source: trunk/src/gl/gl_program.cc @ 37

// Copyright (C) 2012-2013 Kornel Kisielewicz
// This file is part of NV Libraries.
// For conditions of distribution and use, see copyright notice in nv.hh

#include "nv/gl/gl_program.hh"

#include "nv/gl/gl_enum.hh"
#include "nv/logging.hh"
#include "nv/lib/gl.hh"

using namespace nv;

gl_shader::gl_shader( uint32 shader_type ) 
        : object_id(0), shader_type( shader_type )
{
        // no op
}

gl_shader::gl_shader( uint32 shader_type, const string& shader_code )
        : object_id(0), shader_type( shader_type )
{
        compile( shader_code );
}

gl_shader::~gl_shader()
{
        free();
}

bool gl_shader::compile( const string& shader_code )
{
        generate();

        const char* pc = shader_code.c_str();

        glShaderSource( object_id,   1, &pc, 0 );
        glCompileShader( object_id );

        return validate();
}

void gl_shader::generate()
{
        if ( is_valid() )
        {
                free();
        }
        object_id = glCreateShader( shader_type );
}

void gl_shader::free()
{
        glDeleteShader( object_id );
        object_id = 0;
}

bool gl_shader::validate()
{
        const uint32 buffer_size = 1024;
        char buffer[ buffer_size ] = { 0 };
        int length;
        glGetShaderInfoLog( object_id, buffer_size, &length, buffer );

        if ( length > 0 )
        {
                NV_LOG( LOG_INFO, "Shader #" << object_id << " compiled: " << buffer );
        }
        else
        {
                NV_LOG( LOG_INFO, "Shader #" << object_id << " compiled successfully." );
        }
        return true;
}

gl_program::gl_program( const string& vertex_program, const string& fragment_program )
        : vertex_shader( GL_VERTEX_SHADER ), fragment_shader( GL_FRAGMENT_SHADER )
{
        compile( vertex_program, fragment_program );
}

gl_program::~gl_program()
{
        if ( is_valid() )
        {
                // Detach the shaders from the program
                glDetachShader( m_name.get_value(), vertex_shader.get_id() );
                glDetachShader( m_name.get_value(), fragment_shader.get_id() );
        }
}

bool gl_program::compile( const string& vertex_program, const string& fragment_program )
{
        if (!vertex_shader.compile( vertex_program )) { return false; }
        if (!fragment_shader.compile( fragment_program )) { return false; }

        glAttachShader( m_name.get_value(), fragment_shader.get_id() );
        glAttachShader( m_name.get_value(), vertex_shader.get_id() );
        glLinkProgram( m_name.get_value() );

        if (!validate())
        {
                return false;
        }
        load_attributes();
        load_uniforms();
        return true;
}

void gl_program::bind()
{
        glUseProgram( m_name.get_value() );
}

void gl_program::unbind()
{
        glUseProgram( 0 );
}

bool gl_program::is_valid() const
{
        return m_name.is_valid();
}

void gl_program::load_attributes()
{
        int params;
        glGetProgramiv( m_name.get_value(), GL_ACTIVE_ATTRIBUTES, &params );

        for ( int i = 0; i < params; ++i )
        {
                int attr_nlen;
                int attr_len;
                unsigned attr_type;
                char name_buffer[128];

                glGetActiveAttrib( m_name.get_value(), i, 128, &attr_nlen, &attr_len, &attr_type, name_buffer );

                string name( name_buffer, attr_nlen );

                // skip built-ins
                if ( name.substr(0,3) == "gl_" ) continue;

                int attr_loc = glGetAttribLocation( m_name.get_value(), name.c_str() );

                m_attribute_map[ name ] = new attribute( name, attr_loc, gl_enum_to_type( attr_type ), attr_len );
        }
}

void gl_program::load_uniforms()
{
        int params;
        glGetProgramiv( m_name.get_value(), GL_ACTIVE_UNIFORMS, &params );

        for ( int i = 0; i < params; ++i )
        {
                int uni_nlen;
                int uni_len;
                unsigned uni_type;
                char name_buffer[128];

                glGetActiveUniform( m_name.get_value(), i, 128, &uni_nlen, &uni_len, &uni_type, name_buffer );

                string name( name_buffer, uni_nlen );

                // skip built-ins
                if ( name.substr(0,3) == "gl_" ) continue;

                int uni_loc = glGetUniformLocation( m_name.get_value(), name.c_str() );
                type utype = gl_enum_to_type( uni_type );
                m_uniform_map[ name ] = create_uniform( utype, name, uni_loc, uni_len );
        }
}

bool gl_program::validate()
{
        const uint32 buffer_size = 2048;
        char buffer[ buffer_size ] = { 0 };
        int length;
        int status;

        glGetProgramiv( m_name.get_value(), GL_LINK_STATUS, &status );
        glGetProgramInfoLog( m_name.get_value(), buffer_size, &length, buffer );

        NV_LOG( LOG_INFO, "Program #" << m_name.get_value() << (status == GL_FALSE ? "failed to compile!" : "compiled successfuly.") );

        if ( length > 0 )
        {
                NV_LOG( LOG_INFO, "Program #" << m_name.get_value() << " log: " << buffer );
        }

        if ( status == GL_FALSE ) 
        {
                return false;
        }

        glValidateProgram( m_name.get_value() );
        glGetProgramiv( m_name.get_value(), GL_VALIDATE_STATUS, &status );

        if ( status == GL_FALSE )
        {
                glGetProgramInfoLog( m_name.get_value(), buffer_size, &length, buffer );
                NV_LOG( LOG_ERROR, "Program #" << m_name.get_value() << " validation error : " << buffer );
                return false;
        }
        return true;
}