opengl_compositor.cpp

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2013-2017 CERN
 * Copyright (C) 2021 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * @author Maciej Suminski <[email protected]>
 *
 * 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 <gal/opengl/opengl_compositor.h>
#include <gal/opengl/utils.h>

#include <gal/color4d.h>

#include <cassert>
#include <memory>
#include <stdexcept>
#include <wx/log.h>
#include <wx/debug.h>

using namespace KIGFX;

OPENGL_COMPOSITOR::OPENGL_COMPOSITOR() :
 m_initialized( false ),
 m_curBuffer( 0 ),
 m_mainFbo( 0 ),
 m_depthBuffer( 0 ),
 m_curFbo( DIRECT_RENDERING ),
 m_currentAntialiasingMode( OPENGL_ANTIALIASING_MODE::NONE )
{
 m_antialiasing = std::make_unique<ANTIALIASING_NONE>( this );
}


OPENGL_COMPOSITOR::~OPENGL_COMPOSITOR()
{
 if( m_initialized )
 {
 try
 {
 clean();
 }
 catch( const std::runtime_error& exc )
 {
 wxLogError( wxT( "Run time exception `%s` occurred in OPENGL_COMPOSITOR destructor." ),
 exc.what() );
 }
 }
}


void OPENGL_COMPOSITOR::SetAntialiasingMode( OPENGL_ANTIALIASING_MODE aMode )
{
 m_currentAntialiasingMode = aMode;

 if( m_initialized )
 clean();
}


OPENGL_ANTIALIASING_MODE OPENGL_COMPOSITOR::GetAntialiasingMode() const
{
 return m_currentAntialiasingMode;
}


void OPENGL_COMPOSITOR::Initialize()
{
 if( m_initialized )
 return;

 switch( m_currentAntialiasingMode )
 {
 case OPENGL_ANTIALIASING_MODE::SMAA:
 m_antialiasing = std::make_unique<ANTIALIASING_SMAA>( this );
 break;
 case OPENGL_ANTIALIASING_MODE::SUPERSAMPLING:
 m_antialiasing = std::make_unique<ANTIALIASING_SUPERSAMPLING>( this );
 break;
 default:
 m_antialiasing = std::make_unique<ANTIALIASING_NONE>( this );
 break;
 }

 VECTOR2U dims = m_antialiasing->GetInternalBufferSize();
 assert( dims.x != 0 && dims.y != 0 );

 GLint maxBufSize;
 glGetIntegerv( GL_MAX_RENDERBUFFER_SIZE_EXT, &maxBufSize );

 // VECTOR2U is unsigned, so no need to check if < 0
 if( dims.x > (unsigned) maxBufSize || dims.y >= (unsigned) maxBufSize )
 throw std::runtime_error( "Requested render buffer size is not supported" );

 // We need framebuffer objects for drawing the screen contents
 // Generate framebuffer and a depth buffer
 glGenFramebuffersEXT( 1, &m_mainFbo );
 checkGlError( "generating framebuffer", __FILE__, __LINE__ );
 bindFb( m_mainFbo );

 // Allocate memory for the depth buffer
 // Attach the depth buffer to the framebuffer
 glGenRenderbuffersEXT( 1, &m_depthBuffer );
 checkGlError( "generating renderbuffer", __FILE__, __LINE__ );
 glBindRenderbufferEXT( GL_RENDERBUFFER_EXT, m_depthBuffer );
 checkGlError( "binding renderbuffer", __FILE__, __LINE__ );

 glRenderbufferStorageEXT( GL_RENDERBUFFER_EXT, GL_DEPTH24_STENCIL8, dims.x, dims.y );
 checkGlError( "creating renderbuffer storage", __FILE__, __LINE__ );
 glFramebufferRenderbufferEXT( GL_FRAMEBUFFER_EXT, GL_DEPTH_STENCIL_ATTACHMENT,
 GL_RENDERBUFFER_EXT, m_depthBuffer );
 checkGlError( "attaching renderbuffer", __FILE__, __LINE__ );

 // Unbind the framebuffer, so by default all the rendering goes directly to the display
 bindFb( DIRECT_RENDERING );

 m_initialized = true;

 m_antialiasing->Init();
}


void OPENGL_COMPOSITOR::Resize( unsigned int aWidth, unsigned int aHeight )
{
 if( m_initialized )
 clean();

 m_antialiasing->OnLostBuffers();

 m_width = aWidth;
 m_height = aHeight;
}


unsigned int OPENGL_COMPOSITOR::CreateBuffer()
{
 return m_antialiasing->CreateBuffer();
}


unsigned int OPENGL_COMPOSITOR::CreateBuffer( VECTOR2U aDimensions )
{
 assert( m_initialized );

 int maxBuffers, maxTextureSize;

