Unfinished integration of multi-process approach

9 files changed, 445 insertions, 221 deletions

diff --git a/Makefile b/Makefile
index 41a09e5..5b0297c 100644
--- a/Makefile
+++ b/Makefile
@@ -8,7 +8,7 @@ server: demoscene-eo
 
 demoscene-eo: src/main.c src/main.h $(wildcard src/scene*.[ch]) Makefile
 	pkg-config --libs --cflags $(PKGLIBS)
-	gcc $(CFLAGS) `pkg-config --libs --cflags $(PKGLIBS)` src/main.c $(wildcard src/scene*.c) -o $@
+	gcc $(CFLAGS) `pkg-config --libs --cflags $(PKGLIBS)` src/main.c $(wildcard src/scene*.c) -pthread -o $@
 
 clean:
 	rm -f demoscene-eo
diff --git a/src/main.c b/src/main.c
index 3f18052..94d6195 100644
--- a/src/main.c
+++ b/src/main.c
@@ -18,127 +18,178 @@
  *  along with demoscene-eo.  If not, see <http://www.gnu.org/licenses/>
  */
 #include "main.h"
-#include "scene00.h"
-#include "scene01.h"
-#include "scene02.h"
+
+#include <stdlib.h>    // calloc()
+#include <strings.h>   // bzero()
+#include <sys/mman.h>  // mmap()
+#include <semaphore.h> // sem_t, sem_init(), Link with -pthread
+#include <unistd.h>    // fork()
+#include <sys/wait.h>  // wait()
+#include <errno.h>     // errno
+#include <stdint.h>    // uint32_t
+#include <stdio.h>     // printf()
+
+#define TRACE(hint) printf("%s(): %s\n", __func__, hint)
 #define SCENE_COUNT 3
-#define SCENE_NEXT do { scene = (scene+1)%SCENE_COUNT; } while(0)
+#define SCENE_NEXT do { shm->scene = (shm->scene+1)%SCENE_COUNT; } while(0)
 
-#define EXPR_MIN_SIZE ( ge.w<80 || ge.h<25 )
+#define EXPR_MIN_SIZE ( shm->ge.w<80 || shm->ge.h<25 )
 #define TEXT_MIN_SIZE "80x25"
 
-int main(void)
-{
-	int done=0, lastscene=-1, scene=0, paused=0, res;
-	Uint32 sdl_win_flags = SDL_WINDOW_OPENGL;
+#define SEM_POST(sem,errcode) \
+	do { \
+		printf("%s(): sem_post(%s,%i) call\n", __func__, #sem, errcode);\
+		if ( sem_post(sem) == -1 ) { return errcode; } \
+		printf("%s(): sem_post(%s,%i) done\n", __func__, #sem, errcode);\
+	} while(0)
+
+#define SEM_WAIT(sem,errcode) \
+	do { \
+		printf("%s(): sem_wait(%s,%i) call\n", __func__, #sem, errcode);\
+		while ( sem_wait(&shm->parent_can_read_result) == -1 ) { \
+			switch(errno) { \
+				case EINTR: \
+				case EAGAIN: \
+					break; \
+				default: \
+					return errcode; \
+			} \
+		} \
+		printf("%s(): sem_wait(%s,%i) done\n", __func__, #sem, errcode);\
+	} while(0)
+
+typedef struct {
+	sem_t worker_gl_can_render, worker_sdl_can_render, parent_can_read_result;
+	int scene, paused, done;
 	graphical_env_t ge;
 	scene00_env_t s00e;
 	scene01_env_t s01e;
 	scene02_env_t s02e;
+} shm_t;
 
-	caca_event_t caca_ev;
-	SDL_RendererInfo renderer_info;
-	SDL_Event sdl_ev;
+int do_fork1();
+int do_fork2();
+int parent();
+int worker_sdl();
+int worker_gl();
 
-	// Initialize libcaca (http://caca.zoy.org/doxygen/libcaca/caca_8h.html)
-	ge.dp = caca_create_display(NULL);
-	if(!ge.dp) return 1;
-	caca_set_display_title(ge.dp, "demoscene-eo");
-	caca_set_display_time(ge.dp, 16666); // 1e6µs/60 = 16666.66... It is ~60 fps
-	ge.cv = caca_get_canvas(ge.dp);
+shm_t *shm;
 
-	ge.d = caca_create_dither(32, 256, 256, 256*4, 0x00ff0000, 0x0000ff00, 0x000000ff, 0);
-	if ( !ge.d ) return 2;
-	caca_set_dither_color(ge.d, "16");
+int main() {
+	TRACE("call");
+	shm = mmap(NULL, sizeof(shm_t), PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANONYMOUS, 0, 0);
+	if ( shm == NULL ) return 1;
+	bzero(shm, sizeof(shm_t));
 
