Cycles: Add voxel texture sampler shader node

The idea of this node is to sampling of 3D voxels at a given coordinate
supporting different mapping strategies (world space mapping, object
local space etc).

Currently not in use, it's a preparation step for supporting point density
textures.

1 files changed, 64 insertions, 0 deletions

diff --git a/intern/cycles/kernel/svm/svm_voxel.h b/intern/cycles/kernel/svm/svm_voxel.h
new file mode 100644
index 00000000000..8752307472f
--- /dev/null
+++ b/intern/cycles/kernel/svm/svm_voxel.h
@@ -0,0 +1,64 @@
+/*
+ * Copyright 2011-2015 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+CCL_NAMESPACE_BEGIN
+
+/* TODO(sergey): Think of making it more generic volume-type attribute
+ * sampler.
+ */
+ccl_device void svm_node_tex_voxel(KernelGlobals *kg,
+                                   ShaderData *sd,
+                                   float *stack,
+                                   uint4 node,
+                                   int *offset)
+{
+	int id = node.y;
+	uint co_offset, density_out_offset, color_out_offset, space;
+	decode_node_uchar4(node.z, &co_offset, &density_out_offset, &color_out_offset, &space);
+	float3 co = stack_load_float3(stack, co_offset);
+	if(space == NODE_TEX_VOXEL_SPACE_OBJECT) {
+		co = volume_normalized_position(kg, sd, co);
+	}
+	else {
+		kernel_assert(space == NODE_TEX_VOXEL_SPACE_WORLD);
+		Transform tfm;
+		tfm.x = read_node_float(kg, offset);
+		tfm.y = read_node_float(kg, offset);
+		tfm.z = read_node_float(kg, offset);
+		tfm.w = read_node_float(kg, offset);
+		co = transform_point(&tfm, co);
+	}
+	if(co.x < 0.0f || co.y < 0.0f || co.z < 0.0f ||
+	   co.x > 1.0f || co.y > 1.0f || co.z > 1.0f)
+	{
+		if (stack_valid(density_out_offset))
+			stack_store_float(stack, density_out_offset, 0.0f);
+		if (stack_valid(color_out_offset))
+			stack_store_float3(stack, color_out_offset, make_float3(0.0f, 0.0f, 0.0f));
+		return;
+	}
+#ifdef __KERNEL_GPU__
+	float4 r = make_float4(0.0f, 0.0f, 0.0f, 0.0f);
+#else
+	float4 r = kernel_tex_image_interp_3d(id, co.x, co.y, co.z);
+#endif
+	if (stack_valid(density_out_offset))
+		stack_store_float(stack, density_out_offset, r.w);
+	if (stack_valid(color_out_offset))
+		stack_store_float3(stack, color_out_offset, make_float3(r.x, r.y, r.z));
+}
+
+CCL_NAMESPACE_END