From f515c558088a232e0796bfb3e46b6d969f5f204a Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Sat, 8 Jul 2023 12:38:13 +0100
Subject: Remove clipping and make the loops more efficient

---
 src/vga.c | 58 ++++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 36 insertions(+), 22 deletions(-)

(limited to 'src/vga.c')

diff --git a/src/vga.c b/src/vga.c
index df79c7c..98cb404 100644
--- a/src/vga.c
+++ b/src/vga.c
@@ -91,59 +91,73 @@ void set_palette(const uint8_t *palette)
 
 void blit(const uint8_t *sprite, const Rect *dst)
 {
-    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 *dbuffer = buffer + dst->x + dst->y * 320;
+
+    for (int16_t j = 0; j < dst->h; j++)
+    {
+        for (int16_t i = 0; i < dst->w; i++)
         {
             uint8_t b = *sprite++;
 
             /* transparent */
             if (b == TRANSPARENT)
+            {
+                dbuffer++;
                 continue;
+            }
 
-            /* clipping */
-            if (i < 0 || i >= 320 || j < 0 || j >= 200 * 320)
-                continue;
-
-            buffer[i + j] = b;
+            *dbuffer++ = b;
         }
+        dbuffer += 320 - dst->w;
+    }
 }
 
 void blit_c(const uint8_t *sprite, const Rect *dst, uint8_t c)
 {
-    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 *dbuffer = buffer + dst->x + dst->y * 320;
+
+    for (int16_t j = 0; j < dst->h; j++)
+    {
+        for (int16_t i = 0; i < dst->w; i++)
         {
             uint8_t b = *sprite++;
 
             /* transparent */
             if (b == TRANSPARENT)
+            {
+                dbuffer++;
                 continue;
+            }
 
-            /* clipping */
-            if (i < 0 || i >= 320 || j < 0 || j >= 200 * 320)
-                continue;
-
-            buffer[i + j] = b ? c : b;
+            *dbuffer++ = b ? c : b;
         }
+        dbuffer += 320 - dst->w;
+    }
 }
 
 void blitrc(const uint8_t *sprite, const Rect *src, const Rect *dst)
 {
-    for (int32_t j = dst->y * 320, sy = src->y * src->w; j < (dst->y + dst->h) * 320; j += 320, sy += src->w)
-        for (int16_t i = dst->x, sx = src->x; i < dst->x + dst->w; i++, sx++)
+    uint8_t *dbuffer = buffer + dst->x + dst->y * 320;
+    sprite += src->x + src->y * src->w;
+
+    for (int16_t j = 0; j < dst->h; j++)
+    {
+        for (int16_t i = 0; i < dst->w; i++)
         {
-            uint8_t b = sprite[sx + sy];
+            uint8_t b = *sprite++;
 
             /* transparent */
             if (b == TRANSPARENT)
+            {
+                dbuffer++;
                 continue;
+            }
 
-            /* clipping */
-            if (i < 0 || i >= 320 || j < 0 || j >= 200 * 320)
-                continue;
-
-            buffer[i + j] = b;
+            *dbuffer++ = b;
         }
+        sprite += src->w - dst->w;
+        dbuffer += 320 - dst->w;
+    }
 }
 
 void blit_erase(uint8_t c)
-- 
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