Fix for #1449 (blocky shadows)

This problem appeared to be a famous one, with some fun read to be found
on the web. The solution as I commit here is described on the site:
http://www.blender3d.org/cms/Misc_improvements.355.0.html

As extra (I needed it quite some!) added requested feature to have the
renderwindow display in titlebar whether the spare page is shown (JKEY)

source/blender/makesdna/DNA_material_types.h

@@ -140,6 +140,7 @@ typedef struct Material {
 #define MA_SHADOW_TRA	0x80000
 #define MA_RAMP_COL		0x100000
 #define MA_RAMP_SPEC	0x200000
+#define MA_RAYBIAS		0x400000
 
 /* diff_shader */
 #define MA_DIFF_LAMBERT		0

source/blender/makesdna/DNA_object_types.h

@@ -198,7 +198,7 @@ typedef struct Object {
 	LBuf lbuf;
 	LBuf port;
 
-	float toonedge, pad2;
+	float toonedge, smoothresh;	/* smoothresh is phong interpolation ray_shadow correction in render */
 } Object;
 
 /* this work object is defined in object.c */

source/blender/render/intern/source/ray.c

@@ -2062,7 +2062,7 @@ void ray_shadow(ShadeInput *shi, LampRen *lar, float *shadfac)
 		VECCOPY(lampco, lar->co);
 	}
 	
-	/* shadow and soft not implemented yet */
+	/* transp-shadow and soft not implemented yet */
 	if(lar->ray_totsamp<2 ||  isec.mode == DDA_SHADOW_TRA) {
 		/* set up isec */
 		VECCOPY(isec.start, shi->co);

source/blender/render/intern/source/rendercore.c

@@ -1899,14 +1899,14 @@ static void ambient_occlusion(World *wrld, ShadeInput *shi, ShadeResult *shr)
 void shade_lamp_loop(ShadeInput *shi, ShadeResult *shr)
 {
 	LampRen *lar;
-	Material *ma;
+	Material *ma= shi->matren;
+	VlakRen *vlr= shi->vlr;
 	float i, inp, inpr, is, t, lv[3], lampdist, ld = 0;
-	float lvrot[3], *vn, *view, shadfac[4], soft;	// shadfac = rgba
+	float lvrot[3], *vn, *view, shadfac[4], soft, phongcorr;	// shadfac = rgba
 	int a;
 
 	vn= shi->vn;
 	view= shi->view;
-	ma= shi->matren;
 	
 	memset(shr, 0, sizeof(ShadeResult));
 	
@@ -1918,7 +1918,7 @@ void shade_lamp_loop(ShadeInput *shi, ShadeResult *shr)
 		for(a=0; a<R.totlamp; a++) {
 			lar= R.la[a];
 			
-			if(lar->mode & LA_LAYER) if((lar->lay & shi->vlr->lay)==0) continue;
+			if(lar->mode & LA_LAYER) if((lar->lay & vlr->lay)==0) continue;
 			
 			lv[0]= shi->co[0]-lar->co[0];
 			lv[1]= shi->co[1]-lar->co[1];
@@ -1953,7 +1953,7 @@ void shade_lamp_loop(ShadeInput *shi, ShadeResult *shr)
 				float shad[4];
 				
 				/* single sided? */
-				if( shi->vlr->n[0]*lv[0] + shi->vlr->n[1]*lv[1] + shi->vlr->n[2]*lv[2] > -0.01) {
+				if( vlr->n[0]*lv[0] + vlr->n[1]*lv[1] + vlr->n[2]*lv[2] > -0.01) {
 					ray_shadow(shi, lar, shad);
 					shadfac[3]+= shad[3];
 					ir+= 1.0;
@@ -2014,7 +2014,7 @@ void shade_lamp_loop(ShadeInput *shi, ShadeResult *shr)
 		lar= R.la[a];
 
 		/* test for lamp layer */
-		if(lar->mode & LA_LAYER) if((lar->lay & shi->vlr->lay)==0) continue;
+		if(lar->mode & LA_LAYER) if((lar->lay & vlr->lay)==0) continue;
 		
 		/* lampdist calculation */
 		if(lar->type==LA_SUN || lar->type==LA_HEMI) {
@@ -2120,6 +2120,17 @@ void shade_lamp_loop(ShadeInput *shi, ShadeResult *shr)
 		
 		inp= vn[0]*lv[0] + vn[1]*lv[1] + vn[2]*lv[2];
 
+		/* phong threshold to prevent backfacing faces having artefacts on ray shadow (terminator problem) */
+		if((ma->mode & MA_RAYBIAS) && (lar->mode & LA_SHAD_RAY) && (vlr->flag & R_SMOOTH)) {
+			float thresh= vlr->ob->smoothresh;
+			if(inp>thresh)
+				phongcorr= (inp-thresh)/(inp*(1.0-thresh));
+			else
+				phongcorr= 0.0;
+		}
+		else phongcorr= 1.0;
+		
+		/* diffuse shaders */
 		if(lar->mode & LA_NO_DIFF) {
 			is= 0.0;	// skip shaders
 		}
@@ -2141,7 +2152,8 @@ void shade_lamp_loop(ShadeInput *shi, ShadeResult *shr)
 			else is= inp;	// Lambert
 		}
 		
