- Fresnel V4.0

Based on feedback (thnx phase!) I found a big disadvantage of the 'real'
fresnel formula. It doesnt degrade to 0.0, causing 2-3 times too many
rays being fired compared to the previous one. So; a lot slower.

Now committed is a hybrid which allows (close to) real, and nice artistic
freedom, *and* it really goes to 0.0 and 1.0, assisting nicely in optimal
render times.
A real doc how it works (with pics) will be made before real release.

- Fixed bug in raytrace: the first renderpass didn't use fresnel for mirror.
- Fixed bug in previewrender, now it closer matches how fresnel renders

8 files changed, 67 insertions, 50 deletions

diff --git a/source/blender/blenkernel/intern/material.c b/source/blender/blenkernel/intern/material.c
index b3b13583e98..cc502b54f99 100644
--- a/source/blender/blenkernel/intern/material.c
+++ b/source/blender/blenkernel/intern/material.c
@@ -108,8 +108,10 @@ void init_material(Material *ma)
 	ma->ang= 1.0;
 	ma->ray_depth= 2;
 	ma->ray_depth_tra= 2;
-	ma->fresnel_mir= 1.0;
-	ma->fresnel_tra= 1.0;
+	ma->fresnel_mir= 0.0;
+	ma->fresnel_tra= 0.0;
+	ma->fresnel_tra_i= 1.25;
+	ma->fresnel_mir_i= 1.25;
 	
 	ma->mode= MA_TRACEBLE+MA_SHADOW+MA_RADIO;	
 }
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index f55d0fa78f7..a8abc0f0798 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -3933,6 +3933,8 @@ static void do_versions(Main *main)
 		Material *ma= main->mat.first;
 		Scene *sce;
 		while(ma) {
+			if(ma->fresnel_tra_i==0.0) ma->fresnel_tra_i= 1.25;
+			if(ma->fresnel_mir_i==0.0) ma->fresnel_mir_i= 1.25;
 			if(ma->ang==0.0) {
 				ma->ang= 1.0;
 				ma->ray_depth= 2;
diff --git a/source/blender/makesdna/DNA_material_types.h b/source/blender/makesdna/DNA_material_types.h
index d75cce4e4b8..f81f79f2b25 100644
--- a/source/blender/makesdna/DNA_material_types.h
+++ b/source/blender/makesdna/DNA_material_types.h
@@ -57,8 +57,8 @@ typedef struct Material {
 	float amb, emit, ang, spectra, ray_mirror;
 	float alpha, ref, spec, zoffs, add;
 	float translucency;
-	float fresnel_mir;
-	float fresnel_tra;
+	float fresnel_mir, fresnel_mir_i;
+	float fresnel_tra, fresnel_tra_i;
 	short ray_depth, ray_depth_tra;
 	short har;
 	char seed1, seed2;
diff --git a/source/blender/render/intern/source/ray.c b/source/blender/render/intern/source/ray.c
index 030dbb7847b..c60b679465c 100644
--- a/source/blender/render/intern/source/ray.c
+++ b/source/blender/render/intern/source/ray.c
@@ -1366,7 +1366,7 @@ static void traceray(short depth, float *start, float *vec, float *col, VlakRen
 
 			if(shi.matren->mode & MA_RAYMIRROR) {
 				f= shi.matren->ray_mirror;
-				if(f!=0.0) f*= fresnel_fac(shi.view, shi.vn, shi.matren->ang, shi.matren->fresnel_mir);
+				if(f!=0.0) f*= fresnel_fac(shi.view, shi.vn, shi.matren->fresnel_mir_i, shi.matren->fresnel_mir);
 			}
 			else f= 0.0;
 			
@@ -1438,6 +1438,9 @@ static float jit_cube5[5*5*5*3]={0.0};
 static float *jitter_plane(int resol)
 {
 	extern float hashvectf[];
+	extern char hash[];
+	extern int temp_x, temp_y;
+	static int offs=0;
 	float dsize, *jit, *fp, *hv;
 	int x, y;
 	
