBut *but)
diff --git a/source/blender/editors/space_sequencer/sequencer_draw.c b/source/blender/editors/space_sequencer/sequencer_draw.c
index 9c2d115108d..f6afd7a16e7 100644
--- a/source/blender/editors/space_sequencer/sequencer_draw.c
+++ b/source/blender/editors/space_sequencer/sequencer_draw.c
@@ -593,7 +593,6 @@ void draw_shadedstrip(Sequence *seq, unsigned char col[3], float x1, float y1, f
 	ymid1 = (y2 - y1) * 0.25f + y1;
 	ymid2 = (y2 - y1) * 0.65f + y1;
 	
-	glShadeModel(GL_SMOOTH);
 	glBegin(GL_QUADS);
 	
 	if (seq->flag & SEQ_INVALID_EFFECT) { col[0] = 255; col[1] = 0; col[2] = 255; }
diff --git a/source/blender/editors/space_view3d/drawanimviz.c b/source/blender/editors/space_view3d/drawanimviz.c
index 9872b05da63..cf738de0202 100644
--- a/source/blender/editors/space_view3d/drawanimviz.c
+++ b/source/blender/editors/space_view3d/drawanimviz.c
@@ -130,7 +130,6 @@ void draw_motion_path_instance(Scene *scene,
 	mpv_start = (mpath->points + sind);
 	
 	/* draw curve-line of path */
-	glShadeModel(GL_SMOOTH);
 	
 	glBegin(GL_LINE_STRIP);
 	for (i = 0, mpv = mpv_start; i < len; i++, mpv++) {
@@ -187,7 +186,6 @@ void draw_motion_path_instance(Scene *scene,
 	}
 	
 	glEnd();
-	glShadeModel(GL_FLAT);
 	
 	glPointSize(1.0);
 	
diff --git a/source/blender/editors/space_view3d/drawarmature.c b/source/blender/editors/space_view3d/drawarmature.c
index 1306e832592..1d9a515a5f2 100644
--- a/source/blender/editors/space_view3d/drawarmature.c
+++ b/source/blender/editors/space_view3d/drawarmature.c
@@ -431,10 +431,9 @@ static void draw_bonevert_solid(void)
 		glNewList(displist, GL_COMPILE);
 		
 		qobj = gluNewQuadric();
-		gluQuadricDrawStyle(qobj, GLU_FILL); 
-		glShadeModel(GL_SMOOTH);
+		gluQuadricDrawStyle(qobj, GLU_FILL);
+		/* Draw tips of a bone */
 		gluSphere(qobj, 0.05, 8, 5);
-		glShadeModel(GL_FLAT);
 		gluDeleteQuadric(qobj);  
 		
 		glEndList();
@@ -890,7 +889,6 @@ static void draw_sphere_bone(const short dt, int armflag, int boneflag, short co
 		GPU_basic_shader_bind(GPU_SHADER_LIGHTING | GPU_SHADER_USE_COLOR);
 		
 		gluQuadricDrawStyle(qobj, GLU_FILL); 
-		glShadeModel(GL_SMOOTH);
 	}
 	else {
 		gluQuadricDrawStyle(qobj, GLU_SILHOUETTE); 
@@ -968,7 +966,6 @@ static void draw_sphere_bone(const short dt, int armflag, int boneflag, short co
 	
 	/* restore */
 	if (dt == OB_SOLID) {
-		glShadeModel(GL_FLAT);
 		GPU_basic_shader_bind(GPU_SHADER_USE_COLOR);
 	}
 	
@@ -1770,7 +1767,6 @@ static void draw_pose_bones(Scene *scene, View3D *v3d, ARegion *ar, Base *base,
 		/* and draw blended distances */
 		if (arm->flag & ARM_POSEMODE) {
 			glEnable(GL_BLEND);
-			//glShadeModel(GL_SMOOTH);
 			
 			if (v3d->zbuf) glDisable(GL_DEPTH_TEST);
 			
@@ -1793,7 +1789,6 @@ static void draw_pose_bones(Scene *scene, View3D *v3d, ARegion *ar, Base *base,
 			
 			if (v3d->zbuf) glEnable(GL_DEPTH_TEST);
 			glDisable(GL_BLEND);
-			//glShadeModel(GL_FLAT);
 		}
 	}
 	
