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8bitworkshop/presets/c64/side_scroller.c

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#include "common.h"
//#link "common.c"
#include "sprites.h"
//#link "sprites.c"
#include "rasterirq.h"
//#link "rasterirq.ca65"
#include "bcd.h"
//#link "bcd.c"
#include "sidmacros.h"
///// SPRITE DATA
#define NUM_SPRITE_PATTERNS 4
/*{w:12,h:21,bpp:2,brev:1,wpimg:64,count:4,aspect:2}*/
const char SPRITE_DATA[64*NUM_SPRITE_PATTERNS] = {
0x0A,0xAA,0x80,0x0A,0xAA,0x80,0x2A,0xAA,
0xA0,0x2A,0xAA,0xA0,0xAA,0xAA,0xA8,0xFF,
0xD5,0x40,0xCD,0xD7,0x40,0x3D,0xD5,0x54,
0x37,0x55,0x54,0x37,0x54,0x50,0x05,0x55,
0x00,0x3A,0xA0,0x00,0xEA,0xA8,0x00,0xAB,
0xAA,0x00,0xAB,0xAA,0x00,0xAB,0xAA,0x80,
0xAA,0xEA,0x80,0xAA,0xAA,0x80,0x0F,0xFC,
0x00,0x0F,0xFC,0x00,0x0F,0xFF,0xC0,0x00,
0x02,0xAA,0xA0,0x02,0xAA,0xA0,0x0A,0xAA,
0xA8,0x0A,0xAA,0xA8,0x2A,0xAA,0xAA,0x01,
0x57,0xFF,0x01,0xD7,0x73,0x15,0x57,0x7C,
0x15,0x55,0xDC,0x05,0x15,0xDC,0x00,0x55,
0x50,0x00,0x0A,0xAC,0x00,0x2A,0xAB,0x00,
0xAA,0xEA,0x00,0xAA,0xEA,0x02,0xAA,0xEA,
0x02,0xAB,0xAA,0x02,0xAA,0xAA,0x00,0x3F,
0xF0,0x00,0x3F,0xF0,0x03,0xFF,0xF0,0x00,
0x03,0xFF,0xF0,0x0E,0xAA,0xAC,0x0E,0xAA,0xAC,
0x3A,0xAE,0xAB,0x3A,0xBB,0xAB,0x3A,0xBA,0xAB,
0x3A,0xBB,0xAB,0x3A,0xAE,0xAB,0x3A,0xAA,0xAB,
0x35,0xAA,0x97,0x04,0x6A,0x44,0x04,0x15,0x04,
0x01,0x04,0x10,0x01,0x04,0x10,0x01,0x04,0x10,
0x00,0x44,0x40,0x00,0x44,0x40,0x00,0xEA,0xC0,
0x00,0xD9,0xC0,0x00,0xE6,0xC0,0x00,0x3F,0x00,
0x00,
0x00,0x00,0x00,0x00,0xFF,0x00,0x03,0xAA,
0xC0,0x0E,0xAA,0xB0,0x3A,0xAA,0xAC,0xE9,
0x69,0x6B,0xEA,0x69,0xAB,0xEA,0xAA,0xAB,
0xEA,0xAA,0xAB,0x3A,0x96,0xAC,0x3A,0x69,
0xAC,0x0E,0xAA,0xB0,0x0E,0xAA,0xB0,0x0F,
0xAA,0xF0,0x3A,0xAA,0xAC,0xEE,0xAA,0xBB,
0xEE,0xAA,0xBB,0x33,0xAA,0xCC,0x03,0xAB,
0x00,0x00,0xEB,0x00,0x00,0x3F,0xC0,0x00,
};
///// DEFINES
#define GAME_BASE 0x400
#define SCORE_BASE 0x2c00
#define SPRITE_SHAPE 192 // first sprite shape #
#define PLAYER_SHAPE SPRITE_SHAPE
#define POWERUP_SHAPE (SPRITE_SHAPE+2)
#define OBSTACLE_SHAPE (SPRITE_SHAPE+3)
#define PLAYER_INDEX 0 // sprite indices
#define POWERUP_INDEX 1
#define OBSTACLE_INDEX 2
#define CENTER_X 172 // sprite start X coord.
