Improve Stbar Color Background Algorithm (#691)

Author: andrikpowell

prboom2/src/r_draw.c

@@ -501,65 +501,37 @@ void R_InitBuffer(int width, int height)
 void R_FillBackColor (void)
 {
   extern patchnum_t stbarbg;
-  byte col, col_top;
-  int i, j, pixel_cnt;
-  int r, g, b;
-  int stbar_top = SCREENHEIGHT - ST_SCALED_HEIGHT;
-  int ST_SCALED_BORDER = brdr_b.height * patches_scaley/2;
-  const unsigned char *playpal = V_GetPlaypal();
-
-  const byte* lump;
-  const byte* p;
-  short width;
-  byte length;
-  byte entry;
-
-  pixel_cnt = 0;
-  r = g = b = 0;
-
-  lump = W_LumpByNum(stbarbg.lumpnum);
-  width = *((const int16_t *) lump);
-  width = LittleShort(width);
-
-  for (i = 0; i < width; ++i) {
-    // Skip irrelevant data in the doom patch header
-    int32_t offset;
-    p = lump + 8 + 4 * i;
-    offset = *((const int32_t *) p);
-    p = lump + LittleLong(offset);
-
-    while (*p != 0xff) {
-      p++;
-      length = *p++;
-      p++;
-
-      // Get RGB values per pixel
-      for (j = 0; j < length; ++j) {
-        entry = *p++;
-        r += playpal[3 * entry + 0];
-        g += playpal[3 * entry + 1];
-        b += playpal[3 * entry + 2];
-        pixel_cnt++;
-      }
+  static byte col;
+  static byte col_top;
+  static int prevlump = -1;
+  const int stbar_top = SCREENHEIGHT - ST_SCALED_HEIGHT;
+  const int ST_SCALED_BORDER = brdr_b.height * patches_scaley/2;
+  int lump = stbarbg.lumpnum;
+
+  if (prevlump != lump)
+  {
+    const unsigned char *playpal = V_GetPlaypal();
+    SDL_Color stbar_color = V_GetPatchColor(lump);
+    int r = stbar_color.r;
+    int g = stbar_color.g;
+    int b = stbar_color.b;
 
-      p++;
-    }
-  }
+    // Convert to palette and tune down saturation
+    col = V_BestColor(playpal, r/3, g/3, b/3);
+    col_top = V_BestColor(playpal, r/2, g/2, b/2);
 
-  // Average RGB values
-  r /= pixel_cnt;
-  g /= pixel_cnt;
-  b /= pixel_cnt;
+    // If colors are the same, brighten top
+    if (col_top == col)
+      col_top = V_BestColor(playpal, r, g, b);
 
-  // Convert to palette and tune down saturation
-  col = V_BestColor(playpal, r/3, g/3, b/3);
-  col_top = V_BestColor(playpal, r/2, g/2, b/2);
+    prevlump = lump;
+  }
 
   V_BeginMenuDraw();
-  V_FillRect(1, 0, stbar_top, SCREENWIDTH, ST_SCALED_HEIGHT, col);
   V_FillRect(1, 0, stbar_top, SCREENWIDTH, ST_SCALED_BORDER, col_top);
+  V_FillRect(1, 0, stbar_top + ST_SCALED_BORDER, SCREENWIDTH, ST_SCALED_HEIGHT - ST_SCALED_BORDER, col);
   V_EndMenuDraw();
- }
+}
 
 //
 // R_FillBackScreen

prboom2/src/v_video.c

@@ -1204,6 +1204,66 @@ int V_GetPlaypalCount(void)
   return (dsda_PlayPalData()->length / PALETTE_SIZE);
 }
 
+//
+// V_GetPatchColor
+// Get the color of a Doom-Format
+// graphic via lumpnum
+//
+
+SDL_Color V_GetPatchColor (int lumpnum)
+{
+  SDL_Color col = {0,0,0,0};
+  int r = 0, g = 0, b = 0;
+  const unsigned char *playpal = V_GetPlaypal();
+  int x, y, pixel_cnt = 0;
+  const byte* lump;
+  short width;
+
+  lump = W_LumpByNum(lumpnum);
+
+  width = *((const int16_t *) lump);
+  width = LittleShort(width);
+
+  for (x = 0; x < width; ++x) {
+    byte length;
+    byte entry;
+    const byte* p;
+    int32_t offset;
+
+    // Only calculate for the leftmost and rightmost 16 columns
+    if (width > 32 && x > 16 && x < width - 16)
+      continue;
+
+    // Skip irrelevant data in the doom patch header
+    p = lump + 8 + 4 * x;
+    offset = *((const int32_t *) p);
+    p = lump + LittleLong(offset);
+
+    while (*p != 0xff) {
+      p++;
+      length = *p++;
+      p++;
+
+      // Get RGB values per pixel
+      for (y = 0; y < length; ++y) {
+        entry = *p++;
+        r += playpal[3 * entry + 0];
+        g += playpal[3 * entry + 1];
+        b += playpal[3 * entry + 2];
+        pixel_cnt++;
+      }
+      p++;
+    }
+  }
+
+  // Average RGB values
+  col.r = r / pixel_cnt;
+  col.g = g / pixel_cnt;
+  col.b = b / pixel_cnt;
+
+  return col;
+}
+
 void V_ClearBorder(void)
 {
   int bordtop, bordbottom, bordleft, bordright;

prboom2/src/v_video.h

@@ -37,6 +37,8 @@
 #ifndef __V_VIDEO__
 #define __V_VIDEO__
 
+#include "SDL.h"
+
 #include "doomtype.h"
 #include "doomdef.h"
 // Needed because we are refering to patches.
@@ -309,6 +311,8 @@ void V_FreePlaypal(void);
 // [XA] get number of palettes in the current playpal
 int V_GetPlaypalCount(void);
 
+SDL_Color V_GetPatchColor (int lumpnum);
+
 // e6y: wide-res
 void V_ClearBorder(void);