@@ -2217,7 +2212,6 @@ static void draw_ebones(View3D *v3d, ARegion *ar, Object *ob, const short dt)
 		
 		/* and draw blended distances */
 		glEnable(GL_BLEND);
-		//glShadeModel(GL_SMOOTH);
 		
 		if (v3d->zbuf) glDisable(GL_DEPTH_TEST);
 
@@ -2232,7 +2226,6 @@ static void draw_ebones(View3D *v3d, ARegion *ar, Object *ob, const short dt)
 		
 		if (v3d->zbuf) glEnable(GL_DEPTH_TEST);
 		glDisable(GL_BLEND);
-		//glShadeModel(GL_FLAT);
 	}
 	
 	/* if solid we draw it first */
diff --git a/source/blender/editors/space_view3d/drawmesh.c b/source/blender/editors/space_view3d/drawmesh.c
index 883f06763de..d8364011036 100644
--- a/source/blender/editors/space_view3d/drawmesh.c
+++ b/source/blender/editors/space_view3d/drawmesh.c
@@ -496,7 +496,6 @@ static void draw_textured_begin(Scene *scene, View3D *v3d, RegionView3D *rv3d, O
 
 	memcpy(Gtexdraw.obcol, obcol, sizeof(obcol));
 	set_draw_settings_cached(1, NULL, NULL, Gtexdraw);
-	glShadeModel(GL_SMOOTH);
 	glCullFace(GL_BACK);
 }
 
@@ -528,7 +527,6 @@ static void draw_textured_end(void)
 		GPU_set_tpage(NULL, 0, 0);
 	}
 
-	glShadeModel(GL_FLAT);
 	glDisable(GL_CULL_FACE);
 	GPU_basic_shader_bind(GPU_SHADER_USE_COLOR);
 
diff --git a/source/blender/editors/space_view3d/drawobject.c b/source/blender/editors/space_view3d/drawobject.c
index 848772600ba..5d1c0bfa72e 100644
--- a/source/blender/editors/space_view3d/drawobject.c
+++ b/source/blender/editors/space_view3d/drawobject.c
@@ -1592,12 +1592,9 @@ static void draw_bundle_sphere(void)
 
 		displist = glGenLists(1);
 		glNewList(displist, GL_COMPILE);
-
 		qobj = gluNewQuadric();
 		gluQuadricDrawStyle(qobj, GLU_FILL);
-		glShadeModel(GL_SMOOTH);
 		gluSphere(qobj, 0.05, 8, 8);
-		glShadeModel(GL_FLAT);
 		gluDeleteQuadric(qobj);
 
 		glEndList();
@@ -1779,8 +1776,6 @@ static void draw_viewport_reconstruction(
 	GPU_basic_shader_colors(NULL, NULL, 0, 1.0f);
 	GPU_basic_shader_bind(GPU_SHADER_LIGHTING | GPU_SHADER_USE_COLOR);
 
-	glShadeModel(GL_SMOOTH);
-
 	tracking_object = tracking->objects.first;
 	while (tracking_object) {
 		draw_viewport_object_reconstruction(
@@ -1791,7 +1786,6 @@ static void draw_viewport_reconstruction(
 	}
 
 	/* restore */
-	glShadeModel(GL_FLAT);
 	GPU_basic_shader_bind(GPU_SHADER_USE_COLOR);
 
 	if ((dflag & DRAW_CONSTCOLOR) == 0) {
@@ -2351,7 +2345,6 @@ static void drawlattice(View3D *v3d, Object *ob)
 		
 		if (ob->defbase.first && lt->dvert) {
 			actdef_wcol = ob->actdef;
-			glShadeModel(GL_SMOOTH);
 		}
 	}
 
