implementing sprites drawn overtop of tilemap

testbed.c

@@ -21,6 +21,7 @@
 #define setAllPlanes() outport(REG_TS, 0x0f02)
 
 #define VID ((volatile char far *)MK_FP(0xa000, 0))
+#define WVID ((volatile int far *)MK_FP(0xa000, 0))
 
 void vid_cleanup() {
   setTextMode();
@@ -377,7 +378,7 @@ int tifLoadEGA(FILE *f, TifImageMeta_t meta, unsigned int vidOffset, int maxY, u
   return y;
 }
 
-int tifLoad(FILE *f, TifImageMeta_t meta, unsigned int *planeBuf, int maxY, int yRepeat) {
+int tifLoad(FILE *f, TifImageMeta_t meta, unsigned int *planeBuf, int maxY, int yRepeat, int planes) {
   int istrip;
   int irow;
   int ipixelpair;
@@ -389,8 +390,9 @@ int tifLoad(FILE *f, TifImageMeta_t meta, unsigned int *planeBuf, int maxY, int
   unsigned int *g = b + planeStride;
   unsigned int *r = g + planeStride;
   unsigned int *i = r + planeStride;
+  unsigned int *m = i + planeStride;
 
-  if (meta.width > MAX_WIDTH || (meta.width % 16) != 0) {
+  if (meta.width > MAX_WIDTH || (meta.width % 16) != 0 || planes < 4 || planes > 5) {
     return 0;
   }
 
@@ -413,11 +415,17 @@ int tifLoad(FILE *f, TifImageMeta_t meta, unsigned int *planeBuf, int maxY, int
 	  *++g = gpair;
 	  *++r = rpair;
 	  *++i = ipair;
+	  if (planes == 5) {
+	    *++m = bpair & gpair & rpair & ipair;
+	  }
 	} else {
 	  *b |= bpair << shift;
 	  *g |= gpair << shift;
 	  *r |= rpair << shift;
 	  *i |= ipair << shift;
+	  if (planes == 5) {
+	    *m |= (bpair & gpair & rpair & ipair) << shift;
+	  }
 	}
       }
       y++;
@@ -425,10 +433,10 @@ int tifLoad(FILE *f, TifImageMeta_t meta, unsigned int *planeBuf, int maxY, int
 	return y;
       }
       if (y % yRepeat == 0) {
-	b += planeStride * 3;
+	b += planeStride * (planes - 1);
-	g += planeStride * 3;
+	g += planeStride * (planes - 1);
-	r += planeStride * 3;
+	r += planeStride * (planes - 1);
-	i += planeStride * 3;
+	i += planeStride * (planes - 1);
       }
     }
   }
@@ -436,12 +444,11 @@ int tifLoad(FILE *f, TifImageMeta_t meta, unsigned int *planeBuf, int maxY, int
 }
 
 /*** T I L E S ***/
-void prepareEgaMemCopy() {
-  setAllPlanes();
-  setWriteMode(1);
-}
 
-#define PAGE_STRIDE 42
+#define PAGE_TILES_W 21
+#define PAGE_TILES_H 13
+#define PAGE_TILES_COUNT (PAGE_TILES_H * PAGE_TILES_W)
+#define PAGE_STRIDE (PAGE_TILES_W << 1)
 
 void tile_init() {
   setLogicalWidth(PAGE_STRIDE >> 1);
@@ -456,19 +463,33 @@ void blitTile(unsigned int offsetFrom, unsigned int offsetTo) {
   }
 }
 
+#define D_NOTHING 0x80
+#define D_BGTILE 0x81
+#define isBufIndex(d) (!((d) & 0x80))
+
+#define NUM_BUFFERS 32
+#define nextBufferIndex(i) ((i + 1) % 32)
+#define BUF_WSTRIDE 16
+#define BUF_WSIZE (BUF_WSTRIDE * 4)
 typedef struct {
   unsigned int w;
   unsigned int h;
   int scrollX;
   int scrollY;
   unsigned int pageOffset[2];
-  unsigned char currentPage;
+  unsigned char dirty[2][PAGE_TILES_COUNT];
   unsigned int tilesOffset;
   unsigned int *memTiles;
   unsigned char *map;
+  unsigned int buffer[NUM_BUFFERS][BUF_WSIZE];
+  unsigned int bufferOffset[NUM_BUFFERS];
+  unsigned char currentPage;
+  unsigned char nextBuffer;
+  unsigned char firstBuffer;
 } TiledScreen_t;
 
