/////////////////////////////////////////////////////////////////////////////
// envsurf.osl -- A surface shader whose color is simply an environment
//                lookup in the direction of I.
//
// Description:
//   Just look up an environment map in the view direction.  This shader
//   does not require (or use) any light sources.
//
// Parameters:
//   Kd - overall scaling of the brightness of the surface
//   envname - name of the environment map
//   envspace - coordinate system giving the orientation of the map
//   envrad - radius of the environment map (0 indicates infinite)
//   blur - amount of blur to add to the environment lookup
//
/////////////////////////////////////////////////////////////////////////////
// Copyright 2004 NVIDIA Corporation.  All Rights Reserved.
// 
// 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 NVIDIA 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.
//
// (This is the Modified BSD License)
/////////////////////////////////////////////////////////////////////////////


surface
envsurf
    [[ string description = "Look up environment map in the I direction" ]]
(
    float Kd = 1
        [[  string descripton = "Overall brightness scale" ]],
    string envname = ""
        [[  string description = "Environment map name",
            string UIlabel = "Environment name",
            string UItype = "environment" ]],
    float blur = 0
        [[  string description = "Environment blur",
            float UImin = 0, float UIsoftmax = 1 ]],
    string envspace = "world"
        [[  string description = "Coordinate system for environment map lookup",
            string UIlabel = "Environment space",
            string UItype = "coordsys" ]],
    float envrad = 0
        [[  string description = "Environment sphere radius for env map lookup",
            float UImin = 0 ]]
)
{
    if (envname) {
		vector D = normalize(transform(envspace, I));
        C *= Kd * environment (envname, D, "blur", blur);
    }

    C *= opacity;
}
