Function to read from the back buffer

2 files changed, 19 insertions, 0 deletions

diff --git a/src/vga.c b/src/vga.c
index 0df25f8..cb2c5a8 100644
--- a/src/vga.c
+++ b/src/vga.c
@@ -129,3 +129,20 @@ void blit_update()
 {
     memcpy(screen, buffer, 320 * 200);
 }
+
+void read_buffer(uint8_t *dst, const Rect *src)
+{
+    for (int32_t j = src->y * 320; j < (src->y + src->h) * 320; j += 320)
+        for (int16_t i = src->x; i < src->x + src->w; i++)
+        {
+            uint8_t b;
+
+            /* clipping */
+            if (i < 0 || i >= 320 || j < 0 || j >= 200 * 320)
+                b = TRANSPARENT;
+            else
+                b = buffer[i + j];
+
+            *dst++ = b;
+        }
+}
diff --git a/src/vga.h b/src/vga.h
index 40dbcdf..e6642f7 100644
--- a/src/vga.h
+++ b/src/vga.h
@@ -26,4 +26,6 @@ void blitrc(const uint8_t *sprite, const Rect *src, const Rect *dst);
 void blit_erase(uint8_t c);
 void blit_update();
 
+/* read from back buffer into memory */
+void read_buffer(uint8_t *dst, const Rect *src);
 #endif /* _VGA_H */