depthShader/depthShader.cpp

//-
// ===========================================================================
// Copyright 2015 Autodesk, Inc.  All rights reserved.
//
// Use of this software is subject to the terms of the Autodesk license
// agreement provided at the time of installation or download, or which
// otherwise accompanies this software in either electronic or hard copy form.
// ===========================================================================
//+

#include <maya/MPxNode.h>
#include <maya/MIOStream.h>
#include <maya/MString.h>
#include <maya/MTypeId.h>
#include <maya/MPlug.h>
#include <maya/MDataBlock.h>
#include <maya/MDataHandle.h>
#include <maya/MArrayDataHandle.h>
#include <maya/MFnNumericAttribute.h>
#include <maya/MFnLightDataAttribute.h>
#include <maya/MFloatVector.h>
#include <maya/MFnPlugin.h>
#include <maya/MDrawRegistry.h>
#include <maya/MPxSurfaceShadingNodeOverride.h>
#include <maya/MViewport2Renderer.h>
#include <maya/MFragmentManager.h>

//
// DESCRIPTION: 
// Produces dependency graph node DepthShader
 
// This node is an example of a surface shader that colors objects based on the distance from the camera.
 
// The inputs for this node are can be found in the Maya UI on the Attribute Editor for the node.
 
// The output attribute of the node is called "outColor". It is a 3 float value that represents the resulting color produced by the node. 
// To use this shader, create a DepthShader with Shading Group or connect its output to a Shading Group's "SurfaceShader" attribute.
//


// Plugin Depth Shader Class Declaration

class depthShader : public MPxNode
{
    public:
                      depthShader();
             ~depthShader() override;

    MStatus   compute( const MPlug&, MDataBlock& ) override;
    void      postConstructor() override;

    static  void *    creator();
    static  MStatus   initialize();

    //  Id tag for use with binary file format
    static  MTypeId   id;

    private:

    // Input attributes
    static MObject aColorNear;
    static MObject aColorFar;
    static MObject aNear;
    static MObject aFar;
    static MObject aPointCamera;

    // Output attributes
    static MObject aOutColor;
};

// Plugin Depth Shader Override Class Declaration

class depthShaderOverride : public MHWRender::MPxSurfaceShadingNodeOverride
{
public:
    static MHWRender::MPxSurfaceShadingNodeOverride* creator(const MObject& obj);

    ~depthShaderOverride() override;

    MHWRender::DrawAPI supportedDrawAPIs() const override;

    MString fragmentName() const override;

private:
    depthShaderOverride(const MObject& obj);

    MString fFragmentName;
};

// Plugin Depth Shader Class Implementation

// static data
MTypeId depthShader::id( 0x81002 );

// Attributes
MObject depthShader::aColorNear;
MObject depthShader::aColorFar;
MObject depthShader::aNear;
MObject depthShader::aFar;
MObject depthShader::aPointCamera;

MObject depthShader::aOutColor;

#define MAKE_INPUT(attr)        \
    CHECK_MSTATUS(attr.setKeyable(true));       \
    CHECK_MSTATUS(attr.setStorable(true));      \
    CHECK_MSTATUS(attr.setReadable(true));      \
    CHECK_MSTATUS(attr.setWritable(true));

#define MAKE_OUTPUT(attr)       \
    CHECK_MSTATUS(attr.setKeyable(false));      \
    CHECK_MSTATUS(attr.setStorable(false));     \
    CHECK_MSTATUS(attr.setReadable(true));      \
    CHECK_MSTATUS(attr.setWritable(false));

void depthShader::postConstructor( )
{
    setMPSafe(true);
}

//
// DESCRIPTION:
depthShader::depthShader()
{
}

//
// DESCRIPTION:
depthShader::~depthShader()
{
}

//
// DESCRIPTION:
void* depthShader::creator()
{
    return new depthShader();
}

//
// DESCRIPTION:
MStatus depthShader::initialize()
{
    MFnNumericAttribute nAttr;

