584 lines
18 KiB
C
584 lines
18 KiB
C
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/*
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* An Astrocade port of the Cosmic Impalas game
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* described in the book
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* "Making 8-bit Arcade Games in C"
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*/
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//#link "acheader.s"
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#include <string.h>
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#define EXIT_CLIPY(y) if (((unsigned char)y)>=VHEIGHT) return
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#define EXIT_CLIPDEST(addr) if ((((word)addr)&0xfff) >= 0xe10) return
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typedef unsigned char byte;
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typedef signed char sbyte;
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typedef unsigned short word;
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/// HARDWARE
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__sfr __at(0x00) hw_col0r; // palette 0
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__sfr __at(0x01) hw_col1r;
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__sfr __at(0x02) hw_col2r;
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__sfr __at(0x03) hw_col3r;
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__sfr __at(0x04) hw_col0l;
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__sfr __at(0x05) hw_col1l;
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__sfr __at(0x06) hw_col2l;
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__sfr __at(0x07) hw_col3l; // palette 7
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__sfr __at(0x09) hw_horcb; // horiz color boundary
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__sfr __at(0x0a) hw_verbl; // vertical blanking line * 2
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__sfr __at(0x0c) hw_magic; // magic register
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__sfr __at(0x19) hw_xpand; // expander register
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__sfr __at(0x08) hw_intst; // intercept test feedback
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__sfr __at(0x10) hw_p1ctrl; // player controls
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__sfr __at(0x11) hw_p2ctrl; // player controls
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__sfr __at(0x12) hw_p3ctrl; // player controls
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__sfr __at(0x13) hw_p4ctrl; // player controls
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#define M_SHIFT0 0x00
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#define M_SHIFT1 0x01
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#define M_SHIFT2 0x02
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#define M_SHIFT3 0x03
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#define M_XPAND 0x08
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#define M_MOVE 0x00
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#define M_OR 0x10
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#define M_XOR 0x20
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#define M_FLOP 0x40
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#define M_SHIFT(x) ((x)&3)
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#define XPAND_COLORS(off,on) (((off)&3) | (((on)&3)<<2))
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/// GRAPHICS FUNCTIONS
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#define VHEIGHT 89 // number of scanlines
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#define VBWIDTH 40 // number of bytes per scanline
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#define PIXWIDTH 160 // 4 pixels per byte