-	// Initialize SDL (http://wiki.libsdl.org/SDL_CreateWindowAndRenderer)
-	// Useful snippet : https://gist.github.com/koute/7391344
-	res = SDL_Init(SDL_INIT_VIDEO);
-	if ( res == -1) return 3;
-	SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
-	SDL_GL_SetAttribute( SDL_GL_ACCELERATED_VISUAL, 1 );
-	SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 8 );
-	SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 8 );
-	SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 8 );
-	SDL_GL_SetAttribute( SDL_GL_ALPHA_SIZE, 8 );
-	SDL_GL_SetAttribute( SDL_GL_CONTEXT_MAJOR_VERSION, 3 );
-	SDL_GL_SetAttribute( SDL_GL_CONTEXT_MINOR_VERSION, 2 );
-	SDL_GL_SetAttribute( SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE );	
+	if (sem_init(&shm->worker_gl_can_render, 1, 0) < 0) return 2;
+	if (sem_init(&shm->worker_sdl_can_render, 1, 0) < 0) return 3;
+	if (sem_init(&shm->parent_can_read_result, 1, 0) < 0) return 4;
 
-	//XXX for final version, consider sdl_win_flags |= SDL_WINDOW_HIDDEN;
-	res = SDL_CreateWindowAndRenderer(256, 256, sdl_win_flags, &ge.sdl_win, &ge.sdl_rndr);
-	if ( res == -1) return 4;
-	SDL_SetWindowTitle(ge.sdl_win, "SDL/GL debug");
-	res = SDL_GetRendererInfo(ge.sdl_rndr, &renderer_info);
-	if ( res < 0 ) return 5;
-	if ( !(renderer_info.flags & SDL_RENDERER_ACCELERATED)) return 6;
-	if ( !(renderer_info.flags & SDL_RENDERER_TARGETTEXTURE)) return 7;
-	ge.sdl_target = SDL_CreateTexture(ge.sdl_rndr, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, 256, 256);
-	if ( ge.sdl_target == NULL ) return 9;
-	ge.raw_target = malloc(256*256*4);
-	if ( ge.raw_target == NULL ) return 10;
+	shm->ge.raw_target = calloc(FBUF_W*FBUF_H, sizeof(uint32_t));
+	if ( shm->ge.raw_target == NULL ) return 5;
 
-	// Initialize OpenGL
-	ge.gl_ctx = SDL_GL_CreateContext(ge.sdl_win);
-	if ( ge.gl_ctx == NULL ) return 11;
+	return do_fork1();
+}
 
-	// Main libcaca loop for caca window (OpenGL could be used in sceneN_next())
-	ge.framecount=0;
+int do_fork1() {
+	TRACE("call");
+	switch (fork()) {
+		case -1: return 4; break;
+		case 0:  return worker_sdl(); break;
+		default: return do_fork2(); break;
+	}
+}
+
+int do_fork2() {
+	TRACE("call");
+	switch (fork()) {
+		case -1: return 5; break;
+		case 0:  return worker_gl(); break;
+		default: return parent(); break;
+	}
+}
+
+int parent() {
+	int lastscene=-1, res, child_status;
+	caca_event_t caca_ev;
+
+	TRACE("call");
+
+	// Initialize libcaca (http://caca.zoy.org/doxygen/libcaca/caca_8h.html)
+	shm->ge.dp = caca_create_display(NULL);
+	if(!shm->ge.dp) return 1;
+	caca_set_display_title(shm->ge.dp, "demoscene-eo");
+	caca_set_display_time(shm->ge.dp, 16666); // 1e6µs/60 = 16666.66... It is ~60 fps
+	shm->ge.cv = caca_get_canvas(shm->ge.dp);
+
+	shm->ge.d = caca_create_dither(32, FBUF_W, FBUF_H, FBUF_W*4, 0x00ff0000, 0x0000ff00, 0x000000ff, 0);
+	if ( !shm->ge.d ) return 2;
+	caca_set_dither_color(shm->ge.d, "16");
+
+	// Main libcaca loop for caca window
+	shm->ge.framecount=0;
 	do {
 		// Check canvas size at every frame because of unreliable CACA_EVENT_RESIZE
-		ge.w = caca_get_canvas_width(ge.cv);
-		ge.h = caca_get_canvas_height(ge.cv);
+		shm->ge.w = caca_get_canvas_width(shm->ge.cv);
+		shm->ge.h = caca_get_canvas_height(shm->ge.cv);
 		if ( EXPR_MIN_SIZE ) {
-			caca_set_color_ansi(ge.cv, CACA_BLACK, CACA_WHITE);
-			caca_put_str(ge.cv, 0, 0, "Need a minimum of " TEXT_MIN_SIZE " terminal");
-		} else if (!paused) {
+			caca_set_color_ansi(shm->ge.cv, CACA_BLACK, CACA_WHITE);
+			caca_put_str(shm->ge.cv, 0, 0, "Need a minimum of " TEXT_MIN_SIZE " terminal");
+		} else if (!shm->paused) {
 			// init / free if scene transition
-			if ( lastscene != scene ) {
+			if ( lastscene != shm->scene ) {
 				switch(lastscene) {
-					case 0: scene00_free(&ge, &s00e); break;
-					case 1: scene01_free(&ge, &s01e); break;
-					case 2: scene02_free(&ge, &s02e); break;
+					case 0: scene00_free(&shm->ge, &shm->s00e); break;
+					case 1: scene01_free(&shm->ge, &shm->s01e); break;
+					case 2: scene02_free(&shm->ge, &shm->s02e); break;
 				}
 			}
-			while ( lastscene != scene ) {
-				ge.sdl_ticks = SDL_GetTicks();
-				ge.sc_framecount = 0;
-				switch(scene) {
-					case 0: res = scene00_init(&ge, &s00e); break;
-					case 1: res = scene01_init(&ge, &s01e); break;
-					case 2: res = scene02_init(&ge, &s02e); break;
+			while ( lastscene != shm->scene ) {
+				shm->ge.sdl_ticks = SDL_GetTicks();
+				shm->ge.sc_framecount = 0;
+				switch(shm->scene) {
+					case 0: res = scene00_init(&shm->ge, &shm->s00e); break;
+					case 1: res = scene01_init(&shm->ge, &shm->s01e); break;
+					case 2: res = scene02_init(&shm->ge, &shm->s02e); break;
 				}
 				// If scene init fail, skip to the next one
-				if (res) SCENE_NEXT; else lastscene = scene;
+				if (res) SCENE_NEXT; else lastscene = shm->scene;
 			}
-			// Compute current scene0 frame
-			ge.sdl_ticks = SDL_GetTicks(); // This value wraps if the program runs for more than ~49 days
-			switch(scene) {
-				case 0: res = scene00_next(&ge, &s00e); break;
-				case 1: res = scene01_next(&ge, &s01e); break;
-				case 2: res = scene02_next(&ge, &s02e); break;
+			shm->ge.sdl_ticks = SDL_GetTicks(); // This value wraps if the program runs for more than ~49 days
+
+			SEM_POST(&shm->worker_gl_can_render,30);
+			SEM_WAIT(&shm->parent_can_read_result,31);
+
+			SEM_POST(&shm->worker_sdl_can_render,32);
+			SEM_WAIT(&shm->parent_can_read_result,33);
+
+			// Compute current scene frame (caca part)
+			switch(shm->scene) {
+				case 0: res = scene00_next_caca(&shm->ge, &shm->s00e); break;
+				case 1: res = scene01_next_caca(&shm->ge, &shm->s01e); break;
+				case 2: res = scene02_next_caca(&shm->ge, &shm->s02e); break;
 			}
 			if (res) SCENE_NEXT;
-			ge.framecount++;
-			ge.sc_framecount++;
+			shm->ge.framecount++;
+			shm->ge.sc_framecount++;
 		}
 		// Display it
-		caca_refresh_display(ge.dp); // Auto framerate limiting (see caca_set_display_time())
+		caca_refresh_display(shm->ge.dp); // Auto framerate limiting (see caca_set_display_time())
 
