From 13dc05cfd2a7d593c9610ab029cec6cd7cac70c3 Mon Sep 17 00:00:00 2001
From: OBattler <oubattler@gmail.com>
Date: Mon, 13 Sep 2021 21:02:15 +0200
Subject: [PATCH] Removed the useless double-buffering in video/video.c,
 improves performance and reduces RAM usage.

---
 src/include/86box/video.h |  2 +-
 src/video/video.c         | 14 ++++----------
 src/vnc.c                 |  2 +-
 src/win/win_opengl.c      | 10 ++++++++--
 src/win/win_sdl.c         | 14 +++++++-------
 5 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/include/86box/video.h b/src/include/86box/video.h
index be7591dc7..479312d1a 100644
--- a/src/include/86box/video.h
+++ b/src/include/86box/video.h
@@ -84,7 +84,7 @@ typedef rgb_t PALETTE[256];
 extern int	changeframecount;
 
 extern volatile int screenshots;
-extern bitmap_t	*buffer32, *render_buffer;
+extern bitmap_t	*buffer32;
 extern PALETTE	cgapal,
 		cgapal_mono[6];
 extern uint32_t	pal_lookup[256];
diff --git a/src/video/video.c b/src/video/video.c
index 008228a00..66323f079 100644
--- a/src/video/video.c
+++ b/src/video/video.c
@@ -74,7 +74,6 @@
 
 volatile int	screenshots = 0;
 bitmap_t	*buffer32 = NULL;
-bitmap_t	*render_buffer = NULL;
 uint8_t		fontdat[2048][8];		/* IBM CGA font */
 uint8_t		fontdatm[2048][16];		/* IBM MDA font */
 uint8_t		fontdatw[512][32];		/* Wyse700 font */
@@ -364,7 +363,7 @@ video_take_screenshot(const char *fn, int startx, int starty, int y1, int y2, in
     for (y = 0; y < h; ++y) {
 	b_rgb[y] = (png_byte *) malloc(png_get_rowbytes(png_ptr, info_ptr));
     	for (x = 0; x < w; ++x) {
-		temp = render_buffer->dat[(y * w) + x];
+		temp = buffer32->line[starty + y][startx + x];
 
 		b_rgb[y][(x) * 3 + 0] = (temp >> 16) & 0xff;
 		b_rgb[y][(x) * 3 + 1] = (temp >> 8) & 0xff;
@@ -436,19 +435,16 @@ void blit_thread(void *param)
 	thread_reset_event(blit_data.wake_blit_thread);
 	MTR_BEGIN("video", "blit_thread");
 
-	if (blit_data.y2 > 0) {
+	if ((video_grayscale || invert_display) && blit_data.y2 > 0) {
 		for (yy = blit_data.y1; yy < blit_data.y2; yy++) {
 			if (((blit_data.y + yy) >= 0) && ((blit_data.y + yy) < buffer32->h)) {
-				if (video_grayscale || invert_display)
-					video_transform_copy(&(render_buffer->dat)[yy * blit_data.w], &(buffer32->line[blit_data.y + yy][blit_data.x]), blit_data.w);
-				else
-					memcpy(&(render_buffer->dat)[yy * blit_data.w], &(buffer32->line[blit_data.y + yy][blit_data.x]), blit_data.w << 2);
+				video_transform_copy(&(buffer32->line[blit_data.y + yy][blit_data.x]), &(buffer32->line[blit_data.y + yy][blit_data.x]), blit_data.w);
 			}
 		}
 	}
 
 	if (screenshots) {
-		if (render_buffer != NULL)
+		if (buffer32 != NULL)
 			video_screenshot(blit_data.x, blit_data.y, blit_data.y1, blit_data.y2, blit_data.w, blit_data.h);
 		screenshots--;
 		video_log("screenshot taken, %i left\n", screenshots);
@@ -833,7 +829,6 @@ video_init(void)
 
