GLSLShader.cpp

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////////////////////////////////////////////////////////////////////////////////
//    Scorched3D (c) 2000-2009
//
//    This file is part of Scorched3D.
//
//    Scorched3D 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.
//
//    Scorched3D 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 Scorched3D; if not, write to the Free Software
//    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
////////////////////////////////////////////////////////////////////////////////

#include <GLSL/GLSLShader.h>
#include <GLEXT/GLStateExtension.h>
#include <common/Defines.h>
#include <string>

GLSLShader::GLSLShader(const char *filename, Type stype,
                                           const defines_list& dl) :
        id_(0)
{
        DIALOG_ASSERT(GLStateExtension::hasShaders());

        switch (stype) 
        {
        case VERTEX:
                id_ = glCreateShader(GL_VERTEX_SHADER);
                break;
        case FRAGMENT:
                id_ = glCreateShader(GL_FRAGMENT_SHADER);
                break;
        default:
                DIALOG_ASSERT(0); // ("invalid shader type");
        }

        DIALOG_ASSERT(id_); // runtime_error("can't create glsl shader");

        // the program as string
        std::string prg;

        // add defines to top of list for preprocessor
        for (defines_list::const_iterator it = dl.begin(); it != dl.end(); ++it) {
                prg += std::string("#define ") + *it + "\n";
        }

        // read lines.
        FILE *in = fopen(filename, "rb");
        if (!in) S3D::dialogExit("GLSLShader",
                S3D::formatStringBuffer("ERROR: Cannot find shader file \"%s\"", filename));

        char buffer[256];
        while (fgets(buffer, 256, in) != 0)
        {
                prg += buffer;
        }
        fclose(in);

        const char* prg_cstr = prg.c_str();
        glShaderSource(id_, 1, &prg_cstr, 0);

        glCompileShader(id_);

        GLint compiled = GL_FALSE;
        glGetShaderiv(id_, GL_COMPILE_STATUS, &compiled);

        // get compile log
        GLint maxlength = 0;
        glGetShaderiv(id_, GL_INFO_LOG_LENGTH, &maxlength);
        std::string logText(maxlength+1, ' ');
        GLsizei length = 0;
        glGetShaderInfoLog(id_, maxlength, &length, &logText[0]);

        if (compiled == GL_FALSE) 
        {
                S3D::dialogExit("GLSLShader", 
                        S3D::formatStringBuffer("Shader compiling failed %s : %s", filename, logText.c_str()));
        }
}

GLSLShader::~GLSLShader()
{
        glDeleteShader(id_);
}

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