 		// Event handling for the libcaca "window" (depending on CACA_DRIVER env variable)
-		if ( caca_get_event(ge.dp, CACA_EVENT_KEY_PRESS|CACA_EVENT_RESIZE|CACA_EVENT_QUIT, &caca_ev, 0) ) {
+		if ( caca_get_event(shm->ge.dp, CACA_EVENT_KEY_PRESS|CACA_EVENT_RESIZE|CACA_EVENT_QUIT, &caca_ev, 0) ) {
 			switch(caca_get_event_type(&caca_ev)) {
 					case CACA_EVENT_QUIT:
-						done = 1;
+						shm->done = 1;
 						break;
 					case CACA_EVENT_KEY_PRESS:
 						switch(caca_get_event_key_ch(&caca_ev)) {
-							case 'q': done = 1; break;
-							case 'p': paused = !paused; break;
+							case 'q': shm->done = 1; break;
+							case 'p': shm->paused = !shm->paused; break;
 							case CACA_KEY_ESCAPE: SCENE_NEXT; break;
 						}
 						break;
-						/* On Debian 10, no CACA_EVENT_RESIZE when using x11 CACA_DRIVER
+						/* On Debian 10, no CACA_EVENT_RESIZE fired when using x11 CACA_DRIVER
 					case CACA_EVENT_RESIZE:
 						w = caca_get_event_resize_width(&caca_ev);
 						h = caca_get_event_resize_height(&caca_ev);
@@ -149,16 +200,68 @@ int main(void)
 						break;
 			}
 		}
-		// Event handling for the SDL/GL window (debug purposes)
+	} while(!shm->done);
+
+	caca_free_dither(shm->ge.d);
+	caca_free_display(shm->ge.dp);
+	shm->ge.cv=NULL;
+
+	// reap forked processes (order doesn't matter)
+	if ( wait(&child_status) != -1 ) {
+		if ( child_status > 0 ) return child_status;
+	}
+	if ( wait(&child_status) != -1 ) {
+		if ( child_status > 0 ) return child_status;
+	}
+	return 0;
+}
+
+int worker_sdl() {
+	int res;
+	Uint32 sdl_win_flags = 0; //XXX for final version, consider sdl_win_flags = SDL_WINDOW_HIDDEN;
+	SDL_RendererInfo renderer_info;
+	SDL_Event sdl_ev;
+
+	TRACE("call");
+
+	// Initialize SDL (http://wiki.libsdl.org/SDL_CreateWindowAndRenderer)
+	// Useful snippet : https://gist.github.com/koute/7391344
+	res = SDL_Init(SDL_INIT_VIDEO);
+	if ( res == -1) return 3;
+	atexit(SDL_Quit);
+
+	res = SDL_CreateWindowAndRenderer(FBUF_W, FBUF_H, sdl_win_flags, &shm->ge.sdl_win, &shm->ge.sdl_rndr);
+	if ( res == -1) return 4;
+	SDL_SetWindowTitle(shm->ge.sdl_win, "SDL debug");
+	res = SDL_GetRendererInfo(shm->ge.sdl_rndr, &renderer_info);
+	if ( res < 0 ) return 5;
+	if ( !(renderer_info.flags & SDL_RENDERER_ACCELERATED)) return 6;
+	if ( !(renderer_info.flags & SDL_RENDERER_TARGETTEXTURE)) return 7;
+	shm->ge.sdl_target = SDL_CreateTexture(shm->ge.sdl_rndr, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, FBUF_W, FBUF_H);
+	if ( shm->ge.sdl_target == NULL ) return 9;
+
+	while ( !shm->done ) {
+		//FIXME change for TRYWAIT for event handling (+delay)
+		SEM_WAIT(&shm->worker_sdl_can_render,20);
+
+		// Compute current scene frame (sdl part)
+		switch(shm->scene) {
+			case 0: res = scene00_next_sdl(&shm->ge, &shm->s00e); break;
+			case 1: res = scene01_next_sdl(&shm->ge, &shm->s01e); break;
+			case 2: res = scene02_next_sdl(&shm->ge, &shm->s02e); break;
+		}
+		if (res) SCENE_NEXT;
+
+		// Event handling for the SDL window (debug purposes)
 		while(SDL_PollEvent(&sdl_ev)) {
 			switch(sdl_ev.type) {
 				case SDL_QUIT:
-					done = 1;
+					shm->done = 1;
 					break;
