modex draw char use rom font height, do not assume 8.

[16.git] / src / lib / modex16 / 16render.c

diff --git a/src/lib/modex16/16render.c b/src/lib/modex16/16render.c
index 198844081b005924553591da69f19964e53a89a7..77598fa55ee14c9616bfbdff3d5b206b29719459 100755 (executable)
--- a/src/lib/modex16/16render.c
+++ b/src/lib/modex16/16render.c
@@ -1,5 +1,5 @@
 /* Project 16 Source Code~\r
- * Copyright (C) 2012-2015 sparky4 & pngwen & andrius4669\r
+ * Copyright (C) 2012-2016 sparky4 & pngwen & andrius4669 & joncampbell123\r
  *\r
  * This file is part of Project 16.\r
  *\r
@@ -434,3 +434,40 @@ modexDrawSpritePBufRegion(page_t *page, int x, int y,
                JNZ PLANE_LOOP    ; do all 4 planes\r
     }\r
 }\r
+\r
+void modexDrawChar(page_t *page, int x/*for planar selection only*/, word t, word col, word bgcol, word addr)\r
+{\r
+       /* vertical drawing routine by joncampbell123.\r
+        *\r
+        * optimize for VGA mode X planar memory to minimize the number of times we do I/O write to map mask register.\r
+        * so, we enumerate over columns (not rows!) to draw every 4th pixel. bit masks are used because of the font bitmap.\r
+        *\r
+        * NTS: addr defines what VGA memory address we use, "x" is redundant except to specify which of the 4 pixels we select in the map mask register. */\r
+       word rows = romFonts[t].charSize;\r
+       word drawaddr;\r
+       word colm, row;\r
+       byte fontbyte;\r
+       byte plane;\r
+       byte m1,m2;\r
+\r
+       plane = x & 3;\r
+       m1 = 0x80; // left half\r
+       m2 = 0x08; // right half\r
+       for (colm=0;colm < 4;colm++) {\r
+               drawaddr = addr;\r
+               modexSelectPlane(PLANE(plane));\r
+               for (row=0;row < rows;row++) {\r
+                       fontbyte = romFontsData.l[row];\r
+                       vga_state.vga_graphics_ram[drawaddr  ] = (fontbyte & m1) ? col : bgcol;\r
+                       vga_state.vga_graphics_ram[drawaddr+1] = (fontbyte & m2) ? col : bgcol;\r
+                       drawaddr += page->width >> 2;\r
+               }\r
+\r
+               m1 >>= 1;\r
+               m2 >>= 1;\r
+               if ((++plane) == 4) {\r
+                       addr++;\r
+                       plane = 0;\r
+               }\r
+       }\r
+}\r