@@ -2380,10 +2373,6 @@ static void drawlattice(View3D *v3d, Object *ob)
 		}
 	}
 	glEnd();
-	
-	/* restoration for weight colors */
-	if (actdef_wcol)
-		glShadeModel(GL_FLAT);
 
 	if (is_edit) {
 		BPoint *actbp = BKE_lattice_active_point_get(lt);
@@ -3248,17 +3237,15 @@ static void draw_em_fancy_edges(BMEditMesh *em, Scene *scene, View3D *v3d,
 			    ((ts->selectmode & SCE_SELECT_VERTEX) || (me->drawflag & ME_DRAWEIGHT)))
 			{
 				if (draw_dm_edges_weight_check(me, v3d)) {
-					glShadeModel(GL_SMOOTH);
+					// Interpolate vertex weights
 					draw_dm_edges_weight_interp(em, cageDM, ts->weightuser);
-					glShadeModel(GL_FLAT);
 				}
 				else if (ts->selectmode == SCE_SELECT_FACE) {
 					draw_dm_edges_sel(em, cageDM, wireCol, selCol, actCol, eed_act);
 				}
 				else {
-					glShadeModel(GL_SMOOTH);
+					// Interpolate vertex selection
 					draw_dm_edges_sel_interp(em, cageDM, wireCol, selCol);
-					glShadeModel(GL_FLAT);
 				}
 			}
 			else {
@@ -4461,10 +4448,6 @@ static void drawDispListsolid(ListBase *lb, Object *ob, const short dflag,
 
 	glEnableClientState(GL_VERTEX_ARRAY);
 
-	if (ob->type == OB_MBALL) {  /* mball always smooth shaded */
-		glShadeModel(GL_SMOOTH);
-	}
-
 	/* track current material, -1 for none (needed for lines) */
 	short col = -1;
 	
@@ -4486,7 +4469,6 @@ static void drawDispListsolid(ListBase *lb, Object *ob, const short dflag,
 
 					// glVertexPointer(3, GL_FLOAT, 0, dl->verts);
 					// glDrawArrays(GL_LINE_STRIP, 0, dl->nr);
-
 					glBegin(GL_LINE_STRIP);
 					for (int nr = dl->nr; nr; nr--, data += 3)
 						glVertex3fv(data);
@@ -4517,15 +4499,15 @@ static void drawDispListsolid(ListBase *lb, Object *ob, const short dflag,
 						GPU_object_material_bind(dl->col + 1, use_glsl ? &gattribs : NULL);
 						col = dl->col;
 					}
-
-					if (dl->rt & CU_SMOOTH) glShadeModel(GL_SMOOTH);
-					else glShadeModel(GL_FLAT);
+					/* FLAT/SMOOTH shading for surfaces */
+					glShadeModel((dl->rt & CU_SMOOTH) ? GL_SMOOTH : GL_FLAT);
 
 					glEnableClientState(GL_NORMAL_ARRAY);
 					glVertexPointer(3, GL_FLOAT, 0, dl->verts);
 					glNormalPointer(GL_FLOAT, 0, dl->nors);
 					glDrawElements(GL_QUADS, 4 * dl->totindex, GL_UNSIGNED_INT, dl->index);
 					glDisableClientState(GL_NORMAL_ARRAY);
+					glShadeModel(GL_SMOOTH);
 				}
 				break;
 
@@ -4570,7 +4552,6 @@ static void drawDispListsolid(ListBase *lb, Object *ob, const short dflag,
 	}
 
 	glDisableClientState(GL_VERTEX_ARRAY);
-	glShadeModel(GL_FLAT);
 	glFrontFace(GL_CCW);
 
 	if (col != -1) {
diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c
index 445a4cbdfd6..bdc2234e246 100644
--- a/source/blender/editors/space_view3d/view3d_draw.c
+++ b/source/blender/editors/space_view3d/view3d_draw.c
@@ -657,7 +657,6 @@ static void draw_rotation_guide(RegionView3D *rv3d)
 
