Improve log rendering performance

Logs are now stored in a circular buffer rather then a shifting list of
strings. This will improve the performance when adding logs but should
not have that much impace since we don't do this on every frame.

However the rendering of the logs has been improved to reduce the
performance impact when generating textures for each log line on every
frame.

Author: LiquidityC

src/gui.c

@@ -36,18 +36,26 @@
 #include "texturecache.h"
 #include "gui_util.h"
 
-#define DEFAULT_LOG { NULL, LOG_LINES_COUNT, 0, 200 }
-#define DEFAULT_EVENT_MESSAGES { NULL, 5, 0, 200 }
+#define DEFAULT_EVENT_MESSAGES { NULL, 5, 0, LOG_LINES_MAX_LEN }
 
 #define POS_Y_COLLECTABLES	 64
 #define POS_Y_XPBAR		128
 
 static struct LogData_t {
-	char **log;
-	unsigned int len;
-	unsigned int count;
-	unsigned int strlen;
-} log_data = DEFAULT_LOG;
+	char log[LOG_LINES_COUNT][LOG_LINES_MAX_LEN];
+	uint8_t capacity;
+	uint8_t head;
+	uint8_t tail;
+	uint8_t count;
+	uint8_t strlen;
+} log_data = {
+	{ "", "", "", "", "", "", "", "", "", "" },
+	LOG_LINES_COUNT,
+	0,
+	0,
+	0,
+	LOG_LINES_MAX_LEN
+};
 
 static struct GuiEventMsgs {
 	char **messages;
@@ -56,19 +64,6 @@ static struct GuiEventMsgs {
 	unsigned int strlen;
 } event_messages = DEFAULT_EVENT_MESSAGES;
 
-static void
-gui_malloc_log(void)
-{
-	if (log_data.log != NULL)
-		return;
-
-	unsigned int i;
-
-	log_data.log = ec_malloc(log_data.len * sizeof(char*));
-	for (i = 0; i < log_data.len; ++i)
-		log_data.log[i] = NULL;
-}
-
 static void
 gui_malloc_eventmessages(void)
 {
@@ -273,7 +268,6 @@ gui_create(Camera *cam)
 				    POS_Y_COLLECTABLES + 32 + 5
 				    ));
 
-	gui_malloc_log();
 	gui_malloc_eventmessages();
 
 	init_sprites(gui, cam);
@@ -599,31 +593,32 @@ gui_reset(Gui *gui, Camera *cam)
 void
 gui_log(const char *fmt, ...)
 {
-	char buffer[200];
-	char *new_message;
+	char buffer[LOG_LINES_MAX_LEN];
+	uint8_t next_idx;
+	char *next_message;
 	char tstamp[10];
 
 	va_list args;
 
-	new_message = ec_malloc(log_data.strlen * sizeof(char));
-	timestamp(tstamp, 10);
+	next_idx = (uint8_t)(log_data.head + 1) % log_data.capacity;
+
+	// Increment indexes
+	if (log_data.count > 0 && log_data.head == log_data.tail) {
+		log_data.tail = (uint8_t)(log_data.tail + 1) % log_data.capacity;
+		log_data.count = log_data.capacity;
+	} else if (log_data.count < log_data.capacity) {
+		log_data.count++;
+	}
+
+	next_message = log_data.log[log_data.head];
+	log_data.head = next_idx;
 
+	// Build log line
+	timestamp(tstamp, 10);
 	va_start(args, fmt);
-	m_vsprintf(buffer, 200, fmt, args);
+	m_vsprintf(buffer, LOG_LINES_MAX_LEN, fmt, args);
 	va_end(args);
-	m_sprintf(new_message, log_data.strlen, "%s > %s", tstamp, buffer);
-
-	log_data.count++;
-	if (log_data.count > log_data.len) {
-		log_data.count = log_data.len;
-		free(log_data.log[0]);
-		log_data.log[0] = NULL;
-		for (size_t i = 0; i < log_data.count - 1; ++i) {
-			log_data.log[i] = log_data.log[i+1];
-			log_data.log[i+1] = NULL;
-		}
-	}
-	log_data.log[log_data.count-1] = new_message;
+	m_sprintf(next_message, log_data.strlen, "%s > %s", tstamp, buffer);
 }
 
 void
@@ -656,15 +651,27 @@ gui_render_tooltip(Gui *gui, Camera *cam)
 void
 gui_render_log(Gui *gui, Camera *cam)
 {
-	SDL_Rect box = { 16, 0, 16, 16 };
+	static uint8_t last_head = 0;
 
 	sprite_render(gui->bottomFrame, cam);
 