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byte __at (0x0000) vmagic[VHEIGHT][VBWIDTH];
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byte __at (0x4000) vidmem[VHEIGHT][VBWIDTH];
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// clear screen and set graphics mode
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void clrscr() {
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memset(vidmem, 0, VHEIGHT*VBWIDTH); // clear page 1
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}
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// draw vertical line
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void vline(byte x, byte y1, byte y2, byte col, byte op) {
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byte xb = x>>2; // divide x by 4
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byte* dest = &vmagic[y1][xb]; // destination address
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byte y;
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hw_magic = M_SHIFT(x) | op; // set magic register
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col <<= 6; // put color in high pixel
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for (y=y1; y<=y2; y++) {
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EXIT_CLIPDEST(dest);
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*dest = col; // shift + xor color
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dest += VBWIDTH; // dest address to next scanline
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}
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}
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// draw a pixel
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void pixel(byte x, byte y, byte col, byte op) {
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vline(x, y, y, col, op); // draw line with 1-pixel height
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}
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// render a sprite with the given graphics operation
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void render_sprite(const byte* src, byte x, byte y, byte op) {
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byte i,j;
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byte w = *src++; // get width from 1st byte of sprite
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byte h = *src++; // get height from 2nd byte of sprite
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byte xb = x>>2; // divide x by 4
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byte* dest = &vmagic[y][xb]; // destination address
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hw_magic = M_SHIFT(x) | op; // set magic register
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for (j=0; j<h; j++) {
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EXIT_CLIPDEST(dest);
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for (i=0; i<w; i++) {
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*dest++ = *src++;
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}
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*dest = 0; // rest of shifted byte
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dest += VBWIDTH-w; // dest address to next scanline
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}
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}
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// erase a sprite
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void erase_sprite(const byte* src, byte x, byte y) {
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byte i,j;
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byte w = *src++; // get width from 1st byte of sprite
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byte h = *src++; // get height from 2nd byte of sprite
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byte xb = x>>2; // divide x by 4
