Render-fucking-targets, motherfuckers!

Makefile

@@ -11,7 +11,8 @@ DEMO = \
 	 main.o \
 	 imgui_impl_sdl.o \
 	 utilities.o \
-	 texture.o
+	 texture.o \
+	 rendertarget.o
 
 DEMO_DEPS = $(DEMO:%.o=.%.d)
 

copy.glsl

@@ -0,0 +1,13 @@
+#version 450 core
+
+layout( location = 0 ) uniform sampler2D u_InputTexture;
+
+layout( location = 0 ) out vec4 color;
+
+void main( void )
+{
+	vec2 tmp = gl_FragCoord.xy / vec2( 1280. , 720. );
+	color = textureLod( u_InputTexture , tmp , 0 );
+	//color.xy *= .75 + tmp * .25;
+}
+

main.cc

@@ -3,6 +3,7 @@
 #include "imgui_impl_sdl.h"
 #include "utilities.hh"
 #include "texture.hh"
+#include "rendertarget.hh"
 
 
 /*= T_Main ===================================================================*/
@@ -27,7 +28,11 @@ struct T_Main
 	T_Camera camera;
 
 	T_FilesWatcher watcher;
-	std::unique_ptr< T_ShaderProgram > program;
+	std::unique_ptr< T_ShaderProgram > spRaymarch;
+	std::unique_ptr< T_ShaderProgram > spCopy;
+
+	std::unique_ptr< T_Texture > txRaymarchOutput;
+	std::unique_ptr< T_Rendertarget > rtRaymarchOutput;
 
 	void startIteration( );
 	void handleCapture( );
@@ -60,8 +65,10 @@ T_Main::T_Main( )
 	ImGui_ImplSdl_Init( window );
 
 	initProgram( );
-
-	//T_Texture textureTest( 512 , 512 , E_TexType::R8 );
+	txRaymarchOutput = std::make_unique< T_Texture >(
+			1280 , 720 , E_TexType::RGBA8 );
+	rtRaymarchOutput = std::make_unique < T_Rendertarget >(
+			T_RendertargetSetup( ).add( *txRaymarchOutput ).create( ) );
 }
 
 void T_Main::mainLoop( )
@@ -158,12 +165,9 @@ void T_Main::makeUI( )
 
 void T_Main::render( )
 {
-	auto const& dspSize( ImGui::GetIO( ).DisplaySize );
-	glViewport( 0 , 0 , (int) dspSize.x, (int) dspSize.y );
-	glClearColor( 1 , 0 , 1 , 1 );
+	if ( spRaymarch->activate( ) && rtRaymarchOutput->activate( ) ) {
+		glClearColor( 0 , 1 , 1 , 1 );
 		glClear( GL_COLOR_BUFFER_BIT );
-
-	if ( program->activate( ) ) {
 		enum {
 			U_TIME			= 0 ,
 			U_RESOLUTION		= 1 ,
@@ -190,6 +194,17 @@ void T_Main::render( )
 		glRectf( -1, -1 , 1 , 1 );
 	}
 
+	T_Rendertarget::MainOutput( );
+	glClearColor( 1 , 0 , 1 , 1 );
+	glClear( GL_COLOR_BUFFER_BIT );
+	if ( spCopy->activate( ) ) {
+		T_TextureBinding tb( 0 );
+		tb.set( 0 , *txRaymarchOutput );
+		tb.bind( );
+		glRectf( -1, -1 , 1 , 1 );
+		glBindTexture( GL_TEXTURE_2D , 0 );
+	}
+
 	glUseProgram( 0 );
 	ImGui::Render( );
 	SDL_GL_SwapWindow( window );
@@ -198,12 +213,17 @@ void T_Main::render( )
 
 void T_Main::initProgram( )
 {
-	program = std::make_unique< T_ShaderProgram >(
+	spRaymarch = std::make_unique< T_ShaderProgram >(
 			GL_FRAGMENT_SHADER , watcher );
-	program->addFile( "raymarch-header.glsl" );
-	program->addFile( "map.glsl" );
-	program->addFile( "raymarcher.glsl" );
-	program->load( );
+	spRaymarch->addFile( "raymarch-header.glsl" );
+	spRaymarch->addFile( "map.glsl" );
+	spRaymarch->addFile( "raymarcher.glsl" );
+	spRaymarch->load( );
+
+	spCopy = std::make_unique< T_ShaderProgram >( GL_FRAGMENT_SHADER ,
+			watcher );
+	spCopy->addFile( "copy.glsl" );
+	spCopy->load( );
 }
 
