antialiasing.cpp

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/*
 * This program source code file is part of KICAD, a free EDA CAD application.
 *
 * Copyright (C) 2016-2021 Kicad Developers, see AUTHORS.txt for contributors.
 *
 * 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/antialiasing.h>
#include <gal/opengl/opengl_compositor.h>
#include <gal/opengl/utils.h>
#include <gal/color4d.h>

#include <memory>
#include <tuple>

#include "gl_builtin_shaders.h"
#include "SmaaAreaTex.h"
#include "SmaaSearchTex.h"

using namespace KIGFX;

// =========================
// ANTIALIASING_NONE
// =========================

ANTIALIASING_NONE::ANTIALIASING_NONE( OPENGL_COMPOSITOR* aCompositor ) :
 compositor( aCompositor )
{
}


bool ANTIALIASING_NONE::Init()
{
 // Nothing to initialize
 return true;
}


VECTOR2U ANTIALIASING_NONE::GetInternalBufferSize()
{
 return compositor->GetScreenSize();
}


void ANTIALIASING_NONE::DrawBuffer( GLuint buffer )
{
 compositor->DrawBuffer( buffer, OPENGL_COMPOSITOR::DIRECT_RENDERING );
}


void ANTIALIASING_NONE::Present()
{
 // Nothing to present, draw_buffer already drew to the screen
}


void ANTIALIASING_NONE::OnLostBuffers()
{
 // Nothing to do
}


void ANTIALIASING_NONE::Begin()
{
 // Nothing to do
}


unsigned int ANTIALIASING_NONE::CreateBuffer()
{
 return compositor->CreateBuffer( compositor->GetScreenSize() );
}


namespace
{
void draw_fullscreen_primitive()
{
 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();
}

} // namespace

// =========================
// ANTIALIASING_SUPERSAMPLING
// =========================

ANTIALIASING_SUPERSAMPLING::ANTIALIASING_SUPERSAMPLING( OPENGL_COMPOSITOR* aCompositor ) :
 compositor( aCompositor ),
 ssaaMainBuffer( 0 ), areBuffersCreated( false ), areShadersCreated( false )
{
}


bool ANTIALIASING_SUPERSAMPLING::Init()
{
 areShadersCreated = false;

 if( !areBuffersCreated )
 {
 ssaaMainBuffer = compositor->CreateBuffer();
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );

 areBuffersCreated = true;
 }

 return true;
}


VECTOR2U ANTIALIASING_SUPERSAMPLING::GetInternalBufferSize()
{
 return compositor->GetScreenSize() * 2;
}


void ANTIALIASING_SUPERSAMPLING::Begin()
{
 compositor->SetBuffer( ssaaMainBuffer );
 compositor->ClearBuffer( COLOR4D::BLACK );
}


void ANTIALIASING_SUPERSAMPLING::DrawBuffer( GLuint aBuffer )
{
 compositor->DrawBuffer( aBuffer, ssaaMainBuffer );
}


void ANTIALIASING_SUPERSAMPLING::Present()
{
 glDisable( GL_BLEND );
 glDisable( GL_DEPTH_TEST );
 glActiveTexture( GL_TEXTURE0 );
 glBindTexture( GL_TEXTURE_2D, compositor->GetBufferTexture( ssaaMainBuffer ) );
 compositor->SetBuffer( OPENGL_COMPOSITOR::DIRECT_RENDERING );

 draw_fullscreen_primitive();
}


void ANTIALIASING_SUPERSAMPLING::OnLostBuffers()
{
 areBuffersCreated = false;
}


unsigned int ANTIALIASING_SUPERSAMPLING::CreateBuffer()
{
 return compositor->CreateBuffer( GetInternalBufferSize() );
}

// ===============================
// ANTIALIASING_SMAA
// ===============================

ANTIALIASING_SMAA::ANTIALIASING_SMAA( OPENGL_COMPOSITOR* aCompositor ) :
 areBuffersInitialized( false ),
 shadersLoaded( false ),
 compositor( aCompositor )
{
 smaaBaseBuffer = 0;
 smaaEdgesBuffer = 0;
 smaaBlendBuffer = 0;
 smaaAreaTex = 0;
 smaaSearchTex = 0;

 pass_1_metrics = 0;
 pass_2_metrics = 0;
 pass_3_metrics = 0;
}


VECTOR2U ANTIALIASING_SMAA::GetInternalBufferSize()
{
 return compositor->GetScreenSize();
}


void ANTIALIASING_SMAA::loadShaders()
{
 // Load constant textures
 glEnable( GL_TEXTURE_2D );
 glActiveTexture( GL_TEXTURE0 );