 	glEnable(GL_BLEND);
 	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-	glShadeModel(GL_SMOOTH);
 	glPointSize(5);
 	glEnable(GL_POINT_SMOOTH);
 	glDepthMask(0);  /* don't overwrite zbuf */
@@ -2999,18 +2998,16 @@ static void view3d_main_region_clear(Scene *scene, View3D *v3d, ARegion *ar)
 				glLoadIdentity();
 				glColor4f(0.0f, 0.0f, 0.0f, 1.0f);
 			}
-
+			// Draw world
 			glEnable(GL_DEPTH_TEST);
 			glDepthFunc(GL_ALWAYS);
-			glShadeModel(GL_SMOOTH);
 			glBegin(GL_TRIANGLE_STRIP);
 			glVertex3f(-1.0, -1.0, 1.0);
 			glVertex3f(1.0, -1.0, 1.0);
 			glVertex3f(-1.0, 1.0, 1.0);
 			glVertex3f(1.0, 1.0, 1.0);
 			glEnd();
-			glShadeModel(GL_FLAT);
-
+			//
 			if (material_not_bound) {
 				glMatrixMode(GL_PROJECTION);
 				glPopMatrix();
@@ -3048,8 +3045,6 @@ static void view3d_main_region_clear(Scene *scene, View3D *v3d, ARegion *ar)
 			glPushMatrix();
 			glLoadIdentity();
 
-			glShadeModel(GL_SMOOTH);
-
 			/* calculate buffers the first time only */
 			if (!buf_calculated) {
 				for (x = 0; x < VIEWGRAD_RES_X; x++) {
@@ -3135,8 +3130,6 @@ static void view3d_main_region_clear(Scene *scene, View3D *v3d, ARegion *ar)
 			glMatrixMode(GL_MODELVIEW);
 			glPopMatrix();
 
-			glShadeModel(GL_FLAT);
-
 #undef VIEWGRAD_RES_X
 #undef VIEWGRAD_RES_Y
 		}
@@ -3160,7 +3153,6 @@ static void view3d_main_region_clear(Scene *scene, View3D *v3d, ARegion *ar)
 
 			glEnable(GL_DEPTH_TEST);
 			glDepthFunc(GL_ALWAYS);
-			glShadeModel(GL_SMOOTH);
 			glBegin(GL_QUADS);
 			UI_ThemeColor(TH_LOW_GRAD);
 			glVertex3f(-1.0, -1.0, 1.0);
@@ -3169,8 +3161,6 @@ static void view3d_main_region_clear(Scene *scene, View3D *v3d, ARegion *ar)
 			glVertex3f(1.0, 1.0, 1.0);
 			glVertex3f(-1.0, 1.0, 1.0);
 			glEnd();
-			glShadeModel(GL_FLAT);
-
 			glDepthFunc(GL_LEQUAL);
 			glDisable(GL_DEPTH_TEST);
 
diff --git a/source/blender/editors/uvedit/uvedit_draw.c b/source/blender/editors/uvedit/uvedit_draw.c
index baa471e920b..94d69a0169f 100644
--- a/source/blender/editors/uvedit/uvedit_draw.c
+++ b/source/blender/editors/uvedit/uvedit_draw.c
@@ -279,8 +279,6 @@ static void draw_uvs_stretch(SpaceImage *sima, Scene *scene, BMEditMesh *em, MTe
 
 			col[3] = 0.5f; /* hard coded alpha, not that nice */
 			
-			glShadeModel(GL_SMOOTH);
-			
 			BM_ITER_MESH (efa, &iter, bm, BM_FACES_OF_MESH) {
 				tf = BM_ELEM_CD_GET_VOID_P(efa, cd_poly_tex_offset);
 				
@@ -344,8 +342,6 @@ static void draw_uvs_stretch(SpaceImage *sima, Scene *scene, BMEditMesh *em, MTe
 			BLI_buffer_free(&av_buf);
 			BLI_buffer_free(&auv_buf);
 
