gbdb,video: improve logging

Add more runtime toggles and add the ability to log to a file for
faster runs and better searchability.

src/gbemu/video.c

@@ -1,5 +1,6 @@
 #include "gbemu/video.h"
 #include "gbemu/memory.h"
+#include "common/common.h"
 #include "common/bmp.h"
 
 #include <string.h>
@@ -30,6 +31,8 @@ static uint8_t color_tbl[4] = {
 void gb_video_init(struct gb_video *video, struct gb_memory *memory)
 {
 	memset(video, 0, sizeof(*video));
+
+	video->debug_logging = 0;
 	video->memory = memory;
 
 	bmp = bmp_new(BMP_GRAYSCALE, BUFFER_WIDTH, BUFFER_HEIGHT);
@@ -47,14 +50,9 @@ static void gb_video_fetch_tile_data(struct gb_video *video, uint8_t *databuf,
 		uint16_t addr = tile_addr + (index * TILE_BYTES) + i;
 		databuf[i] = gb_mem_read(video->memory, addr);
 		if (log && databuf[i] != 0) {
-			printf("addr=%x, databuf[%d]=%x\n", addr, i, databuf[i]);
 			logged = 1;
 		}
 	}
-
-	if (log && logged) {
-		printf("\n");
-	}
 }
 
 static void gb_video_screenshot(struct gb_video *video)
@@ -69,7 +67,6 @@ static void gb_video_screenshot(struct gb_video *video)
 	int log = id == 30;
 
 	snprintf(filename, sizeof(filename), "screenshot-%d.bmp", id++);
-	printf("Rendering screenshot %s\n", filename);
 
 	if (!(video->lcdcont & 1)) {
 		goto out;
@@ -84,11 +81,6 @@ static void gb_video_screenshot(struct gb_video *video)
 			tile = gb_mem_read(video->memory, addr);
 			gb_video_fetch_tile_data(video, tile_data, tile, log);
 
-			if (log) {
-				printf("Tile_x=%d, tile_y=%d, addr=%x, tile=%d\n",
-					   tile_x, tile_y, addr, tile);
-			}
-
 			for (i = 0 ; i < TILE_WIDTH * TILE_HEIGHT; i++) {
 				int offset_x = i % TILE_WIDTH;
 				int offset_y = i / TILE_WIDTH;
@@ -103,11 +95,6 @@ static void gb_video_screenshot(struct gb_video *video)
 				total_x = tile_x * TILE_WIDTH + (7 - offset_x);
 				total_y = tile_y * TILE_HEIGHT + offset_y;
 
-				if (log && color != 0) {
-					printf("offset=%d, total_x=%d, total_y=%d, td_index=%d, color=%d\n",
-						   total_y * BUFFER_WIDTH + total_x, total_x, total_y, td_index, color);
-				}
-
 				buffer[(BUFFER_HEIGHT - total_y) * BUFFER_WIDTH + total_x] = color_tbl[color];
 			}
 		}
@@ -134,31 +121,52 @@ void gb_video_cycle(struct gb_video *video, int cycles)
 
 uint8_t gb_video_mem_read(struct gb_video *video, uint16_t addr)
 {
+	uint8_t val;
+
 	switch (addr) {
 	case 0xFF40:
-		return video->lcdcont;
+		val = video->lcdcont;
+		break;
 	case 0xFF41:
-		return video->lcdstat;
+		val = video->lcdstat;
+		break;
 	case 0xFF42:
-		return video->scrolly;
+		val = video->scrolly;
+		break;
 	case 0xFF43:
-		return video->scrollx;
+		val = video->scrollx;
+		break;
 	case 0xFF44:
-		return video->curline;
+		val = video->curline;
+		break;
 	case 0xFF45:
-		return video->cmpline;
+		val = video->cmpline;
+		break;
 	case 0xFF4A:
-		return video->wndposy;
+		val = video->wndposy;
+		break;
 	case 0xFF4B:
-		return video->wndposx;
+		val = video->wndposx;
+		break;
 	default:
-		return 0;
+		val = 0;
 	}
+
+	if (video->debug_logging) {
+		gb_log("Read Video[%x]=0x%x\n", addr, val);
+	}
+
+	return val;
 }
 
 void gb_video_mem_write(struct gb_video *video, uint16_t addr, uint8_t val)
 {
 	uint8_t *write_addr;
+
+	if (video->debug_logging) {
+		gb_log("Video[%x]=%x\n", addr, val);
+	}
+
 	switch (addr) {
 	case 0xFF40:
 		write_addr = &video->lcdcont;