shader.cpp

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/*
 * This program source code file is part of KICAD, a free EDA CAD application.
 *
 * Copyright (C) 2012 Torsten Hueter, torstenhtr <at> gmx.de
 * Copyright (C) 2012-2021 Kicad Developers, see AUTHORS.txt for contributors.
 *
 * Graphics Abstraction Layer (GAL) for OpenGL
 *
 * Shader class
 *
 * 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, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
#include <iostream>
#include <fstream>
#include <stdexcept>
 
#include <cstring>
#include <cassert>
 
#include <gal/opengl/shader.h>
#include <vector>
 
using namespace KIGFX;
 
SHADER::SHADER() :
 isProgramCreated( false ),
 isShaderLinked( false ),
 active( false ),
 maximumVertices( 4 ),
 geomInputType( GL_LINES ),
 geomOutputType( GL_LINES )
 
{
 // Do not have uninitialized members:
 programNumber = 0;
}
 
 
SHADER::~SHADER()
{
 if( active )
 Deactivate();
 
 if( isProgramCreated )
 {
 if( glIsShader )
 {
 // Delete the shaders and the program
 for( std::deque<GLuint>::iterator it = shaderNumbers.begin(); it != shaderNumbers.end();
 ++it )
 {
 GLuint shader = *it;
 
 if( glIsShader( shader ) )
 {
 glDetachShader( programNumber, shader );
 glDeleteShader( shader );
 }
 }
 
 glDeleteProgram( programNumber );
 }
 }
}
 
 
bool SHADER::LoadShaderFromFile( SHADER_TYPE aShaderType, const std::string& aShaderSourceName )
{
 // Load shader sources
 const std::string shaderSource = ReadSource( aShaderSourceName );
 
 return LoadShaderFromStrings( aShaderType, shaderSource );
}
 
 
void SHADER::ConfigureGeometryShader( GLuint maxVertices, GLuint geometryInputType,
 GLuint geometryOutputType )
{
 maximumVertices = maxVertices;
 geomInputType = geometryInputType;
 geomOutputType = geometryOutputType;
}
 
 
bool SHADER::Link()
{
 // Shader linking
 glLinkProgram( programNumber );
 programInfo( programNumber );
 
 // Check the Link state
 GLint tmp;
 glGetProgramiv( programNumber, GL_LINK_STATUS, &tmp );
 isShaderLinked = !!tmp;
 
#ifdef DEBUG
 if( !isShaderLinked )
 {
 int maxLength;
 glGetProgramiv( programNumber, GL_INFO_LOG_LENGTH, &maxLength );
 maxLength = maxLength + 1;
 char* linkInfoLog = new char[maxLength];
 glGetProgramInfoLog( programNumber, maxLength, &maxLength, linkInfoLog );
 std::cerr << "Shader linking error:" << std::endl;
 std::cerr << linkInfoLog;
 delete[] linkInfoLog;
 }
#endif /* DEBUG */
 
 return isShaderLinked;
}
 
 
int SHADER::AddParameter( const std::string& aParameterName )
{
 GLint location = glGetUniformLocation( programNumber, aParameterName.c_str() );
 
 if( location >= 0 )
 parameterLocation.push_back( location );
 else
 throw std::runtime_error( "Could not find shader uniform: " + aParameterName );
 
 return static_cast<int>( parameterLocation.size() ) - 1;
}
 
 
void SHADER::SetParameter( int parameterNumber, float value ) const
{
 assert( (unsigned) parameterNumber < parameterLocation.size() );
 
 glUniform1f( parameterLocation[parameterNumber], value );
}
 
 
void SHADER::SetParameter( int parameterNumber, int value ) const
{
 assert( (unsigned) parameterNumber < parameterLocation.size() );
 
 glUniform1i( parameterLocation[parameterNumber], value );
}
 
void SHADER::SetParameter( int parameterNumber, float f0, float f1, float f2, float f3 ) const
{
 assert( (unsigned) parameterNumber < parameterLocation.size() );
 float arr[4] = { f0, f1, f2, f3 };
 glUniform4fv( parameterLocation[parameterNumber], 1, arr );
}
 
void SHADER::SetParameter( int aParameterNumber, const VECTOR2D& aValue ) const
{
 assert( (unsigned) aParameterNumber < parameterLocation.size() );
 glUniform2f( parameterLocation[aParameterNumber], static_cast<GLfloat>( aValue.x ), static_cast<GLfloat>( aValue.y ) );
}
 
 
int SHADER::GetAttribute( const std::string& aAttributeName ) const
{
 return glGetAttribLocation( programNumber, aAttributeName.c_str() );
}
 
 
void SHADER::programInfo( GLuint aProgram )
{
 GLint glInfoLogLength = 0;
 GLint writtenChars = 0;
 
