From f90846d5a7a82573f85a58306c7b866baef95703 Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Thu, 8 Jun 2023 08:01:02 +0100
Subject: Use a rectangle struct

---
 src/main.c | 14 +++++++-------
 src/vga.c  |  8 ++++----
 src/vga.h  |  9 ++++++++-
 3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/src/main.c b/src/main.c
index 88e2e98..c0e7dc3 100644
--- a/src/main.c
+++ b/src/main.c
@@ -33,26 +33,26 @@ int main(int argc, char *argv[])
     blit_update();
 
     uint8_t bg[24 * 24] = { 0 };
-    uint16_t x = 10, y = 10;
+    Rect dst = { 10, 10, 24, 24 };
     int8_t ix = 1, iy = 1;
     uint8_t c = 0;
 
     while (!keys[KEY_ESC])
     {
         // erase
-        blit(bg, x, y, 24, 24);
+        blit(bg, &dst);
 
-        x += ix;
-        y += iy;
+        dst.x += ix;
+        dst.y += iy;
 
-        if (x >= 320 - 24 || x == 0)
+        if (dst.x >= 320 - 24 || dst.x == 0)
         {
             ix *= -1;
             c = (c + 1) % 15;
             blit_erase(c);
             memset(bg, c, 24 * 24);
         }
-        if (y >= 200 - 24 || y == 0)
+        if (dst.y >= 200 - 24 || dst.y == 0)
         {
             iy *= -1;
             c = (c + 1) % 15;
@@ -61,7 +61,7 @@ int main(int argc, char *argv[])
         }
 
         // draw
-        blit(binary_sprites_start, x, y, 24, 24);
+        blit(binary_sprites_start, &dst);
 
         wait_vsync();
         blit_update();
diff --git a/src/vga.c b/src/vga.c
index a408f71..6665c79 100644
--- a/src/vga.c
+++ b/src/vga.c
@@ -44,12 +44,12 @@ void set_palette(const uint8_t *palette)
         outportb(0x3c9, palette[i] >> 2);
 }
 
-void blit(const uint8_t *src, uint16_t x, uint16_t y, uint16_t w, uint16_t h)
+void blit(const uint8_t *sprite, const Rect *dst)
 {
-    for (int32_t j = y * 320; j < (y + h) * 320; j += 320)
-        for (int16_t i = x; i < x + w; i++)
+    for (int32_t j = dst->y * 320; j < (dst->y + dst->h) * 320; j += 320)
+        for (int16_t i = dst->x; i < dst->x + dst->w; i++)
         {
-            uint8_t b = *src++;
+            uint8_t b = *sprite++;
 
             /* transparent */
             if (b == TRANSPARENT)
diff --git a/src/vga.h b/src/vga.h
index ef183ca..a185974 100644
--- a/src/vga.h
+++ b/src/vga.h
@@ -4,6 +4,13 @@
 /* palette index to be used as transparent color */
 #define TRANSPARENT 16
 
+typedef struct {
+    uint16_t x;
+    uint16_t y;
+    uint16_t w;
+    uint16_t h;
+} Rect;
+
 uint8_t open_framebuffer();
 void close_framebuffer();
 
@@ -13,7 +20,7 @@ void wait_vsync();
 /* the palette is expected to be 8 bit per color, and will be converted to VGA's 6 bit per color */
 void set_palette(const uint8_t *palette);
 
-void blit(const uint8_t *src, uint16_t x, uint16_t y, uint16_t w, uint16_t h);
+void blit(const uint8_t *sprite, const Rect *dst);
 void blit_erase(uint8_t c);
 void blit_update();
 
-- 
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