Sunsky / Atmoshphere:

- Added blending mode and factor option, so it's more clear and
  controllable what happens with it. Also nice for crazy effects
  of course!
- Preview render now shows preview for it too

On the todos:

- have this in World buttons (as well) for quicker sky setups
- review math of color clamping and scaling, this is definitely 
  not good... but a fix will make old files look very different.

4 files changed, 16 insertions, 27 deletions

diff --git a/source/blender/render/intern/include/sunsky.h b/source/blender/render/intern/include/sunsky.h
index c61a637269a..c5e547097d2 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;
+    short effect_type, skyblendtype;
     float turbidity;
     float theta, phi;
     
@@ -53,7 +53,8 @@ typedef struct SunSky
     float sun_brightness;
     float sun_size;
     float backscattered_light;
-    
+    float skyblendfac;
+	
     float atm_HGg;
 
     float atm_SunIntensity;
@@ -84,7 +85,8 @@ typedef struct SunSky
  * back_scatter, controls back scatter light
  * */
 void InitSunSky(struct SunSky *sunsky, float turb, float *toSun, float horizon_brightness, 
-				float spread,float sun_brightness, float sun_size, float back_scatter);
+				float spread,float sun_brightness, float sun_size, float back_scatter,
+				float skyblendfac, short skyblendtype);
 
 /**
  * GetSkyXYZRadiance:
diff --git a/source/blender/render/intern/source/convertblender.c b/source/blender/render/intern/source/convertblender.c
index 45d79be2f62..7d92b92a728 100644
--- a/source/blender/render/intern/source/convertblender.c
+++ b/source/blender/render/intern/source/convertblender.c
@@ -3638,7 +3638,8 @@ static GroupObject *add_render_lamp(Render *re, Object *ob)
 		    Normalize(vec);
 		    
 			InitSunSky(lar->sunsky, la->atm_turbidity, vec, la->horizon_brightness, 
-					la->spread, la->sun_brightness, la->sun_size, la->backscattered_light);
+					la->spread, la->sun_brightness, la->sun_size, la->backscattered_light,
+					   la->skyblendfac, la->skyblendtype);
 			
 			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 ef723eea6b5..4a567042d12 100644
--- a/source/blender/render/intern/source/pixelshading.c
+++ b/source/blender/render/intern/source/pixelshading.c
@@ -45,6 +45,7 @@
 
 #include "BKE_image.h"
 #include "BKE_global.h"
+#include "BKE_material.h"
 #include "BKE_texture.h"
 #include "BKE_utildefines.h"
 
@@ -604,12 +605,9 @@ void shadeSunView(struct SunSky *sunsky, float *colf, float *rco, float *view, f
  */
 void shadeSkyPixel(float *collector, float fx, float fy) 
 {
-	float view[3], dxyview[2];
-	float sun_collector[3];
-	float suns_color[3];
-	short num_sun_lamp;
 	GroupObject *go;
 	LampRen *lar;
+	float view[3], dxyview[2];
 
 	/*
 	  The rules for sky:
@@ -657,33 +655,18 @@ void shadeSkyPixel(float *collector, float fx, float fy)
 		collector[3] = 0.0f;
 	}
 		
-	suns_color[0] = suns_color[1] = suns_color[2] = 0;
-	num_sun_lamp = 0;
 	for(go=R.lights.first; go; go= go->next) {
 		lar= go->lampren;
 		if(lar->type==LA_SUN &&	lar->sunsky && (lar->sunsky->effect_type & LA_SUN_EFFECT_SKY)){
-
-			num_sun_lamp ++;
+			float sun_collector[3];
+			
 			calc_view_vector(view, fx, fy);
 			Normalize(view);
 
 			shadeSunView(lar->sunsky, sun_collector, NULL, view, NULL);
-			suns_color[0] += sun_collector[0];
-			suns_color[1] += sun_collector[1];
-			suns_color[2] += sun_collector[2];
-
+			ramp_blend(lar->sunsky->skyblendtype, collector, collector+1, collector+2, lar->sunsky->skyblendfac, sun_collector);
 		}
 	}
-	if( num_sun_lamp > 0 ){
-		suns_color[0] /= num_sun_lamp;
-		suns_color[1] /= num_sun_lamp;
-		suns_color[2] /= num_sun_lamp;
-
-		collector[0] += suns_color[0];
-		collector[1] += suns_color[1];
-		collector[2] += suns_color[2];
-		ClipColor(collector);
-	}
 }
 
 /* aerial perspective */
diff --git a/source/blender/render/intern/source/sunsky.c b/source/blender/render/intern/source/sunsky.c
index 191867765a3..e1c7933cea1 100644
--- a/source/blender/render/intern/source/sunsky.c
+++ b/source/blender/render/intern/source/sunsky.c
@@ -135,7 +135,8 @@ float PerezFunction(struct SunSky *sunsky, const float *lam, float theta, float
  * back_scatter, controls back scatter light
  * */
 void InitSunSky(struct SunSky *sunsky, float turb, float *toSun, float horizon_brightness, 
-				float spread,float sun_brightness, float sun_size, float back_scatter)
+				float spread,float sun_brightness, float sun_size, float back_scatter,
+				float skyblendfac, short skyblendtype)
 {
     
    	float theta2;
@@ -151,6 +152,8 @@ void InitSunSky(struct SunSky *sunsky, float turb, float *toSun, float horizon_b
 	sunsky->sun_brightness = sun_brightness;
 	sunsky->sun_size = sun_size;
 	sunsky->backscattered_light = back_scatter;
+	sunsky->skyblendfac= skyblendfac;
+	sunsky->skyblendtype= skyblendtype;
 	
 	sunsky->toSun[0] = toSun[0];
     sunsky->toSun[1] = toSun[1];