@@ -1453,15 +1456,17 @@ static float *jitter_plane(int resol)
 	case 7: jit= jit_plane7; break;
 	default: jit= jit_plane8; break;
 	}
-	if(jit[0]!=0.0) return jit;
+	//if(jit[0]!=0.0) return jit;
+
+	offs++;
 
 	dsize= 1.0/(resol-1.0);
 	fp= jit;
-	hv= hashvectf;
+	hv= hashvectf+3*(hash[ (temp_x&3)+4*(temp_y&3) ]);
 	for(x=0; x<resol; x++) {
 		for(y=0; y<resol; y++, fp+= 3, hv+=3) {
-			fp[0]= -0.5 + (x+0.25*hv[0])*dsize;
-			fp[1]= -0.5 + (y+0.25*hv[1])*dsize;
+			fp[0]= -0.5 + (x+0.5*hv[0])*dsize;
+			fp[1]= -0.5 + (y+0.5*hv[1])*dsize;
 			fp[2]= fp[0]*fp[0] + fp[1]*fp[1];
 			if(resol>2)
 				if(fp[2]>0.3) fp[2]= 0.0;
@@ -1586,7 +1591,7 @@ void ray_trace(ShadeInput *shi, ShadeResult *shr, int mask)
 		}
 		
 		if(div!=0.0) {
-			i= shi->matren->ray_mirror;
+			i= shi->matren->ray_mirror*fresnel_fac(shi->view, shi->vn, shi->matren->fresnel_mir_i, shi->matren->fresnel_mir);
 			fr= shi->matren->mirr;
 			fg= shi->matren->mirg;
 			fb= shi->matren->mirb;
@@ -1619,7 +1624,7 @@ void ray_trace(ShadeInput *shi, ShadeResult *shr, int mask)
 		
 		if(do_mir) {
 		
-			i= shi->matren->ray_mirror*fresnel_fac(shi->view, shi->vn, shi->matren->ang, shi->matren->fresnel_mir);
+			i= shi->matren->ray_mirror*fresnel_fac(shi->view, shi->vn, shi->matren->fresnel_mir_i, shi->matren->fresnel_mir);
 			if(i!=0.0) {
 				fr= shi->matren->mirr;
 				fg= shi->matren->mirg;
diff --git a/source/blender/render/intern/source/rendercore.c b/source/blender/render/intern/source/rendercore.c
index cb7fa627e3c..1406cb51380 100644
--- a/source/blender/render/intern/source/rendercore.c
+++ b/source/blender/render/intern/source/rendercore.c
@@ -1500,24 +1500,18 @@ void calc_R_ref(ShadeInput *shi)
 
 }
 
-float fresnel_fac(float *view, float *vn, float ior, float fac)
+/* mix of 'real' fresnel and allowing control. grad defines blending gradient */
+float fresnel_fac(float *view, float *vn, float grad, float fac)
 {
-	float rf, t1, t2;
+	float t1, t2;
 	
 	if(fac==0.0) return 1.0;
 	
-	rf = ((ior-1.0)/(ior+1.0));
-	rf*= rf;
-
 	t1= (view[0]*vn[0] + view[1]*vn[1] + view[2]*vn[2]);
-	if(t1>0.0) t1= 1.0-t1;
-	else t1 = 1.0+t1;
+	if(t1>0.0)  t2= 1.0+t1;
+	else t2= 1.0-t1;
 	
-	if(fac==5.0) {
-		t2 = t1*t1;
-		t2= rf + (1.0-rf)*t1*t2*t2;
-	}
-	else t2= rf + (1.0-rf)*pow(t1, fac);
+	t2= grad + (1.0-grad)*pow(t2, fac);
 
 	if(t2<0.0) return 0.0;
 	else if(t2>1.0) return 1.0;
@@ -1547,7 +1541,7 @@ void shade_color(ShadeInput *shi, ShadeResult *shr)
 
 	if(ma->mode & (MA_ZTRA|MA_RAYTRANSP)) {
 		if(ma->fresnel_tra!=1.0) 
-			ma->alpha*= fresnel_fac(shi->view, shi->vn, ma->ang, ma->fresnel_tra);
+			ma->alpha*= fresnel_fac(shi->view, shi->vn, ma->fresnel_tra_i, ma->fresnel_tra);
 	}
 
 	shr->diff[0]= ma->r;
@@ -1879,7 +1873,7 @@ void shade_lamp_loop(ShadeInput *shi, ShadeResult *shr, int mask)
 
 	if(ma->mode & (MA_ZTRA|MA_RAYTRANSP)) {
 		if(ma->fresnel_tra!=1.0) 
-			ma->alpha*= fresnel_fac(shi->view, shi->vn, ma->ang, ma->fresnel_tra);
+			ma->alpha*= fresnel_fac(shi->view, shi->vn, ma->fresnel_tra_i, ma->fresnel_tra);
 
 		if(ma->spectra!=0.0) {
 
@@ -2182,6 +2176,8 @@ void shade_input_set_coords(ShadeInput *shi, float u, float v, int i1, int i2, i
 	}
 }
 
