nortti
/
switcher
1
0
Fork 0
Code Issues Pull Requests Projects Releases 1 Wiki Activity

Implement jumping

This commit is contained in:
Juhani Krekelä 2022-01-14 17:18:57 +00:00
parent 790bcddfa9
commit 4cab2a66b9
1 changed files with 74 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

90
platformer.c
View File

@ -29,9 +29,9 @@ static char tilemap[] = " "
" " " "
" " " "
" " " "
"gg " "gg g "
" " " g g"
" " " g "
" g " " g "
" g g " " g g "
"gggggggggg"; "gggggggggg";
@ -49,6 +49,10 @@ static void on_disconnect(void *context) {
static bool left_held, right_held, jump_held; static bool left_held, right_held, jump_held;
static double jump_maxhold = 0.3;
static double jump_maxheight = 21;
static double jump_duration = 0.4;
static void on_keyboard(void *context, uint32_t window, uint32_t codepoint) { static void on_keyboard(void *context, uint32_t window, uint32_t codepoint) {
(void) context; (void) context;
if (window != main_window) if (window != main_window)
@ -62,7 +66,14 @@ static void on_keyboard(void *context, uint32_t window, uint32_t codepoint) {
case -KBKEY_RIGHT: right_held = false; break; case -KBKEY_RIGHT: right_held = false; break;
case KBKEY_SPACE: jump_held = true; break; case KBKEY_SPACE: jump_held = true; break;
case -KBKEY_SPACE: jump_held = false; break; case -KBKEY_SPACE: jump_held = false; break;
case KBKEY_Q: jump_maxhold += 0.1; break;
case KBKEY_A: jump_maxhold -= 0.1; break;
case KBKEY_W: jump_maxheight += 0.1; break;
case KBKEY_S: jump_maxheight -= 0.1; break;
case KBKEY_E: jump_duration += 0.1; break;
case KBKEY_D: jump_duration -= 0.1; break;
} }
printf("hold %i height %i duration %i\n", (int)(jump_maxhold * 10), (int)(jump_maxheight * 10), (int)(jump_duration * 10));
} }
static void on_quit(void *context, uint32_t window) { static void on_quit(void *context, uint32_t window) {
@ -91,21 +102,67 @@ static char sample_tilemap(size_t x, size_t y) {
return tilemap[ty * TILES + tx]; return tilemap[ty * TILES + tx];
} }
static double player_x, player_y; static bool jumping = false;
static bool on_ground = false;
static double jump_start_y;
static double in_jump;
static double player_x = 0, player_y = 80;
static double player_dx, player_dy; static double player_dx, player_dy;
static void update(struct timespec now, struct timespec dt_timespec) { static void update(struct timespec now, struct timespec dt_timespec) {
(void) now; (void) now;
double dt = timespec2double(dt_timespec); double dt = timespec2double(dt_timespec);
player_x += player_dx * dt; player_x += player_dx * dt;
player_y += player_dy * dt; //player_y += player_dy * dt;
if (left_held) player_dx = -30; if (left_held) player_dx = -30;
else if (right_held) player_dx = 30; else if (right_held) player_dx = 30;
else player_dx = 0; else player_dx = 0;
if (jump_held) player_dy = -30; if (on_ground && jump_held && !jumping) {
else player_dy = 30; jumping = true;
in_jump = 0;
jump_start_y = player_y;
}
if (!on_ground && !jumping) {
// TODO: implement proper falling
jumping = true;
in_jump = jump_duration;
jump_start_y = player_y + jump_maxheight;
}
if (jumping) {
in_jump += dt;
// Jump is a quadratic arc
// h = at^2 + bt + c
//
// Beginning of jump, zero height
// t = 0, h = 0
// 0 = a0^2 + b0 + c
// c = 0
//
// At 2*duration, zero height
// t = 2T, h = 0
// 0 = a(2T)^2 + b(2T) + 0
// 0 = 4aT^2 + 2bT
// 0 = 2aT^2 + bT
// 0 = 2aT + b
// b = -2aT
//
// At duration, maximum height
// t = T, h = H
// H = aT^2 + bT + 0
// H = aT^2 - 2aT^2
// H = -aT^2
// a = -H / (T^2)
// b
double a = -jump_maxheight / (jump_duration * jump_duration);
double b = -2 * a * jump_duration;
double jump_height = a * in_jump * in_jump + b * in_jump;
player_y = jump_start_y - jump_height;
// player_dy is negative of derivative of jump_height
// H = a*t^2 + b*t
// H' = 2*a*t + b
player_dy = -2 * a * in_jump - b;
}
// Collision against walls of the map // Collision against walls of the map
if (player_x < 0) { if (player_x < 0) {
@ -129,7 +186,7 @@ static void update(struct timespec now, struct timespec dt_timespec) {
size_t left_cx = px - 1; size_t left_cx = px - 1;
size_t right_cx = px + TILE_SIDE; size_t right_cx = px + TILE_SIDE;
size_t leftright_top_cy = py; size_t leftright_top_cy = py;
size_t leftright_bottom_cy = py + TILE_SIDE - 1; size_t leftright_bottom_cy = py + TILE_SIDE - 2;
if ((sample_tilemap(left_cx, leftright_top_cy) != ' ' || if ((sample_tilemap(left_cx, leftright_top_cy) != ' ' ||
sample_tilemap(left_cx, leftright_bottom_cy) != ' ') && sample_tilemap(left_cx, leftright_bottom_cy) != ' ') &&
player_dx < 0) { player_dx < 0) {
@ -152,14 +209,15 @@ static void update(struct timespec now, struct timespec dt_timespec) {
size_t top_cy = py - 1; size_t top_cy = py - 1;
size_t bottom_cy = py + TILE_SIDE; size_t bottom_cy = py + TILE_SIDE;
bool on_ground = false; on_ground = false;
if ((sample_tilemap(topbottom_left_cx, bottom_cy) != ' ' || if (sample_tilemap(topbottom_left_cx, bottom_cy) != ' ' ||
sample_tilemap(topbottom_right_cx, bottom_cy) != ' ') && sample_tilemap(topbottom_right_cx, bottom_cy) != ' ') {
player_dy > 0) {
on_ground = true; on_ground = true;
size_t snapped_py = py / TILE_SIDE * TILE_SIDE; if (player_dy > 0) {
player_y = snapped_py; jumping = false;
player_dy = 0; size_t snapped_py = py / TILE_SIDE * TILE_SIDE;
player_y = snapped_py;
}
} }
if ((sample_tilemap(topbottom_left_cx, top_cy) != ' ' || if ((sample_tilemap(topbottom_left_cx, top_cy) != ' ' ||
sample_tilemap(topbottom_right_cx, top_cy) != ' ') && sample_tilemap(topbottom_right_cx, top_cy) != ' ') &&