World background working on cycle nodes.

This is added in the spirit of the general cycles GLSL system
which is pretty much WIP still.

This will only work on cycles at the moment but generating for blender
internal is possible too of course though it will be done in a separate
commit.

This hasn't been tested with all and every node in cycles, but
environment and regular textures with texture coordinates work.

There is some difference between the way cycles treats some coordinates,
which is in world space and the way GLSL treats them, which is in view
space.
We might want to explore and improve this further in the future.

...also </drumroll>

1 files changed, 45 insertions, 0 deletions

diff --git a/source/blender/gpu/shaders/gpu_shader_material.glsl b/source/blender/gpu/shaders/gpu_shader_material.glsl
index 867270a6d7a..c463fb25ded 100644
--- a/source/blender/gpu/shaders/gpu_shader_material.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_material.glsl
@@ -2256,6 +2256,22 @@ void node_emission(vec4 color, float strength, vec3 N, out vec4 result)
 	result = color*strength;
 }
 
+/* background */
+
+void background_transform_to_world(vec3 viewvec, out vec3 worldvec)
+{
+	vec4 v = (gl_ProjectionMatrix[3][3] == 0.0) ? vec4(viewvec, 1.0) : vec4(0.0, 0.0, 1.0, 1.0);
+	vec4 co_homogenous = (gl_ProjectionMatrixInverse * v);
+
+	vec4 co = vec4(co_homogenous.xyz / co_homogenous.w, 0.0);
+	worldvec = (gl_ModelViewMatrixInverse * co).xyz;
+}
+
+void node_background(vec4 color, float strength, vec3 N, out vec4 result)
+{
+	result = color*strength;
+}
+
 /* closures */
 
 void node_mix_shader(float fac, vec4 shader1, vec4 shader2, out vec4 shader)
@@ -2364,6 +2380,30 @@ void node_tex_coord(vec3 I, vec3 N, mat4 viewinvmat, mat4 obinvmat,
 	reflection = (viewinvmat*vec4(view_reflection, 0.0)).xyz;
 }
 
+void node_tex_coord_background(vec3 I, vec3 N, mat4 viewinvmat, mat4 obinvmat,
+	vec3 attr_orco, vec3 attr_uv,
+	out vec3 generated, out vec3 normal, out vec3 uv, out vec3 object,
+	out vec3 camera, out vec3 window, out vec3 reflection)
+{
+	vec4 v = (gl_ProjectionMatrix[3][3] == 0.0) ? vec4(I, 1.0) : vec4(0.0, 0.0, 1.0, 1.0);
+	vec4 co_homogenous = (gl_ProjectionMatrixInverse * v);
+
+	vec4 co = vec4(co_homogenous.xyz / co_homogenous.w, 0.0);
+
+	co = normalize(co);
+	vec3 coords = (gl_ModelViewMatrixInverse * co).xyz;
+
+	generated = coords;
+	normal = -coords;
+	uv = attr_uv;
+	object = coords;
+
+	camera = co.xyz;
+	window = mtex_2d_mapping(I);
+
+	reflection = -coords;
+}
+
 /* textures */
 
 void node_tex_gradient(vec3 co, out vec4 color, out float fac)
@@ -2525,6 +2565,11 @@ void node_output_material(vec4 surface, vec4 volume, float displacement, out vec
 	result = surface;
 }
 
+void node_output_world(vec4 surface, vec4 volume, out vec4 result)
+{
+	result = surface;
+}
+
 /* ********************** matcap style render ******************** */
 
 void material_preview_matcap(vec4 color, sampler2D ima, vec4 N, vec4 mask, out vec4 result)