#define FLOOR_Y (128 << 8) // sprite start Y (fixed 8.8)
#define JUMP_VELOCITY (-900) // jump velocity (fixed 8.8)
#define GRAVITY 32 // gravity (fixed 8.8)
#define POWERUP_Y 80 // sprite Y of power up
#define OBSTACLE_Y 96 // sprite Y of obstacle
#define SCROLL_TOP 8 // scroll top row
#define SCROLL_ROWS 14 // scroll # of rows
#define GROUND_ROW 7 // ground row (+ top row)
///// VARIABLES
word player_x; // player X
word player_y; // player Y (fixed 8.8)
signed int player_vel_y; // player Y velocity (fixed 8.8)
byte faceleft = 0; // 0 = face right, 1 = face left
word scroll_x = 0; // current scroll X position
word score = 0; // current player score
///// FUNCTIONS
// display list used by rasterirq.h
// draws scoreboard and sets scroll register
void display_list() {
// set x scroll register to scroll value
SET_SCROLL_X(scroll_x);
// set background color
VIC.bgcolor[0] = COLOR_CYAN;
// next interrupt is two rows from bottom
DLIST_NEXT(248-16);
// set background color
VIC.bgcolor[0] = COLOR_BLUE;
// screen memory = 0x2800
SET_VIC_SCREEN(SCORE_BASE);
// clear x scroll register
SET_SCROLL_X(0);
// next interrupt is bottom of frame
DLIST_NEXT(250);
// reset screen to 0x400
SET_VIC_SCREEN(0x400);
// next interrupt is above top of next frame
DLIST_RESTART(40);
}
void update_scoreboard() {
draw_bcd_word(SCRNADR(SCORE_BASE,7,24), score);
}
void add_score(int delta) {
score = bcd_add(score, delta);
update_scoreboard();
}
// clear scoreboard and draw initial strings
void init_scoreboard() {
memset((void*)SCORE_BASE, ' ', 1024);
memcpy((void*)SCRNADR(SCORE_BASE,1,24), "SCORE:", 6);
update_scoreboard();
}
void init_sprite_shapes() {
sprite_set_shapes(SPRITE_DATA,
SPRITE_SHAPE,
NUM_SPRITE_PATTERNS);
}
void init_sprite_positions() {
// setup sprite positions
player_x = CENTER_X;
player_y = FLOOR_Y;
player_vel_y = 0;
sprshad.spr_color[POWERUP_INDEX] = COLOR_YELLOW;
sprshad.spr_color[OBSTACLE_INDEX] = COLOR_GRAY3;
}
void move_player(byte joy) {
// move sprite based on joystick
if (JOY_LEFT(joy)) {
player_x -= 2;
faceleft = 1;
}
if (JOY_RIGHT(joy)) {
player_x += 1;
faceleft = 0;
}
if (JOY_BTN_1(joy) && player_y == FLOOR_Y) {
player_vel_y = JUMP_VELOCITY;
}
// apply velocity
player_y += player_vel_y;
// apply gravity
player_vel_y += GRAVITY;
// stop velocity when falling thru floor
if (player_y >= FLOOR_Y) {
player_y = FLOOR_Y; // reset Y position
player_vel_y = 0; // reset velocity
}
// keep player from moving offscreen
if (player_x < 36) player_x = 36;
if (player_x > 300) player_x = 300;
// draw player into sprite shadow buffer
sprite_draw(PLAYER_INDEX,
player_x,
player_y >> 8, // fixed point conversion
PLAYER_SHAPE + faceleft);
}
void move_items() {
// move in sync with scrolling world
// draw powerup
sprite_draw(POWERUP_INDEX,
((scroll_x*2) & 0x1ff),
POWERUP_Y,
POWERUP_SHAPE);
// draw obstacle
sprite_draw(OBSTACLE_INDEX,
((scroll_x+256) & 0x1ff),
OBSTACLE_Y,
OBSTACLE_SHAPE);
}
byte get_char_for_row(byte row) {
// ground?
if (row >= GROUND_ROW) { return 253; }
// obstacle?
