GLSLShader.cpp

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// Copyright (C) 2005 Dave Griffiths
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

#include "GLSLShader.h"
#include <iostream>
#include "Trace.h"
#include "SearchPaths.h"

using namespace std;
using namespace Fluxus;

bool GLSLShader::m_Enabled(false);

GLSLShader::GLSLShader(const string &vertexfilename, const string &fragmentfilename) :
m_Program(0)
{
    Load(vertexfilename, fragmentfilename);
}

GLSLShader::~GLSLShader()
{
    #ifdef GLSL
    if (!m_Enabled) return;
    glDeleteProgram(m_Program);
    #endif
}

void GLSLShader::Init()
{
    #ifdef GLSL
    m_Enabled = glewIsSupported("GL_VERSION_2_0");
    #endif
}

void GLSLShader::Apply() 
{ 
    #ifdef GLSL
    if (!m_Enabled) return;
    glUseProgram(m_Program); 
    #endif
}

void GLSLShader::Unapply() 
{ 
    #ifdef GLSL
    if (!m_Enabled) return;
    glUseProgram(0); 
    #endif
}

void GLSLShader::SetInt(const string &name, int s)
{
    #ifdef GLSL
    if (!m_Enabled) return;
    GLuint param = glGetUniformLocation(m_Program, name.c_str());
    glUniform1i(param,s);
    #endif
}

void GLSLShader::SetFloat(const string &name, float s)
{
    #ifdef GLSL
    if (!m_Enabled) return;
    GLuint param = glGetUniformLocation(m_Program, name.c_str());
    glUniform1f(param,s);
    #endif
}

void GLSLShader::SetVector(const string &name, dVector s)
{
    #ifdef GLSL
    if (!m_Enabled) return;
    GLuint param = glGetUniformLocation(m_Program, name.c_str());
    glUniform3f(param,s.x,s.y,s.z);
    #endif
}

void GLSLShader::SetColour(const string &name, dColour s)
{
    #ifdef GLSL
    if (!m_Enabled) return;
    GLuint param = glGetUniformLocation(m_Program, name.c_str());
    glUniform4f(param,s.r,s.g,s.b,s.a);
    #endif
}

void GLSLShader::SetFloatArray(const string &name, const vector<float> &s)
{
    #ifdef GLSL
    if (!m_Enabled) return;
    GLuint attrib = glGetAttribLocation(m_Program, name.c_str());
    glEnableVertexAttribArray(attrib);
    glVertexAttribPointer(attrib,1,GL_FLOAT,false,0,&(*s.begin()));
    #endif
}

void GLSLShader::SetVectorArray(const string &name, const vector<dVector> &s)
{
    #ifdef GLSL
    if (!m_Enabled) return;
    GLuint attrib = glGetAttribLocation(m_Program, name.c_str());
    glEnableVertexAttribArray(attrib);
    glVertexAttribPointer(attrib,4,GL_FLOAT,false,0,&(*s.begin()));
    #endif
}

void GLSLShader::SetColourArray(const string &name, const vector<dColour> &s)
{
    #ifdef GLSL
    if (!m_Enabled) return;
    GLuint attrib = glGetAttribLocation(m_Program, name.c_str());
    glEnableVertexAttribArray(attrib);
    glVertexAttribPointer(attrib,4,GL_FLOAT,false,0,&(*s.begin()));
    #endif
}

bool GLSLShader::Load(const string &vertexfilename, const string &fragmentfilename)
{
    #ifdef GLSL
    if (!m_Enabled) return true;
    if (m_Program!=0) glDeleteProgram(m_Program);

    m_Program = glCreateProgram();

    bool bOk = true;
    unsigned int vertex = LoadShader(SearchPaths::Get()->GetFullPath(vertexfilename),GL_VERTEX_SHADER);

    if (vertex==0) 
    { 
        glDeleteProgram(m_Program);
        m_Program = 0;
        return false; 
    }
    glAttachShader(m_Program, vertex);

    unsigned int fragment = LoadShader(SearchPaths::Get()->GetFullPath(fragmentfilename),GL_FRAGMENT_SHADER);
    if (fragment==0) 
    { 
        glDeleteProgram(m_Program);
        m_Program = 0;
        return false; 
    }
    glAttachShader(m_Program, fragment);

    glLinkProgram(m_Program);

    GLint status = GL_FALSE;
    glGetProgramiv(m_Program, GL_LINK_STATUS, &status);
    if(status != GL_TRUE)
    {
        GLsizei size = 0;
        char log[1024];
        glGetProgramInfoLog(m_Program, 1024, &size, log);
        Trace::Stream<<log<<endl;
    }
    #endif
    return true;
}
    
    
unsigned int GLSLShader::LoadShader(string filename, unsigned int type)
{
    #ifdef GLSL
    if (!m_Enabled) return 0;
    FILE* file = fopen(filename.c_str(), "r");
    if (!file) 
    {
        Trace::Stream<<"Couldn't open shader ["<<filename<<"]"<<endl;
        return 0;
    }

    fseek(file, 0, SEEK_END);
    unsigned int size = ftell(file);
    fseek(file, 0, SEEK_SET);

    char* code = new char[size+1];
    code[size]='\0';

    if (fread(code,1,size,file)!=size)
    {
        Trace::Stream<<"Error reading shader ["<<filename<<"]"<<endl;
        delete[] code;
        fclose(file);
        return 0;
    }
    else
    {
        unsigned int shader = glCreateShader(type);
        glShaderSource(shader, 1, (const char**)&code, NULL);
        glCompileShader(shader);

        GLint status = GL_FALSE;
        glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
        if(status != GL_TRUE)
        {   
            GLsizei size = 0;
            char log[1024];

            glGetShaderInfoLog(shader, 1024, &size, log);
            Trace::Stream<<"compile errors for ["<<filename<<"]"<<endl;
            Trace::Stream<<log<<endl;

            glDeleteShader(shader);
            delete[] code;
            fclose(file);
            return 0;
        }
        
        delete[] code;
        fclose(file);
        return shader;
    }
    #endif
    return 0;
}

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