 

rendertarget.cc

@@ -0,0 +1,146 @@
+#include "externals.hh"
+#include "texture.hh"
+#include "rendertarget.hh"
+
+
+T_RendertargetSetup::T_RendertargetSetup( )
+	: hasAttachments_( false )
+{ }
+
+T_RendertargetSetup& T_RendertargetSetup::add(
+		__rw__ T_Texture& texture ,
+		__rd__ const uint32_t level )
+{
+	checkAttachment( texture , level );
+	colorAttachments_.push_back( T_Attachment_{ texture , level } );
+	return *this;
+}
+
+
+T_RendertargetSetup& T_RendertargetSetup::depth(
+		__rw__ T_Texture& texture )
+{
+	assert( !depthAttachment_ );
+	checkAttachment( texture , 0 );
+	depthAttachment_ = std::make_unique< T_Attachment_ >( texture , 0 );
+	return *this;
+}
+
+
+void T_RendertargetSetup::checkAttachment(
+		__rw__ T_Texture const& texture ,
+		__rd__ const uint32_t level )
+{
+	const uint32_t tw( texture.width( ) >> level ) ,
+			th( texture.height( ) >> level );
+	if ( hasAttachments_ ) {
+		assert( tw == width_ );
+		assert( th == height_ );
+	} else {
+		width_ = tw;
+		height_ = th;
+		hasAttachments_ = true;
+	}
+}
+
+
+T_Rendertarget T_RendertargetSetup::create( )
+{
+	const auto nca( colorAttachments_.size( ) );
+	assert( hasAttachments_ );
+	assert( nca != 0 );
+
+	// Generate / setup the GL framebuffer
+	GLuint id( 0 );
+	glGenFramebuffers( 1 , &id );
+	glBindFramebuffer( GL_FRAMEBUFFER , id );
+	for ( auto i = 0u ; i < nca ; i ++ ) {
+		glFramebufferTexture( GL_FRAMEBUFFER ,
+				GL_COLOR_ATTACHMENT0 + i ,
+				colorAttachments_[ i ].texture->id( ) ,
+				colorAttachments_[ i ].level );
+	}
+	if ( depthAttachment_ ) {
+		glFramebufferTexture( GL_FRAMEBUFFER ,
+				GL_DEPTH_ATTACHMENT ,
+				depthAttachment_->texture->id( ) ,
+				depthAttachment_->level );
+	}
+	assert( glCheckFramebufferStatus( GL_FRAMEBUFFER ) == GL_FRAMEBUFFER_COMPLETE );
+	glBindFramebuffer( GL_FRAMEBUFFER , 0 );
+
+	assert( glGetError( ) == GL_NO_ERROR );
+
+	// Reset config
+	hasAttachments_ = false;
+	colorAttachments_.clear( );
+	depthAttachment_.reset( );
+
+	return T_Rendertarget( id , nca , width_ , height_ );
+}
+
+/*============================================================================*/
+
+T_Rendertarget::T_Rendertarget(
+		__rd__ const uint32_t id ,
+		__rd__ const uint32_t nCats ,
+		__rd__ const uint32_t width ,
+		__rd__ const uint32_t height )
+	: id_( id ) , nCats_( nCats ) , width_( width ) , height_( height )
+{ }
+
+T_Rendertarget::T_Rendertarget(
+		__rw__ T_Rendertarget&& other ) noexcept
+	: id_( 0 ) , nCats_( other.nCats_ ) , width_( other.width_ ) ,
+		height_( other.height_ )
+{
+	std::swap( id_ , other.id_ );
+}
+
+T_Rendertarget& T_Rendertarget::operator =(
+		__rw__ T_Rendertarget&& other ) noexcept
+{
+	std::swap( id_ , other.id_ );
+	std::swap( nCats_ , other.nCats_ );
+	std::swap( width_ , other.width_ );
+	std::swap( height_ , other.height_ );
+	return *this;
+}
+
+T_Rendertarget::~T_Rendertarget( )
+{
+	if ( id_ != 0 ) {
+		glDeleteFramebuffers( 1 , &id_ );
+	}
+}
+
+bool T_Rendertarget::activate( )
+{
+	if ( id_ != 0 ) {
+#ifdef INTRUSIVE_TRACES
+		printf( "ACTIVATING FB %d (%dx%d, %d c.a.)\n" ,
+				id_ , width_ , height_ , nCats_ );
+#endif
+		if ( nCats_ != buffers_.size( ) ) {
+			buffers_.clear( );
+			for ( auto i = 0u ; i < nCats_ ; i ++ ) {
+				buffers_.push_back( GL_COLOR_ATTACHMENT0 + i );
+			}
+		}
+		glBindFramebuffer( GL_FRAMEBUFFER , id_ );
+		glViewport( 0 , 0 , width_ , height_ );
+		glDrawBuffers( nCats_ , &buffers_[ 0 ] );
+
+		assert( glCheckFramebufferStatus( GL_FRAMEBUFFER )
+				== GL_FRAMEBUFFER_COMPLETE );
+		assert( glGetError( ) == GL_NO_ERROR );
+	}
+	return id_ != 0;
+}
+
+void T_Rendertarget::MainOutput( )
+{
+	auto const& dspSize( ImGui::GetIO( ).DisplaySize );
+	glBindFramebuffer( GL_FRAMEBUFFER , 0 );
+	glViewport( 0 , 0 , (int) dspSize.x, (int) dspSize.y );
+}

