From: Shamus Hammons <jlhamm@acm.org>
Date: Thu, 3 Sep 2009 19:52:07 +0000 (+0000)
Subject: Small refactoring to sprite draw code in anticipation of major refactoring
X-Git-Url: http://shamusworld.gotdns.org/cgi-bin/gitweb.cgi?p=thunder;a=commitdiff_plain;h=d6a4e86c4d3e3a48254975400715ea985311a346

Small refactoring to sprite draw code in anticipation of major refactoring
of sprite draw code. :-)
---

diff --git a/src/screen.cpp b/src/screen.cpp
index 0d65192..fef69a0 100755
--- a/src/screen.cpp
+++ b/src/screen.cpp
@@ -36,10 +36,10 @@ uint8 palette[768];										// Screen palette
 uint8 ccolor[256][8];									// Character colors
 uint8 scolor[128][16];									// Sprite colors
 bool charbase;											// Character base pointer...
-uint8 hScrollOffset;										// Horizontal scroll offset
-uint8 vScrollOffset;										// Vertical scroll offset
+uint8 hScrollOffset;									// Horizontal scroll offset
+uint8 vScrollOffset;									// Vertical scroll offset
 uint8 spr_color_index;									// Sprite color index
-uint32 offsets[8] = { 0, 1, 2, 3, 4, 5, 6, 7 };			// Scroll offsets...
+uint32 hoffsets[8] = { 0, 1, 2, 3, 4, 5, 6, 7 };		// Scroll offsets...
 uint32 voffsets[8] = { 0, 320, 640, 960, 1280, 1600, 1920, 2240 };
 
 extern bool show_text;									// Whether or not to show text
@@ -132,16 +132,14 @@ void BlitChar(SDL_Surface * scr, uint8 * chr, uint8 * ram)
 	// Rolling Thunder screen size is 288 x 224. Virtual is this, real may not be...
 
 	// Doubled pixel blit (should be faster now!)
-//	uint8 * pMem = (uint8 *)scr->pixels + ((scr->pitch * 8 + 16) * 2);
 	uint8 * pMem = (uint8 *)scr->pixels;
-	uint32 src = (uint32)(offsets[hScrollOffset] + voffsets[vScrollOffset]),
+	uint32 src = (uint32)(hoffsets[hScrollOffset] + voffsets[vScrollOffset]),
 		dst1 = 0, dst2 = scr->pitch;
-//	uint32 srcAdd = 320 - 288, dstAdd = (scr->pitch * 2) - (288 * 2);
-	uint32 srcAdd = 320 - 288, dstAdd = (scr->pitch * 2) - (288 * 2);
+	uint32 srcAdd = 320 - VIRTUAL_SCREEN_WIDTH, dstAdd = (scr->pitch * 2) - (VIRTUAL_SCREEN_WIDTH * 2);
 
-	for(int i=0; i<224; i++)
+	for(int i=0; i<VIRTUAL_SCREEN_HEIGHT; i++)
 	{
-		for (int j=0; j<288; j++)
+		for (int j=0; j<VIRTUAL_SCREEN_WIDTH; j++)
 		{
 			pMem[dst1] = pMem[dst1 + 1] = pMem[dst2] = pMem[dst2 + 1] = my_scr[src++];
 			dst1 += 2;
@@ -195,24 +193,36 @@ static inline void DrawChar(uint8 * chr, uint8 * ram, uint8 sx, uint8 sy, uint16
 //
 void DrawSprites(uint8 priority)
 {
-	extern uint8 gram1[];								// Game RAM space
+	// Sprite blocks:
+	//
+	// Offset  Note
+	// ------  -----------------------------------------------------------------------------------
+	// 4       h.fb .nnn (f = horz. flip, h = horz. expand, b = sprite offset lo bit, nnn = upper bits of sprite #)
+	// 5       Lower 7 bits of sprite #
+	// 6       Sprite color index (top 7 bits only), bottom bit is bit 8 of X position
+	// 7       Sprite X position (bits 0-7)
+	// 8       Top two bits are sprite priority, bits 4 & 2 are sprite offset hi bit, vert. expand
+	// 9       Sprite Y position (192 - value)
+
+	extern uint8 gram1[];							// Game RAM space
 
 	for(uint16 i=0x5800; i<0x6000; i+=0x10)
 	{
-		if ((gram1[i + 8] & 0xC0) == priority)			// Check for correct layer...
+		if ((gram1[i + 8] & 0xC0) == priority)		// Check for correct layer...
 		{
-			spr_color_index = gram1[i + 6] >> 1;		// Set color...
+			spr_color_index = gram1[i + 6] >> 1;	// Set color...
 			uint16 x = ((gram1[i + 6] & 0x01) << 8) | gram1[i + 7];
 
