shader.hpp

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#pragma once

#include <gls/headercheck.hpp>
#include <gls/errorcheck.hpp>
#include <gls/objects/object.hpp>

#if !defined( NDEBUG )
    #if !defined( GLS_ERROR_STREAM )
        #include <iostream>
        #define GLS_ERROR_STREAM std::cerr
    #endif
#endif

namespace gls {

namespace priv {
    template<GLenum Type>
    void create_shader( GLsizei, GLuint* name ) { *name = glCreateShader( Type ); }
    void delete_shader( GLsizei, const GLuint* name ) { glDeleteShader( *name ); }
}

template<GLenum Type>
class shader {
public:
    GLuint name() const {
        return m_object.name();
    }

    bool compile( const std::string& source ) {
        auto c_str = source.c_str();

        check_gl_error( glShaderSource( name(), 1, reinterpret_cast<const GLchar**>( &c_str ), nullptr ) );
        check_gl_error( glCompileShader( name() ) );

        auto compile_status = GL_FALSE;
        check_gl_error( glGetShaderiv( name(), GL_COMPILE_STATUS, &compile_status ) );

#if !defined( NDEBUG )
        auto info_log = get_info_log();

        if( !info_log.empty() ) {
            GLS_ERROR_STREAM << std::move( info_log );
        }
#endif

        return compile_status == GL_TRUE;
    }

    std::string get_info_log() const {
        auto info_log_length = GLint();
        check_gl_error( glGetShaderiv( name(), GL_INFO_LOG_LENGTH, &info_log_length ) );

        if( !info_log_length ) {
            return std::string();
        }

        auto info_log = std::vector<GLchar>( static_cast<std::size_t>( info_log_length ), 0 );
        check_gl_error( glGetShaderInfoLog( name(), info_log_length, nullptr, info_log.data() ) );

        return std::string( static_cast<const char*>( info_log.data() ) );
    }

private:
    object<priv::create_shader<Type>, priv::delete_shader> m_object;
};

}