+int temp_x, temp_y;
+
   /* x,y: window coordinate from 0 to rectx,y */
   /* return pointer to rendered face */
 void *shadepixel(float x, float y, int vlaknr, int mask, float *col)
@@ -2193,6 +2189,8 @@ void *shadepixel(float x, float y, int vlaknr, int mask, float *col)
 	if(vlaknr< 0) {	/* error */
 		return NULL;
 	}
+temp_x= floor(x);
+temp_y= floor(y);
 	
 	if(vlaknr==0) {	/* sky */
 		col[0]= 0.0; col[1]= 0.0; col[2]= 0.0; col[3]= 0.0;
diff --git a/source/blender/src/buttons_scene.c b/source/blender/src/buttons_scene.c
index 4583fd8d813..4a66f064966 100644
--- a/source/blender/src/buttons_scene.c
+++ b/source/blender/src/buttons_scene.c
@@ -1058,7 +1058,7 @@ static void render_panel_render()
 	uiBlockBeginAlign(block);
 	uiDefButI(block, TOG|BIT|6,0,"Fields",  564,50,60,23,&G.scene->r.mode, 0, 0, 0, 0, "Enables field rendering");
 	uiDefButI(block, TOG|BIT|13,0,"Odd",	624,50,40,23,&G.scene->r.mode, 0, 0, 0, 0, "Enables Odd field first rendering (Default: Even field)");
-	uiDefButI(block, TOG|BIT|7,0,"x",		655,50,20,23,&G.scene->r.mode, 0, 0, 0, 0, "Disables time difference in field calculations");
+	uiDefButI(block, TOG|BIT|7,0,"x",		665,50,20,23,&G.scene->r.mode, 0, 0, 0, 0, "Disables time difference in field calculations");
 
 	uiDefButI(block, TOG|BIT|17,0,"Gauss",	564,30,60,20, &G.scene->r.mode, 0, 0, 0, 0, "Enable Gauss sampling filter for antialiasing");
 	uiDefButF(block, NUM,B_DIFF,"",			624,30,60,20,&G.scene->r.gauss,0.5, 2.0, 0, 0, "Sets the Gauss filter size)");
diff --git a/source/blender/src/buttons_shading.c b/source/blender/src/buttons_shading.c
index f228bee4fde..75f19245550 100644
--- a/source/blender/src/buttons_shading.c
+++ b/source/blender/src/buttons_shading.c
@@ -2251,30 +2251,34 @@ static void material_panel_tramir(Material *ma)
 	uiNewPanelTabbed("Shaders", "Material");
 	if(uiNewPanel(curarea, block, "Mirror Transp", "Material", 640, 0, 318, 204)==0) return;
 
+	uiDefButI(block, TOG|BIT|18, B_MATPRV,"Ray Mirror",210,180,100,20, &(ma->mode), 0, 0, 0, 0, "Enables raytracing for mirror reflection rendering");
+
 	uiBlockBeginAlign(block);
-	uiDefButF(block, NUMSLI, B_MATPRV, "RayMir ",	10,180,200,19, &(ma->ray_mirror), 0.0, 1.0, 100, 2, "Sets the amount mirror reflection for raytrace");
-	uiDefButI(block, TOG|BIT|18, B_MATPRV,"Ray Mirror",210,180,100,19, &(ma->mode), 0, 0, 0, 0, "Enables raytracing for mirror reflection rendering");
-	uiDefButF(block, NUMSLI, B_MATPRV, "Fresnel ",	10,160,200,19, &(ma->fresnel_mir), 0.0, 5.0, 100, 2, "Power of Fresnel for mirror reflection");
-	uiDefButS(block, NUM, B_MATPRV, "Depth:",		210,160,100,19, &(ma->ray_depth), 0.0, 10.0, 100, 0, "Amount of inter-reflections calculated maximal ");
+	uiDefButF(block, NUMSLI, B_MATPRV, "RayMir ",	10,160,200,20, &(ma->ray_mirror), 0.0, 1.0, 100, 2, "Sets the amount mirror reflection for raytrace");
+	uiDefButS(block, NUM, B_MATPRV, "Depth:",		210,160,100,20, &(ma->ray_depth), 0.0, 10.0, 100, 0, "Amount of inter-reflections calculated maximal ");
+
+	uiDefButF(block, NUMSLI, B_MATPRV, "Fresnel ",	10,140,160,20, &(ma->fresnel_mir), 0.0, 5.0, 10, 2, "Power of Fresnel for mirror reflection");
+	uiDefButF(block, NUMSLI, B_MATPRV, "Fac ",		170,140,140,20, &(ma->fresnel_mir_i), 1.0, 5.0, 10, 2, "Blending factor for Fresnel");
 