    // Create input attributes

    aColorNear = nAttr.createColor("color", "c");
    MAKE_INPUT(nAttr);
    CHECK_MSTATUS(nAttr.setDefault(0., 1., 0.));            // Green

    aColorFar = nAttr.createColor("colorFar", "cf");
    MAKE_INPUT(nAttr);
    CHECK_MSTATUS(nAttr.setDefault(0., 0., 1.));            // Blue

    aNear = nAttr.create("near", "n", MFnNumericData::kFloat);
    MAKE_INPUT(nAttr);
    CHECK_MSTATUS(nAttr.setMin(0.0f));
    CHECK_MSTATUS(nAttr.setSoftMax(1000.0f));

    aFar = nAttr.create("far", "f", MFnNumericData::kFloat);
    MAKE_INPUT(nAttr);
    CHECK_MSTATUS(nAttr.setMin(0.0f));
    CHECK_MSTATUS(nAttr.setSoftMax(1000.0f));
    CHECK_MSTATUS(nAttr.setDefault(2.0f));

    aPointCamera = nAttr.createPoint("pointCamera", "p");
    MAKE_INPUT(nAttr);
    CHECK_MSTATUS(nAttr.setHidden(true));

    // Create output attributes
    aOutColor = nAttr.createColor("outColor", "oc");
    MAKE_OUTPUT(nAttr);

    CHECK_MSTATUS(addAttribute(aColorNear));
    CHECK_MSTATUS(addAttribute(aColorFar));
    CHECK_MSTATUS(addAttribute(aNear) );
    CHECK_MSTATUS(addAttribute(aFar));
    CHECK_MSTATUS(addAttribute(aPointCamera));
    CHECK_MSTATUS(addAttribute(aOutColor));

    CHECK_MSTATUS(attributeAffects(aColorNear, aOutColor));
    CHECK_MSTATUS(attributeAffects(aColorFar, aOutColor));
    CHECK_MSTATUS(attributeAffects(aNear, aOutColor));
    CHECK_MSTATUS(attributeAffects(aFar, aOutColor));
    CHECK_MSTATUS(attributeAffects(aPointCamera, aOutColor));

    return MS::kSuccess;
}

//
// DESCRIPTION:
MStatus depthShader::compute(
const MPlug&      plug,
      MDataBlock& block )
{
    // outColor or individial R, G, B channel
    if((plug != aOutColor) && (plug.parent() != aOutColor))
        return MS::kUnknownParameter;

    MFloatVector resultColor;

    // get sample surface shading parameters
    MFloatVector& pCamera = block.inputValue(aPointCamera).asFloatVector();
    MFloatVector& cNear   = block.inputValue(aColorNear).asFloatVector();
    MFloatVector& cFar    = block.inputValue(aColorFar).asFloatVector();
    float nearClip        = block.inputValue(aNear).asFloat();
    float farClip         = block.inputValue(aFar).asFloat();

    // pCamera.z is negative
    float ratio = (farClip + pCamera.z) / ( farClip - nearClip);
    resultColor = cNear * ratio + cFar*(1.f - ratio);

    // set ouput color attribute
    MDataHandle outColorHandle = block.outputValue( aOutColor );
    MFloatVector& outColor = outColorHandle.asFloatVector();
    outColor = resultColor;
    outColorHandle.setClean();

    return MS::kSuccess;
}

// Plugin Depth Shader Override Class Implementation

MHWRender::MPxSurfaceShadingNodeOverride* depthShaderOverride::creator(
    const MObject& obj)
{
    return new depthShaderOverride(obj);
}

