From ba1e7299689f2f6b0d60349e81830cf9faf07916 Mon Sep 17 00:00:00 2001
From: Onkar Raut <onkar.raut@renesas.com>
Date: Tue, 23 Jan 2024 00:40:45 -0800
Subject: [PATCH 1/2] Added simple changes which should allow relocating
 buffers into bss if desired. Added in code to rotate the buffer.

---
 doomgeneric/doomgeneric.c |  9 ++++++---
 doomgeneric/i_video.c     | 38 +++++++++++++++++++++++++++++++++++---
 2 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/doomgeneric/doomgeneric.c b/doomgeneric/doomgeneric.c
index 782a7e716..820a51966 100644
--- a/doomgeneric/doomgeneric.c
+++ b/doomgeneric/doomgeneric.c
@@ -4,7 +4,7 @@
 
 #include "doomgeneric.h"
 
-uint32_t* DG_ScreenBuffer = 0;
+uint32_t* DG_ScreenBuffer = NULL;
 
 void M_FindResponseFile(void);
 void D_DoomMain (void);
@@ -18,10 +18,13 @@ void doomgeneric_Create(int argc, char **argv)
 
 	M_FindResponseFile();
 
-	DG_ScreenBuffer = malloc(DOOMGENERIC_RESX * DOOMGENERIC_RESY * 4);
-
 	DG_Init();
 
+	if(NULL == DG_ScreenBuffer)
+	{
+	    DG_ScreenBuffer = malloc(DOOMGENERIC_RESX * DOOMGENERIC_RESY * 4);
+	}
+
 	D_DoomMain ();
 }
 
diff --git a/doomgeneric/i_video.c b/doomgeneric/i_video.c
index 34b661505..eaacab484 100644
--- a/doomgeneric/i_video.c
+++ b/doomgeneric/i_video.c
@@ -48,6 +48,7 @@ rcsid[] = "$Id: i_x.c,v 1.6 1997/02/03 22:45:10 b1 Exp $";
 #include <sys/types.h>
 
 //#define CMAP256
+#// define ROTATE_SCREENBUFFER  // Needs testing at resolution > 320 * 200
 
 struct FB_BitField
 {
@@ -74,6 +75,7 @@ struct FB_ScreenInfo
 static struct FB_ScreenInfo s_Fb;
 int fb_scaling = 1;
 int usemouse = 0;
+static int free_videoBuffer = 0;
 
 struct color {
     uint32_t b:8;
@@ -126,6 +128,8 @@ typedef struct
 
 static uint16_t rgb565_palette[256];
 
+byte videoBufferLineOut[DOOMGENERIC_RESX * sizeof(uint32_t)];
+
 void cmap_to_rgb565(uint16_t * out, uint8_t * in, int in_pixels)
 {
     int i, j;
@@ -219,7 +223,11 @@ void I_InitGraphics (void)
 
 
     /* Allocate screen to draw to */
-	I_VideoBuffer = (byte*)Z_Malloc (SCREENWIDTH * SCREENHEIGHT, PU_STATIC, NULL);  // For DOOM to draw on
+    if (NULL == I_VideoBuffer)
+	{
+        I_VideoBuffer = (byte*)Z_Malloc (SCREENWIDTH * SCREENHEIGHT, PU_STATIC, NULL);  // For DOOM to draw on
+        free_videoBuffer = 1;
+	}
 
 	screenvisible = true;
 
@@ -229,7 +237,10 @@ void I_InitGraphics (void)
 
 void I_ShutdownGraphics (void)
 {
-	Z_Free (I_VideoBuffer);
+    if(free_videoBuffer)
+	{
+        Z_Free (I_VideoBuffer);
+	}
 }
 
 void I_StartFrame (void)
@@ -267,7 +278,11 @@ void I_FinishUpdate (void)
 
     /* DRAW SCREEN */
     line_in  = (unsigned char *) I_VideoBuffer;
+#ifndef ROTATE_SCREENBUFFER
     line_out = (unsigned char *) DG_ScreenBuffer;
+#else
+    line_out = (unsigned char *) &videoBufferLineOut[0];
+#endif
 
     y = SCREENHEIGHT;
 
@@ -276,6 +291,8 @@ void I_FinishUpdate (void)
         int i;
         for (i = 0; i < fb_scaling; i++) {
             line_out += x_offset;
+
+#ifndef ROTATE_SCREENBUFFER
 #ifdef CMAP256
             for (fb_scaling == 1) {
                 memcpy(line_out, line_in, SCREENWIDTH); /* fb_width is bigger than Doom SCREENWIDTH... */
@@ -285,9 +302,24 @@ void I_FinishUpdate (void)
 #else
             //cmap_to_rgb565((void*)line_out, (void*)line_in, SCREENWIDTH);
             cmap_to_fb((void*)line_out, (void*)line_in, SCREENWIDTH);
-#endif
+#endif /* CMAP256 */
+
+#else
+            cmap_to_fb((void*)videoBufferLineOut, (void*)line_in, SCREENWIDTH);
+#endif /* ROTATE_SCREENBUFFER */
             line_out += (SCREENWIDTH * fb_scaling * (s_Fb.bits_per_pixel/8)) + x_offset_end;
         }
+
+#ifdef ROTATE_SCREENBUFFER
+        for(int m = 0, n = y;
+                m < sizeof(videoBufferLineOut);
+                m+=(s_Fb.bits_per_pixel/8), n+=DOOMGENERIC_RESY)
+        {
+            uint32_t * pixelIn  = &videoBufferLineOut[m];
+            uint32_t * pixelOut = &DG_ScreenBuffer[n];
+            *pixelOut = *pixelIn;
+        }
+#endif /* ROTATE_SCREENBUFFER */
         line_in += SCREENWIDTH;
     }
 

From 29b1db0bf2179ddeee0da63fbfdb74db5299136b Mon Sep 17 00:00:00 2001
From: Onkar Raut <onkar.raut@renesas.com>
Date: Tue, 23 Jan 2024 00:47:48 -0800
Subject: [PATCH 2/2] Fixed an oops.

---
 doomgeneric/i_video.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doomgeneric/i_video.c b/doomgeneric/i_video.c
index eaacab484..fb132d845 100644
--- a/doomgeneric/i_video.c
+++ b/doomgeneric/i_video.c
@@ -48,7 +48,7 @@ rcsid[] = "$Id: i_x.c,v 1.6 1997/02/03 22:45:10 b1 Exp $";
 #include <sys/types.h>
 
 //#define CMAP256
-#// define ROTATE_SCREENBUFFER  // Needs testing at resolution > 320 * 200
+//#define ROTATE_SCREENBUFFER  // Needs testing at resolution > 320 * 200
 
 struct FB_BitField
 {