//-
// ===========================================================================
//
// 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.
// ===========================================================================
//+
//
// Description : Contrast shader plugin
// Produces dependency graph node ContrastNode
// This node is an example of color manipulation.
// The inputs for this node are input color, contrast and bias.
// The contrast and bias inputs are 3 float values so that they can be applied to each rgb channel of an input color separately.
// The output attribute of the ContrastNode node is called "outColor".
// It is a 3 float value that represents the resulting color derived from the effective contrast and bias settings.
// To use this shader, create a ContrastNode and connect its output to an input of a surface/shader node such as Color.
//
// Notes : The contrast operation consists of
// redistributing the energy around the middle
// point. In other words: every intensity below
// 0.5 is pushed towards black, and every
// intensity above is pushed towards white.
// The trick is to do that in a "smooth" way.
//
// The way to do that is:
// On interval [0,0.5] apply a gamma to intensity
// On interval [0.5,1] apply an "inverted" gamma to intensity
//
// That is:
// When I<0.5, newI=0.5*(2*I)^contrast
// When I>=0.5, newI=1-0.5*(2*(1-I))^contrast
//
// This function is C1 on [0,1], and if contrast==1, it is the
// identity.
//
// The bias value stems from: why 0.5 and not something else ?
// So, we use a function f to remap the [0,1] interval on itself
// with the constraint:
// f(0)=0
// f(bias)=0.5
// f(1)=1
// and we compose with the above function.
//
// Of course, when bias=0.5, f *has* to be the identity, and of
// course, f *has* to be smooth.
// A good candidate is f(x)=x^alpha, with alpha=log(0.5)/log(bias)
//
#include <math.h>
#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/MFnNumericAttribute.h>
#include <maya/MFloatVector.h>
#include <maya/MFnPlugin.h>
#include <maya/MDrawRegistry.h>
#include <maya/MViewport2Renderer.h>
#include <maya/MFragmentManager.h>
//
// Node declaration
class Contrast:public MPxNode
{
public:
Contrast();
virtual ~Contrast();
virtual MStatus compute( const MPlug&, MDataBlock& );
virtual void postConstructor();
static void *creator();
static MStatus initialize();
// Id tag for use with binary file format
static MTypeId id;
private:
// Input attributes
static MObject aColor;
static MObject aContrast;
static MObject aBias;
// Output attributes
static MObject aOutColor;
};
//
// Override declaration
{
public:
virtual ~ContrastOverride();
virtual MString fragmentName() const;
private:
ContrastOverride(const MObject& obj);
MString fFragmentName;
};
//
// Node definition
// static data
MTypeId Contrast::id( 0x81008 );
// Attributes
MObject Contrast::aColor;
MObject Contrast::aContrast;
MObject Contrast::aBias;
MObject Contrast::aOutColor;
#define MAKE_INPUT(attr) \
CHECK_MSTATUS(attr.setKeyable(true)); \
CHECK_MSTATUS(attr.setStorable(true)); \
CHECK_MSTATUS(attr.setWritable(true));
#define MAKE_OUTPUT(attr) \
CHECK_MSTATUS(attr.setKeyable(false)); \
CHECK_MSTATUS(attr.setStorable(false)); \
CHECK_MSTATUS(attr.setWritable(false));
//
// DESCRIPTION:
void Contrast::postConstructor( )
{
setMPSafe(true);
}
//
// DESCRIPTION:
Contrast::Contrast()
{
}
//
// DESCRIPTION:
Contrast::~Contrast()
{
}
//
// DESCRIPTION:
void *Contrast::creator()
{
return new Contrast();
}
//
// DESCRIPTION:
MStatus Contrast::initialize()
{
// Create input attributes
aColor = nAttr.createColor("inputColor", "ic");
MAKE_INPUT(nAttr);
aContrast = nAttr.createColor("contrast", "c");
MAKE_INPUT(nAttr);
CHECK_MSTATUS(nAttr.setDefault(1.f, 1.f, 1.f));
aBias = nAttr.createColor("bias", "b");
MAKE_INPUT(nAttr);
CHECK_MSTATUS(nAttr.setDefault(.5f, .5f, .5f));
// Create output attributes
aOutColor = nAttr.createColor("outColor", "oc");
MAKE_OUTPUT(nAttr);
/* Plug inputs and outputs
---------------------------*/
/* Build dependancies
----------------------*/
CHECK_MSTATUS(attributeAffects(aColor, aOutColor));
CHECK_MSTATUS(attributeAffects(aContrast, aOutColor));
CHECK_MSTATUS(attributeAffects(aBias, aOutColor));
return MS::kSuccess;
}
//
// DESCRIPTION:
MStatus Contrast::compute(const MPlug& plug, MDataBlock& block)
{
// outColor or individial R, G, B channel
if((plug != aOutColor) && (plug.parent() != aOutColor))
MFloatVector resultColor;
MFloatVector & col = block.inputValue(aColor).asFloatVector();
MFloatVector & cont = block.inputValue(aContrast).asFloatVector();
MFloatVector & bias = block.inputValue(aBias).asFloatVector();
float xp;
float logp5= logf(0.5F);
xp = powf(col[0], logp5/logf(bias[0]));
resultColor[0] = xp<0.5F ?