depthShaderOverride::depthShaderOverride(const MObject& obj)
: MPxSurfaceShadingNodeOverride(obj)
, fFragmentName("")
{
    // Define fragments needed for VP2 version of shader, this could also be
    // defined in a separate XML file
    //
    // Define the input and output parameter names to match the input and
    // output attribute names so that the values are automatically populated
    // on the shader.
    //
    // Define a separate fragment for computing the camera space position so
    // that the operation can be done in the vertex shader rather than the
    // pixel shader. Then connect the two fragments together in a graph.
    static const MString sFragmentName("depthShaderPluginFragment");
    static const char* sFragmentBody =
        "<fragment uiName=\"depthShaderPluginFragment\" name=\"depthShaderPluginFragment\" type=\"plumbing\" class=\"ShadeFragment\" version=\"1.0\">"
        "   <description><![CDATA[Depth shader fragment]]></description>"
        "   <properties>"
        "       <float name=\"depthValue\" />"
        "       <float3 name=\"color\" />"
        "       <float3 name=\"colorFar\" />"
        "       <float name=\"near\" />"
        "       <float name=\"far\" />"
        "   </properties>"
        "   <values>"
        "       <float name=\"depthValue\" value=\"0.0\" />"
        "       <float3 name=\"color\" value=\"0.0,1.0,0.0\" />"
        "       <float3 name=\"colorFar\" value=\"0.0,0.0,1.0\" />"
        "       <float name=\"near\" value=\"0.0\" />"
        "       <float name=\"far\" value=\"2.0\" />"
        "   </values>"
        "   <outputs>"
        "       <float3 name=\"outColor\" />"
        "   </outputs>"
        "   <implementation>"
        "   <implementation render=\"OGSRenderer\" language=\"Cg\" lang_version=\"2.1\">"
        "       <function_name val=\"depthShaderPluginFragment\" />"
        "       <source><![CDATA["
        "float3 depthShaderPluginFragment(float depthValue, float3 cNear, float3 cFar, float nearClip, float farClip) \n"
        "{ \n"
        "   float ratio = (farClip + depthValue)/(farClip - nearClip); \n"
        "   return cNear*ratio + cFar*(1.0f - ratio); \n"
        "} \n]]>"
        "       </source>"
        "   </implementation>"
        "   <implementation render=\"OGSRenderer\" language=\"HLSL\" lang_version=\"11.0\">"
        "       <function_name val=\"depthShaderPluginFragment\" />"
        "       <source><![CDATA["
        "float3 depthShaderPluginFragment(float depthValue, float3 cNear, float3 cFar, float nearClip, float farClip) \n"
        "{ \n"
        "   float ratio = (farClip + depthValue)/(farClip - nearClip); \n"
        "   return cNear*ratio + cFar*(1.0f - ratio); \n"
        "} \n]]>"
        "       </source>"
        "   </implementation>"
        "   <implementation render=\"OGSRenderer\" language=\"GLSL\" lang_version=\"3.0\">"
        "       <function_name val=\"depthShaderPluginFragment\" />"
        "       <source><![CDATA["
        "vec3 depthShaderPluginFragment(float depthValue, vec3 cNear, vec3 cFar, float nearClip, float farClip) \n"
        "{ \n"
        "   float ratio = (farClip + depthValue)/(farClip - nearClip); \n"
        "   return cNear*ratio + cFar*(1.0f - ratio); \n"
        "} \n]]>"
        "       </source>"
        "   </implementation>"
        "   </implementation>"
        "</fragment>";

