Updated color calculus for sunsky

- removed ugly clamping function (it was dividing XYZ based on max of
  one of the values)
- added option to use Exposure, this only works for brightness (Y).
  results look very pleasant, foggy and hazy results are possible.
  with exposre==0, no exposure happens for HDR extreme range skies,
  this is how yafray rendered it.
- added menu for choosing color spaces (CIE = modern lcds)

Please review! (and yes i know it's still not in World :)

9 files changed, 54 insertions, 36 deletions

diff --git a/source/blender/blenkernel/BKE_blender.h b/source/blender/blenkernel/BKE_blender.h
index f7af2e4b938..0105587c5b4 100644
--- a/source/blender/blenkernel/BKE_blender.h
+++ b/source/blender/blenkernel/BKE_blender.h
@@ -41,7 +41,7 @@ struct ListBase;
 struct MemFile;
 
 #define BLENDER_VERSION			247
-#define BLENDER_SUBVERSION		8
+#define BLENDER_SUBVERSION		9
 
 #define BLENDER_MINVERSION		245
 #define BLENDER_MINSUBVERSION	15
diff --git a/source/blender/blenkernel/intern/object.c b/source/blender/blenkernel/intern/object.c
index 2dfa849fc43..ec110c6ea7c 100644
--- a/source/blender/blenkernel/intern/object.c
+++ b/source/blender/blenkernel/intern/object.c
@@ -758,7 +758,9 @@ void *add_lamp(char *name)
 	la->sun_intensity = 1.0;
 	la->skyblendtype= MA_RAMP_ADD;
 	la->skyblendfac= 1.0f;
-
+	la->sky_colorspace= BLI_CS_CIE;
+	la->sky_exposure= 1.0f;
+	
 	curvemapping_initialize(la->curfalloff);
 	return la;
 }
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 0999c8b0ce3..4ec773409da 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -7920,6 +7920,15 @@ static void do_versions(FileData *fd, Library *lib, Main *main)
 		}
 	}
 
+	if (main->versionfile < 247 || (main->versionfile == 247 && main->subversionfile < 9)) {
+		Lamp *la= main->lamp.first;
+		for(; la; la= la->id.next) {
+			la->sky_exposure= 1.0f;
+		}
+	}
+		
+		
+		
 	/* WATCH IT!!!: pointers from libdata have not been converted yet here! */
 	/* WATCH IT 2!: Userdef struct init has to be in src/usiblender.c! */
 
diff --git a/source/blender/makesdna/DNA_lamp_types.h b/source/blender/makesdna/DNA_lamp_types.h
index 217e3ed1463..f8f2255c1a7 100644
--- a/source/blender/makesdna/DNA_lamp_types.h
+++ b/source/blender/makesdna/DNA_lamp_types.h
@@ -91,7 +91,9 @@ typedef struct Lamp {
     float atm_extinction_factor;
     float atm_distance_factor;
 	float skyblendfac;
-
+	float sky_exposure;
+	short sky_colorspace, pad4;
+	
 	/* yafray: photonlight params */
 	int YF_numphotons, YF_numsearch;
 	short YF_phdepth, YF_useqmc, YF_bufsize, YF_pad;
diff --git a/source/blender/render/intern/include/sunsky.h b/source/blender/render/intern/include/sunsky.h
index c5e547097d2..f61338bcf27 100644
--- a/source/blender/render/intern/include/sunsky.h
+++ b/source/blender/render/intern/include/sunsky.h
@@ -33,7 +33,7 @@
 
 typedef struct SunSky
 {
-    short effect_type, skyblendtype;
+    short effect_type, skyblendtype, sky_colorspace;
     float turbidity;
     float theta, phi;
     
@@ -54,6 +54,7 @@ typedef struct SunSky
     float sun_size;
     float backscattered_light;
     float skyblendfac;
+	float sky_exposure;
 	
     float atm_HGg;
 
@@ -86,7 +87,7 @@ typedef struct SunSky
  * */
 void InitSunSky(struct SunSky *sunsky, float turb, float *toSun, float horizon_brightness, 
 				float spread,float sun_brightness, float sun_size, float back_scatter,
-				float skyblendfac, short skyblendtype);
+				float skyblendfac, short skyblendtype, float sky_exposure, float sky_colorspace);
 