 				case SDL_KEYDOWN:
 					switch(sdl_ev.key.keysym.sym) {
-						case SDLK_q: done = 1; break;
-						case SDLK_p: paused = !paused; break;
+						case SDLK_q: shm->done = 1; break;
+						case SDLK_p: shm->paused = !shm->paused; break;
 						case SDLK_ESCAPE: SCENE_NEXT; break;
 					}
 					break;
@@ -166,15 +269,82 @@ int main(void)
 					break;
 			}
 		}
-	} while(!done);
-
-	caca_free_dither(ge.d);
-	caca_free_display(ge.dp);
-	ge.cv=NULL;
-	SDL_GL_DeleteContext(ge.gl_ctx);
-	SDL_DestroyTexture(ge.sdl_target);
-	SDL_DestroyRenderer(ge.sdl_rndr);
-	SDL_DestroyWindow(ge.sdl_win);
-	SDL_Quit();
+
+		SEM_POST(&shm->parent_can_read_result, 21);
+	}
+
+	SDL_DestroyRenderer(shm->ge.sdl_rndr);
+	SDL_DestroyTexture(shm->ge.sdl_target);
+	SDL_DestroyWindow(shm->ge.sdl_win);
+
+	return 0;
+}
+
+int worker_gl() {
+	int res;
+	//Uint32 sdl_win_flags = SDL_WINDOW_OPENGL;
+	SDL_Event gl_ev;
+
+	TRACE("call");
+
+	// Initialize SDL (http://wiki.libsdl.org/SDL_CreateWindowAndRenderer)
+	// Useful snippet : https://gist.github.com/koute/7391344
+	res = SDL_Init(SDL_INIT_VIDEO);
+	if ( res == -1) return 3;
+	atexit(SDL_Quit);
+
+	SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
+	SDL_GL_SetAttribute( SDL_GL_ACCELERATED_VISUAL, 1 );
+	SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 8 );
+	SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 8 );
+	SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 8 );
+	SDL_GL_SetAttribute( SDL_GL_ALPHA_SIZE, 8 );
+	SDL_GL_SetAttribute( SDL_GL_CONTEXT_MAJOR_VERSION, 3 );
+	SDL_GL_SetAttribute( SDL_GL_CONTEXT_MINOR_VERSION, 2 );
+	SDL_GL_SetAttribute( SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE );
+
+	// Initialize OpenGL
+	shm->ge.gl_win = SDL_CreateWindow("GL Debug", 0, SDL_WINDOWPOS_CENTERED, FBUF_W, FBUF_H, SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN );
+	shm->ge.gl_ctx = SDL_GL_CreateContext(shm->ge.gl_win);
+	if ( shm->ge.gl_ctx == NULL ) return 11;
+
+	while ( !shm->done ) {
+		//FIXME change for TRYWAIT for event handling (+delay)
+		SEM_WAIT(&shm->worker_gl_can_render,10);
+
+		// Compute current scene frame (gl part)
+		switch(shm->scene) {
+			case 0: res = scene00_next_gl(&shm->ge, &shm->s00e); break;
+			case 1: res = scene01_next_gl(&shm->ge, &shm->s01e); break;
+			case 2: res = scene02_next_gl(&shm->ge, &shm->s02e); break;
+		}
+		if (res) SCENE_NEXT;
+
+
+		// Event handling for the GL window (debug purposes)
+		while(SDL_PollEvent(&gl_ev)) {
+			switch(gl_ev.type) {
+				case SDL_QUIT:
+					shm->done = 1;
+					break;
+				case SDL_KEYDOWN:
+					switch(gl_ev.key.keysym.sym) {
+						case SDLK_q: shm->done = 1; break;
+						case SDLK_p: shm->paused = !shm->paused; break;
+						case SDLK_ESCAPE: SCENE_NEXT; break;
+					}
+					break;
+				default:
+					break;
+			}
+		}
+
+		SEM_POST(&shm->parent_can_read_result, 11);
+	}
+
+	//SDL_DestroyTexture(shm->ge.gl_target);
+	SDL_GL_DeleteContext(shm->ge.gl_ctx);
+	SDL_DestroyWindow(shm->ge.gl_win);
+
 	return 0;
 }
diff --git a/src/main.h b/src/main.h
index 1ff41ec..907bc53 100644
--- a/src/main.h
+++ b/src/main.h
@@ -9,17 +9,30 @@
 #include <GL/glu.h>
 