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byte* dest = &vidmem[y][xb]; // destination address
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for (j=0; j<h; j++) {
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EXIT_CLIPDEST(dest);
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for (i=0; i<w; i++) {
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*dest++ = 0;
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}
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*dest = 0; // rest of shifted byte
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dest += VBWIDTH-w; // dest address to next scanline
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}
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}
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// FONT FUNCTIONS
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#define LOCHAR 32
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#define HICHAR 127
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#define FONT_BWIDTH 1
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#define FONT_HEIGHT 8
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const char FONT[HICHAR-LOCHAR+1][FONT_HEIGHT*FONT_BWIDTH] = {
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{ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, },{ 0x00,0x00,0x00,0x20,0x20,0x20,0x00,0x20, },{ 0x00,0x00,0x50,0x50,0x50,0x00,0x00,0x00, },{ 0x00,0x00,0x00,0x50,0xF8,0x50,0xF8,0x50, },{ 0x00,0x00,0x00,0xF8,0xA0,0xF8,0x28,0xF8, },{ 0x00,0x00,0x00,0xC8,0xD0,0x20,0x58,0x98, },{ 0x00,0x00,0x00,0xE0,0xA8,0xF8,0x90,0xF8, },{ 0x00,0x00,0x40,0x40,0x40,0x00,0x00,0x00, },{ 0x00,0x00,0x30,0x20,0x20,0x20,0x20,0x20, },{ 0x00,0x00,0x60,0x20,0x20,0x20,0x20,0x20, },{ 0x00,0x00,0x00,0x20,0xA8,0x70,0xA8,0x20, },{ 0x00,0x00,0x00,0x20,0x20,0xF8,0x20,0x20, },{ 0x00,0x00,0x00,0x00,0x00,0x00,0x60,0x60, },{ 0x00,0x00,0x00,0x00,0x00,0xF8,0x00,0x00, },{ 0x00,0x00,0x00,0x00,0x00,0x00,0x60,0x60, },{ 0x00,0x00,0x00,0x08,0x10,0x20,0x40,0x80, },{ 0x00,0x00,0x00,0xF8,0x88,0xE8,0x88,0xF8, },{ 0x00,0x00,0x00,0x10,0x30,0x50,0x10,0x10, },{ 0x00,0x00,0x00,0xF8,0x08,0xF8,0x80,0xF8, },{ 0x00,0x00,0x00,0xF8,0x08,0xF8,0x08,0xF8, },{ 0x00,0x00,0x00,0x38,0x48,0x88,0xF8,0x08, },{ 0x00,0x00,0x00,0xF8,0x80,0xF8,0x08,0xF8, },{ 0x00,0x00,0x00,0xF8,0x80,0xF8,0x88,0xF8, },{ 0x00,0x00,0x00,0xF8,0x08,0x10,0x20,0x40, },{ 0x00,0x00,0x00,0xF8,0x88,0xF8,0x88,0xF8, },{ 0x00,0x00,0x00,0xF8,0x88,0xF8,0x08,0xF8, },{ 0x00,0x00,0x00,0x30,0x30,0x00,0x30,0x30, },{ 0x00,0x00,0x00,0x30,0x30,0x00,0x30,0x30, },{ 0x00,0x00,0x08,0x10,0x20,0x40,0x20,0x10, },{ 0x00,0x00,0x00,0x00,0xF8,0x00,0xF8,0x00, },{ 0x00,0x00,0x40,0x20,0x10,0x08,0x10,0x20, },{ 0x00,0x00,0x00,0xF8,0x08,0x78,0x00,0x60, },{ 0x00,0x00,0x00,0xF8,0xA8,0xB8,0x80,0xF8, },{ 0x00,0x00,0x00,0xF8,0x88,0xF8,0x88,0x88, },{ 0x00,0x00,0x00,0xF0,0x90,0xF8,0x88,0xF8, },{ 0x00,0x00,0x00,0xF8,0x80,0x80,0x80,0xF8, },{ 0x00,0x00,0x00,0xE0,0x90,0x88,0x88,0xF8, },{ 0x00,0x00,0x00,0xF8,0x80,0xF8,0x80,0xF8, },{ 0x00,0x00,0x00,0xF8,0x80,0xF8,0x80,0x80, },{ 0x00,0x00,0x00,0xF8,0x80,0xB8,0x88,0xF8, },{ 0x00,0x00,0x00,0x88,0x88,0xF8,0x88,0x88, },{ 0x00,0x00,0x00,0x40,0x40,0x40,0x40,0x40, },{ 0x00,0x00,0x00,0x08,0x08,0x88,0x88,0xF8, },{ 0x00,0x00,0x00,0x88,0x90,0xA0,0x90,0x88, },{ 0x00,0x00,0x00,0x80,0x80,0x80,0x80,0xF8, },{ 0x00,0x00,0x00,0xFE,0x92,0x92,0x92,0x92, },{ 0x00,0x00,0x00,0x88,0xC8,0xA8,0x98,0x88, },{ 0x00,0x00,0x00,0xF8,0x88,0x88,0x88,0xF8, },{ 0x00,0x00,0x00,0xF8,0x88,0x88,0xF8,0x80, },{ 0x00,0x00,0x00,0xF8,0x88,0xA8,0xA8,0xF8, },{ 0x00,0x00,0x00,0xF8,0x88,0xF8,0x90,0x88, },{ 0x00,0x00,0x00,0xF8,0x80,0xF8,0x08,0xF8, },{ 0x00,0x00,0x00,0xF8,0x20,0x20,0x20,0x20, },{ 0x00,0x00,0x00,0x88,0x88,0x88,0x88,0xF8, },{ 0x00,0x00,0x00,0x88,0x88,0x90,0xA0,0xC0, },{ 0x00,0x00,0x00,0x92,0x92,0x92,0x92,0xFE, },{ 0x00,0x00,0x00,0x88,0x50,0x20,0x50,0x88, },{ 0x00,0x00,0x00,0x88,0x88,0xF8,0x08,0xF8, },{ 0x00,0x00,0x00,0xF8,0x10,0x20,0x40,0xF8, },{ 