joeylib2/examples/spacetaxi/stLevel.c

144 lines
3.8 KiB
C

// Space Taxi -- level loader.
//
// Reads a level .dat file produced by `tools/spacetaxi/mkLevel.py`
// (see assets/levels/format.md for the byte layout).
//
// A level file is small (~2-3 KB raw, plus a name + per-pad config),
// loaded once per scene change. Read fully into RAM; tilemap + colormap
// stay inside the StLevelT struct for the life of the game state.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "spacetaxi.h"
JOEYLIB_SEGMENT("STAXI")
// STL2 adds the per-level physics templates (xAccel/yAccel/xGrav/yGrav)
// and the full VIC color block ($7D00-$7D08). Drops the patience byte
// from each fare entry (Space Taxi proper has no patience timeout).
#define ST_LEVEL_MAGIC0 'S'
#define ST_LEVEL_MAGIC1 'T'
#define ST_LEVEL_MAGIC2 'L'
#define ST_LEVEL_MAGIC3 '2'
static bool readByte(FILE *fp, uint8_t *out) {
int c = fgetc(fp);
if (c == EOF) {
return false;
}
*out = (uint8_t)c;
return true;
}
static bool readBytes(FILE *fp, void *dst, size_t n) {
return fread(dst, 1, n, fp) == n;
}
bool stLevelLoad(StLevelT *out, const char *path) {
FILE *fp;
uint8_t hdr[4];
uint8_t nameLen;
uint8_t i;
size_t cells;
memset(out, 0, sizeof(*out));
fp = fopen(path, "rb");
if (fp == NULL) {
return false;
}
if (!readBytes(fp, hdr, 4) ||
hdr[0] != ST_LEVEL_MAGIC0 || hdr[1] != ST_LEVEL_MAGIC1 ||
hdr[2] != ST_LEVEL_MAGIC2 || hdr[3] != ST_LEVEL_MAGIC3) {
fclose(fp);
return false;
}
if (!readByte(fp, &nameLen) || nameLen >= sizeof(out->name)) {
fclose(fp);
return false;
}
if (!readBytes(fp, out->name, nameLen)) {
fclose(fp);
return false;
}
out->name[nameLen] = '\0';
if (!readByte(fp, &out->tileBankId) ||
!readByte(fp, &out->musicId) ||
!readByte(fp, &out->bgColor) ||
!readByte(fp, &out->borderColor) ||
!readByte(fp, &out->taxiSpawnTileX) ||
!readByte(fp, &out->taxiSpawnTileY)) {
fclose(fp);
return false;
}
{
uint8_t xGravByte;
uint8_t yGravByte;
if (!readByte(fp, &out->xAccel) ||
!readByte(fp, &out->yAccel) ||
!readByte(fp, &xGravByte) ||
!readByte(fp, &yGravByte)) {
fclose(fp);
return false;
}
out->xGrav = (int8_t)xGravByte;
out->yGrav = (int8_t)yGravByte;
}
if (!readByte(fp, &out->bgColor1) ||
!readByte(fp, &out->bgColor2) ||
!readByte(fp, &out->bgColor3) ||
!readByte(fp, &out->spriteMc0) ||
!readByte(fp, &out->spriteMc1) ||
!readByte(fp, &out->sprite0Color) ||
!readByte(fp, &out->sprite1Color)) {
fclose(fp);
return false;
}
if (!readByte(fp, &out->padCount) || out->padCount > ST_MAX_PADS) {
fclose(fp);
return false;
}
for (i = 0u; i < out->padCount; i++) {
if (!readByte(fp, &out->pads[i].letter) ||
!readByte(fp, &out->pads[i].tileX) ||
!readByte(fp, &out->pads[i].tileY) ||
!readByte(fp, &out->pads[i].tileW)) {
fclose(fp);
return false;
}
}
if (!readByte(fp, &out->fareCount) || out->fareCount > ST_MAX_FARES) {
fclose(fp);
return false;
}
for (i = 0u; i < out->fareCount; i++) {
if (!readByte(fp, &out->fares[i].spawnPad) ||
!readByte(fp, &out->fares[i].destPad)) {
fclose(fp);
return false;
}
}
cells = (size_t)ST_TILEMAP_W * (size_t)ST_PLAYFIELD_ROWS;
if (!readBytes(fp, out->tilemap, cells) ||
!readBytes(fp, out->colormap, cells)) {
fclose(fp);
return false;
}
fclose(fp);
return true;
}