start optimizing

bun.c

@@ -66,41 +66,63 @@ void teardownBun(void) {
   }
 }
 
+#define BLITTER_ASCENDING (0)
+#define BLITTER_DESCENDING (1)
+
+struct BunClear {
+  uint16_t memoryStartOffsetBytes;
+  uint16_t widthWords;
+  uint16_t heightRows;
+  uint8_t direction;
+};
+
+#define BUN_OFF_RIGHT_SIDE (0)
+#define BUN_OFF_LEFT_SIDE (1)
+#define BUN_ANYWHERE (2)
+
+uint8_t *coolbunPlaneStarts[3][2];
+
 void bun_offRightSide(
   int plusXValue,
   int y,
   struct ScreenSetup *screenSetup,
-  struct CurrentScreen *currentScreen
+  struct CurrentScreen *currentScreen,
+  struct BunClear *bunClear
 ) {
   uint8_t i, plane = 0;
   uint8_t shift = plusXValue & 15;
   uint8_t wordShift = (plusXValue >> 4);
   uint16_t bltalwm;
 
-  for (plane = 0; plane < 2; ++plane) {
+  bunClear->memoryStartOffsetBytes =  (y * screenSetup->byteWidth) +
-    custom.bltcon0 = BLTCON0(0xc0, 0, 1, 0, 1, shift);
-    custom.bltcon1 = BLTCON1(0, shift);
-
-    custom.bltadat = 0xffff;
-    custom.bltbpt = coolbunArea +
-      plane * COOL_BUN_PLANE_SIZE;
-    custom.bltdpt = currentScreen->planes[plane] +
-      (y * screenSetup->byteWidth) +
     screenSetup->byteWidth - COOL_BUN_WIDTH_BYTES +
     wordShift * 2;
+  bunClear->heightRows = COOL_BUN_HEIGHT;
+  bunClear->widthWords = 2 - wordShift;
+  bunClear->direction = BLITTER_ASCENDING;
 
-    custom.bltafwm = 0xffff;
   bltalwm = 0x0000;
   for (i = 0; i <= 15 - shift; ++i) {
     bltalwm += (1 << (15 - i));
   }
+
+  for (plane = 0; plane < 2; ++plane) {
+    custom.bltcon0 = BLTCON0(0xc0, 0, 1, 0, 1, shift);
+    custom.bltcon1 = BLTCON1(bunClear->direction, shift);
+
+    custom.bltadat = 0xffff;
+    custom.bltbpt = coolbunPlaneStarts[BUN_OFF_LEFT_SIDE][plane];
+    custom.bltdpt = currentScreen->planes[plane] +
+      bunClear->memoryStartOffsetBytes;
+
+    custom.bltafwm = 0xffff;
     custom.bltalwm = bltalwm;
 
     custom.bltbmod = wordShift * 2;
     custom.bltdmod = screenSetup->byteWidth - COOL_BUN_WIDTH_BYTES +
       wordShift * 2;
 
-    custom.bltsize = 2 - wordShift + (COOL_BUN_HEIGHT << 6);
+    custom.bltsize = bunClear->widthWords + (bunClear->heightRows << 6);
 
     WaitBlit();
   }
@@ -110,7 +132,8 @@ void bun_offLeftSide(
   int minusXValue,
   int y,
   struct ScreenSetup *screenSetup,
-  struct CurrentScreen *currentScreen
+  struct CurrentScreen *currentScreen,
+  struct BunClear *bunClear
 ) {
   unsigned char plane;
   uint8_t shift = minusXValue & 15;
@@ -121,35 +144,37 @@ void bun_offLeftSide(
   // y can't be 0 otherwise we will corrupt memory for now
   if (y == 0) return;
 
-  for (plane = 0; plane < 2; ++plane) {
+  bunClear->memoryStartOffsetBytes = (screenSetup->byteWidth * (y + COOL_BUN_LAST_ROW)) +
-    // shift left, so descending
+    2 - wordShift * 2;
-    custom.bltcon0 = BLTCON0(0xc0, 0, 1, 0, 1, shift);
+  bunClear->heightRows = COOL_BUN_HEIGHT;
-    custom.bltcon1 = BLTCON1(1, shift);
+  bunClear->widthWords = 2 - wordShift;
+  bunClear->direction = BLITTER_DESCENDING;
 
