mirror of
https://github.com/sehugg/8bitworkshop.git
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106 lines
2.5 KiB
C
106 lines
2.5 KiB
C
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/*
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If you have more objects than will fit into the 64 hardware
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sprites, you can omit some of the sprites each frame.
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We also use oam_meta_spr_pal() to change the color of each
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metasprite.
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*/
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#include <stdlib.h>
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#include <string.h>
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// include NESLIB header
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#include "neslib.h"
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// include CC65 NES Header (PPU)
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#include <nes.h>
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// link the pattern table into CHR ROM
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//#link "chr_generic.s"
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///// METASPRITES
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#define TILE 0xd8
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#define ATTR 0x0
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// define a 2x2 metasprite
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const unsigned char metasprite[]={
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0, 0, TILE+0, ATTR,
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0, 8, TILE+1, ATTR,
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8, 0, TILE+2, ATTR,
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8, 8, TILE+3, ATTR,
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128};
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/*{pal:"nes",layout:"nes"}*/
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const char PALETTE[32] = {
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0x03, // screen color
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0x11,0x30,0x27,0x0, // background palette 0
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0x1c,0x20,0x2c,0x0, // background palette 1
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0x00,0x10,0x20,0x0, // background palette 2
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0x06,0x16,0x26,0x0, // background palette 3
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0x16,0x35,0x24,0x0, // sprite palette 0
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0x00,0x37,0x25,0x0, // sprite palette 1
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0x0d,0x2d,0x3a,0x0, // sprite palette 2
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0x0d,0x27,0x2a // sprite palette 3
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};
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// setup PPU and tables
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void setup_graphics() {
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// clear sprites
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oam_clear();
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// set palette colors
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pal_all(PALETTE);
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// turn on PPU
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ppu_on_all();
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}
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// number of actors (4 h/w sprites each)
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#define NUM_ACTORS 24
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// actor x/y positions
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byte actor_x[NUM_ACTORS];
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byte actor_y[NUM_ACTORS];
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// actor x/y deltas per frame (signed)
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sbyte actor_dx[NUM_ACTORS];
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sbyte actor_dy[NUM_ACTORS];
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// main program
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void main() {
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byte i; // actor index
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// setup PPU
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setup_graphics();
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// initialize actors with random values
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for (i=0; i<NUM_ACTORS; i++) {
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actor_x[i] = rand();
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actor_y[i] = rand();
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actor_dx[i] = (rand() & 7) - 3;
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actor_dy[i] = (rand() & 7) - 3;
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}
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// loop forever
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while (1) {
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// start with OAMid/sprite 0
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oam_off = 0;
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// draw and move all actors
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// (note we don't reset i each loop iteration)
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while (oam_off < 256-4*4) {
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// advance and wrap around actor array
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if (++i >= NUM_ACTORS)
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i -= NUM_ACTORS;
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// draw and move actor
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oam_meta_spr_pal(
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actor_x[i] += actor_dx[i], // add x+dx and pass param
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actor_y[i] += actor_dy[i], // add y+dy and pass param
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i&3, // palette color
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metasprite); // metasprites
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}
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// hide rest of sprites
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oam_hide_rest(oam_off);
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// wait for next NMI
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// we don't want to skip frames b/c it makes flicker worse
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ppu_wait_nmi();
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}
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}
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