cdo/retro-rpg
2
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Create entity_t struct and define entityupdate() and entitydraw()

Browse Source
This commit is contained in:
Camden Dixie O'Brien 2024-12-31 13:01:48 +00:00
parent e7a19b7d91
commit b39189b6d1
1 changed files with 102 additions and 59 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

161
app/main.c
View File

@ -62,14 +62,32 @@ typedef struct {
bool left, right, up, down;
} input_state_t;
typedef struct {
int x, y;
} ivec_t;
typedef struct {
double x, y;
} dvec_t;
typedef struct {
dvec_t off, ext;
} dbox_t;
typedef struct {
int svar, animlen;
double speed;
dvec_t pos, dir;
ivec_t animstep, svarstep;
dbox_t fbox;
SDL_Texture *tex;
SDL_Rect src;
} entity_t;
static SDL_Window *window;
static SDL_Renderer *renderer;
static unsigned map[MAPWIDTH][MAPHEIGHT];
static SDL_Texture *tstex, *pidle, *pwalk, *ptex;
static SDL_Texture *tstex, *pidle, *pwalk;
static input_state_t input;
static dvec_t vpos = { -128, -96 };
static const unsigned impassable[] = { 284 };
@ -104,6 +122,58 @@ static inline bool tilepassable(int x, int y)
return true;
}
static void entityupdate(entity_t *e, double dt)
{
if (0 == e->speed)
return;
// Update sprite variant
if (e->dir.y >= 0) {
if (e->dir.x > 0)
e->svar = SPRITE_DIR_RIGHT_DOWN;
else if (e->dir.x < 0)
e->svar = SPRITE_DIR_LEFT_DOWN;
else
e->svar = SPRITE_DIR_DOWN;
} else if (e->dir.y < 0) {
if (e->dir.x > 0)
e->svar = SPRITE_DIR_RIGHT_UP;
else if (e->dir.x < 0)
e->svar = SPRITE_DIR_LEFT_UP;
else
e->svar = SPRITE_DIR_UP;
}
// Apply velocity (handling map collisions)
const double nextx = e->pos.x + dt * e->speed * e->dir.x;
const double nexty = e->pos.y + dt * e->speed * e->dir.y;
const dvec_t pfb
= { .x = nextx + e->fbox.off.x, .y = nexty + e->fbox.off.y };
bool valid = true;
valid &= tilepassable(pfb.x, pfb.y);
valid &= tilepassable(pfb.x + e->fbox.ext.x, pfb.y);
valid &= tilepassable(pfb.x, pfb.y + e->fbox.ext.y);
valid &= tilepassable(pfb.x + e->fbox.ext.x, pfb.y + e->fbox.ext.y);
if (valid) {
e->pos.x = nextx;
e->pos.y = nexty;
}
}
static void entitydraw(entity_t *e, uint64_t t)
{
const unsigned frame = (t / BASEANIMPERIOD) % e->animlen;
e->src.x = e->animstep.x * frame + e->svarstep.x * e->svar;
e->src.y = e->animstep.y * frame + e->svarstep.y * e->svar;
SDL_Rect dest = {
.x = SCALE * (int)(e->pos.x - vpos.x - e->src.w / 2),
.y = SCALE * (int)(e->pos.y - vpos.y - e->src.h / 2),
.w = SCALE * e->src.w,
.h = SCALE * e->src.h,
};
SDL_RenderCopy(renderer, e->tex, &e->src, &dest);
}
int main(int argc, char *argv[])
{
char path[MAX_PATH_LEN];
@ -214,18 +284,26 @@ int main(int argc, char *argv[])
assert(NULL != pwalk);
// Initialize player
SDL_Rect psrc = { .y = 0, .w = PWIDTH, .h = PHEIGHT };
SDL_Rect pdest = { .w = SCALE * PWIDTH, .h = SCALE * PHEIGHT };
dvec_t pvel = { 0, 0 }, ppos = { 0, 0 };
sprite_dir_t pdir = SPRITE_DIR_DOWN;
ptex = pidle;
entity_t p = {
.svar = SPRITE_DIR_DOWN,
.animlen = PANIMLEN,
