implement text in graphics mode

1 files changed, 76 insertions, 2 deletions

diff --git a/drivers/gfx.c b/drivers/gfx.c
index 538dadb..38a6591 100644
--- a/drivers/gfx.c
+++ b/drivers/gfx.c
@@ -1,5 +1,9 @@
+#include <stdbool.h>
 #include <stddef.h>
+#include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
+#include "gfx_font.h"
 #include "log.h"
 #include "multiboot.h"
 #include "panic.h"
@@ -8,6 +12,7 @@
 static uint8_t *framebuffer = NULL;
 static uint16_t fb_width;
 static uint16_t fb_height;
+
 /* this is BYTES per pixel */
 static uint8_t  fb_bpp;
 
@@ -30,13 +35,82 @@ void gfx_clear(uint32_t col)
     }
 }
 
-void gfx_init(struct vbe_info_t *vbe_mode_info)
+void gfx_drawchar(int x, int y, char c, uint32_t fg, uint32_t bg)
+{
+    int stride = fb_bpp * fb_width;
+    uint8_t *line_addr = framebuffer + (x * fb_bpp) + (y * fb_width * fb_bpp);
+    for(int i = y; i < y + FONT_HEIGHT; ++i)
+    {
+        uint32_t line_buf[8] = {bg};
+        uint8_t mask = 0x80;
+        for(int j = 0; j < 8; ++j, mask >>= 1)
+        {
+            if(gfx_font[(int)c][i] & mask)
+                line_buf[j] = fg;
+        }
+        memcpy(line_addr, line_buf, sizeof(line_buf));
+        line_addr += stride;
+    }
+}
+
+static int cursor_x, cursor_y;
+static uint32_t fgcol, bgcol;
+
+void gfx_putchar(char ch)
+{
+    if(ch != '\n')
+    {
+        gfx_drawchar(cursor_x, cursor_y, ch, fgcol, bgcol);
+        cursor_x += FONT_WIDTH;
+        if(cursor_x >= fb_width)
+        {
+            cursor_x = 0;
+            cursor_y += FONT_HEIGHT;
+            if(cursor_y >= fb_height)
+            {
+                gfx_clear(bgcol);
+                cursor_y = 0;
+            }
+        }
+    }
+    else
+    {
+        cursor_x = 0;
+        cursor_y += FONT_HEIGHT;
+        if(cursor_y >= fb_height)
+        {
+            gfx_clear(bgcol);
+            cursor_y = 0;
+        }
+    }
+}
+
+void gfx_puts(const char* str)
+{
+    while(*str)
+    {
+        gfx_putchar(*str++);
+    }
+}
+
+bool gfx_init(struct vbe_info_t *vbe_mode_info)
 {
     framebuffer = (uint8_t*)vbe_mode_info->physbase;
     fb_width = vbe_mode_info->Xres;
     fb_height = vbe_mode_info->Yres;
     fb_bpp = vbe_mode_info->bpp / 8;
     if(fb_bpp != 4)
-        panic("BPP *MUST* be 32!!!\n");
+    {
+        printf("WARNING: BPP != 32, falling back to text mode...\n");
+        return false;
+    }
     gfx_clear(VGA_RGBPACK(0, 0, 0));
+    cursor_y = 0;
+    cursor_x = 0;
+    fgcol = VGA_RGBPACK(0xff, 0xff, 0xff);
+    bgcol = VGA_RGBPACK(0, 0, 0);
+    set_putchar(gfx_putchar);
+    set_puts(gfx_puts);
+
+    return true;
 }