 glGenTextures( 1, &smaaAreaTex );
 glBindTexture( GL_TEXTURE_2D, smaaAreaTex );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 glTexImage2D( GL_TEXTURE_2D, 0, GL_RG8, AREATEX_WIDTH, AREATEX_HEIGHT, 0, GL_RG,
 GL_UNSIGNED_BYTE, areaTexBytes );
 checkGlError( "loading smaa area tex", __FILE__, __LINE__ );

 glGenTextures( 1, &smaaSearchTex );
 glBindTexture( GL_TEXTURE_2D, smaaSearchTex );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 glTexImage2D( GL_TEXTURE_2D, 0, GL_R8, SEARCHTEX_WIDTH, SEARCHTEX_HEIGHT, 0, GL_RED,
 GL_UNSIGNED_BYTE, searchTexBytes );
 checkGlError( "loading smaa search tex", __FILE__, __LINE__ );

 // Quality settings:
 // THRESHOLD: intended to exclude spurious edges in photorealistic game graphics
 // but in a high-contrast CAD application, all edges are intentional
 // should be set fairly low, so user color choices do not affect antialiasing
 // MAX_SEARCH_STEPS: steps of 2px, searched in H/V direction to discover true angle of edges
 // improves AA for lines close H/V but creates fuzzyness at junctions
 // MAX_SEARCH_STEPS_DIAG: steps of 1px, searched in diagonal direction
 // improves lines close to 45deg but turns small circles into octagons
 // CORNER_ROUNDING: SMAA can distinguish actual corners from aliasing jaggies,
 // we want to preserve those as much as possible
 // Edge Detection: In Eeschema, when a single pixel line changes color, edge detection using
 // color is too aggressive and leads to a white spot at the transition point
 std::string quality_string;
 const char* edge_detect_shader;

 // trades imperfect AA of shallow angles for a near artifact-free reproduction of fine features
 // jaggies are smoothed over max 5px (original step + 2px in both directions)
 quality_string = "#define SMAA_THRESHOLD 0.005\n"
 "#define SMAA_MAX_SEARCH_STEPS 1\n"
 "#define SMAA_MAX_SEARCH_STEPS_DIAG 2\n"
 "#define SMAA_LOCAL_CONTRAST_ADAPTATION_FACTOR 1.5\n"
 "#define SMAA_CORNER_ROUNDING 0\n";
 edge_detect_shader = BUILTIN_SHADERS::smaa_pass_1_fragment_shader_luma;

 // set up shaders
 std::string vert_preamble( R"SHADER(
#version 120
#define SMAA_GLSL_2_1
#define SMAA_INCLUDE_VS 1
#define SMAA_INCLUDE_PS 0
uniform vec4 SMAA_RT_METRICS;
)SHADER" );

 std::string frag_preamble( R"SHADER(
#version 120
#define SMAA_GLSL_2_1
#define SMAA_INCLUDE_VS 0
#define SMAA_INCLUDE_PS 1
uniform vec4 SMAA_RT_METRICS;
)SHADER" );

 std::string smaa_source = std::string( BUILTIN_SHADERS::smaa_base_shader_p1 )
 + std::string( BUILTIN_SHADERS::smaa_base_shader_p2 )
 + std::string( BUILTIN_SHADERS::smaa_base_shader_p3 )
 + std::string( BUILTIN_SHADERS::smaa_base_shader_p4 );

 //
 // Set up pass 1 Shader
 //
 pass_1_shader = std::make_unique<SHADER>();
 pass_1_shader->LoadShaderFromStrings( KIGFX::SHADER_TYPE_VERTEX, vert_preamble, quality_string,
 smaa_source, BUILTIN_SHADERS::smaa_pass_1_vertex_shader );
 pass_1_shader->LoadShaderFromStrings( KIGFX::SHADER_TYPE_FRAGMENT, frag_preamble,
 quality_string, smaa_source, edge_detect_shader );
 pass_1_shader->Link();
 checkGlError( "linking pass 1 shader", __FILE__, __LINE__ );

 GLint smaaColorTexParameter = pass_1_shader->AddParameter( "colorTex" );
 checkGlError( "pass1: getting colorTex uniform", __FILE__, __LINE__ );
 pass_1_metrics = pass_1_shader->AddParameter( "SMAA_RT_METRICS" );
 checkGlError( "pass1: getting metrics uniform", __FILE__, __LINE__ );

 pass_1_shader->Use();
 checkGlError( "pass1: using shader", __FILE__, __LINE__ );
 pass_1_shader->SetParameter( smaaColorTexParameter, 0 );
 checkGlError( "pass1: setting colorTex uniform", __FILE__, __LINE__ );
 pass_1_shader->Deactivate();
 checkGlError( "pass1: deactivating shader", __FILE__, __LINE__ );

