From 7d16b704b527e3e0b2b1e9f998cca03e6a473cff Mon Sep 17 00:00:00 2001
From: Emmanuel Benoit <tseeker@nocternity.net>
Date: Sat, 30 Sep 2017 12:08:18 +0200
Subject: [PATCH] Better abstraction for shader programs

---
 .vim.local/scripts/vimmake.test |  2 +-
 main.cc                         | 46 +++++----------------
 map.glsl                        |  4 +-
 utilities.cc                    | 71 +++++++++++++++++++++++++++++++++
 utilities.hh                    | 29 ++++++++++++++
 5 files changed, 115 insertions(+), 37 deletions(-)

diff --git a/.vim.local/scripts/vimmake.test b/.vim.local/scripts/vimmake.test
index 749a225..e41a604 100755
--- a/.vim.local/scripts/vimmake.test
+++ b/.vim.local/scripts/vimmake.test
@@ -1,4 +1,4 @@
 #!/bin/bash
 if make -j 8; then
-	./editor tests/test.json
+	optirun ./demo
 fi
diff --git a/main.cc b/main.cc
index 99ca730..aa148fe 100644
--- a/main.cc
+++ b/main.cc
@@ -26,23 +26,19 @@ struct T_Main
 	T_Camera camera;
 
 	T_FilesWatcher watcher;
-	T_WatchedFiles shaderFiles;
-	GLuint prog;
+	std::unique_ptr< T_ShaderProgram > program;
 
 	void startIteration( );
 	void handleCapture( );
 	void makeUI( );
 	void render( );
 
-	void loadProgram( );
+	void initProgram( );
 };
 
 /*----------------------------------------------------------------------------*/
 
 T_Main::T_Main( )
-	: shaderFiles( watcher , [this] {
-			this->loadProgram( );
-		} )
 {
 	SDL_Init( SDL_INIT_VIDEO | SDL_INIT_TIMER );
 
@@ -62,7 +58,7 @@ T_Main::T_Main( )
 	glewInit();
 	ImGui_ImplSdl_Init( window );
 
-	loadProgram( );
+	initProgram( );
 }
 
 void T_Main::mainLoop( )
@@ -157,9 +153,7 @@ void T_Main::render( )
 
 	// FIXME draw the fuck
 	//project->render( );
-	if ( prog != 0 ) {
-		glUseProgram( prog );
-
+	if ( program->activate( ) ) {
 		enum {
 			U_TIME			= 0 ,
 			U_RESOLUTION		= 1 ,
@@ -192,32 +186,14 @@ void T_Main::render( )
 }
 
 
-void T_Main::loadProgram( )
+void T_Main::initProgram( )
 {
-	std::vector< std::string > errors;
-
-	if ( prog != 0 ) {
-		glDeleteProgram( prog );
-		prog = 0;
-	}
-
-	shaderFiles.clear( );
-	shaderFiles.watch( "raymarch-header.glsl" );
-	shaderFiles.watch( "map.glsl" );
-	shaderFiles.watch( "raymarcher.glsl" );
-
-	T_ShaderCode shader( 3 );
-	shader.loadPart( 0 , "raymarch-header.glsl" , errors );
-	shader.loadPart( 1 , "map.glsl" , errors );
-	shader.loadPart( 2 , "raymarcher.glsl" , errors );
-
-	prog = shader.createProgram( GL_FRAGMENT_SHADER , errors );
-
-	if ( errors.size( ) != 0 ) {
-		for ( auto const& str : errors ) {
-			printf( "ERR: %s\n" , str.c_str( ) );
-		}
-	}
+	program = std::make_unique< T_ShaderProgram >(
+			GL_FRAGMENT_SHADER , watcher );
+	program->addFile( "raymarch-header.glsl" );
+	program->addFile( "map.glsl" );
+	program->addFile( "raymarcher.glsl" );
+	program->load( );
 }
 