 typedef struct {
+	// libcaca
 	caca_display_t *dp;
 	caca_canvas_t *cv;
    	caca_dither_t *d;
 	int w, h; // caca terminal size in characters
+	// SDL worker
 	SDL_Window* sdl_win;
 	SDL_Renderer *sdl_rndr;
 	SDL_Texture *sdl_target;
-	void *raw_target;
+	// OpenGL worker
+	SDL_Window* gl_win;
 	SDL_GLContext gl_ctx;
+	// framebuffer to inject OpenGL or SDL result in caca canvas
+	uint32_t *raw_target;
+	// Timing
 	Uint32 sdl_ticks;
 	Uint32 framecount;
 	Uint32 sc_framecount;
 } graphical_env_t;
+
+#define FBUF_W 256
+#define FBUF_H 256
+
+#include "scene00.h"
+#include "scene01.h"
+#include "scene02.h"
 #endif
diff --git a/src/scene00.c b/src/scene00.c
index 746db29..7bb1738 100644
--- a/src/scene00.c
+++ b/src/scene00.c
@@ -31,11 +31,14 @@ void scene00_free(graphical_env_t *ge, scene00_env_t *se) {
 	SDL_DestroyTexture(se->eo1); se->eo1=NULL;
 }
 
-int scene00_next(graphical_env_t *ge, scene00_env_t *se) {
+int scene00_next_gl(graphical_env_t *ge, scene00_env_t *se) {
+	return 0;
+}
+
+int scene00_next_sdl(graphical_env_t *ge, scene00_env_t *se) {
 	// Shorthands
 	caca_canvas_t *cv = ge->cv;
 	int w = ge->w, h = ge->h;
-	Uint32 frame = ge->sc_framecount;
 	SDL_Renderer *r = ge->sdl_rndr;
 	// Local vars
 	int res;
@@ -54,11 +57,21 @@ int scene00_next(graphical_env_t *ge, scene00_env_t *se) {
 	SDL_RenderPresent(r);
 	
 	// Download the rendered texture from videocard to main memory
+	SDL_SetRenderTarget(r, ge->sdl_target);
 	res = SDL_RenderReadPixels(r, NULL, 0, ge->raw_target, 256*4);
 
 	// "convert" the raw pixel stream to ASCII art on caca canevas
 	if ( res == 0 ) caca_dither_bitmap(cv, 0, 0, w, h, ge->d, ge->raw_target);
 
+	return 0;
+}
+
+int scene00_next_caca(graphical_env_t *ge, scene00_env_t *se) {
+	// Shorthands
+	caca_canvas_t *cv = ge->cv;
+	int w = ge->w, h = ge->h;
+	Uint32 frame = ge->sc_framecount;
+
 	// Add things on top of caca canvas
 	caca_set_color_ansi(cv, CACA_BLACK, CACA_WHITE);
 	caca_put_str(cv, (w-17)/2, h/2, "This is a message");
diff --git a/src/scene00.h b/src/scene00.h
index b1c9d9d..ec6eb9a 100644
--- a/src/scene00.h
+++ b/src/scene00.h
@@ -8,5 +8,7 @@ typedef struct {
 
 int scene00_init(graphical_env_t *ge, scene00_env_t *se);
 void scene00_free(graphical_env_t *ge, scene00_env_t *se);
-int scene00_next(graphical_env_t *ge, scene00_env_t *se);
+int scene00_next_gl(graphical_env_t *ge, scene00_env_t *se);
+int scene00_next_sdl(graphical_env_t *ge, scene00_env_t *se);
+int scene00_next_caca(graphical_env_t *ge, scene00_env_t *se);
 #endif
diff --git a/src/scene01.c b/src/scene01.c
index 80cbae2..b817e71 100644
--- a/src/scene01.c
+++ b/src/scene01.c
@@ -24,130 +24,129 @@ typedef float t_mat4x4[16];
 
 static inline void mat4x4_ortho( t_mat4x4 out, float left, float right, float bottom, float top, float znear, float zfar )
 {
-    #define T(a, b) (a * 4 + b)
+	#define T(a, b) (a * 4 + b)
 
