Cycles / Wireframe node:

* Added a wireframe node (Input category) to get access to Mesh wireframe data. 
The thickness can be controlled via a "Size" parameter, and is available in world units (default) and screen pixel size. 
* Only the triangulated mesh is available now, quads is for later. 

Documentation:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/More#Wireframe

Render and Example file:
http://www.pasteall.org/pic/show.php?id=51731
http://www.pasteall.org/blend/21510

1 files changed, 97 insertions, 0 deletions

diff --git a/intern/cycles/kernel/svm/svm_wireframe.h b/intern/cycles/kernel/svm/svm_wireframe.h
new file mode 100644
index 00000000000..efe09051403
--- /dev/null
+++ b/intern/cycles/kernel/svm/svm_wireframe.h
@@ -0,0 +1,97 @@
+/*
+ * Adapted from Open Shading Language with this license:
+ *
+ * Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
+ * All Rights Reserved.
+ *
+ * Modifications Copyright 2013, Blender Foundation.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * * Neither the name of Sony Pictures Imageworks nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+CCL_NAMESPACE_BEGIN
+
+/* Wireframe Node */
+
+__device void svm_node_wireframe(KernelGlobals *kg, ShaderData *sd, float *stack, uint in_size, uint out_fac, uint use_pixel_size)
+{
+	/* Input Data */
+	float size = stack_load_float(stack, in_size);
+	int pixel_size = (int)use_pixel_size;
+	
+	/* Output */
+	float f = 0.0f;
+
+	/* Calculate wireframe */
+#ifdef __HAIR__
+	if (sd->segment == ~0) {
+#else
+	{
+#endif
+		float3 Co[3];
+		float pixelwidth = 1.0f;
+
+		/* Triangles */
+		float np = 3;
+		
+		triangle_vertices(kg, sd->prim, Co);
+
+		if(!(sd->flag & SD_TRANSFORM_APPLIED)) {
+			object_position_transform(kg, sd, &Co[0]);
+			object_position_transform(kg, sd, &Co[1]);
+			object_position_transform(kg, sd, &Co[2]);
+		}
+		
+		if(pixel_size) {
+			// Project the derivatives of P to the viewing plane defined
+			// by I so we have a measure of how big is a pixel at this point
+			float pixelwidth_x = len(sd->dP.dx - dot(sd->dP.dx, sd->I) * sd->I);
+			float pixelwidth_y = len(sd->dP.dy - dot(sd->dP.dy, sd->I) * sd->I);
+			// Take the average of both axis' length
+			pixelwidth = (pixelwidth_x + pixelwidth_y) * 0.5f;
+		}
+		
+		// Use half the width as the neighbor face will render the
+		// other half. And take the square for fast comparison
+		pixelwidth *= 0.5f * size;
+		pixelwidth *= pixelwidth;
+		for (int i = 0; i < np; i++) {
+			int i2 = i ? i - 1 : np - 1;
+			float3 dir = sd->P - Co[i];
+			float3 edge = Co[i] - Co[i2];
+			float3 crs = cross(edge, dir);
+			// At this point dot(crs, crs) / dot(edge, edge) is
+			// the square of area / length(edge) == square of the
+			// distance to the edge.
+			if (dot(crs, crs) < (dot(edge, edge) * pixelwidth))
+				f = 1.0f;
+		}
+	}
+	
+	if (stack_valid(out_fac))
+		stack_store_float(stack, out_fac, f);
+}
+
+CCL_NAMESPACE_END
+