     /* Account for overscan. */
     buffer32 = create_bitmap(2048 + 64, 2048 + 64);
-    render_buffer = create_bitmap(2048 + 64, 2048 + 64);
 
     for (c = 0; c < 64; c++) {
 	cgapal[c + 64].r = (((c & 4) ? 2 : 0) | ((c & 0x10) ? 1 : 0)) * 21;
@@ -902,7 +897,6 @@ video_close(void)
     free(video_8togs);
     free(video_6to8);
 
-    destroy_bitmap(render_buffer);
     destroy_bitmap(buffer32);
 
     if (fontdatksc5601) {
diff --git a/src/vnc.c b/src/vnc.c
index 09c00831f..5f687a9f3 100644
--- a/src/vnc.c
+++ b/src/vnc.c
@@ -176,7 +176,7 @@ vnc_blit(int x, int y, int y1, int y2, int w, int h)
 	p = (uint32_t *)&(((uint32_t *)rfb->frameBuffer)[yy*VNC_MAX_X]);
 
 	if ((y+yy) >= 0 && (y+yy) < VNC_MAX_Y)
-		memcpy(p, &(render_buffer->dat[yy * w]), w*4);
+		memcpy(p, &(buffer32->line[yy]), w*4);
     }
  
     video_blit_complete();
diff --git a/src/win/win_opengl.c b/src/win/win_opengl.c
index 9d44fc47e..1d8239af8 100644
--- a/src/win/win_opengl.c
+++ b/src/win/win_opengl.c
@@ -810,14 +810,20 @@ static void opengl_main(void* param)
 
 static void opengl_blit(int x, int y, int y1, int y2, int w, int h)
 {
-	if (y1 == y2 || h <= 0 || render_buffer == NULL || thread == NULL ||
+	int yy;
+
+	if (y1 == y2 || h <= 0 || buffer32 == NULL || thread == NULL ||
 		atomic_flag_test_and_set(&blit_info[write_pos].in_use))
 	{
 		video_blit_complete();
 		return;
 	}
 
-	memcpy(blit_info[write_pos].buffer, &(render_buffer->dat)[y1 * w], w * (y2 - y1) * sizeof(uint32_t));
+	for (yy = y1; yy < y2; yy++) {
+		if ((y + yy) >= 0 && (y + yy) < buffer32->h)
+			memcpy(blit_info[write_pos].buffer + (yy * w * 4),
+			       &(((uint32_t *) buffer32->line[y + yy])[x]), w * 4);
+	}
 
 	video_blit_complete();
 
diff --git a/src/win/win_sdl.c b/src/win/win_sdl.c
index 8a748fb2b..c5978501f 100644
--- a/src/win/win_sdl.c
+++ b/src/win/win_sdl.c
@@ -234,24 +234,24 @@ sdl_blit(int x, int y, int y1, int y2, int w, int h)
     SDL_Rect r_src;
     int ret;
 
-    if (!sdl_enabled || (y1 == y2) || (h <= 0) || (render_buffer == NULL) || (sdl_render == NULL) || (sdl_tex == NULL)) {
+    if (!sdl_enabled || (y1 == y2) || (h <= 0) || (buffer32 == NULL) || (sdl_render == NULL) || (sdl_tex == NULL)) {
 	video_blit_complete();
 	return;
     }
 
     SDL_LockMutex(sdl_mutex);
 
-    r_src.x = 0;
-    r_src.y = y1;
+    r_src.x = x;
+    r_src.y = y;
     r_src.w = w;
-    r_src.h = y2 - y1;
-    SDL_UpdateTexture(sdl_tex, &r_src, &(render_buffer->dat)[y1 * w], w * 4);
+    r_src.h = h;
+    SDL_UpdateTexture(sdl_tex, &r_src, &(buffer32->line[y][x]), (2048 + 64) * 4);
     video_blit_complete();
 
     SDL_RenderClear(sdl_render);
 
-    r_src.x = 0;
-    r_src.y = 0;
+    r_src.x = x;
+    r_src.y = y;
     r_src.w = w;
     r_src.h = h;