Erase old sprite (if same numbered sprite) pixels.

diff --git a/custom.cpp b/custom.cpp
index 19dce57140735ded3010a78282f02e5d5625bd4c..25dc3bab4f9022659e3cb1eb09a42fe9e088fcd6 100644 (file)
--- a/custom.cpp
+++ b/custom.cpp
@@ -3858,6 +3858,7 @@ static void do_sprite_collisions (void)
 static void record_sprite_1 (int sprxp, uae_u16 *buf, uae_u32 datab, int num, int dbl,
        unsigned int mask, int do_collisions, uae_u32 collision_mask)
 {
+       uae_u16 erasemask = ~(3 << (2 * num));
        int j = 0;
        while (datab) {
                unsigned int col = 0;
@@ -3870,14 +3871,14 @@ static void record_sprite_1 (int sprxp, uae_u16 *buf, uae_u32 datab, int num, in
                        col ^= (uaerand () << 16) | uaerand ();
 #endif
                if ((j & mask) == 0) {
-                       unsigned int tmp = (*buf) | col;
+                       unsigned int tmp = ((*buf) & erasemask) | col;
                        *buf++ = tmp;
                        if (do_collisions)
                                coltmp |= tmp;
                        sprxp++;
                }
                if (dbl > 0) {
-                       unsigned int tmp = (*buf) | col;
+                       unsigned int tmp = ((*buf) & erasemask) | col;
                        *buf++ = tmp;
                        if (do_collisions)
                                coltmp |= tmp;
@@ -3885,11 +3886,11 @@ static void record_sprite_1 (int sprxp, uae_u16 *buf, uae_u32 datab, int num, in
                }
                if (dbl > 1) {
                        unsigned int tmp;
-                       tmp = (*buf) | col;
+                       tmp = ((*buf) & erasemask) | col;
                        *buf++ = tmp;
                        if (do_collisions)
                                coltmp |= tmp;
-                       tmp = (*buf) | col;
+                       tmp = ((*buf) & erasemask) | col;
                        *buf++ = tmp;
                        if (do_collisions)
                                coltmp |= tmp;