Implement map scrolling

testbed.c

@@ -26,42 +26,37 @@ void vid_cleanup() {
   setTextMode();
 }
 
-typedef struct {
-  unsigned int b[16];
-  unsigned int g[16];
-  unsigned int r[16];
-  unsigned int i[16];
-} Tile_t;
-
-unsigned int PAGE[] = { 0x04, 0x24 };
-
 #define setWriteMode(m) outport(REG_GDC, 0x05 | m << 8)
 void setSplitScreen(unsigned int y) {
-// TODO: VGA registers??
-  outport(REG_CRTC, 0x1018);// | y << 8);
-  outport(REG_CRTC, 0x0107);
+  int val;
+  outport(REG_CRTC, 0x18 | (y << 8));
+  outp(REG_CRTC, 7);
+  val = inp(REG_CRTC + 1);
+  val &= ~0x10;
+  val |= (y & 0x100) >> 4;
+  outp(REG_CRTC + 1, val);
+  outp(REG_CRTC, 9);
+  val = inp(REG_CRTC + 1);
+  val &= ~0x40;
+  outp(REG_CRTC + 1, val);
 }
+
 void unsetSplitScreen() {
   outport(REG_CRTC, 0xff18);
   outport(REG_CRTC, 0x1107);
+  outport(REG_CRTC, 0x0f09);
 }
 
-void prepareEgaMemCopy() {
-  setAllPlanes();
-  setWriteMode(1);
-}
-#define PAGE_STRIDE 40
-void blitTile(unsigned int offsetFrom, unsigned int offsetTo) {
-  int y;
-  for (y = 0; y < 16; y ++) {
-    VID[offsetTo] = VID[offsetFrom ++];
-    VID[offsetTo + 1] = VID[offsetFrom ++];
-    offsetTo += PAGE_STRIDE;
-  }
-}
 
 #define flipPage(p) outport(REG_CRTC, 0x0c | (p << 8))
 
+void setDisplayOffset(unsigned int offset) {
+  outport(REG_CRTC, 0x0c | (offset & 0xff00));
+  outport(REG_CRTC, 0x0d | (offset << 8));
+}
+
+#define setLogicalWidth(w) outport(REG_CRTC, 0x13 | (w << 8))
+ 
 /*** K E Y B O A R D ***/
 #define KBD_INT 0x09
 void interrupt (*oldKbdISR)() = NULL;
@@ -325,7 +320,7 @@ fail:
 
 #define MAX_WIDTH 320
 
-int tifLoadEGA(FILE *f, TifImageMeta_t meta, unsigned int vidOffset, int maxY) {
+int tifLoadEGA(FILE *f, TifImageMeta_t meta, unsigned int vidOffset, int maxY, unsigned int w) {
   int istrip;
   int irow;
   int ipixelpair;
@@ -376,6 +371,7 @@ int tifLoadEGA(FILE *f, TifImageMeta_t meta, unsigned int vidOffset, int maxY) {
       if (y == maxY) {
 	return y;
       }
+      out += (w - meta.width) >> 3;
     }
   }
   return y;
@@ -439,30 +435,87 @@ int tifLoad(FILE *f, TifImageMeta_t meta, unsigned int *planeBuf, int maxY, int
   return y;
 }
 
-/*** S C R A T C H ***/
-void paintPattern(int r, int g, int b, int t) {
-  int i;
+/*** T I L E S ***/
+void prepareEgaMemCopy() {
+  setAllPlanes();
+  setWriteMode(1);
+}
 