0.5F*powf(2.0F*xp, cont[0]) :
1.0F-0.5F*powf(2.0F*(1.0F-xp), cont[0]);
xp = powf(col[1], logp5/logf(bias[1]));
resultColor[1] = xp<0.5F ?
0.5F*powf(2.0F*xp, cont[1]) :
1.0F-0.5F*powf(2.0F*(1.0F-xp), cont[1]);
xp = powf(col[2], logp5/logf(bias[2]));
resultColor[2] = xp<0.5F ?
0.5F*powf(2.0F*xp, cont[2]) :
1.0F-0.5F*powf(2.0F*(1.0F-xp), cont[2]);
// set ouput color attribute
MDataHandle outColorHandle = block.outputValue( aOutColor );
MFloatVector& outColor = outColorHandle.asFloatVector();
outColor = resultColor;
outColorHandle.setClean();
return MS::kSuccess;
}
//
// Override definition
const MObject& obj)
{
return new ContrastOverride(obj);
}
ContrastOverride::ContrastOverride(const MObject& 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
static const char* sFragmentBody =
" <description><![CDATA[Contrast utility fragment]]></description>"
" <properties>"
" <float3 name=\"inputColor\" />"
" <float3 name=\"contrast\" />"
" <float3 name=\"bias\" />"
" </properties>"
" <values>"
" <float3 name=\"inputColor\" value=\"0.5,0.5,0.5\" />"
" <float3 name=\"contrast\" value=\"1.0,1.0,1.0\" />"
" <float3 name=\"bias\" value=\"0.5,0.5,0.5\" />"
" </values>"
" <outputs>"
" <float3 name=\"outColor\" />"
" </outputs>"
" <implementation>"
" <implementation render=\"OGSRenderer\" language=\"Cg\" lang_version=\"2.1\">"
" <source><![CDATA["
"float3 contrastShaderPluginFragment(float3 inputColor, float3 contrast, float3 bias) \n"
"{ \n"
" const float logp5 = log(0.5f); \n"
" float3 result; \n"
" float xp = pow(inputColor.r, logp5/log(bias.r)); \n"
" if (xp < 0.5f) { \n"
" result.r = 0.5f*pow(2.0f*xp, contrast.r); \n"
" } else { \n"
" result.r = 1.0f - 0.5f*pow(2.0f*(1.0f-xp), contrast.r); \n"
" } \n"
" xp = pow(inputColor.g, logp5/log(bias.g)); \n"
" if (xp < 0.5f) { \n"
" result.g = 0.5f*pow(2.0f*xp, contrast.g); \n"
" } else { \n"
" result.g = 1.0f - 0.5f*pow(2.0f*(1.0f-xp), contrast.g); \n"
" } \n"
" xp = pow(inputColor.b, logp5/log(bias.b)); \n"
" if (xp < 0.5f) { \n"
" result.b = 0.5f*pow(2.0f*xp, contrast.b); \n"
" } else { \n"
" result.b = 1.0f - 0.5f*pow(2.0f*(1.0f-xp), contrast.b); \n"
" } \n"
" return result; \n"
"} \n]]>"
" </source>"
" </implementation>"
" <implementation render=\"OGSRenderer\" language=\"HLSL\" lang_version=\"11.0\">"
" <source><![CDATA["
"float3 contrastShaderPluginFragment(float3 inputColor, float3 contrast, float3 bias) \n"
