Cycles / Sky Texture:

* Added a new sky model by Hosek and Wilkie: "An Analytic Model for Full Spectral Sky-Dome Radiance" http://cgg.mff.cuni.cz/projects/SkylightModelling/ 

Example render:
http://archive.dingto.org/2013/blender/code/new_sky_model.png
Documentation:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/Textures#Sky_Texture

Details:
* User can choose between the older Preetham and the new Hosek / Wilkie model via a dropdown. For older files, backwards compatibility is preserved. When we add a new Sky texture, it defaults to the new model though. 
* For the new model, you can specify the ground albedo (see documentation for details). 
* Turbidity now has a UI soft range between 1 and 10, higher values (up to 30) are still possible, but can result in weird colors or black. 
* Removed the limitation of 1 sky texture per SVM stack. (Patch by Lukas Tönne, thanks!)

Thanks to Brecht for code review and some help! 

This is part of my GSoC 2013 project, SVN merge of r59214, r59220, r59251 and r59601.

1 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/nodes/shader/nodes/node_shader_tex_sky.c b/source/blender/nodes/shader/nodes/node_shader_tex_sky.c
index f9cd4b72912..c80b5282de3 100644
--- a/source/blender/nodes/shader/nodes/node_shader_tex_sky.c
+++ b/source/blender/nodes/shader/nodes/node_shader_tex_sky.c
@@ -48,6 +48,8 @@ static void node_shader_init_tex_sky(bNodeTree *UNUSED(ntree), bNode *node)
 	tex->sun_direction[1] = 0.0f;
 	tex->sun_direction[2] = 1.0f;
 	tex->turbidity = 2.2f;
+	tex->ground_albedo = 0.3f;
+	tex->sky_model = SHD_SKY_NEW;
 
 	node->storage = tex;
 }
@@ -70,6 +72,7 @@ void register_node_type_sh_tex_sky(void)
 	sh_node_type_base(&ntype, SH_NODE_TEX_SKY, "Sky Texture", NODE_CLASS_TEXTURE, 0);
 	node_type_compatibility(&ntype, NODE_NEW_SHADING);
 	node_type_socket_templates(&ntype, sh_node_tex_sky_in, sh_node_tex_sky_out);
+	node_type_size_preset(&ntype, NODE_SIZE_MIDDLE);
 	node_type_init(&ntype, node_shader_init_tex_sky);
 	node_type_storage(&ntype, "NodeTexSky", node_free_standard_storage, node_copy_standard_storage);
 	node_type_gpu(&ntype, node_shader_gpu_tex_sky);