-	for (Uint32 i = 0; i < log_data.count; ++i) {
+	// Update log textures
+	const uint8_t visible = log_data.count;
+	if (log_data.head != last_head) {
+		for (uint8_t i = 0; i < visible; ++i) {
+			const uint8_t log_index = (uint8_t)((log_data.tail + i) % log_data.capacity);
+			Texture *t = gui->log_lines[i];
+			texture_load_from_text(t, log_data.log[log_index], C_WHITE, C_BLACK, cam->renderer);
+		}
+	}
+	last_head = log_data.head;
+
+	// Render log textures
+	SDL_Rect box = { 16, 0, 16, 16 };
+	for (uint8_t i = 0; i < visible; ++i) {
 		Texture *t;
 		box.y = 16 + ((LOG_FONT_SIZE+5) * i);
 		t = gui->log_lines[i];
-		texture_load_from_text(t, log_data.log[i], C_WHITE, C_BLACK, cam->renderer);
 		box.w = t->dim.width;
 		box.h = t->dim.height;
 		texture_render(t, &box, cam);
@@ -714,25 +721,12 @@ gui_clear_message_log(void)
 	}
 	event_messages.count = 0;
 
-	for (size_t i = 0; i < log_data.count; ++i)
-		free(log_data.log[i]);
+	// Don't need to clear the log buffer. Just reset the head/tail
+	log_data.head = 0;
+	log_data.tail = 0;
 	log_data.count = 0;
 }
 
-static void
-destroy_log(void)
-{
-	if (log_data.log == NULL)
-		return;
-
-	unsigned int i;
-	for (i = 0; i < log_data.count; ++i)
-		free(log_data.log[i]);
-
-	free(log_data.log);
-	log_data.log = NULL;
-}
-
 static void
 destroy_event_messages(void)
 {
@@ -750,7 +744,6 @@ destroy_event_messages(void)
 void
 gui_destroy(Gui *gui)
 {
-	destroy_log();
 	destroy_event_messages();
 
 	timer_destroy(gui->event_message_timer);

src/gui.h

@@ -21,6 +21,7 @@
 
 #include "roommatrix.h"
 #define LOG_LINES_COUNT	10
+#define LOG_LINES_MAX_LEN 200
 #define LOG_FONT_SIZE	8
 #define LABEL_FONT_SIZE	8
 

src/main.c

@@ -1013,15 +1013,29 @@ run_game_update(void)
 static void
 render_gui(void)
 {
+	TIME_FUNC_BEGIN();
+	TIME_BLOCK_BEGIN(gui_render_panel);
 	SDL_SetRenderViewport(gRenderer, &statsGuiViewport);
 	gui_render_panel(gGui, gCamera);
+	TIME_BLOCK_END(gui_render_panel);
+
+	TIME_BLOCK_BEGIN(render_minimap);
 	SDL_SetRenderViewport(gRenderer, &minimapViewport);
 	gui_render_minimap(gGui, gCamera);
+	TIME_BLOCK_END(render_minimap);
+
+	TIME_BLOCK_BEGIN(render_skillbar);
 	SDL_SetRenderViewport(gRenderer, &skillBarViewport);
 	skillbar_render(gSkillBar, gPlayer, gCamera);
+	TIME_BLOCK_END(render_skillbar);
+
+	TIME_BLOCK_BEGIN(render_log);
 	SDL_SetRenderViewport(gRenderer, &bottomGuiViewport);
 	gui_render_log(gGui, gCamera);
+	TIME_BLOCK_END(render_log);
+
 	SDL_SetRenderViewport(gRenderer, &mainViewport);
+	TIME_FUNC_END();
 }
 
 static void