0x00,0x00,0x38,0x20,0x20,0x20,0x20,0x20, },{ 0x00,0x00,0x00,0x80,0x40,0x20,0x10,0x08, },{ 0x00,0x00,0x70,0x10,0x10,0x10,0x10,0x10, },{ 0x00,0x00,0x00,0x20,0x50,0x88,0x00,0x00, },{ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, },{ 0x00,0x00,0x40,0x20,0x10,0x00,0x00,0x00, },{ 0x00,0x00,0x00,0xF8,0x88,0xF8,0x88,0x88, },{ 0x00,0x00,0x00,0xF0,0x90,0xF8,0x88,0xF8, },{ 0x00,0x00,0x00,0xF8,0x80,0x80,0x80,0xF8, },{ 0x00,0x00,0x00,0xE0,0x90,0x88,0x88,0xF8, },{ 0x00,0x00,0x00,0xF8,0x80,0xF8,0x80,0xF8, },{ 0x00,0x00,0x00,0xF8,0x80,0xF8,0x80,0x80, },{ 0x00,0x00,0x00,0xF8,0x80,0xB8,0x88,0xF8, },{ 0x00,0x00,0x00,0x88,0x88,0xF8,0x88,0x88, },{ 0x00,0x00,0x00,0x40,0x40,0x40,0x40,0x40, },{ 0x00,0x00,0x00,0x08,0x08,0x88,0x88,0xF8, },{ 0x00,0x00,0x00,0x88,0x90,0xA0,0x90,0x88, },{ 0x00,0x00,0x00,0x80,0x80,0x80,0x80,0xF8, },{ 0x00,0x00,0x00,0xFE,0x92,0x92,0x92,0x92, },{ 0x00,0x00,0x00,0x88,0xC8,0xA8,0x98,0x88, },{ 0x00,0x00,0x00,0xF8,0x88,0x88,0x88,0xF8, },{ 0x00,0x00,0x00,0xF8,0x88,0x88,0xF8,0x80, },{ 0x00,0x00,0x00,0xF8,0x88,0xA8,0xA8,0xF8, },{ 0x00,0x00,0x00,0xF8,0x88,0xF8,0x90,0x88, },{ 0x00,0x00,0x00,0xF8,0x80,0xF8,0x08,0xF8, },{ 0x00,0x00,0x00,0xF8,0x20,0x20,0x20,0x20, },{ 0x00,0x00,0x00,0x88,0x88,0x88,0x88,0xF8, },{ 0x00,0x00,0x00,0x88,0x88,0x90,0xA0,0xC0, },{ 0x00,0x00,0x00,0x92,0x92,0x92,0x92,0xFE, },{ 0x00,0x00,0x00,0x88,0x50,0x20,0x50,0x88, },{ 0x00,0x00,0x00,0x88,0x88,0xF8,0x08,0xF8, },{ 0x00,0x00,0x00,0xF8,0x10,0x20,0x40,0xF8, },{ 0x00,0x00,0x38,0x20,0x20,0xE0,0x20,0x20, },{ 0x00,0x00,0x20,0x20,0x20,0x20,0x20,0x20, },{ 0x00,0x00,0xE0,0x20,0x20,0x38,0x20,0x20, },{ 0x00,0x00,0x00,0xE8,0xB8,0x00,0x00,0x00, },{ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, },};
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// draw a letter
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void draw_char(byte ch, byte x, byte y, byte op) {
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const byte* src = &FONT[(ch-LOCHAR)][0];
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byte xb = x>>2; // divide x by 4
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byte* dest = &vmagic[y][xb]; // destination address
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hw_magic = M_SHIFT(x) | M_XPAND | op;
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for (byte i=0; i<8; i++) {
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char b = *src++;
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EXIT_CLIPDEST(dest);
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*dest++ = b; // expand lower nibble -> 1st byte
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*dest++ = b; // expand upper nibble -> 2nd byte
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*dest++ = 0; // leftover -> 3rd byte
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*dest = 0; // reset upper/lower flag
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dest += VBWIDTH-3; // we incremented 3 bytes for this line
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}
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}
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void draw_string(const char* str, byte x, byte y) {
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do {
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byte ch = *str++;
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if (!ch) break;
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draw_char(ch, x, y, M_MOVE);
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x += 8;
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} while (1);
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}
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void draw_bcd_word(word bcd, byte x, byte y, byte op) {
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byte j;
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x += 3*8;
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for (j=0; j<4; j++) {