-			glShadeModel(GL_FLAT);
-
 			break;
 		}
 	}
@@ -794,8 +790,7 @@ static void draw_uvs(SpaceImage *sima, Scene *scene, Object *obedit)
 				UI_GetThemeColor4ubv(TH_EDGE_SELECT, col1);
 
 				if (interpedges) {
-					glShadeModel(GL_SMOOTH);
-
+					GPU_basic_shader_bind(GPU_SHADER_USE_COLOR);
 					BM_ITER_MESH (efa, &iter, bm, BM_FACES_OF_MESH) {
 						if (!BM_elem_flag_test(efa, BM_ELEM_TAG))
 							continue;
@@ -810,8 +805,6 @@ static void draw_uvs(SpaceImage *sima, Scene *scene, Object *obedit)
 						}
 						glEnd();
 					}
-
-					glShadeModel(GL_FLAT);
 				}
 				else {
 					BM_ITER_MESH (efa, &iter, bm, BM_FACES_OF_MESH) {
diff --git a/source/blender/gpu/GPU_basic_shader.h b/source/blender/gpu/GPU_basic_shader.h
index 8e38ac8876f..6c78aec2ec7 100644
--- a/source/blender/gpu/GPU_basic_shader.h
+++ b/source/blender/gpu/GPU_basic_shader.h
@@ -51,7 +51,8 @@ typedef enum GPUBasicShaderOption {
 	GPU_SHADER_SOLID_LIGHTING =   (1 << 5),   /* use faster lighting (set automatically) */
 	GPU_SHADER_STIPPLE =          (1 << 6),   /* use stipple */
 	GPU_SHADER_LINE =             (1 << 7),   /* draw lines */
-	GPU_SHADER_OPTIONS_NUM = 8,
+	GPU_SHADER_FLAT_NORMAL =      (1 << 8),   /* use flat normals */
+	GPU_SHADER_OPTIONS_NUM = 9,
 	GPU_SHADER_OPTION_COMBINATIONS = (1 << GPU_SHADER_OPTIONS_NUM)
 } GPUBasicShaderOption;
 
diff --git a/source/blender/gpu/intern/gpu_basic_shader.c b/source/blender/gpu/intern/gpu_basic_shader.c
index 4be50a078b7..c5a2d07bdc8 100644
--- a/source/blender/gpu/intern/gpu_basic_shader.c
+++ b/source/blender/gpu/intern/gpu_basic_shader.c
@@ -376,6 +376,8 @@ static GPUShader *gpu_basic_shader(int options)
 			strcat(defines, "#define DRAW_LINE\n");
 			geom_glsl = datatoc_gpu_shader_basic_geom_glsl;
 		}
+		if (options & GPU_SHADER_FLAT_NORMAL)
+			strcat(defines, "#define USE_FLAT_NORMAL\n");
 		if (options & GPU_SHADER_SOLID_LIGHTING)
 			strcat(defines, "#define USE_SOLID_LIGHTING\n");
 		else if (options & GPU_SHADER_LIGHTING)
@@ -507,6 +509,12 @@ void GPU_basic_shader_bind(int options)
 				glDisable(GL_POLYGON_STIPPLE);
 		}
 
+		if (options & GPU_SHADER_FLAT_NORMAL) {
+			glShadeModel(GL_FLAT);
+		}
+		else {
+			glShadeModel(GL_SMOOTH);
+		}
 	}
 
 	GPU_MATERIAL_STATE.bound_options = options;
diff --git a/source/blender/gpu/intern/gpu_buffers.c b/source/blender/gpu/intern/gpu_buffers.c
index e8605e27595..35bfc687052 100644
--- a/source/blender/gpu/intern/gpu_buffers.c
+++ b/source/blender/gpu/intern/gpu_buffers.c
@@ -1863,10 +1863,14 @@ void GPU_draw_pbvh_buffers(GPU_PBVH_Buffers *buffers, DMSetMaterial setMaterial,
 			GPU_buffer_bind(buffers->index_buf, GPU_BINDING_INDEX);
 		}
 