    static const MString sVertexFragmentName("depthShaderPluginInterpolantFragment");
    static const char* sVertexFragmentBody =
        "<fragment uiName=\"depthShaderPluginInterpolantFragment\" name=\"depthShaderPluginInterpolantFragment\" type=\"interpolant\" class=\"ShadeFragment\" version=\"1.0\">"
        "   <description><![CDATA[Depth shader vertex fragment]]></description>"
        "   <properties>"
        "       <float3 name=\"Pm\" semantic=\"Pm\" flags=\"varyingInputParam\" />"
        "       <float4x4 name=\"worldViewProj\" semantic=\"worldviewprojection\" />"
        "   </properties>"
        "   <values>"
        "   </values>"
        "   <outputs>"
        "       <float name=\"outDepthValue\" ^1s/>"
        "   </outputs>"
        "   <implementation>"
        "   <implementation render=\"OGSRenderer\" language=\"Cg\" lang_version=\"2.1\">"
        "       <function_name val=\"depthShaderPluginInterpolantFragment\" />"
        "       <source><![CDATA["
        "float depthShaderPluginInterpolantFragment(float depthValue) \n"
        "{ \n"
        "   return depthValue; \n"
        "} \n]]>"
        "       </source>"
        "       <vertex_source><![CDATA["
        "float idepthShaderPluginInterpolantFragment(float3 Pm, float4x4 worldViewProj) \n"
        "{ \n"
        "   float4 pCamera = mul(worldViewProj, float4(Pm, 1.0f)); \n"
        "   return (pCamera.z - pCamera.w*2.0f); \n"
        "} \n]]>"
        "       </vertex_source>"
        "   </implementation>"
        "   <implementation render=\"OGSRenderer\" language=\"HLSL\" lang_version=\"11.0\">"
        "       <function_name val=\"depthShaderPluginInterpolantFragment\" />"
        "       <source><![CDATA["
        "float depthShaderPluginInterpolantFragment(float depthValue) \n"
        "{ \n"
        "   return depthValue; \n"
        "} \n]]>"
        "       </source>"
        "       <vertex_source><![CDATA["
        "float idepthShaderPluginInterpolantFragment(float3 Pm, float4x4 worldViewProj) \n"
        "{ \n"
        "   float4 pCamera = mul(float4(Pm, 1.0f), worldViewProj); \n"
        "   return (pCamera.z - pCamera.w*2.0f); \n"
        "} \n]]>"
        "       </vertex_source>"
        "   </implementation>"
        "   <implementation render=\"OGSRenderer\" language=\"GLSL\" lang_version=\"3.0\">"
        "       <function_name val=\"depthShaderPluginInterpolantFragment\" />"
        "       <source><![CDATA["
        "float depthShaderPluginInterpolantFragment(float depthValue) \n"
        "{ \n"
        "   return depthValue; \n"
        "} \n]]>"
        "       </source>"
        "       <vertex_source><![CDATA["
        "float idepthShaderPluginInterpolantFragment(vec3 Pm, mat4 worldViewProj) \n"
        "{ \n"
        "   vec4 pCamera = worldViewProj * vec4(Pm, 1.0f); \n"
        "   return (pCamera.z - pCamera.w*2.0f); \n"
        "} \n]]>"
        "       </vertex_source>"
        "   </implementation>"
        "   </implementation>"
        "</fragment>";

    static const MString sFragmentGraphName("depthShaderPluginGraph");
    static const char* sFragmentGraphBody =
        "<fragment_graph name=\"depthShaderPluginGraph\" ref=\"depthShaderPluginGraph\" class=\"FragmentGraph\" version=\"1.0\">"
        "   <fragments>"
        "           <fragment_ref name=\"depthShaderPluginFragment\" ref=\"depthShaderPluginFragment\" />"
        "           <fragment_ref name=\"depthShaderPluginInterpolantFragment\" ref=\"depthShaderPluginInterpolantFragment\" />"
        "   </fragments>"
        "   <connections>"
        "       <connect from=\"depthShaderPluginInterpolantFragment.outDepthValue\" to=\"depthShaderPluginFragment.depthValue\" />"
        "   </connections>"
        "   <properties>"
        "       <float3 name=\"Pm\" ref=\"depthShaderPluginInterpolantFragment.Pm\" semantic=\"Pm\" flags=\"varyingInputParam\" />"
        "       <float4x4 name=\"worldViewProj\" ref=\"depthShaderPluginInterpolantFragment.worldViewProj\" semantic=\"worldviewprojection\" />"
        "       <float3 name=\"color\" ref=\"depthShaderPluginFragment.color\" />"
        "       <float3 name=\"colorFar\" ref=\"depthShaderPluginFragment.colorFar\" />"
        "       <float name=\"near\" ref=\"depthShaderPluginFragment.near\" />"
        "       <float name=\"far\" ref=\"depthShaderPluginFragment.far\" />"
        "   </properties>"
        "   <values>"
        "       <float3 name=\"color\" value=\"0.0,1.0,0.0\" />"
        "       <float3 name=\"colorFar\" value=\"0.0,0.0,1.0\" />"
        "       <float name=\"near\" value=\"0.0\" />"
        "       <float name=\"far\" value=\"2.0\" />"
        "   </values>"
        "   <outputs>"
        "       <float3 name=\"outColor\" ref=\"depthShaderPluginFragment.outColor\" />"
        "   </outputs>"
        "</fragment_graph>";