if (row >= GROUND_ROW-3) {
// only show obstacle for certain values of scroll_x
if ((scroll_x & 0b1110000) == 0) { return 247; }
}
// default is the sky (empty space)
return 32;
}
void draw_right_column() {
// get the top-right corner address of scroll area
word addr = SCRNADR(GAME_BASE, 39, SCROLL_TOP);
byte row;
// draw one character per row
for (row=0; row<SCROLL_ROWS; row++) {
POKE(addr, get_char_for_row(row));
addr += 40;
}
}
void scroll_one_column_left() {
// copy several rows of screen memory
// backwards one byte
const word start = SCRNADR(GAME_BASE, 0, SCROLL_TOP);
const word nbytes = SCROLL_ROWS*40-1;
memcpy((byte*)start, (byte*)start+1, nbytes);
// draw the right column of characters
draw_right_column();
}
void scroll_one_pixel_left() {
// scroll left one pixel
scroll_x -= 1;
// set scroll register with lower three bits
VIC.ctrl2 = (VIC.ctrl2 & ~7) | (scroll_x & 7);
// move screen memory if the scroll register
// has just gone past 0 and wrapped to 7
if ((scroll_x & 7) == 7) {
scroll_one_column_left();
}
}
void detect_player_collision(byte bg_coll, byte spr_coll) {
// did we hit a powerup? (#0 and #1)
bool hit_powerup = (spr_coll & 0b011) == 0b011;
// did player and obstacle sprite (#0 and #2) collide?
bool hit_obstacle = (spr_coll & 0b101) == 0b101;
// did player (#0) collide with background?
hit_obstacle |= (bg_coll & 0b001) != 0;
// did we hit anything bad?
if (hit_obstacle) {
// make player fall downward and backward
player_vel_y = -JUMP_VELOCITY;
player_x -= 1;
sprshad.spr_color[PLAYER_INDEX] = COLOR_LIGHTRED;
SID_PLAY_TONE(500);
if (score != 0) { add_score(0x9999); } // BCD -1
} else {
sprshad.spr_color[PLAYER_INDEX] = COLOR_GREEN;
}
// did we hit powerup?
if (hit_powerup) {
sprshad.spr_color[POWERUP_INDEX] += 1; // cycle colors
SID_PLAY_TONE(8000);
add_score(1);
}
}
void main() {
// clear screen, set background color
clrscr();
VIC.bgcolor[0] = COLOR_CYAN;
VIC.bordercolor = COLOR_BLUE;
// set vertical scroll = 3, 25 rows
VIC.ctrl1 = 0b00011011;
// set 38 column mode (for X scrolling)
VIC.ctrl2 = 0b00000000;
// set uniform color of characters
memset(COLOR_RAM, COLOR_WHITE, 1000);
// install the joystick driver
joy_install (joy_static_stddrv);
// setup sound
SID_INIT(8,0);
// set multicolor sprites and colors in shadow buffer
sprite_clear(); // clear shadow buffer
sprshad.spr_mcolor = 0b11111111; // all sprites multicolor
sprshad.spr_exp_y = 1; // double height
// set colors
sprshad.spr_color[PLAYER_INDEX] = COLOR_GREEN;
VIC.spr_mcolor0 = COLOR_GRAY2;
VIC.spr_mcolor1 = COLOR_BLACK;
// setup sprites
init_sprite_shapes();
init_sprite_positions();
// setup scoreboard
init_scoreboard();
// setup rasterirq library for scoreboard split
DLIST_SETUP(display_list);
// game loop, repeat forever
while (1) {
// saved collision flags
byte spr_coll, bg_coll;
// wait for end of frame
waitvsync();
//--- START TIME CRITICAL SECTION
// grab and reset collision flags
spr_coll = VIC.spr_coll;
bg_coll = VIC.spr_bg_coll;
// update sprite registers from sprite shadow buffer
sprite_update(DEFAULT_SCREEN);
// scroll screen
scroll_one_pixel_left();
//--- END TIME CRITICAL SECTION
// use collision flags to see if player collided
detect_player_collision(bg_coll, spr_coll);
// get joystick bits and move player
move_player(joy_read(0));
// move obstacle and powerup sprites
move_items();
}
}
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