 /**
  * GetSkyXYZRadiance:
diff --git a/source/blender/render/intern/source/convertblender.c b/source/blender/render/intern/source/convertblender.c
index aba96fae1c2..4af6bf6f543 100644
--- a/source/blender/render/intern/source/convertblender.c
+++ b/source/blender/render/intern/source/convertblender.c
@@ -3528,7 +3528,7 @@ static GroupObject *add_render_lamp(Render *re, Object *ob)
 		    
 			InitSunSky(lar->sunsky, la->atm_turbidity, vec, la->horizon_brightness, 
 					la->spread, la->sun_brightness, la->sun_size, la->backscattered_light,
-					   la->skyblendfac, la->skyblendtype);
+					   la->skyblendfac, la->skyblendtype, la->sky_exposure, la->sky_colorspace);
 			
 			InitAtmosphere(lar->sunsky, la->sun_intensity, 1.0, 1.0, la->atm_inscattering_factor, la->atm_extinction_factor,
 					la->atm_distance_factor);
diff --git a/source/blender/render/intern/source/pixelshading.c b/source/blender/render/intern/source/pixelshading.c
index 9551a7b3227..a13829d0306 100644
--- a/source/blender/render/intern/source/pixelshading.c
+++ b/source/blender/render/intern/source/pixelshading.c
@@ -573,7 +573,6 @@ void shadeSkyView(float *colf, float *rco, float *view, float *dxyview)
 void shadeSunView(struct SunSky *sunsky, float *colf, float *rco, float *view, float *dxyview)
 {
 	float colorxyz[3];
-	float scale;
 			
 	/**
 	sunAngle = sqrt(sunsky->sunSolidAngle / M_PI);
@@ -588,15 +587,10 @@ void shadeSunView(struct SunSky *sunsky, float *colf, float *rco, float *view, f
 	if (view[2] < 0.0)
 		view[2] = 0.0;
 	Normalize(view);
+	
 	GetSkyXYZRadiancef(sunsky, view, colorxyz);
-	scale = MAX3(colorxyz[0], colorxyz[1], colorxyz[2]);
-	colorxyz[0] /= scale;
-	colorxyz[1] /= scale;
-	colorxyz[2] /= scale;
 	
-	xyz_to_rgb(colorxyz[0], colorxyz[1], colorxyz[2], &colf[0], &colf[1], &colf[2], BLI_CS_SMPTE);
-
-	ClipColor(colf);
+	xyz_to_rgb(colorxyz[0], colorxyz[1], colorxyz[2], &colf[0], &colf[1], &colf[2], sunsky->sky_colorspace);
 }
 
 
diff --git a/source/blender/render/intern/source/sunsky.c b/source/blender/render/intern/source/sunsky.c
index e1c7933cea1..2b490e71142 100644
--- a/source/blender/render/intern/source/sunsky.c
+++ b/source/blender/render/intern/source/sunsky.c
@@ -22,7 +22,7 @@
 #include "sunsky.h"
 #include "math.h"
 #include "BLI_arithb.h"
-
+#include "BKE_global.h"
 
 /**
  * These macros are defined for vector operations
@@ -111,15 +111,14 @@ static void DirectionToThetaPhi(float *toSun, float *theta, float *phi)
 float PerezFunction(struct SunSky *sunsky, const float *lam, float theta, float gamma, float lvz)
 {
     float den, num;
-
+	
     den = ((1 + lam[0] * exp(lam[1])) *
-                   (1 + lam[2] * exp(lam[3] * sunsky->theta) + lam[4] * cos(sunsky->theta) * cos(sunsky->theta)));
-
+		   (1 + lam[2] * exp(lam[3] * sunsky->theta) + lam[4] * cos(sunsky->theta) * cos(sunsky->theta)));
+	
     num = ((1 + lam[0] * exp(lam[1] / cos(theta))) *
-                   (1 + lam[2] * exp(lam[3] * gamma) + lam[4] * cos(gamma) * cos(gamma)));
-
-    return(lvz * num / den);
-}
+		   (1 + lam[2] * exp(lam[3] * gamma) + lam[4] * cos(gamma) * cos(gamma)));
+	
+    return(lvz * num / den);}
 
