Implement jumping
This commit is contained in:
Juhani Krekelä
parent
790bcddfa9
commit
4cab2a66b9
90
platformer.c
90
platformer.c
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@ -29,9 +29,9 @@ static char tilemap[] = " "
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" "
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" "
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" "
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"gg "
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" "
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" "
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"gg g "
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" g g"
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" g "
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" g "
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" g g "
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"gggggggggg";
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@ -49,6 +49,10 @@ static void on_disconnect(void *context) {
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static bool left_held, right_held, jump_held;
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static double jump_maxhold = 0.3;
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static double jump_maxheight = 21;
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static double jump_duration = 0.4;
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static void on_keyboard(void *context, uint32_t window, uint32_t codepoint) {
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(void) context;
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if (window != main_window)
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@ -62,7 +66,14 @@ static void on_keyboard(void *context, uint32_t window, uint32_t codepoint) {
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case -KBKEY_RIGHT: right_held = false; break;
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case KBKEY_SPACE: jump_held = true; break;
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case -KBKEY_SPACE: jump_held = false; break;
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case KBKEY_Q: jump_maxhold += 0.1; break;
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case KBKEY_A: jump_maxhold -= 0.1; break;
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case KBKEY_W: jump_maxheight += 0.1; break;
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case KBKEY_S: jump_maxheight -= 0.1; break;
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case KBKEY_E: jump_duration += 0.1; break;
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case KBKEY_D: jump_duration -= 0.1; break;
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}
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printf("hold %i height %i duration %i\n", (int)(jump_maxhold * 10), (int)(jump_maxheight * 10), (int)(jump_duration * 10));
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}
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static void on_quit(void *context, uint32_t window) {
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@ -91,21 +102,67 @@ static char sample_tilemap(size_t x, size_t y) {
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return tilemap[ty * TILES + tx];
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}
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static double player_x, player_y;
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static bool jumping = false;
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static bool on_ground = false;
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static double jump_start_y;
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static double in_jump;
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static double player_x = 0, player_y = 80;
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static double player_dx, player_dy;
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static void update(struct timespec now, struct timespec dt_timespec) {
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(void) now;
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double dt = timespec2double(dt_timespec);
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player_x += player_dx * dt;
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player_y += player_dy * dt;
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//player_y += player_dy * dt;
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if (left_held) player_dx = -30;
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else if (right_held) player_dx = 30;
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else player_dx = 0;
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if (jump_held) player_dy = -30;
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else player_dy = 30;
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if (on_ground && jump_held && !jumping) {
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jumping = true;
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in_jump = 0;
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jump_start_y = player_y;
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}
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if (!on_ground && !jumping) {
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// TODO: implement proper falling
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jumping = true;
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in_jump = jump_duration;
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jump_start_y = player_y + jump_maxheight;
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}
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if (jumping) {
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in_jump += dt;
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// Jump is a quadratic arc
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// h = at^2 + bt + c
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//
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// Beginning of jump, zero height
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// t = 0, h = 0
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// 0 = a0^2 + b0 + c
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// c = 0
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//
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// At 2*duration, zero height
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// t = 2T, h = 0
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// 0 = a(2T)^2 + b(2T) + 0
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// 0 = 4aT^2 + 2bT
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// 0 = 2aT^2 + bT
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// 0 = 2aT + b
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// b = -2aT
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//
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// At duration, maximum height
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// t = T, h = H
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// H = aT^2 + bT + 0
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// H = aT^2 - 2aT^2
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// H = -aT^2
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// a = -H / (T^2)
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// b
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double a = -jump_maxheight / (jump_duration * jump_duration);
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double b = -2 * a * jump_duration;
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double jump_height = a * in_jump * in_jump + b * in_jump;
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player_y = jump_start_y - jump_height;
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// player_dy is negative of derivative of jump_height
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// H = a*t^2 + b*t
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// H' = 2*a*t + b
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player_dy = -2 * a * in_jump - b;
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}
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// Collision against walls of the map
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if (player_x < 0) {
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@ -129,7 +186,7 @@ static void update(struct timespec now, struct timespec dt_timespec) {
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size_t left_cx = px - 1;
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size_t right_cx = px + TILE_SIDE;
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size_t leftright_top_cy = py;
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size_t leftright_bottom_cy = py + TILE_SIDE - 1;
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size_t leftright_bottom_cy = py + TILE_SIDE - 2;
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if ((sample_tilemap(left_cx, leftright_top_cy) != ' ' ||
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sample_tilemap(left_cx, leftright_bottom_cy) != ' ') &&
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player_dx < 0) {
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@ -152,14 +209,15 @@ static void update(struct timespec now, struct timespec dt_timespec) {
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size_t top_cy = py - 1;
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size_t bottom_cy = py + TILE_SIDE;
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bool on_ground = false;
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if ((sample_tilemap(topbottom_left_cx, bottom_cy) != ' ' ||
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sample_tilemap(topbottom_right_cx, bottom_cy) != ' ') &&
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player_dy > 0) {
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on_ground = false;
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if (sample_tilemap(topbottom_left_cx, bottom_cy) != ' ' ||
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sample_tilemap(topbottom_right_cx, bottom_cy) != ' ') {
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on_ground = true;
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size_t snapped_py = py / TILE_SIDE * TILE_SIDE;
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player_y = snapped_py;
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player_dy = 0;
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if (player_dy > 0) {
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jumping = false;
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size_t snapped_py = py / TILE_SIDE * TILE_SIDE;
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player_y = snapped_py;
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}
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}
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if ((sample_tilemap(topbottom_left_cx, top_cy) != ' ' ||
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sample_tilemap(topbottom_right_cx, top_cy) != ' ') &&
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