linecrunch

presets/c64/linecrunch.c

@@ -0,0 +1,96 @@
+
+#include "common.h"
+//#link "common.c"
+
+#include "rasterirq.h"
+//#link "rasterirq.ca65"
+
+#include "bcd.h"
+//#link "bcd.c"
+
+extern const unsigned char sinustable[0x100];
+//#link "sinustable.c"
+
+///// VARIABLES
+
+byte frame = 0;
+byte scroll_y = 0;
+byte target_line = 0;
+
+///// FUNCTIONS
+
+void line_crunch() {
+  // load scroll y
+  asm("lda %v", scroll_y);
+  asm("and #7");
+  asm("ora #$18");
+  asm("tax");
+  // get current raster line
+  asm("lda $d012");
+  // wait for next raster line
+  asm("@loop:");
+  asm("cmp $d012");
+  asm("beq @loop");
+  // set y scroll (ctrl1)
+  asm("stx $d011");
+}
+
+void display_list(void) {
+
+  // set initial YSCROLL
+  VIC.ctrl1 = 0x18 | (scroll_y & 7);
+
+  // do line crunch?
+  if (scroll_y < 24) {
+    // wait for target line
+    target_line = 47 + (scroll_y & 7);
+    while (VIC.rasterline != target_line) { }
+    // increment YSCROLL
+    scroll_y++;
+    line_crunch();
+    // do additional line crunches?
+    if (scroll_y < 17) {
+      scroll_y++;
+      line_crunch();
+      if (scroll_y < 10) {
+        scroll_y++;
+        line_crunch();
+      }
+    }
+  }
+
+  VIC.bgcolor[0] = COLOR_CYAN;
+  VIC.bordercolor = COLOR_BLUE;
+
+  DLIST_RESTART(40);
+}
+
+void main() {
+  int i;
+
+  clrscr();
+
+  memset(COLOR_RAM, COLOR_BLUE, 1000);
+
+  for (i=0; i<40*25; i++)
+    POKE(0x400 + i, 205 + (rand() & 1));
+  for (i=40*25; i<1024; i++)
+    POKE(0x400 + i, i);
+  for (i=0; i<1024; i+=40)
+    POKE(0x400 + i, 122);
+
+  SET_VIC_BITMAP(0x1000);
+
+  // setup rasterirq library for scoreboard split
+  DLIST_SETUP(display_list);
+
+  // game loop, repeat forever
+  while (1) {    
+    // wait for end of frame
+    waitvsync();
+
+    // animate and set scroll_y
+    frame += 4;
+    scroll_y = sinustable[frame] >> 3;
+  }
+}

presets/c64/sinustable.c

@@ -0,0 +1,35 @@
+
+const unsigned char sinustable[0x100] = {
+    0x80, 0x7d, 0x7a, 0x77, 0x74, 0x70, 0x6d, 0x6a,
+    0x67, 0x64, 0x61, 0x5e, 0x5b, 0x58, 0x55, 0x52,
+    0x4f, 0x4d, 0x4a, 0x47, 0x44, 0x41, 0x3f, 0x3c,
+    0x39, 0x37, 0x34, 0x32, 0x2f, 0x2d, 0x2b, 0x28,
+    0x26, 0x24, 0x22, 0x20, 0x1e, 0x1c, 0x1a, 0x18,
+    0x16, 0x15, 0x13, 0x11, 0x10, 0x0f, 0x0d, 0x0c,
+    0x0b, 0x0a, 0x08, 0x07, 0x06, 0x06, 0x05, 0x04,
+    0x03, 0x03, 0x02, 0x02, 0x02, 0x01, 0x01, 0x01,
+    0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, 0x03,
+    0x03, 0x04, 0x05, 0x06, 0x06, 0x07, 0x08, 0x0a,
+    0x0b, 0x0c, 0x0d, 0x0f, 0x10, 0x11, 0x13, 0x15,
+    0x16, 0x18, 0x1a, 0x1c, 0x1e, 0x20, 0x22, 0x24,
+    0x26, 0x28, 0x2b, 0x2d, 0x2f, 0x32, 0x34, 0x37,
+    0x39, 0x3c, 0x3f, 0x41, 0x44, 0x47, 0x4a, 0x4d,
+    0x4f, 0x52, 0x55, 0x58, 0x5b, 0x5e, 0x61, 0x64,
+    0x67, 0x6a, 0x6d, 0x70, 0x74, 0x77, 0x7a, 0x7d,
+    0x80, 0x83, 0x86, 0x89, 0x8c, 0x90, 0x93, 0x96,
+    0x99, 0x9c, 0x9f, 0xa2, 0xa5, 0xa8, 0xab, 0xae,
+    0xb1, 0xb3, 0xb6, 0xb9, 0xbc, 0xbf, 0xc1, 0xc4,
+    0xc7, 0xc9, 0xcc, 0xce, 0xd1, 0xd3, 0xd5, 0xd8,
+    0xda, 0xdc, 0xde, 0xe0, 0xe2, 0xe4, 0xe6, 0xe8,
+    0xea, 0xeb, 0xed, 0xef, 0xf0, 0xf1, 0xf3, 0xf4,
+    0xf5, 0xf6, 0xf8, 0xf9, 0xfa, 0xfa, 0xfb, 0xfc,
+    0xfd, 0xfd, 0xfe, 0xfe, 0xfe, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xfe, 0xfe, 0xfe, 0xfd,
+    0xfd, 0xfc, 0xfb, 0xfa, 0xfa, 0xf9, 0xf8, 0xf6,
+    0xf5, 0xf4, 0xf3, 0xf1, 0xf0, 0xef, 0xed, 0xeb,
+    0xea, 0xe8, 0xe6, 0xe4, 0xe2, 0xe0, 0xde, 0xdc,
+    0xda, 0xd8, 0xd5, 0xd3, 0xd1, 0xce, 0xcc, 0xc9,
+    0xc7, 0xc4, 0xc1, 0xbf, 0xbc, 0xb9, 0xb6, 0xb3,
+    0xb1, 0xae, 0xab, 0xa8, 0xa5, 0xa2, 0x9f, 0x9c,
+    0x99, 0x96, 0x93, 0x90, 0x8c, 0x89, 0x86, 0x83
+};

src/platform/c64.ts

@@ -32,6 +32,7 @@ const C64_PRESETS : Preset[] = [
   {id:'climber.c', name:'Climber Game'},
   {id:'test_border_sprites.c', name:'Sprites in the Borders'},
   {id:'sprite_stretch.c', name:'Sprite Stretching'},
+  {id:'linecrunch.c', name:'Linecrunch'},
   {id:'plasma.c', name:'Plasma Demo'},
   {id:'23matches.c', name:'23 Matches'},
   {id:'tgidemo.c', name:'TGI Graphics Demo'},