"{ \n"
" const float logp5 = log(0.5f); \n"
" float3 result; \n"
" float xp = pow(inputColor.r, logp5/log(bias.r)); \n"
" if (xp < 0.5f) { \n"
" result.r = 0.5f*pow(2.0f*xp, contrast.r); \n"
" } else { \n"
" result.r = 1.0f - 0.5f*pow(2.0f*(1.0f-xp), contrast.r); \n"
" } \n"
" xp = pow(inputColor.g, logp5/log(bias.g)); \n"
" if (xp < 0.5f) { \n"
" result.g = 0.5f*pow(2.0f*xp, contrast.g); \n"
" } else { \n"
" result.g = 1.0f - 0.5f*pow(2.0f*(1.0f-xp), contrast.g); \n"
" } \n"
" xp = pow(inputColor.b, logp5/log(bias.b)); \n"
" if (xp < 0.5f) { \n"
" result.b = 0.5f*pow(2.0f*xp, contrast.b); \n"
" } else { \n"
" result.b = 1.0f - 0.5f*pow(2.0f*(1.0f-xp), contrast.b); \n"
" } \n"
" return result; \n"
"} \n]]>"
" </source>"
" </implementation>"
" <implementation render=\"OGSRenderer\" language=\"GLSL\" lang_version=\"3.0\">"
" <source><![CDATA["
"vec3 contrastShaderPluginFragment(vec3 inputColor, vec3 contrast, vec3 bias) \n"
"{ \n"
" const float logp5 = log(0.5f); \n"
" vec3 result; \n"
" float xp = pow(inputColor.r, logp5/log(bias.r)); \n"
" if (xp < 0.5f) { \n"
" result.r = 0.5f*pow(2.0f*xp, contrast.r); \n"
" } else { \n"
" result.r = 1.0f - 0.5f*pow(2.0f*(1.0f-xp), contrast.r); \n"
" } \n"
" xp = pow(inputColor.g, logp5/log(bias.g)); \n"
" if (xp < 0.5f) { \n"
" result.g = 0.5f*pow(2.0f*xp, contrast.g); \n"
" } else { \n"
" result.g = 1.0f - 0.5f*pow(2.0f*(1.0f-xp), contrast.g); \n"
" } \n"
" xp = pow(inputColor.b, logp5/log(bias.b)); \n"
" if (xp < 0.5f) { \n"
" result.b = 0.5f*pow(2.0f*xp, contrast.b); \n"
" } else { \n"
" result.b = 1.0f - 0.5f*pow(2.0f*(1.0f-xp), contrast.b); \n"
" } \n"
" return result; \n"
"} \n]]>"
" </source>"
" </implementation>"
" </implementation>"
"</fragment>";
// Register fragments with the manager if needed
if (theRenderer)
{
theRenderer->getFragmentManager();
if (fragmentMgr)
{
{
}
// Use the fragment on successful add
{
fFragmentName = sFragmentName;
}
}
}
}
ContrastOverride::~ContrastOverride()
{
}
MHWRender::DrawAPI ContrastOverride::supportedDrawAPIs() const
{
}
MString ContrastOverride::fragmentName() const
{
return fFragmentName;
}
//
// Plugin setup
MStatus initializePlugin( MObject obj )
{
MFnPlugin plugin( obj, PLUGIN_COMPANY, "4.5", "Any");
CHECK_MSTATUS( plugin.registerNode("contrastNode", Contrast::id,
Contrast::creator, Contrast::initialize,
MPxNode::kDependNode, &UserClassify ) );