Shading: Add a clamp option to the Map Range node.

If the option is enabled, the output is clamped to the target range.
The target range is [To Min, To Max]. The option is enabled by default.

The clamp option is implemented in EEVEE by linking to the `clamp_value`
GLSL function. And it is implemented in Cycles using a graph expand
function.

Reviewers: brecht, JacquesLucke

Differential Revision: https://developer.blender.org/D5477

2 files changed, 12 insertions, 2 deletions

diff --git a/source/blender/nodes/NOD_static_types.h b/source/blender/nodes/NOD_static_types.h
index 2f70e1a39e6..796ad9e5d5b 100644
--- a/source/blender/nodes/NOD_static_types.h
+++ b/source/blender/nodes/NOD_static_types.h
@@ -50,7 +50,7 @@ DefNode(ShaderNode,     SH_NODE_MAPPING,         def_sh_mapping,         "MAPPIN
 DefNode(ShaderNode,     SH_NODE_CURVE_VEC,       def_vector_curve,       "CURVE_VEC",      VectorCurve,      "Vector Curves",     ""              )
 DefNode(ShaderNode,     SH_NODE_CURVE_RGB,       def_rgb_curve,          "CURVE_RGB",      RGBCurve,         "RGB Curves",        ""              )
 DefNode(ShaderNode,     SH_NODE_CAMERA,          0,                      "CAMERA",         CameraData,       "Camera Data",       ""              )
-DefNode(ShaderNode,     SH_NODE_MAP_RANGE,       0,                      "MAP_RANGE",      MapRange,         "Map Range",         ""              )
+DefNode(ShaderNode,     SH_NODE_MAP_RANGE,       def_map_range,          "MAP_RANGE",      MapRange,         "Map Range",         ""              )
 DefNode(ShaderNode,     SH_NODE_CLAMP,           0,                      "CLAMP",          Clamp,            "Clamp",             ""              )
 DefNode(ShaderNode,     SH_NODE_MATH,            def_math,               "MATH",           Math,             "Math",              ""              )
 DefNode(ShaderNode,     SH_NODE_VECT_MATH,       def_vector_math,        "VECT_MATH",      VectorMath,       "Vector Math",       ""              )
diff --git a/source/blender/nodes/shader/nodes/node_shader_map_range.c b/source/blender/nodes/shader/nodes/node_shader_map_range.c
index 8bb1b9324e3..7ebf3faf1f3 100644
--- a/source/blender/nodes/shader/nodes/node_shader_map_range.c
+++ b/source/blender/nodes/shader/nodes/node_shader_map_range.c
@@ -37,13 +37,22 @@ static bNodeSocketTemplate sh_node_map_range_out[] = {
     {-1, 0, ""},
 };
 
+static void node_shader_init_map_range(bNodeTree *UNUSED(ntree), bNode *node)
+{
+  node->custom1 = true;
+}
+
 static int gpu_shader_map_range(GPUMaterial *mat,
                                 bNode *node,
                                 bNodeExecData *UNUSED(execdata),
                                 GPUNodeStack *in,
                                 GPUNodeStack *out)
 {
-  return GPU_stack_link(mat, node, "map_range", in, out);
+  GPU_stack_link(mat, node, "map_range", in, out);
+  if (node->custom1) {
+    GPU_link(mat, "clamp_value", out[0].link, in[3].link, in[4].link, &out[0].link);
+  }
+  return 1;
 }
 
 void register_node_type_sh_map_range(void)
@@ -52,6 +61,7 @@ void register_node_type_sh_map_range(void)
 
   sh_node_type_base(&ntype, SH_NODE_MAP_RANGE, "Map Range", NODE_CLASS_CONVERTOR, 0);
   node_type_socket_templates(&ntype, sh_node_map_range_in, sh_node_map_range_out);
+  node_type_init(&ntype, node_shader_init_map_range);
   node_type_gpu(&ntype, gpu_shader_map_range);
 
   nodeRegisterType(&ntype);