 	uiBlockBeginAlign(block);
-	uiDefButF(block, NUMSLI, B_MATPRV, "Alpha ",		10,130,200,19, &(ma->alpha), 0.0, 1.0, 0, 0, "Sets the material's opacity and transparency mix");
-	uiDefButI(block, TOG|BIT|6, B_MATZTRANSP,"ZTransp",	210,130,100,19, &(ma->mode), 0, 0, 0, 0, "Enables Z-Buffering of transparent faces");
+	uiDefButI(block, TOG|BIT|6, B_MATZTRANSP,"ZTransp",	110,110,100,20, &(ma->mode), 0, 0, 0, 0, "Enables Z-Buffering of transparent faces");
+	uiDefButI(block, TOG|BIT|17, B_MATRAYTRANSP,"Ray Transp",210,110,100,20, &(ma->mode), 0, 0, 0, 0, "Enables raytracing for transparency rendering");
 
-	uiDefButF(block, NUMSLI, B_MATPRV, "IOR ",		10,110,200,19, &(ma->ang), 1.0, 3.0, 100, 2, "Sets the angular index of refraction for raytrace");
-	uiDefButI(block, TOG|BIT|17, B_MATRAYTRANSP,"Ray Transp",210,110,100,19, &(ma->mode), 0, 0, 0, 0, "Enables raytracing for transparency rendering");
+	uiBlockBeginAlign(block);
+	uiDefButF(block, NUMSLI, B_MATPRV, "IOR ",	10,90,200,20, &(ma->ang), 1.0, 3.0, 100, 2, "Sets the angular index of refraction for raytrace");
+	uiDefButS(block, NUM, B_MATPRV, "Depth:",	210,90,100,20, &(ma->ray_depth_tra), 0.0, 10.0, 100, 0, "Amount of refractions calculated maximal ");
 
-	uiDefButF(block, NUMSLI, B_MATPRV, "Fresnel ",	10,90,200,19, &(ma->fresnel_tra), 0.0, 5.0, 100, 2, "Power of Fresnel for transparency");
-	uiDefButS(block, NUM, B_MATPRV, "Depth:",		210,90,100,19, &(ma->ray_depth_tra), 0.0, 10.0, 100, 0, "Amount of refractions calculated maximal ");
+	uiDefButF(block, NUMSLI, B_MATPRV, "Fresnel ",	10,70,160,20, &(ma->fresnel_tra), 0.0, 5.0, 10, 2, "Power of Fresnel for transparency");
+	uiDefButF(block, NUMSLI, B_MATPRV, "Fac ",		170,70,140,20, &(ma->fresnel_tra_i), 1.0, 5.0, 10, 2, "Blending factor for Fresnel");
 
 	uiBlockBeginAlign(block);
-	uiDefButF(block, NUMSLI, B_MATPRV, "SpecTra ",	10,60,150,19, &(ma->spectra), 0.0, 1.0, 0, 0, "Makes specular areas opaque on transparent materials");
-	uiDefButF(block, NUMSLI, B_MATPRV, "Add ",		160,60,150,19, &(ma->add), 0.0, 1.0, 0, 0, "Sets a glow factor for transparant materials");
+	uiDefButF(block, NUMSLI, B_MATPRV, "SpecTra ",	10,40,150,20, &(ma->spectra), 0.0, 1.0, 0, 0, "Makes specular areas opaque on transparent materials");
+	uiDefButF(block, NUMSLI, B_MATPRV, "Add ",		160,40,150,20, &(ma->add), 0.0, 1.0, 0, 0, "Sets a glow factor for transparant materials");
 