 //
 // set up pass 2 shader
 //
 pass_2_shader = std::make_unique<SHADER>();
 pass_2_shader->LoadShaderFromStrings( KIGFX::SHADER_TYPE_VERTEX, vert_preamble, quality_string,
 smaa_source, BUILTIN_SHADERS::smaa_pass_2_vertex_shader );
 pass_2_shader->LoadShaderFromStrings( KIGFX::SHADER_TYPE_FRAGMENT, frag_preamble,
 quality_string, smaa_source,
 BUILTIN_SHADERS::smaa_pass_2_fragment_shader );
 pass_2_shader->Link();
 checkGlError( "linking pass 2 shader", __FILE__, __LINE__ );

 GLint smaaEdgesTexParameter = pass_2_shader->AddParameter( "edgesTex" );
 checkGlError( "pass2: getting colorTex uniform", __FILE__, __LINE__ );
 GLint smaaAreaTexParameter = pass_2_shader->AddParameter( "areaTex" );
 checkGlError( "pass2: getting areaTex uniform", __FILE__, __LINE__ );
 GLint smaaSearchTexParameter = pass_2_shader->AddParameter( "searchTex" );
 checkGlError( "pass2: getting searchTex uniform", __FILE__, __LINE__ );
 pass_2_metrics = pass_2_shader->AddParameter( "SMAA_RT_METRICS" );
 checkGlError( "pass2: getting metrics uniform", __FILE__, __LINE__ );

 pass_2_shader->Use();
 checkGlError( "pass2: using shader", __FILE__, __LINE__ );
 pass_2_shader->SetParameter( smaaEdgesTexParameter, 0 );
 checkGlError( "pass2: setting colorTex uniform", __FILE__, __LINE__ );
 pass_2_shader->SetParameter( smaaAreaTexParameter, 1 );
 checkGlError( "pass2: setting areaTex uniform", __FILE__, __LINE__ );
 pass_2_shader->SetParameter( smaaSearchTexParameter, 3 );
 checkGlError( "pass2: setting searchTex uniform", __FILE__, __LINE__ );
 pass_2_shader->Deactivate();
 checkGlError( "pass2: deactivating shader", __FILE__, __LINE__ );

 //
 // set up pass 3 shader
 //
 pass_3_shader = std::make_unique<SHADER>();
 pass_3_shader->LoadShaderFromStrings( KIGFX::SHADER_TYPE_VERTEX, vert_preamble, quality_string,
 smaa_source, BUILTIN_SHADERS::smaa_pass_3_vertex_shader );
 pass_3_shader->LoadShaderFromStrings( KIGFX::SHADER_TYPE_FRAGMENT, frag_preamble,
 quality_string, smaa_source,
 BUILTIN_SHADERS::smaa_pass_3_fragment_shader );
 pass_3_shader->Link();

 GLint smaaP3ColorTexParameter = pass_3_shader->AddParameter( "colorTex" );
 checkGlError( "pass3: getting colorTex uniform", __FILE__, __LINE__ );
 GLint smaaBlendTexParameter = pass_3_shader->AddParameter( "blendTex" );
 checkGlError( "pass3: getting blendTex uniform", __FILE__, __LINE__ );
 pass_3_metrics = pass_3_shader->AddParameter( "SMAA_RT_METRICS" );
 checkGlError( "pass3: getting metrics uniform", __FILE__, __LINE__ );

 pass_3_shader->Use();
 checkGlError( "pass3: using shader", __FILE__, __LINE__ );
 pass_3_shader->SetParameter( smaaP3ColorTexParameter, 0 );
 checkGlError( "pass3: setting colorTex uniform", __FILE__, __LINE__ );
 pass_3_shader->SetParameter( smaaBlendTexParameter, 1 );
 checkGlError( "pass3: setting blendTex uniform", __FILE__, __LINE__ );
 pass_3_shader->Deactivate();
 checkGlError( "pass3: deactivating shader", __FILE__, __LINE__ );

 shadersLoaded = true;
}


void ANTIALIASING_SMAA::updateUniforms()
{
 auto dims = compositor->GetScreenSize();

 pass_1_shader->Use();
 checkGlError( "pass1: using shader", __FILE__, __LINE__ );
 pass_1_shader->SetParameter( pass_1_metrics, 1.f / float( dims.x ), 1.f / float( dims.y ),
 float( dims.x ), float( dims.y ) );
 checkGlError( "pass1: setting metrics uniform", __FILE__, __LINE__ );
 pass_1_shader->Deactivate();
 checkGlError( "pass1: deactivating shader", __FILE__, __LINE__ );