 // Get the length of the info string
 glGetProgramiv( aProgram, GL_INFO_LOG_LENGTH, &glInfoLogLength );
 
 // Print the information
 if( glInfoLogLength > 2 )
 {
 GLchar* glInfoLog = new GLchar[glInfoLogLength];
 glGetProgramInfoLog( aProgram, glInfoLogLength, &writtenChars, glInfoLog );
 
 delete[] glInfoLog;
 }
}
 
 
void SHADER::shaderInfo( GLuint aShader )
{
 GLint glInfoLogLength = 0;
 GLint writtenChars = 0;
 
 // Get the length of the info string
 glGetShaderiv( aShader, GL_INFO_LOG_LENGTH, &glInfoLogLength );
 
 // Print the information
 if( glInfoLogLength > 2 )
 {
 GLchar* glInfoLog = new GLchar[glInfoLogLength];
 glGetShaderInfoLog( aShader, glInfoLogLength, &writtenChars, glInfoLog );
 
 delete[] glInfoLog;
 }
}
 
 
std::string SHADER::ReadSource( const std::string& aShaderSourceName )
{
 // Open the shader source for reading
 std::ifstream inputFile( aShaderSourceName.c_str(), std::ifstream::in );
 std::string shaderSource;
 
 if( !inputFile )
 throw std::runtime_error( "Can't read the shader source: " + aShaderSourceName );
 
 std::string shaderSourceLine;
 
 // Read all lines from the text file
 while( getline( inputFile, shaderSourceLine ) )
 {
 shaderSource += shaderSourceLine;
 shaderSource += "\n";
 }
 
 return shaderSource;
}
 
 
bool SHADER::loadShaderFromStringArray( SHADER_TYPE aShaderType, const char** aArray, size_t aSize )
{
 assert( !isShaderLinked );
 
 // Create the program
 if( !isProgramCreated )
 {
 programNumber = glCreateProgram();
 isProgramCreated = true;
 }
 
 // Create a shader
 GLuint shaderNumber = glCreateShader( aShaderType );
 shaderNumbers.push_back( shaderNumber );
 
 // Get the program info
 programInfo( programNumber );
 
 // Attach the sources
 glShaderSource( shaderNumber, static_cast<GLsizei>( aSize ), (const GLchar**) aArray, nullptr );
 programInfo( programNumber );
 
 // Compile and attach shader to the program
 glCompileShader( shaderNumber );
 GLint status;
 glGetShaderiv( shaderNumber, GL_COMPILE_STATUS, &status );
 
 if( status != GL_TRUE )
 {
 shaderInfo( shaderNumber );
 
 GLint maxLength = 0;
 glGetShaderiv( shaderNumber, GL_INFO_LOG_LENGTH, &maxLength );
 
 // The maxLength includes the NULL character
 std::vector<GLchar> errorLog( (size_t) maxLength );
 glGetShaderInfoLog( shaderNumber, maxLength, &maxLength, &errorLog[0] );
 
 // Provide the infolog in whatever manor you deem best.
 // Exit with failure.
 glDeleteShader( shaderNumber ); // Don't leak the shader.
 
 throw std::runtime_error( &errorLog[0] );
 }
 
 glAttachShader( programNumber, shaderNumber );
 programInfo( programNumber );
 
 // Special handling for the geometry shader
 if( aShaderType == SHADER_TYPE_GEOMETRY )
 {
 glProgramParameteriEXT( programNumber, GL_GEOMETRY_VERTICES_OUT_EXT, maximumVertices );
 glProgramParameteriEXT( programNumber, GL_GEOMETRY_INPUT_TYPE_EXT, geomInputType );
 glProgramParameteriEXT( programNumber, GL_GEOMETRY_OUTPUT_TYPE_EXT, geomOutputType );
 }
 
 return true;
}