'wide pixels'

should get better color on the composite video because the
scanlines will be fuller of data

mandel.s

@@ -234,9 +234,9 @@ display_list_len = display_list_end - display_list_start
 color_map:
     .byte 0
     .repeat 85
-        .byte 1
-        .byte 2
-        .byte 3
+        .byte %01010101
+        .byte %10101010
+        .byte %11111111
     .endrepeat
 
 
@@ -285,6 +285,11 @@ fill_masks:
     .byte %00000001
     .byte %00000000
 
+pixel_masks:
+    .byte %11111111
+    .byte %11110000
+    .byte %11000000
+
 viewport_zoom:
     .byte 1
     .byte 6
@@ -1130,8 +1135,11 @@ enough:
     ; iter -> color
     ldx iter
     lda color_map,x
+    ldx fill_level
+    and pixel_masks,x
     sta pixel_color
-    lda #(255 - 3)
+    lda pixel_masks,x
+    eor #$ff
     sta pixel_mask
 
     ; sy -> line base address in temp
@@ -1180,18 +1188,15 @@ point:
     ; pixel_mask <<= pixel_shift (shifting in ones)
     and #3
     sta pixel_shift
-    lda #3
-    sec
-    sbc pixel_shift
     tax
 shift_loop:
     beq shift_done
-    asl pixel_color
-    asl pixel_color
+    lsr pixel_color
+    lsr pixel_color
     sec
-    rol pixel_mask
+    ror pixel_mask
     sec
-    rol pixel_mask
+    ror pixel_mask
     dex
     jmp shift_loop
 shift_done:

todo.md

@@ -11,8 +11,7 @@ things to try:
 
 * y-axis mirror optimization
 
-* 'wide pixels' 2x and 4x for a fuller initial image in the tiered rendering
-  * maybe redo tiering to just 4x4, 2x2, 1x1?
+* try filling in the extra scanlines on 4x4 and 2x2 tiering
 
 * extract viewport for display & re-input via keyboard