-  setPlane(PLANE_R);
-  for (i = 0; i < 8000; i ++) {
-    VID[i] = r;
+#define PAGE_STRIDE 42
+
+void tile_init() {
+  setLogicalWidth(PAGE_STRIDE >> 1);
 }
-  setPlane(PLANE_G);
-  for (i = 0; i < 8000; i ++) {
-    VID[i] = g;
+
+void blitTile(unsigned int offsetFrom, unsigned int offsetTo) {
+  int y;
+  for (y = 0; y < 16; y ++) {
+    VID[offsetTo] = VID[offsetFrom ++];
+    VID[offsetTo + 1] = VID[offsetFrom ++];
+    offsetTo += PAGE_STRIDE;
   }
-  setPlane(PLANE_B);
-  for (i = 0; i < 8000; i ++) {
-    VID[i] = b;
 }
-  setPlane(PLANE_I);
-  for (i = 0; i < 8000; i ++) {
-    VID[i] = t;
+
+typedef struct {
+  unsigned int w;
+  unsigned int h;
+  int scrollX;
+  int scrollY;
+  unsigned int pageOffset;
+  unsigned char *tiles;
+} TilePage_t;
+
+#define OFF_TILES 0x4840
+
+void scrollPage(TilePage_t *page, int x, int y) {
+  x = min(max(x, 0), (page->w << 4) - 320);
+  y = min(max(y, 0), (page->h << 4) - 176);
+  page->scrollX = x;
+  page->scrollY = y;
+}
+
+void drawPage(TilePage_t *page) {
+  unsigned int startX = page->scrollX >> 4;
+  unsigned int startY = page->scrollY >> 4;
+  unsigned int offsetX = page->scrollX - (startX << 4);
+  unsigned int offsetY = page->scrollY - (startY << 4);
+  unsigned int drawOffset = page->pageOffset;
+  unsigned int scrollOffset = drawOffset + (offsetX >> 3) + (offsetY * PAGE_STRIDE);
+  unsigned int x, y;
+
+  prepareEgaMemCopy();
+
+  for (y = startY; y < startY + 13; y ++) {
+    for (x = startX; x < startX + 21; x ++) {
+      blitTile(OFF_TILES + page->tiles[x + (y * page->w)], drawOffset);
+      drawOffset += 2;
+    }
+    drawOffset += PAGE_STRIDE * 15;
+  }
+
+  setDisplayOffset(scrollOffset);
+}
+
+/*** S C R A T C H ***/
+
+unsigned char tiles[10000];
+TilePage_t pages[2] = {
+  { 100, 100, 0, 0, 0x0400, tiles },
+  { 100, 100, 0, 0, 0x2620, tiles }
+};
+
+void fillTiles() {
+  unsigned int x, y, z;
+  z = 0;
+
+  for (y = 0; y < 100; y ++) {
+    for (x = 0; x < 100; x ++) {
+      tiles[x + (y * 100)] = (((x + y + z) >> 2) % 3) << 5;
+    }
   }
 }
 
 int main() {
-  Tile_t tiles[16];
   FILE *f;
   TifImageMeta_t meta;
   int plane;
@@ -472,41 +525,39 @@ int main() {
   unsigned int drawOffset;
   unsigned int page = 0;
 
-  #define OFF_TILES 0x4200
-
   setEGAMode();
   atexit(vid_cleanup);
 
   f = fopen("FOOTER.TIF", "rb");
   meta = tifLoadMeta(f);
-  tifLoadEGA(f, meta, 0, 24);
+  tifLoadEGA(f, meta, 0, 24, 336);
   fclose(f);
 
   f = fopen("TILES.TIF", "rb");
   meta = tifLoadMeta(f);
-  tifLoadEGA(f, meta, OFF_TILES, 256);
+  tifLoadEGA(f, meta, OFF_TILES, 256, 16);
   fclose(f);
 
-  mouse_init();
   kbd_init();
+  tile_init();
+  setSplitScreen(351);
+
+  fillTiles();
 
   while (!keyPressed(K_ESC)) {
     page ^= 1;
 
-    prepareEgaMemCopy();
-    drawOffset = PAGE[page] << 8;
-    for (y = 0; y < 11; y ++) {
-      for (x = 0; x < 20; x ++) {
-	blitTile(OFF_TILES + ((((x + y + z) >> 2) % 3) << 5), drawOffset);
-	drawOffset += 2;
-      }
-      drawOffset += 600; // 40 bytes per line * 15 more lines
-    }
+    x = pages[page].scrollX;
+    y = pages[page].scrollY;
+    if (keyPressed(K_LEFT))  x -= 4;
+    if (keyPressed(K_RIGHT)) x += 4;
+    if (keyPressed(K_UP))    y -= 4;
+    if (keyPressed(K_DOWN))  y += 4;
+    scrollPage(&pages[0], x, y);
+    scrollPage(&pages[1], x, y);
+    drawPage(&pages[page]);
 
-    flipPage(PAGE[page]);
-    setSplitScreen(16);
-
-    kbd_wait();
+//    kbd_wait();
     z++;
   }