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draw_char('0'+(bcd&0xf), x, y, op);
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x -= 8;
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bcd >>= 4;
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}
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}
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// add two 16-bit BCD values
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word bcd_add(word a, word b) {
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a; b; // to avoid warning
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__asm
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ld hl,#4
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add hl,sp
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ld iy,#2
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add iy,sp
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ld a,0 (iy)
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add a, (hl)
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daa
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ld c,a
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ld a,1 (iy)
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inc hl
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adc a, (hl)
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daa
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ld b,a
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ld l, c
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ld h, b
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__endasm;
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}
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/////
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//
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// GAME GRAPHICS
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//
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const byte player_bitmap[] =
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{3,14,/*{w:12,h:16,bpp:2,brev:1}*/0x00,0x3C,0x00,0x00,0x18,0x00,0x00,0x3C,0x00,0x00,0x18,0x00,0x04,0x18,0x20,0x0C,0x3C,0x30,0x3C,0x3C,0x3C,0x1F,0xE7,0xF4,0x1F,0x66,0xF4,0x17,0xE7,0xE4,0x17,0xE7,0xE4,0x1C,0x7E,0x34,0x1C,0xFF,0x34,0x3C,0x18,0x3C,0x0C,0x18,0x30,0x04,0x18,0x20};
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const byte bomb_bitmap[] =
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{1,5,/*{w:8,h:5,bpp:2,brev:1}*/0x88,0x55,0x77,0x55,0x88};
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const byte bullet_bitmap[] =
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{1,5,/*{w:8,h:5,bpp:2,brev:1}*/0x14,0x28,0x14,0x14,0x28};
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const byte enemy1_bitmap[] =
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{2,8,/*{w:16,h:8,bpp:2,brev:1}*/0x00,0x00,0x70,0x38,0xF8,0x7C,0xFC,0xFC,0xFE,0xFC,0xFE,0xFF,0xFC,0xFF,0xF8,0x7F,0xF0,0x3F,0x88,0x47,0xF0,0x3F,0xF0,0x3F,0xD0,0x2F,0x8C,0xC7,0x48,0x48,0x80,0x04};
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const byte enemy2_bitmap[] =
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{2,8,/*{w:16,h:8,bpp:2,brev:1}*/0x00,0x00,0x30,0x0C,0x14,0x28,0x2E,0x74,0x08,0x10,0x20,0x04,0xE0,0x07,0xD0,0x0B,0xB0,0x0D,0xB2,0x4D,0x19,0x98,0x8E,0x71,0x82,0x41,0xB1,0x8D,0x59,0x9A,0x4A,0x52};
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const byte enemy3_bitmap[] =
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{2,8,/*{w:16,h:8,bpp:2,brev:1}*/0x00,0x00,0x00,0x00,0x04,0x20,0x05,0xA0,0x05,0xA0,0x25,0xA4,0xA7,0xE5,0xF7,0xEF,0xF7,0xEF,0xFE,0x7F,0xFC,0x3F,0xBC,0x3D,0xE4,0x27,0x20,0x00,0x00,0x00,0x00,0x00};
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const byte enemy4_bitmap[] =
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{2,8,/*{w:16,h:8,bpp:2,brev:1}*/0x00,0x00,0x00,0x00,0xF0,0x0F,0xF8,0x1F,0xD8,0x1B,0xF8,0x1F,0xF8,0x1F,0xF8,0x1F,0xF0,0x0F,0xA8,0x15,0xCC,0x33,0xE8,0x17,0x66,0x66,0x33,0xCC,0x61,0x86,0x40,0x02};