-    out[T(0,0)] = 2.0f / (right - left);
-    out[T(0,1)] = 0.0f;
-    out[T(0,2)] = 0.0f;
-    out[T(0,3)] = 0.0f;
+	out[T(0,0)] = 2.0f / (right - left);
+	out[T(0,1)] = 0.0f;
+	out[T(0,2)] = 0.0f;
+	out[T(0,3)] = 0.0f;
 
-    out[T(1,1)] = 2.0f / (top - bottom);
-    out[T(1,0)] = 0.0f;
-    out[T(1,2)] = 0.0f;
-    out[T(1,3)] = 0.0f;
+	out[T(1,1)] = 2.0f / (top - bottom);
+	out[T(1,0)] = 0.0f;
+	out[T(1,2)] = 0.0f;
+	out[T(1,3)] = 0.0f;
 
-    out[T(2,2)] = -2.0f / (zfar - znear);
-    out[T(2,0)] = 0.0f;
-    out[T(2,1)] = 0.0f;
-    out[T(2,3)] = 0.0f;
+	out[T(2,2)] = -2.0f / (zfar - znear);
+	out[T(2,0)] = 0.0f;
+	out[T(2,1)] = 0.0f;
+	out[T(2,3)] = 0.0f;
 
-    out[T(3,0)] = -(right + left) / (right - left);
-    out[T(3,1)] = -(top + bottom) / (top - bottom);
-    out[T(3,2)] = -(zfar + znear) / (zfar - znear);
-    out[T(3,3)] = 1.0f;
+	out[T(3,0)] = -(right + left) / (right - left);
+	out[T(3,1)] = -(top + bottom) / (top - bottom);
+	out[T(3,2)] = -(zfar + znear) / (zfar - znear);
+	out[T(3,3)] = 1.0f;
 
-    #undef T
+	#undef T
 }
 
 static const char * vertex_shader =
-    "#version 130\n"
-    "in vec2 i_position;\n"
-    "in vec4 i_color;\n"
-    "out vec4 v_color;\n"
-    "uniform mat4 u_projection_matrix;\n"
-    "void main() {\n"
-    "    v_color = i_color;\n"
-    "    gl_Position = u_projection_matrix * vec4( i_position, 0.0, 1.0 );\n"
-    "}\n";
+	"#version 130\n"
+	"in vec2 i_position;\n"
+	"in vec4 i_color;\n"
+	"out vec4 v_color;\n"
+	"uniform mat4 u_projection_matrix;\n"
+	"void main() {\n"
+	"	v_color = i_color;\n"
+	"	gl_Position = u_projection_matrix * vec4( i_position, 0.0, 1.0 );\n"
+	"}\n";
 
 static const char * fragment_shader =
-    "#version 130\n"
-    "in vec4 v_color;\n"
-    "out vec4 o_color;\n"
-    "void main() {\n"
-    "    o_color = v_color;\n"
-    "}\n";
+	"#version 130\n"
+	"in vec4 v_color;\n"
+	"out vec4 o_color;\n"
+	"void main() {\n"
+	"	o_color = v_color;\n"
+	"}\n";
 
 typedef enum t_attrib_id
 {
-    attrib_position,
-    attrib_color
+	attrib_position,
+	attrib_color
 } t_attrib_id;
 