-		i= is;
+		i= is*phongcorr;
+		
 		if(i>0.0) {
 			i*= lampdist*ma->ref;
 		}
@@ -2157,10 +2169,7 @@ void shade_lamp_loop(ShadeInput *shi, ShadeResult *shr)
 							shadfac[3] = testshadowbuf(lar->shb, shi->co, inp);
 						}
 						else if(lar->mode & LA_SHAD_RAY) {
-							// this extra 0.001 prevents boundary cases (shadow on smooth sphere)
-							if((shi->vlr->n[0]*lv[0] + shi->vlr->n[1]*lv[1] + shi->vlr->n[2]*lv[2]) > -0.001) 
 							ray_shadow(shi, lar, shadfac);
-							else shadfac[3]= 0.0;
 						}
 	
 						/* warning, here it skips the loop */
@@ -2773,7 +2782,7 @@ void *shadepixel(float x, float y, int vlaknr, int mask, float *col)
 			if(shi.mat->mode & MA_RAYTRANSP) shr.alpha= 1.0;
 		}
 		
-		VecAddf(col, shr.diff, shr.spec);
+		VECADD(col, shr.diff, shr.spec);
 		
 		/* exposure correction */
 		if(R.wrld.exp!=0.0 || R.wrld.range!=1.0) {

source/blender/renderconverter/intern/convertBlenderScene.c

@@ -145,10 +145,10 @@ static void init_render_object(Object *ob);
 static HaloRen *initstar(float *vec, float hasize);
 
 /* Displacement Texture */
-void displace_render_face(VlakRen *vlr, float *scale);
-void do_displacement(Object *ob, int startface, int numface, int startvert, int numvert);
-short test_for_displace(Object *ob);
-void displace_render_vert(ShadeInput *shi, VertRen *vr, float *scale);
+static void displace_render_face(VlakRen *vlr, float *scale);
+static void do_displacement(Object *ob, int startface, int numface, int startvert, int numvert);
+static short test_for_displace(Object *ob);
+static void displace_render_vert(ShadeInput *shi, VertRen *vr, float *scale);
 
 /* more prototypes for autosmoothing below */
 
@@ -2493,6 +2493,54 @@ static void init_render_curve(Object *ob)
 	}
 }
 
+/* prevent phong interpolation for giving ray shadow errors (terminator problem) */
+static void set_phong_threshold(Object *ob, int startface, int numface, int startvert, int numvert )
+{
+	VertRen *ver;
+	VlakRen *vlr;
+	float thresh= 0.0, dot;
+	int tot=0, i;
+	
+	/* Added check for 'pointy' situations, only dotproducts of 0.9 and larger 
+	   are taken into account. This threshold is meant to work on smooth geometry, not
+	   for extreme cases (ton) */
+	
+	for(i=startface; i<startface+numface; i++) {
+		vlr= RE_findOrAddVlak(i);
+		if(vlr->flag & R_SMOOTH) {
+			dot= INPR(vlr->n, vlr->v1->n);
+			dot= ABS(dot);
+			if(dot>0.9) {
+				thresh+= dot; tot++;
+			}
+			dot= INPR(vlr->n, vlr->v2->n);
+			dot= ABS(dot);
+			if(dot>0.9) {
+				thresh+= dot; tot++;
+			}
+
+			dot= INPR(vlr->n, vlr->v3->n);
+			dot= ABS(dot);
+			if(dot>0.9) {
+				thresh+= dot; tot++;
+			}
+
+			if(vlr->v4) {
+				dot= INPR(vlr->n, vlr->v4->n);
+				dot= ABS(dot);
+				if(dot>0.9) {
+					thresh+= dot; tot++;
+				}
+			}
+		}
+	}
+	
+	if(tot) {
+		thresh/= (float)tot;
+		ob->smoothresh= cos(0.5*M_PI-acos(thresh));
+	}
+}
+
 static void init_render_object(Object *ob)
 {
 	float mat[4][4];
@@ -2518,11 +2566,20 @@ static void init_render_object(Object *ob)
 		MTC_Mat4Invert(ob->imat, mat);
 	}
 	
+	/* generic post process here */
+	if(startvert!=R.totvert) {
+	
 		/* the exception below is because displace code now is in init_render_mesh call, 
 		I will look at means to have autosmooth enabled for all object types 
 		and have it as general postprocess, like displace */
 		if (ob->type!=OB_MESH && test_for_displace( ob ) ) 
 			do_displacement(ob, startface, R.totvlak-startface, startvert, R.totvert-startvert);
+	
+		/* phong normal interpolation can cause error in tracing (terminator prob) */
+		ob->smoothresh= 0.0;
+		if( (R.r.mode & R_RAYTRACE) && (R.r.mode & R_SHADOW) ) 
+			set_phong_threshold(ob, startface, R.totvlak-startface, startvert, R.totvert-startvert);
+	}
 }
 
 void RE_freeRotateBlenderScene(void)
@@ -2927,7 +2984,7 @@ void RE_rotateBlenderScene(void)
 /* **************************************************************** */
 /*                Displacement mapping                              */
 /* **************************************************************** */
-short test_for_displace(Object *ob)
+static short test_for_displace(Object *ob)
 {
 	/* return 1 when this object uses displacement textures. */
 	Material *ma;
@@ -2942,7 +2999,7 @@ short test_for_displace(Object *ob)
 }
 