 	uiBlockBeginAlign(block);
-	uiDefButI(block, TOG|BIT|10, 0,	"OnlyShadow",	10,10,100,19, &(ma->mode), 0, 0, 0, 0, "Renders shadows falling on material only");
-	uiDefButI(block, TOG|BIT|14, 0,	"No Mist",		110,10,100,19, &(ma->mode), 0, 0, 0, 0, "Sets the material to ignore mist values");
-	uiDefButI(block, TOG|BIT|9, 0,	"Env",			210,10,100,19, &(ma->mode), 0, 0, 0, 0, "Causes faces to render with alpha zero: allows sky/backdrop to show through");
+	uiDefButI(block, TOG|BIT|10, 0,	"OnlyShadow",	10,10,100,20, &(ma->mode), 0, 0, 0, 0, "Renders shadows falling on material only");
+	uiDefButI(block, TOG|BIT|14, 0,	"No Mist",		110,10,100,20, &(ma->mode), 0, 0, 0, 0, "Sets the material to ignore mist values");
+	uiDefButI(block, TOG|BIT|9, 0,	"Env",			210,10,100,20, &(ma->mode), 0, 0, 0, 0, "Causes faces to render with alpha zero: allows sky/backdrop to show through");
 	uiBlockEndAlign(block);
 
 
diff --git a/source/blender/src/previewrender.c b/source/blender/src/previewrender.c
index b5554dbfccd..ef43ca66ad0 100644
--- a/source/blender/src/previewrender.c
+++ b/source/blender/src/previewrender.c
@@ -783,7 +783,13 @@ static void shade_preview_pixel(ShadeInput *shi, float *vec, int x, int y,char *
 		}
 		
 	}
+	/* set it here, because ray_mirror will affect it */
+	alpha= mat->alpha;
 	
+	if(mat->mode & (MA_ZTRA|MA_RAYTRANSP)) 
+		if(mat->fresnel_tra!=0.0) 
+			alpha*= fresnel_fac(view, shi->vn, mat->fresnel_tra_i, mat->fresnel_tra);
+
 	if(mat->mode & MA_SHLESS) {
 		temp= 255.0*(mat->r);
 		if(temp>255) rect[0]= 255; else if(temp<0) rect[0]= 0; else rect[0]= temp;
@@ -860,8 +866,14 @@ static void shade_preview_pixel(ShadeInput *shi, float *vec, int x, int y,char *
 			/* scale */
 			div= (0.85*shi->ref[1]);
 			
-			shi->refcol[0]= mat->ray_mirror*fresnel_fac(view, shi->vn, mat->ang, mat->fresnel_mir);
-
+			shi->refcol[0]= mat->ray_mirror*fresnel_fac(view, shi->vn, mat->fresnel_mir_i, mat->fresnel_mir);
+			/* not real 'alpha', but mirror overriding transparency */
+			if(mat->mode & MA_RAYTRANSP) {
+				float fac= sqrt(shi->refcol[0]);
+				alpha= alpha*(1.0-fac) + fac;
+			}
+			else alpha= alpha*(1.0-shi->refcol[0]) + shi->refcol[0];
+			
 			if(div<0.0) {
 				/* minus 0.5 prevents too many small tiles in distance */
 				fac= (int)(shi->ref[0]/(div-0.1) ) + (int)(shi->ref[2]/(div-0.1) );
@@ -903,12 +915,6 @@ static void shade_preview_pixel(ShadeInput *shi, float *vec, int x, int y,char *
 		}
 	}
 
-	alpha= mat->alpha;
-	
-	if(mat->mode & (MA_ZTRA|MA_RAYTRANSP)) 
-		if(mat->fresnel_tra!=0.0) 
-			alpha*= fresnel_fac(view, shi->vn, mat->ang, mat->fresnel_tra);
-	
 		/* ztra shade */
 	if(mat->spectra!=0.0) {
 		inp = MAX3(isr, isg, isb);
@@ -916,7 +922,7 @@ static void shade_preview_pixel(ShadeInput *shi, float *vec, int x, int y,char *
 		if(inp>1.0) inp= 1.0;
 		alpha= (1.0-inp)*alpha+inp;
 	}
-	
+
 	if(alpha!=1.0) {
 		if(mat->mode & MA_RAYTRANSP) {
 			refraction_prv(&x, &y, shi->vn, mat->ang);