-TiledScreen_t screen = { 0, 0, 0, 0, { 0x0400, 0x2620 }, 0, 0, NULL, NULL };
+TiledScreen_t screen = { 0, 0, 0, 0, { 0x0400, 0x2620 }, 0, 0, NULL, NULL,
+  0, 0, 0, 0, 0 };
 
 void loadTiles(unsigned int tilesOffset, unsigned int *memTiles) {
   screen.tilesOffset = tilesOffset;
@@ -481,11 +502,85 @@ void loadMap(unsigned char *map, unsigned int w, unsigned int h) {
   screen.h = h;
 }
 
+int prepareBuffer(int pageX, int pageY) {
+  unsigned char *dirty = &screen.dirty[screen.currentPage][pageX + (pageY * PAGE_TILES_W)];
+  if (!isBufIndex(*dirty)) {
+    unsigned int startX = screen.scrollX >> 4;
+    unsigned int startY = screen.scrollY >> 4;
+    unsigned char tile = screen.map[startX + pageX + ((startY + pageY) * screen.w)];
+    unsigned char ibuffer = screen.nextBuffer;
+    screen.nextBuffer = nextBufferIndex(screen.nextBuffer);
+    *dirty = ibuffer;
+    memcpy(screen.buffer[ibuffer], &screen.memTiles[tile * BUF_WSIZE], BUF_WSIZE);
+    screen.bufferOffset[ibuffer] = screen.pageOffset[screen.currentPage]
+      + (pageX << 1) + (pageY * PAGE_STRIDE);
+  }
+  return *dirty;
+}
+
+void drawSpriteToBuf(unsigned int *sprite, int pageX, int pageY, int shift, int yStart) {
+  unsigned int *buf, *mask;
+  int y, h, plane;
+  if (pageX < 0 || pageY < 0 ||
+      pageX >= PAGE_TILES_W || pageY >= PAGE_TILES_H ||
+      shift >= 16 || shift <= -16 ||
+      yStart <= -16 || yStart >= 16) {
+    return;
+  }
+
+  buf = screen.buffer[prepareBuffer(pageX, pageY)];
+/*  if (yStart < 0) {
+    sprite = &sprite[-yStart];
+    h = yStart + 16;
+  } else {
+    buf = &buf[yStart];
+    h = 16 - yStart;
+  }
+  mask = &sprite[16 * 4];
+  if (shift < 0) {
+    shift = -shift;
+    for (plane = 0; plane < 4; plane ++) {
+      for (y = 0; y < h; y ++) {
+	buf[y] = (buf[y] & ~(mask[y] << shift)) | (sprite[y] << shift);
+      }
+      sprite += BUF_WSTRIDE;
+      buf += BUF_WSTRIDE;
+    }
+  } else {
+    for (plane = 0; plane < 4; plane ++) {
+      for (y = 0; y < h; y ++) {
+	buf[y] = (buf[y] & ~(mask[y] >> shift)) | (sprite[y] >> shift);
+      }
+      sprite += BUF_WSTRIDE;
+      buf += BUF_WSTRIDE;
+    }
+  }*/
+}
+
+void drawSprite(unsigned int *sprite, int x, int y) {
+  unsigned int startX = screen.scrollX >> 4;
+  unsigned int startY = screen.scrollY >> 4;
+  int pageX = (x - startX) >> 4;
+  int pageY = (y - startY) >> 4;
+  int pageOffsetX = x - (pageX << 4);
+  int pageOffsetY = y - (pageY << 4);
+
+  drawSpriteToBuf(sprite, pageX, pageY, pageOffsetX, pageOffsetY);
+  drawSpriteToBuf(sprite, pageX + 1, pageY, pageOffsetX - 16, pageOffsetY);
+  drawSpriteToBuf(sprite, pageX, pageY + 1, pageOffsetX, pageOffsetY - 16);
+  drawSpriteToBuf(sprite, pageX + 1, pageY + 1, pageOffsetX - 16, pageOffsetY - 16);
+}
+
 void scroll(int x, int y) {
+  unsigned int startX = screen.scrollX >> 4;
+  unsigned int startY = screen.scrollY >> 4;
   x = min(max(x, 0), (screen.w << 4) - 320);
   y = min(max(y, 0), (screen.h << 4) - 176);
   screen.scrollX = x;
   screen.scrollY = y;
+  if (startX != (x >> 4) || startY != (y >> 4)) {
+    memset(screen.dirty, D_BGTILE, 2 * PAGE_TILES_COUNT);
+  }
 }
 
 void drawScreen() {
@@ -495,27 +590,51 @@ void drawScreen() {
   unsigned int offsetY = screen.scrollY - (startY << 4);
   unsigned int drawOffset = screen.pageOffset[screen.currentPage];
   unsigned int scrollOffset = drawOffset + (offsetX >> 3) + (offsetY * PAGE_STRIDE);
-  unsigned int x, y;
+  unsigned char *dirty = screen.dirty[screen.currentPage];
+  unsigned int x, y, di, plane;
 
