cxShaderCallback.cpp

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/*=========================================================================
This file is part of CustusX, an Image Guided Therapy Application.

Copyright (c) 2008-2014, SINTEF Department of Medical Technology
All rights reserved.

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modification, are permitted provided that the following conditions are met:

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   this list of conditions and the following disclaimer.

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   may be used to endorse or promote products derived from this software
   without specific prior written permission.

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#include "cxShaderCallback.h"

#include <vtkShaderProgram.h>
#include <vtkShader.h>
#include <vtkOpenGLHelper.h>
#include <vtkOpenGLVertexArrayObject.h>
#include <vtkOpenGLBufferObject.h>
#include <vtkTextureObject.h>
#include <vtkOpenGLIndexBufferObject.h>
#include <vtkOpenGLRenderWindow.h>

#include "cxGLHelpers.h"
#include "cxLogger.h"
#include "GL/glew.h"

#ifdef __APPLE__
#include <glu.h>
#else
#include <GL/glu.h>
#endif

#include "cxOpenGLShaders.h"

namespace cx
{


ShaderCallback::ShaderCallback()
{
}

ShaderCallback::~ShaderCallback()
{
}

ShaderCallback *ShaderCallback::New()
{
        return new ShaderCallback;
}

void ShaderCallback::printDebugInfo(vtkOpenGLHelper *OpenGLHelper)
{
        if(!OpenGLHelper)
        {
                return;
        }

        vtkShaderProgram *program = OpenGLHelper->Program;
        std::cout << "Program is compiled? " << program->GetCompiled() << std::endl;
        std::cout << "Program is bound? " << program->isBound() << std::endl;
        std::cout << "IBO index count " << OpenGLHelper->IBO->IndexCount << std::endl;
        std::string vertexshader = program->GetVertexShader()->GetSource();
        std::cout << "Vertexshader:\n " << vertexshader << std::endl;
        std::string fragmentshader = program->GetFragmentShader()->GetSource();
        std::cout << "Fragmentshader:\n " << fragmentshader << std::endl;
        report_gl_error();
}

void ShaderCallback::Execute(vtkObject *, unsigned long eventId, void *cbo)
{
        report_gl_error();

        vtkOpenGLHelper *OpenGLHelper = reinterpret_cast<vtkOpenGLHelper*>(cbo);

        if(!OpenGLHelper || !OpenGLHelper->VAO || !OpenGLHelper->Program)
        {
                return;
        }


        if(eventId == vtkCommand::UpdateShaderEvent)
        {
                report_gl_error();


                int textures_to_add = this->getNumberOfUploadedTextures();

                //Bind fragmentshader output variable
                // (glsl: vec4)
                if(textures_to_add != 0)
                {
                        this->bindFSOutputVariable(OpenGLHelper->Program);
                }

                report_gl_error();

                //Bind VAO (Vertext Array Object - aka saved input to the vertex shader)
                OpenGLHelper->VAO->Bind();
                report_gl_error();

                for(int i=0; i< textures_to_add; ++i)
                {
                        ShaderItemPtr shaderItem = mShaderItems.at(i);
                        //      texture coordinates (glsl: vec3)
                        vtkOpenGLBufferObjectPtr texture_coordinates = shaderItem->mTextureCoordinates;

                        if(texture_coordinates)
                        {
                                if(!texture_coordinates->Bind())
                                {
                                        CX_LOG_WARNING() << "Could not bind texture coordinates";
                                }

                                this->addArrayToAttributeArray(OpenGLHelper->Program, texture_coordinates, VS_In_Vec3_TextureCoordinate, i);
                        }
                        else
                        {
                                CX_LOG_WARNING() << "NO TEXTURE COORDINATES!";
                        }

                        report_gl_error();

                        //      3D texture pointer (glsl: sampler3D)
                        vtkTextureObjectPtr texture = shaderItem->mTexture;

                        if(texture)
                        {
                                texture->Activate();
                                this->addUniformiArray(OpenGLHelper->Program, getVectorNameFromName(FS_Uniform_3DTexture_Volume, i), texture->GetTextureUnit());
                        }
                        else
                        {
                                CX_LOG_WARNING() << "NO 3D TEXTURE!";
                        }

                        report_gl_error();

                        //      1D texture pointer (glsl: sampler1D)
                        vtkTextureObjectPtr lut = shaderItem->mLUT;

                        if(lut)
                        {
                                lut->Activate();
                                this->addUniformiArray(OpenGLHelper->Program, getVectorNameFromName(FS_Uniform_1DTexture_LUT, i), lut->GetTextureUnit());
                        }
                        else
                        {
                                CX_LOG_WARNING() << "NO 1D TEXTURE!";
                        }

                        report_gl_error();