-    // a has a mask we're shifting
-    custom.bltadat = 0xffff;
-    // b has bun data
-    custom.bltbpt = coolbunArea + 2 +
-      COOL_BUN_LAST_ROW_BYTES +
-      plane * COOL_BUN_PLANE_SIZE;
-
-    // d is the part on screen
-    custom.bltdpt = currentScreen->planes[plane] +
-      (screenSetup->byteWidth * (y + COOL_BUN_LAST_ROW)) +
-      2 -
-      wordShift * 2;
-
-    custom.bltafwm = 0xffff;
   bltalwm = 0x0000;
   for (i = 0; i <= 15 - shift; ++i) {
     bltalwm += (1 << i);
   }
+
+  for (plane = 0; plane < 2; ++plane) {
+    // shift left, so descending
+    custom.bltcon0 = BLTCON0(0xc0, 0, 1, 0, 1, shift);
+    custom.bltcon1 = BLTCON1(bunClear->direction, shift);
+
+    // a has a mask we're shifting
+    custom.bltadat = 0xffff;
+    // b has bun data
+    custom.bltbpt = coolbunPlaneStarts[BUN_OFF_RIGHT_SIDE][plane];
+
+    // d is the part on screen
+    custom.bltdpt = currentScreen->planes[plane] + bunClear->memoryStartOffsetBytes;
+
+    custom.bltafwm = 0xffff;
     custom.bltalwm = bltalwm;
 
     custom.bltbmod = wordShift * 2;
     custom.bltdmod = screenSetup->byteWidth - 4 + wordShift * 2;
 
-    custom.bltsize = 2 - wordShift + (COOL_BUN_HEIGHT << 6);
+    custom.bltsize = bunClear->widthWords + (bunClear->heightRows << 6);
 
     WaitBlit();
   }
@@ -159,24 +184,31 @@ void bun_anywhere(
   int x,
   int y,
   struct ScreenSetup *screenSetup,
-  struct CurrentScreen *currentScreen
+  struct CurrentScreen *currentScreen,
+  struct BunClear *bunClear
 ) {
   uint8_t plane;
   uint8_t shift = x & 15;
   uint8_t needsExtraWord = shift != 0;
 
+  bunClear->memoryStartOffsetBytes = WORD_ALIGNED_BYTE_POSITION(screenSetup->width, x, y);
+
+  bunClear->heightRows = COOL_BUN_HEIGHT;
+  bunClear->widthWords = 2 + needsExtraWord;
+  bunClear->direction = BLITTER_ASCENDING;
+
   for (plane = 0; plane < 2; ++plane) {
     // if we extend the bun area by a word, we only need one write
 
     // buns will never interfere with a background so they don't need a mask
     // they do need the scratch area though
     custom.bltcon0 = BLTCON0(0xc0, 0, 1, 0, 1, shift);
-    custom.bltcon1 = BLTCON1(0, shift);
+    custom.bltcon1 = BLTCON1(bunClear->direction, shift);
 
     custom.bltadat = 0xffff;
-    custom.bltbpt = coolbunArea + plane * COOL_BUN_PLANE_SIZE;
+    custom.bltbpt = coolbunPlaneStarts[BUN_ANYWHERE][plane];
     custom.bltdpt = currentScreen->planes[plane] +
-      WORD_ALIGNED_BYTE_POSITION(screenSetup->width, x, y);
+      bunClear->memoryStartOffsetBytes;
 
    // custom.bltdpt = screenSetup.memoryStart;
     custom.bltafwm = 0xffff;
@@ -188,7 +220,7 @@ void bun_anywhere(
 
     custom.bltbmod = -(needsExtraWord * 2);
     custom.bltdmod = screenSetup->byteWidth - COOL_BUN_WIDTH_BYTES - (needsExtraWord * 2);
-    custom.bltsize = (2 + needsExtraWord) + (COOL_BUN_HEIGHT << 6);
+    custom.bltsize = bunClear->widthWords + (bunClear->heightRows << 6);
 
     WaitBlit();
   }
@@ -198,7 +230,8 @@ void renderBun(
   int x,
   int y,
   struct ScreenSetup *screenSetup,
-  struct CurrentScreen *currentScreen
+  struct CurrentScreen *currentScreen,
+  struct BunClear *bunClear
 ) {
   /**
     * Conditions that will cause the program to crash if met. If your bun
@@ -212,11 +245,29 @@ void renderBun(
   if (y > screenSetup->height- COOL_BUN_HEIGHT - 1) return;
 
   if (x < 0) {
-    bun_offLeftSide(-x, y, screenSetup, currentScreen);
+    bun_offLeftSide(
+      -x,
+      y,
+      screenSetup,
+      currentScreen,
+      bunClear
+    );
   } else if (x > screenSetup->width - COOL_BUN_WIDTH) {
-    bun_offRightSide(x - (screenSetup->width - COOL_BUN_WIDTH), y, screenSetup, currentScreen);
+    bun_offRightSide(
+      x - (screenSetup->width - COOL_BUN_WIDTH),
+      y,
+      screenSetup,
+      currentScreen,
+      bunClear
+    );
   } else {
-    bun_anywhere(x, y, screenSetup, currentScreen);
+    bun_anywhere(
+      x,
+      y,
+      screenSetup,
+      currentScreen,
+      bunClear
+    );
   }
 }
 