-		if (wireframe)
+		if (wireframe) {
 			glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
-		else
-			glShadeModel((buffers->smooth || buffers->face_indices_len) ? GL_SMOOTH : GL_FLAT);
+		}
+		else {
+			bound_options = GPU_basic_shader_bound_options();
+			GPU_basic_shader_bind(bound_options | ((buffers->smooth || buffers->face_indices_len) ?
+			                      0 : GPU_SHADER_FLAT_NORMAL));
+		}
 
 		if (buffers->tot_quad) {
 			const char *offset = base;
diff --git a/source/blender/gpu/intern/gpu_draw.c b/source/blender/gpu/intern/gpu_draw.c
index b6f977d12ab..f998dc9904e 100644
--- a/source/blender/gpu/intern/gpu_draw.c
+++ b/source/blender/gpu/intern/gpu_draw.c
@@ -1995,8 +1995,9 @@ int GPU_object_material_bind(int nr, void *attribs)
 		}
 		else {
 			/* or do fixed function opengl material */
-			GPU_basic_shader_colors(GMS.matbuf[nr].diff,
-				GMS.matbuf[nr].spec, GMS.matbuf[nr].hard, GMS.matbuf[nr].alpha);
+			GPU_basic_shader_colors(
+			        GMS.matbuf[nr].diff,
+			        GMS.matbuf[nr].spec, GMS.matbuf[nr].hard, GMS.matbuf[nr].alpha);
 
 			if (GMS.two_sided_lighting)
 				GPU_basic_shader_bind(GPU_SHADER_LIGHTING | GPU_SHADER_TWO_SIDED);
@@ -2290,8 +2291,6 @@ void GPU_state_init(void)
 	/* scaling matrices */
 	glEnable(GL_NORMALIZE);
 
-	glShadeModel(GL_FLAT);
-
 	glDisable(GL_ALPHA_TEST);
 	glDisable(GL_BLEND);
 	glDisable(GL_DEPTH_TEST);
diff --git a/source/blender/gpu/shaders/gpu_shader_basic_frag.glsl b/source/blender/gpu/shaders/gpu_shader_basic_frag.glsl
index ea5f6aef005..01a335af048 100644
--- a/source/blender/gpu/shaders/gpu_shader_basic_frag.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_basic_frag.glsl
@@ -28,8 +28,11 @@
 #define STIPPLE_S3D_INTERLACE_CHECKERBOARD_SWAP        11
 
 #if defined(USE_SOLID_LIGHTING) || defined(USE_SCENE_LIGHTING)
+#if defined(USE_FLAT_NORMAL)
+varying vec3 eyespace_vert_pos;
+#else
 varying vec3 varying_normal;
-
+#endif
 #ifndef USE_SOLID_LIGHTING
 varying vec3 varying_position;
 #endif
@@ -146,7 +149,11 @@ void main()
 
 #if defined(USE_SOLID_LIGHTING) || defined(USE_SCENE_LIGHTING)
 	/* compute normal */
+#if defined(USE_FLAT_NORMAL)
+	vec3 N = normalize(cross(dFdx(eyespace_vert_pos), dFdy(eyespace_vert_pos)));
+#else
 	vec3 N = normalize(varying_normal);
+#endif
 
 #ifdef USE_TWO_SIDED
 	if (!gl_FrontFacing)
diff --git a/source/blender/gpu/shaders/gpu_shader_basic_vert.glsl b/source/blender/gpu/shaders/gpu_shader_basic_vert.glsl
index cef28ea3026..42fbdadf1d1 100644
--- a/source/blender/gpu/shaders/gpu_shader_basic_vert.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_basic_vert.glsl
@@ -1,6 +1,10 @@
 
 #if defined(USE_SOLID_LIGHTING) || defined(USE_SCENE_LIGHTING)
+#if defined(USE_FLAT_NORMAL)
+varying vec3 eyespace_vert_pos;
+#else
 varying vec3 varying_normal;
+#endif
 
 #ifndef USE_SOLID_LIGHTING
 varying vec3 varying_position;
@@ -28,7 +32,13 @@ void main()
 	vec4 co = gl_ModelViewMatrix * gl_Vertex;
 
 #if defined(USE_SOLID_LIGHTING) || defined(USE_SCENE_LIGHTING)
+#if !defined(USE_FLAT_NORMAL)
 	varying_normal = normalize(gl_NormalMatrix * gl_Normal);
+#endif
+#if defined(USE_FLAT_NORMAL)
+	/* transform vertex into eyespace */
+	eyespace_vert_pos = (gl_ModelViewMatrix * gl_Vertex).xyz;
+#endif
 
 #ifndef USE_SOLID_LIGHTING
 	varying_position = co.xyz;