1 /*
2  * Adapted from Open Shading Language with this license:
3  *
4  * Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al.
5  * All Rights Reserved.
6  *
7  * Modifications Copyright 2013, Blender Foundation.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions are
11  * met:
12  * * Redistributions of source code must retain the above copyright
13  *   notice, this list of conditions and the following disclaimer.
14  * * Redistributions in binary form must reproduce the above copyright
15  *   notice, this list of conditions and the following disclaimer in the
16  *   documentation and/or other materials provided with the distribution.
17  * * Neither the name of Sony Pictures Imageworks nor the names of its
18  *   contributors may be used to endorse or promote products derived from
19  *   this software without specific prior written permission.
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 CCL_NAMESPACE_BEGIN
34 
35 /* Wireframe Node */
36 
wireframe(KernelGlobals * kg,ShaderData * sd,float size,int pixel_size,float3 * P)37 ccl_device_inline float wireframe(
38     KernelGlobals *kg, ShaderData *sd, float size, int pixel_size, float3 *P)
39 {
40 #ifdef __HAIR__
41   if (sd->prim != PRIM_NONE && sd->type & PRIMITIVE_ALL_TRIANGLE)
42 #else
43   if (sd->prim != PRIM_NONE)
44 #endif
45   {
46     float3 Co[3];
47     float pixelwidth = 1.0f;
48 
49     /* Triangles */
50     int np = 3;
51 
52     if (sd->type & PRIMITIVE_TRIANGLE)
53       triangle_vertices(kg, sd->prim, Co);
54     else
55       motion_triangle_vertices(kg, sd->object, sd->prim, sd->time, Co);
56 
57     if (!(sd->object_flag & SD_OBJECT_TRANSFORM_APPLIED)) {
58       object_position_transform(kg, sd, &Co[0]);
59       object_position_transform(kg, sd, &Co[1]);
60       object_position_transform(kg, sd, &Co[2]);
61     }
62 
63     if (pixel_size) {
64       // Project the derivatives of P to the viewing plane defined
65       // by I so we have a measure of how big is a pixel at this point
66       float pixelwidth_x = len(sd->dP.dx - dot(sd->dP.dx, sd->I) * sd->I);
67       float pixelwidth_y = len(sd->dP.dy - dot(sd->dP.dy, sd->I) * sd->I);
68       // Take the average of both axis' length
69       pixelwidth = (pixelwidth_x + pixelwidth_y) * 0.5f;
70     }
71 
72     // Use half the width as the neighbor face will render the
73     // other half. And take the square for fast comparison
74     pixelwidth *= 0.5f * size;
75     pixelwidth *= pixelwidth;
76     for (int i = 0; i < np; i++) {
77       int i2 = i ? i - 1 : np - 1;
78       float3 dir = *P - Co[i];
79       float3 edge = Co[i] - Co[i2];
80       float3 crs = cross(edge, dir);
81       // At this point dot(crs, crs) / dot(edge, edge) is
82       // the square of area / length(edge) == square of the
83       // distance to the edge.
84       if (dot(crs, crs) < (dot(edge, edge) * pixelwidth))
85         return 1.0f;
86     }
87   }
88   return 0.0f;
89 }
90 
svm_node_wireframe(KernelGlobals * kg,ShaderData * sd,float * stack,uint4 node)91 ccl_device void svm_node_wireframe(KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node)
92 {
93   uint in_size = node.y;
94   uint out_fac = node.z;
95   uint use_pixel_size, bump_offset;
96   svm_unpack_node_uchar2(node.w, &use_pixel_size, &bump_offset);
97 
98   /* Input Data */
99   float size = stack_load_float(stack, in_size);
100   int pixel_size = (int)use_pixel_size;
101 
102   /* Calculate wireframe */
103 #ifdef __SPLIT_KERNEL__
104   /* TODO(sergey): This is because sd is actually a global space,
105    * which makes it difficult to re-use same wireframe() function.
106    *
107    * With OpenCL 2.0 it's possible to avoid this change, but for until
108    * then we'll be living with such an exception.
109    */
110   float3 P = sd->P;
111   float f = wireframe(kg, sd, size, pixel_size, &P);
112 #else
113   float f = wireframe(kg, sd, size, pixel_size, &sd->P);
114 #endif
115 
116   /* TODO(sergey): Think of faster way to calculate derivatives. */
117   if (bump_offset == NODE_BUMP_OFFSET_DX) {
118     float3 Px = sd->P - sd->dP.dx;
119     f += (f - wireframe(kg, sd, size, pixel_size, &Px)) / len(sd->dP.dx);
120   }
121   else if (bump_offset == NODE_BUMP_OFFSET_DY) {
122     float3 Py = sd->P - sd->dP.dy;
123     f += (f - wireframe(kg, sd, size, pixel_size, &Py)) / len(sd->dP.dy);
124   }
125 
126   if (stack_valid(out_fac))
127     stack_store_float(stack, out_fac, f);
128 }
129 
130 CCL_NAMESPACE_END
131