 pass_2_shader->Use();
 checkGlError( "pass2: using shader", __FILE__, __LINE__ );
 pass_2_shader->SetParameter( pass_2_metrics, 1.f / float( dims.x ), 1.f / float( dims.y ),
 float( dims.x ), float( dims.y ) );
 checkGlError( "pass2: setting metrics uniform", __FILE__, __LINE__ );
 pass_2_shader->Deactivate();
 checkGlError( "pass2: deactivating shader", __FILE__, __LINE__ );

 pass_3_shader->Use();
 checkGlError( "pass3: using shader", __FILE__, __LINE__ );
 pass_3_shader->SetParameter( pass_3_metrics, 1.f / float( dims.x ), 1.f / float( dims.y ),
 float( dims.x ), float( dims.y ) );
 checkGlError( "pass3: setting metrics uniform", __FILE__, __LINE__ );
 pass_3_shader->Deactivate();
 checkGlError( "pass3: deactivating shader", __FILE__, __LINE__ );
}


bool ANTIALIASING_SMAA::Init()
{
 if( !shadersLoaded )
 loadShaders();

 if( !areBuffersInitialized )
 {
 smaaBaseBuffer = compositor->CreateBuffer();
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );

 smaaEdgesBuffer = compositor->CreateBuffer();
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );

 smaaBlendBuffer = compositor->CreateBuffer();
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );

 updateUniforms();
 areBuffersInitialized = true;
 }

 // Nothing to initialize
 return true;
}


void ANTIALIASING_SMAA::OnLostBuffers()
{
 areBuffersInitialized = false;
}


unsigned int ANTIALIASING_SMAA::CreateBuffer()
{
 return compositor->CreateBuffer( compositor->GetScreenSize() );
}


void ANTIALIASING_SMAA::DrawBuffer( GLuint buffer )
{
 // draw to internal buffer
 compositor->DrawBuffer( buffer, smaaBaseBuffer );
}


void ANTIALIASING_SMAA::Begin()
{
 compositor->SetBuffer( smaaBaseBuffer );
 compositor->ClearBuffer( COLOR4D::BLACK );
}


namespace
{
void draw_fullscreen_triangle()
{
 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, -1.0f );
 glVertex2f( -1.0f, -3.0f );
 glTexCoord2f( 2.0f, 1.0f );
 glVertex2f( 3.0f, 1.0f );
 glEnd();

 glPopMatrix();
 glMatrixMode( GL_MODELVIEW );
 glPopMatrix();
}
} // namespace


void ANTIALIASING_SMAA::Present()
{
 auto sourceTexture = compositor->GetBufferTexture( smaaBaseBuffer );

 glDisable( GL_BLEND );
 glDisable( GL_DEPTH_TEST );
 glEnable( GL_TEXTURE_2D );

 //
 // pass 1: main-buffer -> smaaEdgesBuffer
 //
 compositor->SetBuffer( smaaEdgesBuffer );
 compositor->ClearBuffer( COLOR4D::BLACK );

 glActiveTexture( GL_TEXTURE0 );
 glBindTexture( GL_TEXTURE_2D, sourceTexture );
 checkGlError( "binding colorTex", __FILE__, __LINE__ );
 pass_1_shader->Use();
 checkGlError( "using smaa pass 1 shader", __FILE__, __LINE__ );
 draw_fullscreen_triangle();
 pass_1_shader->Deactivate();

 //
 // pass 2: smaaEdgesBuffer -> smaaBlendBuffer
 //
 compositor->SetBuffer( smaaBlendBuffer );
 compositor->ClearBuffer( COLOR4D::BLACK );

 auto edgesTex = compositor->GetBufferTexture( smaaEdgesBuffer );

 glActiveTexture( GL_TEXTURE0 );
 glBindTexture( GL_TEXTURE_2D, edgesTex );
 glActiveTexture( GL_TEXTURE1 );
 glBindTexture( GL_TEXTURE_2D, smaaAreaTex );
 glActiveTexture( GL_TEXTURE3 );
 glBindTexture( GL_TEXTURE_2D, smaaSearchTex );

 pass_2_shader->Use();
 draw_fullscreen_triangle();
 pass_2_shader->Deactivate();

 //
 // pass 3: colorTex + BlendBuffer -> output
 //
 compositor->SetBuffer( OPENGL_COMPOSITOR::DIRECT_RENDERING );
 compositor->ClearBuffer( COLOR4D::BLACK );
 auto blendTex = compositor->GetBufferTexture( smaaBlendBuffer );

 glActiveTexture( GL_TEXTURE0 );
 glBindTexture( GL_TEXTURE_2D, sourceTexture );
 glActiveTexture( GL_TEXTURE1 );
 glBindTexture( GL_TEXTURE_2D, blendTex );

 pass_3_shader->Use();
 draw_fullscreen_triangle();
 pass_3_shader->Deactivate();
}