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const byte* const enemy_bitmaps[4] = {
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enemy1_bitmap,
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enemy2_bitmap,
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enemy3_bitmap,
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enemy4_bitmap
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};
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#define COLOR_BUNKER 1
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#define COLOR_GROUND 2
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#define COLOR_SCORE 3
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//
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// GAME CODE
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//
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#define MAXLIVES 5
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#define PLYRHEIGHT 14
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#define ENEMY_SPACING_X 17
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#define ENEMY_SPACING_Y 11
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#define ENEMY_MARCH_X 1
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#define ENEMY_MARCH_Y 2
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typedef struct {
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byte x,y;
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const byte* shape; // need const here
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} Enemy;
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#define MAX_ENEMIES 28
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Enemy enemies[MAX_ENEMIES];
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byte enemy_index;
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byte num_enemies;
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typedef struct {
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int right:1;
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int down:1;
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} MarchMode;
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MarchMode this_mode, next_mode;
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byte attract;
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word score;
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byte lives;
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const byte player_y = VHEIGHT-PLYRHEIGHT-1;
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byte player_x;
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byte bullet_x;
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byte bullet_y;
|
|
byte bomb_x;
|
|
byte bomb_y;
|
|
|
|
void draw_lives() {
|
|
byte i;
|
|
byte n = lives;
|
|
byte y = 0;
|
|
byte x = PIXWIDTH-4*5;
|
|
hw_xpand = XPAND_COLORS(0, COLOR_SCORE);
|
|
for (i=0; i<MAXLIVES; i++) {
|
|
draw_char(i<n?'|':' ', x, y, M_MOVE);
|
|
x += 4;
|
|
}
|
|
}
|
|
|
|
void draw_score() {
|
|
byte x = 10*8;
|
|
byte y = 0;
|
|
hw_xpand = XPAND_COLORS(0, COLOR_SCORE);
|
|
draw_bcd_word(score, x, y, M_MOVE);
|
|
}
|
|
|
|
void draw_bunker(byte x, byte y, byte y2, byte h, byte w) {
|
|
byte i,a=0,b=0;
|
|
for (i=0; i<h; i++) {
|
|
a = y-y2-i*2;
|
|
b = y-i;
|
|
vline(x+i, a, b, M_XOR, COLOR_BUNKER);
|
|
vline(x+h*2+w-i-1, a, b, M_XOR, COLOR_BUNKER);
|
|
}
|
|
for (i=0; i<w; i++) {
|
|
vline(x+h+i, a, b, M_XOR, COLOR_BUNKER);
|
|
}
|
|
}
|
|
|
|
void draw_playfield() {
|
|
byte i;
|
|
clrscr();
|
|
hw_xpand = XPAND_COLORS(0, COLOR_SCORE);
|
|
draw_string("PLAYER 1", 0, 0);
|
|
draw_score();
|
|
draw_lives();
|
|
for (i=0; i<PIXWIDTH; i++)
|
|
pixel(i, VHEIGHT-1, COLOR_GROUND, M_OR);
|
|
// TODO: const
|
|
draw_bunker(20, 65, 15, 15, 20);
|
|
draw_bunker(100, 65, 15, 15, 20);
|