 // Get the maximum number of buffers
 glGetIntegerv( GL_MAX_COLOR_ATTACHMENTS, (GLint*) &maxBuffers );

 if( (int) usedBuffers() >= maxBuffers )
 {
 throw std::runtime_error( "Cannot create more framebuffers. OpenGL rendering backend "
 "requires at least 3 framebuffers. You may try to update/change "
 "your graphic drivers." );
 }

 glGetIntegerv( GL_MAX_TEXTURE_SIZE, (GLint*) &maxTextureSize );

 if( maxTextureSize < (int) aDimensions.x || maxTextureSize < (int) aDimensions.y )
 {
 throw std::runtime_error( "Requested texture size is not supported. "
 "Could not create a buffer." );
 }

 // GL_COLOR_ATTACHMENTn are consecutive integers
 GLuint attachmentPoint = GL_COLOR_ATTACHMENT0 + usedBuffers();
 GLuint textureTarget;

 // Generate the texture for the pixel storage
 glActiveTexture( GL_TEXTURE0 );
 glGenTextures( 1, &textureTarget );
 checkGlError( "generating framebuffer texture target", __FILE__, __LINE__ );
 glBindTexture( GL_TEXTURE_2D, textureTarget );
 checkGlError( "binding framebuffer texture target", __FILE__, __LINE__ );

 // Set texture parameters
 glTexEnvf( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA8, aDimensions.x, aDimensions.y, 0, GL_RGBA,
 GL_UNSIGNED_BYTE, nullptr );
 checkGlError( "creating framebuffer texture", __FILE__, __LINE__ );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );

 // Bind the texture to the specific attachment point, clear and rebind the screen
 bindFb( m_mainFbo );
 glFramebufferTexture2DEXT( GL_FRAMEBUFFER_EXT, attachmentPoint, GL_TEXTURE_2D, textureTarget,
 0 );

 // Check the status, exit if the framebuffer can't be created
 GLenum status = glCheckFramebufferStatusEXT( GL_FRAMEBUFFER_EXT );

 if( status != GL_FRAMEBUFFER_COMPLETE_EXT )
 {
 switch( status )
 {
 case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_EXT:
 throw std::runtime_error( "The framebuffer attachment points are incomplete." );

 case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT_EXT:
 throw std::runtime_error( "No images attached to the framebuffer." );

 case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT:
 throw std::runtime_error( "The framebuffer does not have at least one "
 "image attached to it." );

 case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT:
 throw std::runtime_error( "The framebuffer read buffer is incomplete." );

 case GL_FRAMEBUFFER_UNSUPPORTED_EXT:
 throw std::runtime_error( "The combination of internal formats of the attached "
 "images violates an implementation-dependent set of "
 "restrictions." );

 case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT:
 throw std::runtime_error( "GL_RENDERBUFFER_SAMPLES is not the same for "
 "all attached renderbuffers" );

 case GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS_EXT:
 throw std::runtime_error( "Framebuffer incomplete layer targets errors." );

 case GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT:
 throw std::runtime_error( "Framebuffer attachments have different dimensions" );

 default:
 throw std::runtime_error( "Unknown error occurred when creating the framebuffer." );
 }
 }

 ClearBuffer( COLOR4D::BLACK );

 // Return to direct rendering (we were asked only to create a buffer, not switch to one)
 bindFb( DIRECT_RENDERING );

 // Store the new buffer
 OPENGL_BUFFER buffer = { aDimensions, textureTarget, attachmentPoint };
 m_buffers.push_back( buffer );

 return usedBuffers();
}


GLenum OPENGL_COMPOSITOR::GetBufferTexture( unsigned int aBufferHandle )
{
 wxASSERT( aBufferHandle > 0 && aBufferHandle <= usedBuffers() );
 return m_buffers[aBufferHandle - 1].textureTarget;
}


void OPENGL_COMPOSITOR::SetBuffer( unsigned int aBufferHandle )
{
 wxASSERT( m_initialized );
 wxASSERT( aBufferHandle <= usedBuffers() );

 // Either unbind the FBO for direct rendering, or bind the one with target textures
 bindFb( aBufferHandle == DIRECT_RENDERING ? DIRECT_RENDERING : m_mainFbo );