    // Register fragments with the manager if needed
    MHWRender::MRenderer* theRenderer = MHWRender::MRenderer::theRenderer();
    if (theRenderer)
    {
        MHWRender::MFragmentManager* fragmentMgr =
            theRenderer->getFragmentManager();
        if (fragmentMgr)
        {
            // Add fragments if needed
            bool fragAdded = fragmentMgr->hasFragment(sFragmentName);
            bool vertFragAdded = fragmentMgr->hasFragment(sVertexFragmentName);
            bool graphAdded = fragmentMgr->hasFragment(sFragmentGraphName);
            if (!fragAdded)
            {
                fragAdded = (sFragmentName == fragmentMgr->addShadeFragmentFromBuffer(sFragmentBody, false));
            }
            if (!vertFragAdded)
            {
                // In DirectX, need to specify a semantic for the output of the vertex shader
                MString vertBody;
                if (theRenderer->drawAPI() == MHWRender::kDirectX11)
                {
                    vertBody.format(MString(sVertexFragmentBody), MString("semantic=\"extraDepth\" "));
                }
                else
                {
                    vertBody.format(MString(sVertexFragmentBody), MString(" "));
                }
                vertFragAdded = (sVertexFragmentName == fragmentMgr->addShadeFragmentFromBuffer(vertBody.asChar(), false));
            }
            if (!graphAdded)
            {
                graphAdded = (sFragmentGraphName == fragmentMgr->addFragmentGraphFromBuffer(sFragmentGraphBody));
            }

            // If we have them all, use the final graph for the override
            if (fragAdded && vertFragAdded && graphAdded)
            {
                fFragmentName = sFragmentGraphName;
            }
        }
    }
}

depthShaderOverride::~depthShaderOverride()
{
}

MHWRender::DrawAPI depthShaderOverride::supportedDrawAPIs() const
{
    return MHWRender::kOpenGL | MHWRender::kDirectX11 | MHWRender::kOpenGLCoreProfile;
}

MString depthShaderOverride::fragmentName() const
{
    return fFragmentName;
}


// Plugin Setup

static const MString sRegistrantId("depthShaderPlugin");

//
// DESCRIPTION:
MStatus initializePlugin( MObject obj )
{
    const MString UserClassify( "shader/surface:drawdb/shader/surface/depthShader" );

    MFnPlugin plugin(obj, PLUGIN_COMPANY, "4.5", "Any");
    CHECK_MSTATUS( plugin.registerNode("depthShader", depthShader::id,
                        depthShader::creator, depthShader::initialize,
                        MPxNode::kDependNode, &UserClassify ) );

    CHECK_MSTATUS(
        MHWRender::MDrawRegistry::registerSurfaceShadingNodeOverrideCreator(
            "drawdb/shader/surface/depthShader",
            sRegistrantId,
            depthShaderOverride::creator));

    return MS::kSuccess;
}

//
// DESCRIPTION:
MStatus uninitializePlugin( MObject obj )
{
    MFnPlugin plugin( obj );
    CHECK_MSTATUS( plugin.deregisterNode( depthShader::id ) );

    CHECK_MSTATUS(
        MHWRender::MDrawRegistry::deregisterSurfaceShadingNodeOverrideCreator(
            "drawdb/shader/surface/depthShader",
            sRegistrantId));

    return MS::kSuccess;
}