|
}
|
|
|
|
void add_score(word pts) {
|
|
if (attract) return;
|
|
score = bcd_add(score, pts);
|
|
draw_score();
|
|
}
|
|
|
|
void xor_player_derez() {
|
|
byte i,j;
|
|
byte x = player_x+13;
|
|
byte y = player_y+PLYRHEIGHT-1;
|
|
byte* rand = (byte*) &clrscr; // use code as random #'s
|
|
for (j=1; j<=0x1f; j++) {
|
|
for (i=0; i<50; i++) {
|
|
signed char xx = x + (*rand++ & 0xf) - 15;
|
|
signed char yy = y - (*rand++ & j);
|
|
pixel(xx, yy, *rand++, M_XOR);
|
|
}
|
|
}
|
|
}
|
|
|
|
void destroy_player() {
|
|
xor_player_derez(); // xor derez pattern
|
|
render_sprite(player_bitmap, player_x, VHEIGHT-PLYRHEIGHT, M_XOR); // erase ship via xor
|
|
xor_player_derez(); // xor 2x to erase derez pattern
|
|
player_x = 0xff;
|
|
lives--;
|
|
}
|
|
|
|
void init_enemies() {
|
|
byte i,x,y,bm;
|
|
x = 0;
|
|
y = ENEMY_SPACING_Y;
|
|
bm=0;
|
|
for (i=0; i<MAX_ENEMIES; i++) {
|
|
Enemy* e = &enemies[i];
|
|
e->x = x;
|
|
e->y = y;
|
|
e->shape = enemy_bitmaps[bm];
|
|
x += ENEMY_SPACING_X;
|
|
if (x >= PIXWIDTH-ENEMY_SPACING_X*2) {
|
|
x = 0;
|
|
y += ENEMY_SPACING_Y;
|
|
bm++; // TODO: can overflow
|
|
}
|
|
}
|
|
enemy_index = 0;
|
|
num_enemies = MAX_ENEMIES;
|
|
this_mode.right = 1;
|
|
this_mode.down = 0;
|
|
next_mode.right = 1;
|
|
next_mode.down = 0;
|
|
}
|
|
|
|
void delete_enemy(Enemy* e) {
|
|
erase_sprite(e->shape, e->x, e->y);
|
|
memmove(e, e+1, sizeof(Enemy)*(enemies-e+MAX_ENEMIES-1));
|
|
num_enemies--; // update_next_enemy() will check enemy_index
|
|
}
|
|
|
|
void update_next_enemy() {
|
|
Enemy* e;
|
|
if (enemy_index >= num_enemies) {
|
|
enemy_index = 0;
|
|
memcpy(&this_mode, &next_mode, sizeof(this_mode));
|
|
}
|
|
e = &enemies[enemy_index];
|
|
erase_sprite(e->shape, e->x, e->y);
|
|
if (this_mode.down) {
|
|
e->y += ENEMY_MARCH_Y;
|
|
// if too close to ground, end game
|
|
if (e->y > VHEIGHT-ENEMY_SPACING_Y) {
|
|
destroy_player();
|
|
lives = 0;
|
|
}
|
|
next_mode.down = 0;
|
|
} else {
|
|
if (this_mode.right) {
|
|
e->x += ENEMY_MARCH_X;
|
|
if (e->x >= PIXWIDTH-ENEMY_SPACING_X) {
|
|
next_mode.down = 1;
|
|
next_mode.right = 0;
|
|
}
|
|
} else {
|
|
e->x -= ENEMY_MARCH_X;
|
|
if (e->x == 0) {
|
|
next_mode.down = 1;
|
|
next_mode.right = 1;
|
|
}
|
|
}
|
|
}
|
|
render_sprite(e->shape, e->x, e->y, M_XOR);
|
|
enemy_index++;
|
|
}
|
|
|
|
char in_rect(Enemy* e, byte x, byte y, byte w, byte h) {
|
|
byte ew = e->shape[0]*8;
|
|
byte eh = e->shape[1];
|
|
return (x >= e->x-w && x <= e->x+ew && y >= e->y-h && y <= e->y+eh);
|
|
}
|
|
|
|
Enemy* find_enemy_at(byte x, byte y) {
|
|
byte i;
|
|
for (i=0; i<num_enemies; i++) {
|
|
Enemy* e = &enemies[i];
|
|
if (in_rect(e, x, y, 0, 2)) {
|
|
return e;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
void check_bullet_hit(byte x, byte y) {
|
|
Enemy* e = find_enemy_at(x,y);
|
|
if (e) {
|
|
delete_enemy(e);
|
|
add_score(0x25);
|
|
}
|
|
}
|
|
|
|
void fire_bullet() {
|
|
bullet_x = player_x + 4;
|
|
bullet_y = VHEIGHT-PLYRHEIGHT-6;
|
|
render_sprite(bullet_bitmap, bullet_x, bullet_y, M_XOR); // draw
|
|
}
|
|
|
|
void move_bullet() {
|
|
byte leftover;
|
|
hw_intst; // reset intercept counters
|
|
render_sprite(bullet_bitmap, bullet_x, bullet_y, M_XOR); // erase
|
|
leftover = (hw_intst & 0xf0); // any pixels leftover?
|
|
if (leftover || bullet_y < 10) {
|
|
erase_sprite(bullet_bitmap, bullet_x, bullet_y);
|
|
check_bullet_hit(bullet_x, bullet_y+2);
|
|
bullet_y = 0;
|
|
} else {
|
|
bullet_y -= 4;
|
|
render_sprite(bullet_bitmap, bullet_x, bullet_y, M_XOR); // draw
|
|
}
|
|
}
|
|
|
|
void drop_bomb() {
|
|
Enemy* e = &enemies[enemy_index];
|
|
bomb_x = e->x + 7;
|
|
bomb_y = e->y + 16;
|
|
render_sprite(bomb_bitmap, bomb_x, bomb_y, M_XOR);
|
|
}
|
|
|
|
void move_bomb() {
|
|
hw_intst; // reset intercept counters
|
|
render_sprite(bomb_bitmap, bomb_x, bomb_y, M_XOR); // erase
|
|
if (bomb_y > VHEIGHT-12) {
|
|
bomb_y = 0;
|
|
} else if (hw_intst & 0xf0) { // any pixels leftover?