.tex = pidle,
.animstep = { .x = PWIDTH },
.svarstep = { .y = PHEIGHT },
.fbox = {
.off = { .x = PFBOFFX, .y = PFBOFFY },
.ext = { .x = PFBWIDTH, .y = PFBHEIGHT },
},
.src = { .w = PWIDTH, .h = PHEIGHT },
};
SDL_Event event;
uint64_t prevt = SDL_GetTicks64();
while (1) {
// Calculate dt
const uint64_t t = SDL_GetTicks64();
const uint64_t dt = t - prevt;
const uint64_t dt_ms = t - prevt;
const double dt = dt_ms / 1000.0;
prevt = t;
// Handle events
@ -277,58 +355,28 @@ int main(int argc, char *argv[])
}
// Calculate and apply velocity
pvel.x = (input.left ? -1 : 0) + (input.right ? 1 : 0);
pvel.y = (input.up ? -1 : 0) + (input.down ? 1 : 0);
const double pspeed = mag(pvel);
if (pspeed != 0) {
pvel.x *= WALKSPEED / pspeed;
pvel.y *= WALKSPEED / pspeed;
// Check for terrain collision, update position if none
const double nextx = ppos.x + (double)dt / 1000.0 * pvel.x;
const double nexty = ppos.y + (double)dt / 1000.0 * pvel.y;
const dvec_t pfb
= { .x = nextx + PFBOFFX, .y = nexty + PFBOFFY };
bool valid = true;
valid &= tilepassable(pfb.x, pfb.y);
valid &= tilepassable(pfb.x + PFBWIDTH, pfb.y);
valid &= tilepassable(pfb.x, pfb.y + PFBHEIGHT);
valid &= tilepassable(pfb.x + PFBWIDTH, pfb.y + PFBHEIGHT);
if (valid) {
ppos.x = nextx;
ppos.y = nexty;
}
// Update direction
if (pvel.y >= 0) {
if (pvel.x > 0)
pdir = SPRITE_DIR_RIGHT_DOWN;
else if (pvel.x < 0)
pdir = SPRITE_DIR_LEFT_DOWN;
else
pdir = SPRITE_DIR_DOWN;
} else if (pvel.y < 0) {
if (pvel.x > 0)
pdir = SPRITE_DIR_RIGHT_UP;
else if (pvel.x < 0)
pdir = SPRITE_DIR_LEFT_UP;
else
pdir = SPRITE_DIR_UP;
}
ptex = pwalk;
p.dir.x = (input.left ? -1 : 0) + (input.right ? 1 : 0);
p.dir.y = (input.up ? -1 : 0) + (input.down ? 1 : 0);
const double dmag = mag(p.dir);
if (dmag != 0) {
p.dir.x /= dmag;
p.dir.y /= dmag;
p.tex = pwalk;
p.speed = WALKSPEED;
} else {
ptex = pidle;
p.tex = pidle;
p.speed = 0;
}
entityupdate(&p, dt);
// Update view
const dvec_t pvdisp = {
.x = ppos.x - (vpos.x + VIEWWIDTH / 2),
.y = ppos.y - (vpos.y + VIEWHEIGHT / 2),
.x = p.pos.x - (vpos.x + VIEWWIDTH / 2),
.y = p.pos.y - (vpos.y + VIEWHEIGHT / 2),
};
if (mag(pvdisp) > 72 && dot(pvdisp, pvel) > 0) {
const double nextx = vpos.x + (double)dt / 1000.0 * pvel.x;
const double nexty = vpos.y + (double)dt / 1000.0 * pvel.y;
if (mag(pvdisp) > 72 && dot(pvdisp, p.dir) > 0) {
const double nextx = vpos.x + dt * p.speed * p.dir.x;
const double nexty = vpos.y + dt * p.speed * p.dir.y;
const bool validx = nextx >= MAPMINX && nextx < MAPMAXX;
const bool validy = nexty >= MAPMINY && nexty < MAPMAXY;
if (validx && validy) {
@ -364,12 +412,7 @@ int main(int argc, char *argv[])
}
// Draw player
const unsigned piframe = (t / BASEANIMPERIOD) % PANIMLEN;
psrc.x = PWIDTH * piframe;
psrc.y = PHEIGHT * pdir;
pdest.x = SCALE * (int)(ppos.x - vpos.x - PWIDTH / 2);
pdest.y = SCALE * (int)(ppos.y - vpos.y - PHEIGHT / 2);
SDL_RenderCopy(renderer, ptex, &psrc, &pdest);
entitydraw(&p, t);
SDL_RenderPresent(renderer);
}