 			if (x > 512 - 32)
-				x -= 512;								// Handle neg x values
+				x -= 512;							// Handle neg x values
 
 			uint16 y = 192 - gram1[i + 9];
-			uint16 hdr = (gram1[i + 4] & 0x90) << 8 | (gram1[i + 8] & 0x14);
-			uint8 flip = gram1[i + 4] & 0x20;			// Horizontal flip
+			uint8 flip = gram1[i + 4] & 0x20;		// Horizontal flip
 			uint32 spr_num = ((gram1[i + 4] & 0x07) << 9) | ((gram1[i + 5] & 0x7F) << 2);
+			spr_num += ((gram1[i + 4] & 0x10) >> 4) + ((gram1[i + 8] & 0x10) >> 3);
 
-			Sprite(spr_num, x, y, flip, hdr);			// Draw sprite...
+			// Draw sprite...
+			Sprite(spr_num, x, y, flip, (gram1[i + 4] & 0x80 ? true : false), (gram1[i + 8] & 0x04 ? true : false));
 		}
 	}
 }
@@ -220,72 +230,19 @@ void DrawSprites(uint8 priority)
 //
 // Sprite handler
 //
-void Sprite(uint32 sprnum, uint16 x, uint16 y, uint8 flip, uint16 spr_id)
+//void Sprite(uint32 sprnum, uint16 x, uint16 y, uint8 flip, uint16 spr_id)
+void Sprite(uint32 sprnum, uint16 x, uint16 y, uint8 flip, bool horiz_bl, bool vert_bl)
 {
 	extern uint8 spr_rom[];
-	// To show or not to show a 16x16 block in the 4x4 grid...
-	bool horiz_bl = false, vert_bl = false;
 	uint32 sc_addr;
 
-	x += hScrollOffset;									// Adjust x-coord
-	y += vScrollOffset;									// Adjust y-coord
+	x += hScrollOffset;							// Adjust x-coord
+	y += vScrollOffset;							// Adjust y-coord
 
-//	8421 8421 8421 8421
-//	1xxx xxxx xxxx xxxx   horiz_bl?
-//	xxxx xxxx xxxx x1xx   vert_bl?
-//	xxxx xxxx xxxx x0xx   y + 16?
-//	xxxB xxxx xxxA xxxx   spr# (AB) to start
+	sprnum <<= 7;								// 128 bytes per sprite
 
-#if 1
-	if (spr_id & 0x8000)
-		horiz_bl = true;
-
-	if (spr_id & 0x0004)
-		vert_bl = true;
-	else
-		y += 16;
-
-	sprnum += ((spr_id & 0x1000) >> 12) + ((spr_id & 0x0010) >> 3);
-#else
-	if (spr_id == 0x8004)
-	{
-		horiz_bl = true;  vert_bl = true;
-	}
-	if (spr_id == 0x8000)
-	{
-		horiz_bl = true;  y += 16;
-	}
-	if (spr_id == 0x8010)
-	{
-		horiz_bl = true;  y += 16;  sprnum += 2;
-	}
-	if (spr_id == 0x0004)
-	{
-		vert_bl = true;
-	}
-	if (spr_id == 0x1004)
-	{
-		vert_bl = true;  sprnum++;
-	}
-	if (spr_id == 0x0000)
-	{
+	if (!vert_bl)
 		y += 16;
-	}
-	if (spr_id == 0x1000)
-	{
-		y += 16;  sprnum++;
-	}
-	if (spr_id == 0x0010)
-	{
-		y += 16;  sprnum += 2;
-	}
-	if (spr_id == 0x1010)
-	{
-		y += 16;  sprnum += 3;
-	}
-#endif
-
-	sprnum <<= 7;									// 128 bytes per sprite
 
 	if (!flip)
 	{
diff --git a/src/screen.h b/src/screen.h
index 832ec8a..f616de0 100755
--- a/src/screen.h
+++ b/src/screen.h
@@ -16,6 +16,7 @@
 
 void SnapPCX(SDL_Surface *);          // Take a PCX snapshot
 void BlitChar(SDL_Surface *, uint8 *, uint8 *); // Show NAMCO screen
-void Sprite(uint32, uint16, uint16, uint8, uint16); // Show sprite on the screen
+//void Sprite(uint32, uint16, uint16, uint8, uint16); // Show sprite on the screen
+void Sprite(uint32 sprnum, uint16 x, uint16 y, uint8 flip, bool horiz_bl, bool vert_bl);
 
 #endif	// __SCREEN_H__