-  prepareEgaMemCopy();
+  setAllPlanes();
+  setWriteMode(1);
 
-  for (y = startY; y < startY + 13; y ++) {
+  di = 0;
-    for (x = startX; x < startX + 21; x ++) {
+  for (y = startY; y < startY + PAGE_TILES_H; y ++) {
+    for (x = startX; x < startX + PAGE_TILES_W; x ++) {
+      if (dirty[di++] == D_BGTILE) {
 	blitTile(screen.tilesOffset + screen.map[x + (y * screen.w)], drawOffset);
+      }
       drawOffset += 2;
     }
     drawOffset += PAGE_STRIDE * 15;
   }
-
+  setWriteMode(0);
+  for(plane = 0; plane < 4; plane ++) {
+    setPlane(plane);
+    for (di = screen.firstBuffer; di != screen.nextBuffer; di = nextBufferIndex(di)) {
+      drawOffset = screen.bufferOffset[di] >> 1;
+      for (y = 0; y < 16; y ++) {
+	WVID[drawOffset] = screen.buffer[di][y + (BUF_WSTRIDE * plane)];
+	drawOffset += PAGE_STRIDE >> 1;
+      }
+    }
+  }
+  setAllPlanes();
   setDisplayOffset(scrollOffset);
   screen.currentPage ^= 1;
+  screen.firstBuffer = screen.nextBuffer;
+  for (di = 0; di < PAGE_TILES_COUNT; di ++) {
+    dirty[di] = isBufIndex(dirty[di]) ? D_BGTILE : D_NOTHING;
+  }
 }
 
 /*** S C R A T C H ***/
-
+#define NUM_TILES 128
-unsigned int tiles[2*16 * 128];
+#define NUM_SPRITES 64
 #define OFF_TILES 0x4840
 
+unsigned int tiles[NUM_TILES][4*16];
+unsigned int sprites[NUM_SPRITES][5*16];
+
+
 unsigned char map[10000];
 
 void fillMap() {
@@ -546,8 +665,13 @@ void game_init() {
 
   f = fopen("TILES.TIF", "rb");
   meta = tifLoadMeta(f);
-  tifLoadEGA(f, meta, OFF_TILES, 256, 16);
+  tifLoadEGA(f, meta, OFF_TILES, NUM_TILES * 16, 16);
-  tifLoad(f, meta, tiles, 128 * 16, 16);
+  tifLoad(f, meta, tiles, NUM_TILES * 16, 16, 4);
+  fclose(f);
+
+  f = fopen("SPRITE.TIF", "rb");
+  meta = tifLoadMeta(f);
+  tifLoad(f, meta, sprites, NUM_SPRITES * 16, 16, 5);
   fclose(f);
 
   setSplitScreen(351);
@@ -558,8 +682,8 @@ void game_init() {
 }
 
 int main() {
-  int x;
+  int x = 100;
-  int y;
+  int y = 100;
   int z = 0;
 
   game_init();
@@ -567,13 +691,13 @@ int main() {
 
   while (!keyPressed(K_ESC)) {
 
-    x = screen.scrollX;
+    if (keyPressed(K_LEFT))  x -= 1;
-    y = screen.scrollY;
+    if (keyPressed(K_RIGHT)) x += 1;
-    if (keyPressed(K_LEFT))  x -= 8;
+    if (keyPressed(K_UP))    y -= 1;
-    if (keyPressed(K_RIGHT)) x += 8;
+    if (keyPressed(K_DOWN))  y += 1;
-    if (keyPressed(K_UP))    y -= 8;
+    scroll(x + 152, y + 90);
-    if (keyPressed(K_DOWN))  y += 8;
+    drawSprite(sprites[0], 50, 50);
-    scroll(x, y);
+    drawSprite(sprites[1], x, y);
     drawScreen();
 
     z++;