                        this->addUniformfArray(OpenGLHelper->Program, getVectorNameFromName(FS_Uniform_Window,i), shaderItem->mWindow);
                        this->addUniformfArray(OpenGLHelper->Program, getVectorNameFromName(FS_Uniform_Level,i), shaderItem->mLevel);
                        this->addUniformfArray(OpenGLHelper->Program, getVectorNameFromName(FS_Uniform_LLR,i), shaderItem->mLLR);
                        this->addUniformfArray(OpenGLHelper->Program, getVectorNameFromName(FS_Uniform_Alpha,i), shaderItem->mAlpha);
                }
        }

        report_gl_error();

}

ShaderCallback::ShaderItemPtr ShaderCallback::getShaderItem(QString image_uid) const
{
        ShaderItemPtr item;

        for(int i=0; i<mShaderItems.size(); ++i)
        {
                item = mShaderItems.at(i);

                if(item->mTextureUid == image_uid)
                {
                        return item;
                }
        }

        CX_LOG_ERROR() << "COULD NOT FIND THE SHADERITEM";
        return item;
}

int ShaderCallback::getNumberOfUploadedTextures() const
{
        return mShaderItems.size();
}

void ShaderCallback::add(ShaderCallback::ShaderItemPtr item)
{
        mShaderItems.push_back(item);
}

void ShaderCallback::clearShaderItems()
{
        mShaderItems.clear();
}

void ShaderCallback::addArrayToAttributeArray(vtkShaderProgram *program, vtkOpenGLBufferObjectPtr buffer, std::string name, int vector_index)
{
        //--------
        //This is information about how the texture coordinates are uploaded.
        int offset = 0;
        int vec_size = 3;
        size_t stride = sizeof(float)*vec_size; //is this correct? was *3;
        int elementType = GL_FLOAT; //VTK_FLOAT
        bool normalize = false;

        //CX_LOG_DEBUG() << "Adding attribute called: " << name << " to vector_index: " << vector_index;
        //--------

        const GLchar *namePtr = static_cast<const GLchar *>(name.c_str());
        GLint start_of_vector_index = glGetAttribLocation(program->GetHandle(), namePtr);
        report_gl_error();


        if(start_of_vector_index != -1)
        {
                GLint position_in_vector_index = start_of_vector_index + vector_index;
                buffer->Bind();

                glEnableVertexAttribArray(position_in_vector_index);

                glVertexAttribPointer(position_in_vector_index,
                                      vec_size,
                                      elementType,
                                      normalize,
                                      static_cast<GLsizei>(stride),
                                      ((char *)NULL + (offset))
                                     );
                report_gl_error();
        }
        else
        {
                CX_LOG_ERROR() << "Error setting attribute " << name << " with vector_index " << vector_index;
        }

}

void ShaderCallback::addUniformiArray(vtkShaderProgram *program, std::string name, int value)
{
        //Note: Set uniform will fail if the uniform is not present OR active (used inside the program).
        report_gl_error();

        //CX_LOG_DEBUG() << "Adding uniform called: " << name << " with value " << value;
        if(!program->SetUniform1iv(name.c_str(), 1, &value))
        {
                CX_LOG_ERROR() << "Could not set uniform named " << name;
        }

        report_gl_error();
}

void ShaderCallback::addUniformfArray(vtkShaderProgram *program, std::string name, float value)
{
        //Note: Set uniform will fail if the uniform is not present OR active (used inside the program).
        report_gl_error();

        //CX_LOG_DEBUG() << "Adding uniform called: " << name << " with value " << value;
        if(!program->SetUniform1fv(name.c_str(), 1, &value))
        {
                CX_LOG_ERROR() << "Could not set uniform named " << name;
        }

        report_gl_error();
}

void ShaderCallback::bindFSOutputVariable(vtkShaderProgram *program)
{
        GLint color_frag_out_index = glGetFragDataLocation(program->GetHandle(), FS_Out_Vec4_Color.c_str());

        if(color_frag_out_index != -1)
        {
                glBindFragDataLocation(program->GetHandle(), color_frag_out_index, FS_Out_Vec4_Color.c_str()); //setting output of fragment shader
                //CX_LOG_DEBUG() << "Binding fragmentshader output to " << FS_Out_Vec4_Color << " at index "<< color_frag_out_index;
        }
        else
        {
                CX_LOG_ERROR() << "Could not find glGetFragDataLocation for " << FS_Out_Vec4_Color;
        }
}

std::string ShaderCallback::getVectorNameFromName(std::string name, int index_of_vector) const
{
        QString fullName = QString("%1[%2]").arg(QString(name.c_str())).arg(index_of_vector);
        return fullName.toStdString();
}

}//namespace cx