 int scene01_init(graphical_env_t *ge, scene01_env_t *se) {
-	int width = 256, height = 256;
-    GLuint vs, fs, program;
-
-    vs = glCreateShader( GL_VERTEX_SHADER );
-    fs = glCreateShader( GL_FRAGMENT_SHADER );
-
-    int length = strlen( vertex_shader );
-    glShaderSource( vs, 1, ( const GLchar ** )&vertex_shader, &length );
-    glCompileShader( vs );
-
-    GLint status;
-    glGetShaderiv( vs, GL_COMPILE_STATUS, &status );
-    if( status == GL_FALSE )
-    {
-        fprintf( stderr, "vertex shader compilation failed\n" );
-        return 1;
-    }
-
-    length = strlen( fragment_shader );
-    glShaderSource( fs, 1, ( const GLchar ** )&fragment_shader, &length );
-    glCompileShader( fs );
-
-    glGetShaderiv( fs, GL_COMPILE_STATUS, &status );
-    if( status == GL_FALSE )
-    {
-        fprintf( stderr, "fragment shader compilation failed\n" );
-        return 1;
-    }
-
-    program = glCreateProgram();
-    glAttachShader( program, vs );
-    glAttachShader( program, fs );
-
-    glBindAttribLocation( program, attrib_position, "i_position" );
-    glBindAttribLocation( program, attrib_color, "i_color" );
-    glLinkProgram( program );
-
-    glUseProgram( program );
-
-    glDisable( GL_DEPTH_TEST );
-    //glClearColor( 0.5, 0.0, 0.0, 0.0 );
-    glClearColor( 0.5, 0.5, 0.0, 0.0 );
-    glViewport( 0, 0, width, height );
-
-    GLuint vbo;
-
-    glGenVertexArrays( 1, &(se->vao) );
-    glGenBuffers( 1, &vbo );
-    glBindVertexArray( se->vao );
-    glBindBuffer( GL_ARRAY_BUFFER, vbo );
-
-    glEnableVertexAttribArray( attrib_position );
-    glEnableVertexAttribArray( attrib_color );
-
-    glVertexAttribPointer( attrib_color, 4, GL_FLOAT, GL_FALSE, sizeof( float ) * 6, 0 );
-    glVertexAttribPointer( attrib_position, 2, GL_FLOAT, GL_FALSE, sizeof( float ) * 6, ( void * )(4 * sizeof(float)) );
-
-    const GLfloat g_vertex_buffer_data[] = {
-    /*  R, G, B, A, X, Y  */
-        1, 0, 0, 1, 0, 0,
-        0, 1, 0, 1, width, 0,
-        0, 0, 1, 1, width, height,
-
-        1, 0, 0, 1, 0, 0,
-        0, 0, 1, 1, width, height,
-        1, 1, 1, 1, 0, height
-    };
-
-    glBufferData( GL_ARRAY_BUFFER, sizeof( g_vertex_buffer_data ), g_vertex_buffer_data, GL_STATIC_DRAW );
-
-    t_mat4x4 projection_matrix;
-    mat4x4_ortho( projection_matrix, 0.0f, (float)width, (float)height, 0.0f, 0.0f, 100.0f );
-    glUniformMatrix4fv( glGetUniformLocation( program, "u_projection_matrix" ), 1, GL_FALSE, projection_matrix );
+	GLuint vs, fs, program;
+
+	vs = glCreateShader( GL_VERTEX_SHADER );
+	fs = glCreateShader( GL_FRAGMENT_SHADER );
+
+	int length = strlen( vertex_shader );
+	glShaderSource( vs, 1, ( const GLchar ** )&vertex_shader, &length );
+	glCompileShader( vs );
+
+	GLint status;
+	glGetShaderiv( vs, GL_COMPILE_STATUS, &status );
+	if( status == GL_FALSE )
+	{
+		fprintf( stderr, "vertex shader compilation failed\n" );
+		return 1;
+	}
+
+	length = strlen( fragment_shader );
+	glShaderSource( fs, 1, ( const GLchar ** )&fragment_shader, &length );
+	glCompileShader( fs );
+
+	glGetShaderiv( fs, GL_COMPILE_STATUS, &status );
+	if( status == GL_FALSE )
+	{
+		fprintf( stderr, "fragment shader compilation failed\n" );
+		return 1;
+	}
+
+	program = glCreateProgram();
+	glAttachShader( program, vs );
+	glAttachShader( program, fs );
+
+	glBindAttribLocation( program, attrib_position, "i_position" );
+	glBindAttribLocation( program, attrib_color, "i_color" );
+	glLinkProgram( program );
+
+	glUseProgram( program );
+
+	glDisable( GL_DEPTH_TEST );
+	//glClearColor( 0.5, 0.0, 0.0, 0.0 );
+	glClearColor( 0.5, 0.5, 0.0, 0.0 );
+	glViewport( 0, 0, FBUF_W, FBUF_H );
+
+	GLuint vbo;
+
+	glGenVertexArrays( 1, &(se->vao) );
+	glGenBuffers( 1, &vbo );
+	glBindVertexArray( se->vao );
+	glBindBuffer( GL_ARRAY_BUFFER, vbo );
+
+	glEnableVertexAttribArray( attrib_position );
+	glEnableVertexAttribArray( attrib_color );
+
+	glVertexAttribPointer( attrib_color, 4, GL_FLOAT, GL_FALSE, sizeof( float ) * 6, 0 );
+	glVertexAttribPointer( attrib_position, 2, GL_FLOAT, GL_FALSE, sizeof( float ) * 6, ( void * )(4 * sizeof(float)) );
+
+	const GLfloat g_vertex_buffer_data[] = {
+	/*  R, G, B, A, X, Y  */
+		1, 0, 0, 1, 0, 0,
+		0, 1, 0, 1, FBUF_W, 0,
+		0, 0, 1, 1, FBUF_W, FBUF_H,
+
+		1, 0, 0, 1, 0, 0,
+		0, 0, 1, 1, FBUF_W, FBUF_H,
+		1, 1, 1, 1, 0, FBUF_H
+	};
+
+	glBufferData( GL_ARRAY_BUFFER, sizeof( g_vertex_buffer_data ), g_vertex_buffer_data, GL_STATIC_DRAW );
+
+	t_mat4x4 projection_matrix;
+	mat4x4_ortho( projection_matrix, 0.0f, (float)FBUF_W, (float)FBUF_H, 0.0f, 0.0f, 100.0f );
+	glUniformMatrix4fv( glGetUniformLocation( program, "u_projection_matrix" ), 1, GL_FALSE, projection_matrix );
 	return 0;
 }
 
