Move scroll increment to PPU module

src/ppu.c

@@ -285,7 +285,16 @@ int nes_ppu_run(nes_ppu* ppu, int cycles) {
                 result = ppu_Result_VBlank_On;
             }
 
-        } else /*if (ppu->scanline % 8 == 1)*/ {
+        } else {
+            if (    ppu->scanline > nes_ppu_prerender &&
+                    ppu->scanline < nes_ppu_render) {
+                ppu->scroll_y++;
+                if (ppu->scroll_y >= nes_ppu_render_h) {
+                    ppu->scroll_y -= nes_ppu_render_h;
+                    ppu->control ^= 0b10;
+                }
+            }
+
             result = ppu_Result_Ready;
         }
     }

src/sdl_render.c

@@ -817,21 +817,6 @@ static void render_scanline(nes_ppu* ppu, int line,
                             data->target, &dst_rect);
         }
     }
-
-    /*if (line + 1 < nes_ppu_height)*/ {
-        ppu->scroll_y++;
-        if (ppu->scroll_y >= nes_ppu_render_h) {
-            ppu->scroll_y -= nes_ppu_render_h;
-            ppu->control ^= 0b10;
-        }
-/*
-        // We check for hits if EITHER layer is enabled.
-        render_bg_scanline(ppu, background);
-        if (ppu->hit_line <= 0) {
-            update_scanline_hit(ppu, background, line + 1);
-        }
-*/
-    }
 }
 
 static int sdl_render(nes_Renderer* rend, nes_ppu* ppu) {