|
|
erase_sprite(bomb_bitmap, bomb_x, bomb_y); // erase bunker
|
|
if (bomb_y > VHEIGHT-23) {
|
|
// player was hit (probably)
|
|
destroy_player();
|
|
}
|
|
bomb_y = 0;
|
|
} else {
|
|
bomb_y += 3;
|
|
render_sprite(bomb_bitmap, bomb_x, bomb_y, M_XOR);
|
|
}
|
|
}
|
|
|
|
byte frame;
|
|
signed char player_dir = 0;
|
|
|
|
void move_player() {
|
|
if (attract) {
|
|
if (bullet_y == 0) fire_bullet();
|
|
player_dir = 0;
|
|
} else {
|
|
byte mask = hw_p1ctrl;
|
|
if (mask & 0x4) {
|
|
if (player_x > 0)
|
|
player_x--;
|
|
}
|
|
if (mask & 0x8) {
|
|
if (player_x < PIXWIDTH-16)
|
|
player_x++;
|
|
}
|
|
if (mask & 0x10) {
|
|
if (bullet_y == 0) {
|
|
fire_bullet();
|
|
}
|
|
}
|
|
}
|
|
// move player
|
|
render_sprite(player_bitmap, player_x, player_y, M_MOVE);
|
|
}
|
|
|
|
void play_round() {
|
|
draw_playfield();
|
|
player_x = PIXWIDTH/2-8;
|
|
bullet_y = 0;
|
|
bomb_y = 0;
|
|
frame = 0;
|
|
while (player_x != 0xff && num_enemies) {
|
|
move_player();
|
|
if (bullet_y) {
|
|
move_bullet();
|
|
}
|
|
update_next_enemy();
|
|
if (frame & 1) {
|
|
if (bomb_y == 0) {
|
|
drop_bomb();
|
|
} else {
|
|
move_bomb();
|
|
}
|
|
}
|
|
frame++;
|
|
}
|
|
}
|
|
|
|
void init_game() {
|
|
score = 0;
|
|
lives = 5;
|
|
}
|
|
|
|
void game_over_msg() {
|
|
byte i;
|
|
byte x=16;
|
|
byte y=10;
|
|
hw_xpand = XPAND_COLORS(0, COLOR_SCORE);
|
|
for (i=0; i<50; i++) {
|
|
draw_string(" *************** ", x, y+0*8);
|
|
draw_string("*** ***", x, y+1*8);
|
|
draw_string("** GAME OVER **", x, y+2*8);
|
|
draw_string("*** ***", x, y+3*8);
|
|
draw_string(" *************** ", x, y+4*8);
|
|
}
|
|
}
|
|
|
|
void play_game() {
|
|
attract = 0;
|
|
init_game();
|
|
init_enemies();
|
|
while (lives) {
|
|
play_round();
|
|
if (num_enemies == 0) {
|
|
init_enemies();
|
|
}
|
|
}
|
|
game_over_msg();
|
|
}
|
|
|
|
void attract_mode() {
|
|
attract = 1;
|
|
while (1) {
|
|
init_enemies();
|
|
play_round();
|
|
}
|
|
}
|
|
|
|
void setup_registers() {
|
|
hw_col0r = 0x00;
|
|
hw_col1r = 0x20;
|
|
hw_col2r = 0xe0;
|
|
hw_col3r = 0xa0;
|
|
hw_col0l = 0x10;
|
|
hw_col1l = 0x30;
|
|
hw_col2l = 0xc0;
|
|
hw_col3l = 0xf0;
|
|
hw_horcb = 0;
|
|
hw_verbl = VHEIGHT*2;
|
|
}
|
|
|
|
|
|
void main() {
|
|
setup_registers();
|
|
// NOTE: initializers don't get run, so we init here
|
|
while (1) {
|
|
//attract_mode();
|
|
play_game();
|
|
}
|
|
}
|