@@ -155,35 +154,50 @@ void scene01_free(graphical_env_t *ge, scene01_env_t *se) {
 	//FIXME scene00 cannot be rendered coorectly after scene01_init done once
 }
 
-int scene01_next(graphical_env_t *ge, scene01_env_t *se) {
+int scene01_next_gl(graphical_env_t *ge, scene01_env_t *se) {
 	// Shorthands
 	caca_canvas_t *cv = ge->cv;
 	int w = ge->w, h = ge->h;
-	Uint32 frame = ge->sc_framecount;
 	SDL_Renderer *r = ge->sdl_rndr;
-	// Locals
+	// Local vars
 	int res;
 
+	// https://gist.github.com/Twinklebear/8265888
+	// https://forums.libsdl.org/viewtopic.php?p=51634
+
 	// Render all the stuff on target texture
-	//SDL_SetRenderTarget(r, ge->sdl_target);
+	SDL_SetRenderTarget(r, ge->sdl_target);
 
 	glClear( GL_COLOR_BUFFER_BIT );
 	glBindVertexArray( se->vao );
 	glDrawArrays( GL_TRIANGLES, 0, 6 );
-	SDL_GL_SwapWindow( ge->sdl_win );
 
 	// Copy the SDL screen to SDL debug window (and display it, not mandatory)
-	//SDL_SetRenderTarget(r, NULL);
-	//SDL_RenderCopy(r, ge->sdl_target, NULL, NULL);
-	//SDL_RenderPresent(r);
+	SDL_SetRenderTarget(r, NULL);
+	SDL_RenderCopy(r, ge->sdl_target, NULL, NULL);
+	SDL_RenderPresent(r);
 	
 	// Download the rendered texture from videocard to main memory
+	SDL_SetRenderTarget(r, ge->sdl_target);
 	res = SDL_RenderReadPixels(r, NULL, 0, ge->raw_target, 256*4);
 
 	// "convert" the raw pixel stream to ASCII art on caca canevas
-	caca_set_dither_gamma(ge->d, (100-frame%100)/100.0);
+	caca_set_dither_gamma(ge->d, 1.0);
 	if ( res == 0 ) caca_dither_bitmap(cv, 0, 0, w, h, ge->d, ge->raw_target);
 
+	return 0;
+}
+
+int scene01_next_sdl(graphical_env_t *ge, scene01_env_t *se) {
+	return 0;
+}
+
+int scene01_next_caca(graphical_env_t *ge, scene01_env_t *se) {
+	// Shorthands
+	caca_canvas_t *cv = ge->cv;
+	int w = ge->w, h = ge->h;
+	Uint32 frame = ge->sc_framecount;
+
 	caca_set_color_ansi(cv, CACA_WHITE, CACA_BLACK);
 	caca_put_str(cv, (w-17)/2, h/2, "This is a message");
 
diff --git a/src/scene01.h b/src/scene01.h
index ecad8df..f6544fb 100644
--- a/src/scene01.h
+++ b/src/scene01.h
@@ -8,5 +8,7 @@ typedef struct {
 
 int scene01_init(graphical_env_t *ge, scene01_env_t *se);
 void scene01_free(graphical_env_t *ge, scene01_env_t *se);
-int scene01_next(graphical_env_t *ge, scene01_env_t *se);
+int scene01_next_gl(graphical_env_t *ge, scene01_env_t *se);
+int scene01_next_sdl(graphical_env_t *ge, scene01_env_t *se);
+int scene01_next_caca(graphical_env_t *ge, scene01_env_t *se);
 #endif
diff --git a/src/scene02.c b/src/scene02.c
index 1989bf0..e8e7340 100644
--- a/src/scene02.c
+++ b/src/scene02.c
@@ -26,7 +26,15 @@ int scene02_init(graphical_env_t *ge, scene02_env_t *se) {
 void scene02_free(graphical_env_t *ge, scene02_env_t *se) {
 }
 
-int scene02_next(graphical_env_t *ge, scene02_env_t *se) {
+int scene02_next_gl(graphical_env_t *ge, scene02_env_t *se) {
+	return 0;
+}
+
+int scene02_next_sdl(graphical_env_t *ge, scene02_env_t *se) {
+	return 0;
+}
+
+int scene02_next_caca(graphical_env_t *ge, scene02_env_t *se) {
 	// Shorthands
 	caca_canvas_t *cv = ge->cv;
 	//int w = ge->w, h = ge->h;
diff --git a/src/scene02.h b/src/scene02.h
index 49abbfb..7032d50 100644
--- a/src/scene02.h
+++ b/src/scene02.h
@@ -8,5 +8,7 @@ typedef struct {
 
 int scene02_init(graphical_env_t *ge, scene02_env_t *se);
 void scene02_free(graphical_env_t *ge, scene02_env_t *se);
-int scene02_next(graphical_env_t *ge, scene02_env_t *se);
+int scene02_next_gl(graphical_env_t *ge, scene02_env_t *se);
+int scene02_next_sdl(graphical_env_t *ge, scene02_env_t *se);
+int scene02_next_caca(graphical_env_t *ge, scene02_env_t *se);
 #endif