 /**
  * InitSunSky:
@@ -136,7 +135,7 @@ float PerezFunction(struct SunSky *sunsky, const float *lam, float theta, float
  * */
 void InitSunSky(struct SunSky *sunsky, float turb, float *toSun, float horizon_brightness, 
 				float spread,float sun_brightness, float sun_size, float back_scatter,
-				float skyblendfac, short skyblendtype)
+				float skyblendfac, short skyblendtype, float sky_exposure, float sky_colorspace)
 {
     
    	float theta2;
@@ -154,6 +153,8 @@ void InitSunSky(struct SunSky *sunsky, float turb, float *toSun, float horizon_b
 	sunsky->backscattered_light = back_scatter;
 	sunsky->skyblendfac= skyblendfac;
 	sunsky->skyblendtype= skyblendtype;
+	sunsky->sky_exposure= -sky_exposure;
+	sunsky->sky_colorspace= sky_colorspace;
 	
 	sunsky->toSun[0] = toSun[0];
     sunsky->toSun[1] = toSun[1];
@@ -262,8 +263,11 @@ void GetSkyXYZRadiance(struct SunSky* sunsky, float theta, float phi, float colo
     // Compute xyY values
     x = PerezFunction(sunsky, sunsky->perez_x, theta, gamma, sunsky->zenith_x);
     y = PerezFunction(sunsky, sunsky->perez_y, theta, gamma, sunsky->zenith_y);
-    Y = nfade * hfade * PerezFunction(sunsky, sunsky->perez_Y, theta, gamma, sunsky->zenith_Y);
+    Y = 6.666666667e-5 * nfade * hfade * PerezFunction(sunsky, sunsky->perez_Y, theta, gamma, sunsky->zenith_Y);
 
+	if(sunsky->sky_exposure!=0.0f)
+		Y = 1.0 - exp(Y*sunsky->sky_exposure);
+	
     X = (x / y) * Y;
     Z = ((1 - x - y) / y) * Y;
 
diff --git a/source/blender/src/buttons_shading.c b/source/blender/src/buttons_shading.c
index 2dafa70a350..c377168bdb8 100644
--- a/source/blender/src/buttons_shading.c
+++ b/source/blender/src/buttons_shading.c
@@ -2892,23 +2892,29 @@ static void lamp_panel_atmosphere(Object *ob, Lamp *la)
 		uiDefButS(block, MENU, B_LAMPPRV, "Mix %x0|Add %x1|Subtract %x3|Multiply %x2|Screen %x4|Overlay %x9|Divide %x5|Difference %x6|Darken %x7|Lighten %x8|Dodge %x10|Burn %x11|Color %x15|Value %x14|Saturation %x13|Hue %x12",
 					 10,y-25,BUTW2/2,19, 
 					 &la->skyblendtype, 0.0f, 0.0f, 0, 0, "Blend type for how it gets combined with sky");
-		uiDefButF(block, NUM, B_LAMPPRV, "",10+BUTW2/2,y-25,BUTW2/2,19, &(la->skyblendfac), 0.0f, 1.0f, 10, 0, "Sets blending factor with sky color");
-		uiBlockEndAlign(block);
+		uiDefButF(block, NUM, B_LAMPPRV, "",10+BUTW2/2,y-25,BUTW2/2,19, &(la->skyblendfac), 0.0f, 2.0f, 10, 0, "Sets blending factor with sky color");
+		
+		uiBlockBeginAlign(block);
+		uiDefButS(block, MENU, B_LAMPPRV, "SMPTE %x0|REC709 %x1|CIE %x2",
+				  10,126,60,22,  &la->sky_colorspace, 0.0f, 0.0f, 0, 0, "Color space");
 		