rendertarget.hh

@@ -0,0 +1,69 @@
+#pragma once
+#ifndef REAL_BUILD
+# include "externals.hh"
+# include "texture.hh"
+#endif
+
+struct T_Rendertarget;
+
+struct T_RendertargetSetup
+{
+	T_RendertargetSetup( );
+
+	T_RendertargetSetup& add(
+			__rw__ T_Texture& texture ,
+			__rd__ const uint32_t level = 0 );
+	T_RendertargetSetup& depth(
+			__rw__ T_Texture& texture );
+
+	T_Rendertarget create( );
+
+    private:
+	struct T_Attachment_ {
+		T_Texture* texture;
+		uint32_t level;
+
+		T_Attachment_(
+				__rw__ T_Texture& texture ,
+				__rd__ const uint32_t level )
+			: texture( &texture ) , level( level )
+		{}
+	};
+
+	void checkAttachment(
+			__rw__ T_Texture const& texture ,
+			__rd__ const uint32_t level );
+
+	bool hasAttachments_;
+	uint32_t width_ , height_;
+	std::vector< T_Attachment_ > colorAttachments_;
+	std::unique_ptr< T_Attachment_ > depthAttachment_;
+};
+
+
+struct T_Rendertarget
+{
+	T_Rendertarget( ) = delete;
+	T_Rendertarget( T_Rendertarget const& ) = delete;
+
+	T_Rendertarget(
+			__rd__ const GLuint id ,
+			__rd__ const uint32_t nCats ,
+			__rd__ const uint32_t width ,
+			__rd__ const uint32_t height );
+
+	T_Rendertarget( __rw__ T_Rendertarget&& other ) noexcept;
+	T_Rendertarget& operator =(
+			__rw__ T_Rendertarget&& ) noexcept;
+
+	~T_Rendertarget( );
+
+	bool activate( );
+
+	static void MainOutput( );
+
+    private:
+	GLuint id_;
+	uint32_t nCats_ , width_ , height_;
+	std::vector< GLenum > buffers_;
+};