/////////////////////////////////////////////////////////////////////////////
// pretexture.osl - texture lookup into C
//
// Description:
//   Intended to be used as a layer before light is gathered, this 
//   shader modifies C according to a texture lookup.
//
// Parameters:
//   texturename - name of the texture file
//   blur - how much to blur the texture lookup
//   projection - type of projection.  Supported projection types include:
//               "st"
//   wrap - texture mode wrap override
//   s,t - texture coordinates (default to u,v)
//
/////////////////////////////////////////////////////////////////////////////
// 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
pretexture
    [[ string description = "Texture map layer that places texture color in C" ]]
(
    string texturename = ""
        [[  string description = "Texture map name (empty for no texture)",
            string UItype = "texture" ]],
    string projection = "st"
        [[  string description = "Projection to use",
            string UItype = "enum:st" ]],
    float blur = 0
        [[  string description = "Texture map blur",
            float UImin = 0, float UIsoftmax = 1,
            string UIenabler = "texturename" ]],
    string wrap = "default"
        [[  string description = "Texture map wrap mode",
            string UIenabler = "texturename" ]],
    float s = u
        [[  string description = "s texture coordinate (defaults to u)",
            string UIenabler = "texturename" ]],
    float t = v
        [[  string description = "t texure coordinate (defaults to v)",
            string UIenabler = "texturename"]]
  )
{
    float ss = s, tt = t;
    if (projection == "st") {
        // Right now, we only support st mapping
    } else {
        error ("unknown projection '%s'\n", projection);
    }

    color Cnew = 1;
    if (texturename)
        Cnew = texture (texturename, ss, tt, "blur", blur, "wrap", wrap);

    C *= Cnew;
}