-		y -= 25;
-		uiDefButF(block, NUM, B_LAMPPRV, "Hor.Bright:",10,y-25,BUTW2,19, &(la->horizon_brightness), 0.00f, 20.00f, 10, 0, "Sets horizon brightness.");
-		uiDefButF(block, NUM, B_LAMPPRV, "Hor.Spread:",10,y-50,BUTW2,19, &(la->spread), 0.00f, 10.00f, 10, 0, "Sets horizon spread.");
-		uiDefButF(block, NUM, B_LAMPPRV, "Sun Bright:",10,y-75,BUTW2,19, &(la->sun_brightness), 0.00f, 10.0f, 10, 0, "Sets sun brightness.");
-		uiDefButF(block, NUM, B_LAMPPRV, "Sun Size:",10,y-100,BUTW2,19, &(la->sun_size), 0.00f, 10.00f, 10, 0, "Sets sun size.");
-		uiDefButF(block, NUM, B_LAMPPRV, "Back Light:",10,y-125,BUTW2,19, &(la->backscattered_light), -1.00f, 1.00f, 10, 0, "Sets backscatter light.");
+		uiDefButF(block, NUM, B_LAMPPRV, "Exp:",70,126,BUTW2-60,22, &(la->sky_exposure), 0.00f, 20.00f, 10, 0, "Exposure correction, zero is no correction.");
+		
+		uiBlockBeginAlign(block);
+		uiDefButF(block, NUM, B_LAMPPRV, "Hor.Bright:",10,98,BUTW2,22, &(la->horizon_brightness), 0.00f, 20.00f, 10, 0, "Sets horizon brightness.");
+		uiDefButF(block, NUM, B_LAMPPRV, "Hor.Spread:",10,76,BUTW2,22, &(la->spread), 0.00f, 10.00f, 10, 0, "Sets horizon spread.");
+		uiDefButF(block, NUM, B_LAMPPRV, "Sun Bright:",10,54,BUTW2,22, &(la->sun_brightness), 0.00f, 10.0f, 10, 0, "Sets sun brightness.");
+		uiDefButF(block, NUM, B_LAMPPRV, "Sun Size:",10,32,BUTW2,22, &(la->sun_size), 0.00f, 10.00f, 10, 0, "Sets sun size.");
+		uiDefButF(block, NUM, B_LAMPPRV, "Back Light:",10,10,BUTW2,22, &(la->backscattered_light), -1.00f, 1.00f, 10, 0, "Sets backscatter light.");
 	}
 
 	if(la->sun_effect_type & LA_SUN_EFFECT_AP)
 	{
-		uiDefButF(block, NUM, B_LAMPREDRAW, "Sun Intens.:",20+BUTW2,y-25,BUTW2,19, &(la->sun_intensity), 0.00f, 10.00f, 10, 0, "Sets sun intensity.");
-		uiDefButF(block, NUM, B_LAMPREDRAW, "Inscattering:",20+BUTW2,y-50,BUTW2,19, &(la->atm_inscattering_factor), 0.00f, 1.00f, 10, 0, "In Scattering Contribution Factor.");
-		uiDefButF(block, NUM, B_LAMPREDRAW, "Extinction:",20+BUTW2,y-75,BUTW2,19, &(la->atm_extinction_factor), 0.00f, 1.00f, 10, 0, "Extinction Scattering Contribution Factor.");
-		uiDefButF(block, NUM, B_LAMPREDRAW, "Distance:",20+BUTW2,y-100,BUTW2,19, &(la->atm_distance_factor), 0.000f, 500.0f, 10, 0, "Scale blender distance to real distance.");
+		uiBlockBeginAlign(block);
+		uiDefButF(block, NUM, B_LAMPREDRAW, "Sun Intens.:",20+BUTW2,76,BUTW2,22, &(la->sun_intensity), 0.00f, 10.00f, 10, 0, "Sets sun intensity.");
+		uiDefButF(block, NUM, B_LAMPREDRAW, "Inscattering:",20+BUTW2,54,BUTW2,22, &(la->atm_inscattering_factor), 0.00f, 1.00f, 10, 0, "In Scattering Contribution Factor.");
+		uiDefButF(block, NUM, B_LAMPREDRAW, "Extinction:",20+BUTW2,32,BUTW2,22, &(la->atm_extinction_factor), 0.00f, 1.00f, 10, 0, "Extinction Scattering Contribution Factor.");
+		uiDefButF(block, NUM, B_LAMPREDRAW, "Distance:",20+BUTW2,10,BUTW2,22, &(la->atm_distance_factor), 0.000f, 500.0f, 10, 0, "Scale blender distance to real distance.");
 	}
 }