Cycles: add Vector Displacement node and extend Displacement node.

This adds midlevel and object/world space for displacement, and a
vector displacement node with tangent/object/world space, midlevel
and scale.

Note that tangent space vector displacement still is not exactly
compatible with maps created by other software, this will require
changes to the tangent computation.

Differential Revision: https://developer.blender.org/D1734

1 files changed, 31 insertions, 2 deletions

diff --git a/source/blender/gpu/shaders/gpu_shader_material.glsl b/source/blender/gpu/shaders/gpu_shader_material.glsl
index a77e7eb7937..d589c8765e6 100644
--- a/source/blender/gpu/shaders/gpu_shader_material.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_material.glsl
@@ -3827,9 +3827,38 @@ void node_bevel(float radius, vec3 N, out vec3 result)
 	result = N;
 }
 
-void node_displacement(float height, float dist, vec3 N, out vec3 result)
+void node_displacement_object(float height, float midlevel, float scale, vec3 N, mat4 obmat, out vec3 result)
 {
-	result = height * dist * N;
+	N = (vec4(N, 0.0) * obmat).xyz;
+	result = (height - midlevel) * scale * normalize(N);
+	result = (obmat * vec4(result, 0.0)).xyz;
+}
+
+void node_displacement_world(float height, float midlevel, float scale, vec3 N, out vec3 result)
+{
+	result = (height - midlevel) * scale * normalize(N);
+}
+
+void node_vector_displacement_tangent(vec4 vector, float midlevel, float scale, vec4 tangent, vec3 normal, mat4 obmat, mat4 viewmat, out vec3 result)
+{
+	vec3 N_object = normalize(((vec4(normal, 0.0) * viewmat) * obmat).xyz);
+	vec3 T_object = normalize(((vec4(tangent.xyz, 0.0) * viewmat) * obmat).xyz);
+	vec3 B_object = tangent.w * normalize(cross(N_object, T_object));
+
+	vec3 offset = (vector.xyz - vec3(midlevel)) * scale;
+	result = offset.x * T_object + offset.y * N_object + offset.z * B_object;
+	result = (obmat * vec4(result, 0.0)).xyz;
+}
+
+void node_vector_displacement_object(vec4 vector, float midlevel, float scale, mat4 obmat, out vec3 result)
+{
+	result = (vector.xyz - vec3(midlevel)) * scale;
+	result = (obmat * vec4(result, 0.0)).xyz;
+}
+
+void node_vector_displacement_world(vec4 vector, float midlevel, float scale, out vec3 result)
+{
+	result = (vector.xyz - vec3(midlevel)) * scale;
 }
 
 /* output */