@@ -286,6 +337,18 @@ void buildBunAngleAdjustments() {
   }
 }
 
+void precalculeBunRenderInfo(void) {
+  int plane;
+
+  for (plane = 0; plane < 2; ++plane) {
+    coolbunPlaneStarts[BUN_OFF_LEFT_SIDE][plane] = coolbunArea + plane * COOL_BUN_PLANE_SIZE;
+    coolbunPlaneStarts[BUN_ANYWHERE][plane] = coolbunArea + plane * COOL_BUN_PLANE_SIZE;
+    coolbunPlaneStarts[BUN_OFF_RIGHT_SIDE][plane] = coolbunArea + 2 +
+      COOL_BUN_LAST_ROW_BYTES +
+      plane * COOL_BUN_PLANE_SIZE;
+  }
+}
+
 void setupBunRenderer(
   struct BunRenderer *bunRenderer,
   struct ScreenSetup *screenSetup,
@@ -296,6 +359,36 @@ void setupBunRenderer(
   setupBun();
   buildBunAngleAdjustments();
   calculateAllBunPositions(screenSetup);
+  precalculeBunRenderInfo();
+}
+
+int hasBunClear[2] = {0,0};
+struct BunClear bunClearForScreen[2][BUN_COUNT];
+
+void clearCurrentBuns(
+  struct BunRenderer *bunRenderer
+) {
+  int bun, plane;
+  struct BunClear *currentBunClear;
+
+  if (!hasBunClear[bunRenderer->currentScreen->currentBuffer]) return;
+
+  for (bun = 0; bun < BUN_COUNT; ++bun) {
+    currentBunClear = &bunClearForScreen[bunRenderer->currentScreen->currentBuffer][bun];
+
+    for (plane = 0; plane < 2; ++plane) {
+      custom.bltcon0 = 0xc0 + (1 << 8);
+      custom.bltcon1 = BLTCON1(currentBunClear->direction, 0);
+      custom.bltadat = 0x0000;
+      custom.bltafwm = 0xffff;
+      custom.bltalwm = 0xffff;
+      custom.bltdpt = bunRenderer->currentScreen->planes[plane] +
+        currentBunClear->memoryStartOffsetBytes;
+      custom.bltdmod = bunRenderer->screenSetup->byteWidth - (currentBunClear->widthWords * 2);
+      custom.bltsize = currentBunClear->widthWords + (currentBunClear->heightRows << 6);
+      WaitBlit();
+    }
+  }
 }
 
 void renderBunFrame(
@@ -311,9 +404,12 @@ void renderBunFrame(
       allBunPositionsByFrame[frame][bun][0],
       allBunPositionsByFrame[frame][bun][1],
       bunRenderer->screenSetup,
-      bunRenderer->currentScreen
+      bunRenderer->currentScreen,
+      &bunClearForScreen[bunRenderer->currentScreen->currentBuffer][bun]
     );
   }
+
+  hasBunClear[bunRenderer->currentScreen->currentBuffer] = 1;
 }
 
 void teardownBunRenderer() {

bun.h

@@ -20,5 +20,8 @@ void renderBunFrame(
   int frame,
   struct BunRenderer *
 );
+void clearCurrentBuns(
+  struct BunRenderer *
+);
 void teardownBunRenderer(void);
 #endif

main.c

@@ -180,6 +180,9 @@ int main(void) {
   while (1) {
     swapCurrentScreenBuffer(&screenSetup, &currentScreen);
 
+    clearCurrentBuns(&bunRenderer);
+
+    /*
     for (plane = 0; plane < 2; ++plane) {
       custom.bltcon0 = 0xc0 + (1 << 8);
       custom.bltcon1 = 0;
@@ -191,6 +194,7 @@ int main(void) {
       custom.bltsize = screenSetup.byteWidth / 2 + (screenSetup.height << 6);
       WaitBlit();
     }
+    */
 
     renderBunFrame(i, &bunRenderer);
 
@@ -228,7 +232,6 @@ int main(void) {
 
 
     WaitTOF();
-    //WaitTOF();
     
     if ((ciaa.ciapra >> 6) != 3) break;