 // Switch the target texture
 if( m_curFbo != DIRECT_RENDERING )
 {
 m_curBuffer = aBufferHandle - 1;
 glDrawBuffer( m_buffers[m_curBuffer].attachmentPoint );
 checkGlError( "setting draw buffer", __FILE__, __LINE__ );

 glViewport( 0, 0, m_buffers[m_curBuffer].dimensions.x,
 m_buffers[m_curBuffer].dimensions.y );
 }
 else
 {
 glViewport( 0, 0, GetScreenSize().x, GetScreenSize().y );
 }
}


void OPENGL_COMPOSITOR::ClearBuffer( const COLOR4D& aColor )
{
 wxASSERT( m_initialized );

 glClearColor( aColor.r, aColor.g, aColor.b, 0.0f );
 glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT );
}


VECTOR2U OPENGL_COMPOSITOR::GetScreenSize() const
{
 return { m_width, m_height };
}


void OPENGL_COMPOSITOR::Begin()
{
 m_antialiasing->Begin();
}


void OPENGL_COMPOSITOR::DrawBuffer( unsigned int aBufferHandle )
{
 m_antialiasing->DrawBuffer( aBufferHandle );
}


void OPENGL_COMPOSITOR::DrawBuffer( unsigned int aSourceHandle, unsigned int aDestHandle )
{
 wxASSERT( m_initialized );
 wxASSERT( aSourceHandle != 0 && aSourceHandle <= usedBuffers() );
 wxASSERT( aDestHandle <= usedBuffers() );

 // Switch to the destination buffer and blit the scene
 SetBuffer( aDestHandle );

 // Depth test has to be disabled to make transparency working
 glDisable( GL_DEPTH_TEST );
 glBlendFunc( GL_ONE, GL_ONE_MINUS_SRC_ALPHA );

 // Enable texturing and bind the main texture
 glEnable( GL_TEXTURE_2D );
 glBindTexture( GL_TEXTURE_2D, m_buffers[aSourceHandle - 1].textureTarget );

 // Draw a full screen quad with the texture
 glMatrixMode( GL_MODELVIEW );
 glPushMatrix();
 glLoadIdentity();
 glMatrixMode( GL_PROJECTION );
 glPushMatrix();
 glLoadIdentity();

 glBegin( GL_TRIANGLES );
 glTexCoord2f( 0.0f, 1.0f );
 glVertex2f( -1.0f, 1.0f );
 glTexCoord2f( 0.0f, 0.0f );
 glVertex2f( -1.0f, -1.0f );
 glTexCoord2f( 1.0f, 1.0f );
 glVertex2f( 1.0f, 1.0f );

 glTexCoord2f( 1.0f, 1.0f );
 glVertex2f( 1.0f, 1.0f );
 glTexCoord2f( 0.0f, 0.0f );
 glVertex2f( -1.0f, -1.0f );
 glTexCoord2f( 1.0f, 0.0f );
 glVertex2f( 1.0f, -1.0f );
 glEnd();

 glPopMatrix();
 glMatrixMode( GL_MODELVIEW );
 glPopMatrix();
}


void OPENGL_COMPOSITOR::Present()
{
 m_antialiasing->Present();
}


void OPENGL_COMPOSITOR::bindFb( unsigned int aFb )
{
 // Currently there are only 2 valid FBOs
 wxASSERT( aFb == DIRECT_RENDERING || aFb == m_mainFbo );

 if( m_curFbo != aFb )
 {
 glBindFramebufferEXT( GL_FRAMEBUFFER, aFb );
 checkGlError( "switching framebuffer", __FILE__, __LINE__ );
 m_curFbo = aFb;
 }
}


void OPENGL_COMPOSITOR::clean()
{
 wxASSERT( m_initialized );

 bindFb( DIRECT_RENDERING );

 for( const OPENGL_BUFFER& buffer : m_buffers )
 glDeleteTextures( 1, &buffer.textureTarget );

 m_buffers.clear();

 if( glDeleteFramebuffersEXT )
 glDeleteFramebuffersEXT( 1, &m_mainFbo );

 if( glDeleteRenderbuffersEXT )
 glDeleteRenderbuffersEXT( 1, &m_depthBuffer );

 m_initialized = false;
}


int OPENGL_COMPOSITOR::GetAntialiasSupersamplingFactor() const
{
 switch ( m_currentAntialiasingMode )
 {
 case OPENGL_ANTIALIASING_MODE::SUPERSAMPLING: return 2;
 default: return 1;
 }
}

VECTOR2D OPENGL_COMPOSITOR::GetAntialiasRenderingOffset() const
{
 switch( m_currentAntialiasingMode )
 {
 case OPENGL_ANTIALIASING_MODE::SUPERSAMPLING: return VECTOR2D( 0.5, -0.5 );
 default: return VECTOR2D( 0, 0 );
 }
}