kicad/common/gal/opengl/opengl_compositor.cpp

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/*
* This program source code file is part of KiCad, a free EDA CAD application.
*
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* Copyright (C) 2013-2016 CERN
* @author Maciej Suminski <maciej.suminski@cern.ch>
*
* 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
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* 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
*/
/**
* @file opengl_compositor.cpp
* @brief Class that handles multitarget rendering (i.e. to different textures/surfaces) and
* later compositing into a single image (OpenGL flavour).
*/
#include <gal/opengl/opengl_compositor.h>
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#include <gal/opengl/utils.h>
#include <stdexcept>
#include <cassert>
using namespace KIGFX;
OPENGL_COMPOSITOR::OPENGL_COMPOSITOR() :
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m_initialized( false ), m_curBuffer( 0 ),
m_mainFbo( 0 ), m_depthBuffer( 0 ), m_curFbo( DIRECT_RENDERING )
{
}
OPENGL_COMPOSITOR::~OPENGL_COMPOSITOR()
{
if( m_initialized )
clean();
}
void OPENGL_COMPOSITOR::Initialize()
{
if( m_initialized )
return;
// We need framebuffer objects for drawing the screen contents
// Generate framebuffer and a depth buffer
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glGenFramebuffersEXT( 1, &m_mainFbo );
checkGlError( "generating framebuffer" );
bindFb( m_mainFbo );
// Allocate memory for the depth buffer
// Attach the depth buffer to the framebuffer
glGenRenderbuffersEXT( 1, &m_depthBuffer );
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checkGlError( "generating renderbuffer" );
glBindRenderbufferEXT( GL_RENDERBUFFER_EXT, m_depthBuffer );
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checkGlError( "binding renderbuffer" );
glRenderbufferStorageEXT( GL_RENDERBUFFER_EXT, GL_DEPTH24_STENCIL8, m_width, m_height );
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checkGlError( "creating renderbuffer storage" );
glFramebufferRenderbufferEXT( GL_FRAMEBUFFER_EXT, GL_DEPTH_STENCIL_ATTACHMENT,
GL_RENDERBUFFER_EXT, m_depthBuffer );
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checkGlError( "attaching renderbuffer" );
// Unbind the framebuffer, so by default all the rendering goes directly to the display
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bindFb( DIRECT_RENDERING );
m_initialized = true;
}
void OPENGL_COMPOSITOR::Resize( unsigned int aWidth, unsigned int aHeight )
{
if( m_initialized )
clean();
m_width = aWidth;
m_height = aHeight;
}
unsigned int OPENGL_COMPOSITOR::CreateBuffer()
{
assert( m_initialized );
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int maxBuffers, maxTextureSize;
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// Get the maximum number of buffers
glGetIntegerv( GL_MAX_COLOR_ATTACHMENTS, (GLint*) &maxBuffers );
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if( (int) usedBuffers() >= maxBuffers )
{
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throw std::runtime_error( "Cannot create more framebuffers. OpenGL rendering "
"backend requires at least 3 framebuffers. You may try to update/change "
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"your graphic drivers." );
}
glGetIntegerv( GL_MAX_TEXTURE_SIZE, (GLint*) &maxTextureSize );
if( maxTextureSize < (int) m_width || maxTextureSize < (int) m_height )
{
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
glGenTextures( 1, &textureTarget );
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checkGlError( "generating framebuffer texture target" );
glBindTexture( GL_TEXTURE_2D, textureTarget );
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checkGlError( "binding framebuffer texture target" );
// Set texture parameters
glTexEnvf( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA8, m_width, m_height, 0, GL_RGBA,
GL_UNSIGNED_BYTE, NULL );
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checkGlError( "creating framebuffer texture" );
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
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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( "Cannot create the framebuffer." );
break;
case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT_EXT:
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throw std::runtime_error( "The framebuffer attachment points are incomplete." );
break;
case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT:
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throw std::runtime_error( "The framebuffer does not have at least one "
"image attached to it." );
break;
case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT:
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throw std::runtime_error( "The framebuffer read buffer is incomplete." );
break;
case GL_FRAMEBUFFER_UNSUPPORTED_EXT:
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throw std::runtime_error( "The combination of internal formats of the attached "
"images violates an implementation-dependent set of restrictions." );
break;
case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT:
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throw std::runtime_error( "GL_RENDERBUFFER_SAMPLES is not the same for "
"all attached renderbuffers" );
break;
case GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS_EXT:
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throw std::runtime_error( "Framebuffer incomplete layer targets errors." );
break;
default:
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throw std::runtime_error( "Cannot create the framebuffer." );
break;
}
return 0;
}
ClearBuffer();
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// Return to direct rendering (we were asked only to create a buffer, not switch to one)
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bindFb( DIRECT_RENDERING );
// Store the new buffer
OPENGL_BUFFER buffer = { textureTarget, attachmentPoint };
m_buffers.push_back( buffer );
return usedBuffers();
}
void OPENGL_COMPOSITOR::SetBuffer( unsigned int aBufferHandle )
{
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assert( m_initialized );
assert( aBufferHandle <= usedBuffers() );
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// Either unbind the FBO for direct rendering, or bind the one with target textures
bindFb( aBufferHandle == DIRECT_RENDERING ? DIRECT_RENDERING : m_mainFbo );
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// Switch the target texture
if( m_curFbo != DIRECT_RENDERING )
{
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m_curBuffer = aBufferHandle - 1;
glDrawBuffer( m_buffers[m_curBuffer].attachmentPoint );
checkGlError( "setting draw buffer" );
}
}
void OPENGL_COMPOSITOR::ClearBuffer()
{
assert( m_initialized );
glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT );
}
void OPENGL_COMPOSITOR::DrawBuffer( unsigned int aBufferHandle )
{
assert( m_initialized );
assert( aBufferHandle != 0 && aBufferHandle <= usedBuffers() );
// Switch to the main framebuffer and blit the scene
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bindFb( DIRECT_RENDERING );
// 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[aBufferHandle - 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( 1.0f, 1.0f );
glVertex2f( 1.0f, -1.0f );
glTexCoord2f( 1.0f, 0.0f );
glVertex2f( 1.0f, 1.0f );
glTexCoord2f( 0.0f, 1.0f );
glVertex2f( -1.0f, -1.0f );
glTexCoord2f( 1.0f, 0.0f );
glVertex2f( 1.0f, 1.0f );
glTexCoord2f( 0.0f, 0.0f );
glVertex2f( -1.0f, 1.0f );
glEnd();
glPopMatrix();
glMatrixMode( GL_MODELVIEW );
glPopMatrix();
}
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void OPENGL_COMPOSITOR::bindFb( unsigned int aFb ) {
// Currently there are only 2 valid FBOs
assert( aFb == DIRECT_RENDERING || aFb == m_mainFbo );
if( m_curFbo != aFb )
{
glBindFramebufferEXT( GL_FRAMEBUFFER, aFb );
checkGlError( "switching framebuffer" );
m_curFbo = aFb;
}
}
void OPENGL_COMPOSITOR::clean()
{
assert( m_initialized );
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bindFb( DIRECT_RENDERING );
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for( OPENGL_BUFFERS::const_iterator it = m_buffers.begin(); it != m_buffers.end(); ++it )
{
glDeleteTextures( 1, &it->textureTarget );
}
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m_buffers.clear();
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glDeleteFramebuffersEXT( 1, &m_mainFbo );
glDeleteRenderbuffersEXT( 1, &m_depthBuffer );
m_initialized = false;
}