 
diff --git a/map.glsl b/map.glsl
index a62fc36..3aec80b 100644
--- a/map.glsl
+++ b/map.glsl
@@ -1,4 +1,6 @@
 vec2 map( vec3 pos )
 {
-	return vec2( length( pos ) - 1. , 0. );
+	vec3 q = pos;
+	q.xy = mod( q.xy + 2. , 4. ) - 2.;
+	return vec2( length( q ) - 2.1 , 0. );
 }
diff --git a/utilities.cc b/utilities.cc
index 429ebd6..ffd3c23 100644
--- a/utilities.cc
+++ b/utilities.cc
@@ -297,6 +297,77 @@ GLuint T_ShaderCode::createProgram(
 }
 
 
+/*= T_ShaderProgram ==========================================================*/
+
+T_ShaderProgram::T_ShaderProgram(
+		__rd__ const GLenum programType ,
+		__rw__ T_FilesWatcher& watcher )
+	: files_( watcher , [this] { load( ); } ) ,
+		programType_( programType ) , program_( 0 )
+{
+}
+
+T_ShaderProgram::~T_ShaderProgram( )
+{
+	if ( program_ != 0 ) {
+		glDeleteProgram( program_ );
+	}
+}
+
+void T_ShaderProgram::addChunk(
+		__rd__ std::string const& string )
+{
+	chunksOrFiles_.push_back( true );
+	parts_.push_back( string );
+}
+
+void T_ShaderProgram::addFile(
+		__rd__ std::string const& source )
+{
+	chunksOrFiles_.push_back( false );
+	parts_.push_back( source );
+}
+
+void T_ShaderProgram::load( )
+{
+	const auto n( parts_.size( ) );
+	errors_.clear( );
+	files_.clear( );
+	if ( program_ != 0 ) {
+		glDeleteProgram( program_ );
+		program_ = 0;
+	}
+
+	T_ShaderCode sc( n );
+	for ( auto i = 0u ; i < n ; i ++ ) {
+		if ( chunksOrFiles_[ i ] ) {
+			sc.setPart( i , parts_[ i ].c_str( ) );
+		} else if ( sc.loadPart( i , parts_[ i ].c_str( ) , errors_ ) ) {
+			files_.watch( parts_[ i ] );
+		}
+	}
+
+	if ( errors_.size( ) == 0 ) {
+		program_ = sc.createProgram( programType_ , errors_ );
+	}
+
+	if ( errors_.size( ) ) {
+		printf( "\n--------------------------------------------------------------------------------\n\n" );
+		for ( auto const& str : errors_ ) {
+			printf( "ERR: %s\n" , str.c_str( ) );
+		}
+	}
+}
+
+bool T_ShaderProgram::activate( ) const
+{
+	if ( program_ != 0 ) {
+		glUseProgram( program_ );
+	}
+	return program_ != 0;
+}
+
+
 /*= T_Camera =================================================================*/
 
 void T_Camera::handleDND(
diff --git a/utilities.hh b/utilities.hh
index b1d8f7e..89523a6 100644
--- a/utilities.hh
+++ b/utilities.hh
@@ -126,6 +126,35 @@ struct T_ShaderCode
 	std::vector< char* > code;
 };
 
+struct T_ShaderProgram
+{
+	T_ShaderProgram( ) = delete;
+	T_ShaderProgram( T_ShaderProgram const& ) = delete;
+	T_ShaderProgram( T_ShaderProgram&& ) = delete;
+
+	T_ShaderProgram(
+			__rd__ GLenum programType ,
+			__rw__ T_FilesWatcher& watcher );
+	~T_ShaderProgram( );
+
+	void addChunk( __rd__ std::string const& string );
+	void addFile( __rd__ std::string const& source );
+
+	void load( );
+	bool activate( ) const;
+
+    private:
+	T_WatchedFiles files_;
+
+	std::vector< bool > chunksOrFiles_;
+	std::vector< std::string > parts_;
+
+	std::vector< std::string > errors_;
+
+	GLenum programType_;
+	GLuint program_;
+};
+
 
 /*= T_Camera =================================================================*/