 
-void do_displacement(Object *ob, int startface, int numface, int startvert, int numvert )
+static void do_displacement(Object *ob, int startface, int numface, int startvert, int numvert )
 {
 	VertRen *vr;
 	VlakRen *vlr;
@@ -2974,7 +3031,7 @@ void do_displacement(Object *ob, int startface, int numface, int startvert, int
 	normalenrender(startvert, startface);
 }
 
-void displace_render_face(VlakRen *vlr, float *scale)
+static void displace_render_face(VlakRen *vlr, float *scale)
 {
 	ShadeInput shi;
 	VertRen vr;
@@ -3042,7 +3099,7 @@ void displace_render_face(VlakRen *vlr, float *scale)
 	
 }
 
-void displace_render_vert(ShadeInput *shi, VertRen *vr, float *scale)
+static void displace_render_vert(ShadeInput *shi, VertRen *vr, float *scale)
 {
 	short texco= shi->matren->texco;
 	float sample=0;

source/blender/src/buttons_shading.c

@@ -2707,14 +2707,15 @@ static void material_panel_shading(Material *ma)
 		uiBlockEndAlign(block);
 
 		uiBlockSetCol(block, TH_BUT_SETTING1);
-		uiDefButI(block, TOG|BIT|0, 0,	"Traceable",		245,140,65,19, &(ma->mode), 0, 0, 0, 0, "Makes material to cast shadows or being detected by ray tracing");
+		uiDefButI(block, TOG|BIT|0, 0,	"Traceable",		245,150,65,19, &(ma->mode), 0, 0, 0, 0, "Makes material to cast shadows or being detected by ray tracing");
 
 		uiBlockBeginAlign(block);
-		uiDefButI(block, TOG|BIT|1, 0,	"Shadow",			245,110,65,19, &(ma->mode), 0, 0, 0, 0, "Makes material receive shadows");
-		uiDefButI(block, TOG|BIT|19, 0, "TraShadow",		245,90,65,19, &(ma->mode), 0, 0, 0, 0, "Recieves transparent shadows based at material color and alpha");
+		uiDefButI(block, TOG|BIT|1, 0,	"Shadow",			245,120,65,19, &(ma->mode), 0, 0, 0, 0, "Makes material receive shadows");
+		uiDefButI(block, TOG|BIT|19, 0, "TraShadow",		245,100,65,19, &(ma->mode), 0, 0, 0, 0, "Recieves transparent shadows based at material color and alpha");
+		uiDefButI(block, TOG|BIT|22, 0, "Bias",				245,80,65,19, &(ma->mode), 0, 0, 0, 0, "Prevents ray traced shadow errors with phong interpolated normals (terminator problem)");
 		uiBlockEndAlign(block);
 
-		uiDefButI(block, TOG|BIT|16, 0,	"Radio",			245,60,65,19, &(ma->mode), 0, 0, 0, 0, "Enables material for radiosty rendering");
+		uiDefButI(block, TOG|BIT|16, 0,	"Radio",			245,55,65,19, &(ma->mode), 0, 0, 0, 0, "Enables material for radiosty rendering");
 
 	}
 

source/blender/src/renderwin.c

@@ -445,18 +445,32 @@ static void renderwin_handler(Window *win, void *user_data, short evt, short val
 	}
 }
 
+static char *renderwin_get_title(int doswap)
+{
+	static int swap= 0;
+	char *title="";
+	
+	swap+= doswap;
+	
+	if(swap & 1) {
+		if (G.scene->r.renderer==R_YAFRAY) title = "YafRay:Render (spare)";
+		else title = "Blender:Render (spare)";
+	}
+	else {
+		if (G.scene->r.renderer==R_YAFRAY) title = "YafRay:Render";
+		else title = "Blender:Render";
+	}
+
+	return title;
+}
 
 /* opens window and allocs struct */
 static void open_renderwin(int winpos[2], int winsize[2])
 {
 	Window *win;
-	/* yafray: Window title change for yafray, totally unnecessary of course, but... */
-	char* title;
-	if (G.scene->r.renderer==R_YAFRAY)
-		title = "YafRay:Render";
-	else
-		title = "Blender:Render";
+	char *title;
 	
+	title= renderwin_get_title(0);	/* 0 = no swap */
 	win= window_open(title, winpos[0], winpos[1], winsize[0], winsize[1], 0);
 
 	render_win= renderwin_alloc(win);
@@ -941,6 +955,7 @@ void BIF_swap_render_rects(void)
 		// don't open render_win if rendering has been
 	    // canceled or the render_win has been actively closed
 		if (render_win) {
+			window_set_title(render_win->win, renderwin_get_title(1));
 			renderwin_queue_redraw(render_win);
 		}
 	} else {