a-game

commit 576ead88e8561f8a1a5ec53a30346f92f1d50d39
parent 6d5d3a11488221a52886c567f4e1ce9137966ef9
Author: amin <dev@aminmesbah.com>
Date:   Fri, 19 Apr 2019 23:17:57 +0000

Do hilariously untuned semi-implicit Euler

Also highlight colliding tiles in a different color.

FossilOrigin-Name: f74669ace8ecb04812bc93e557869f0823e7cdd81336970ad865818e54568b54
Diffstat:
M
src/game.c
 | 
41
++++++++++++++++++++++++++++++++++-------
M
src/game.h
 | 
2
++
M
src/glmth.h
 | 
6
++++++

3 files changed, 42 insertions(+), 7 deletions(-)
diff --git a/src/game.c b/src/game.c
@@ -123,28 +123,51 @@ void game_update_and_render(struct GameMemory *game_memory, struct GameInput *ga
 
     // update player
     {
+        struct Entity *player = &game_state->player;
+        f32 dt = game_input->dt;
         f32 max_meters_per_second = 5.0f;
-        f32 movement_speed = max_meters_per_second * game_input->dt;
+        f32 acceleration_rate = 10.0f;
 
         if (game_input->key_up)
         {
-            game_state->player.pos.y += movement_speed;
+            player->acceleration.y = +acceleration_rate;
         }
         else if (game_input->key_down)
         {
-            game_state->player.pos.y -= movement_speed;
+            player->acceleration.y = -acceleration_rate;
+        }
+        else
+        {
+            player->acceleration.y = 0.0f;
         }
 
         if (game_input->key_left)
         {
-            game_state->player.pos.x -= movement_speed;
+            player->acceleration.x = -acceleration_rate;
         }
         else if (game_input->key_right)
         {
-            game_state->player.pos.x += movement_speed;
+            player->acceleration.x = +acceleration_rate;
+        }
+        else
+        {
+            player->acceleration.x = 0.0f;
         }
-        glmth_clamp(&(game_state->player.pos.x), 0, ROOM_TILE_DIM_X);
-        glmth_clamp(&(game_state->player.pos.y), 0, ROOM_TILE_DIM_Y);
+
+        glmth_clamp(&player->velocity.x, -max_meters_per_second, max_meters_per_second);
+
+        // Semi implicit Euler integration: https://gafferongames.com/post/integration_basics/
+        player->velocity = glmth_v2_a(player->velocity, glmth_v2f_m(player->acceleration, dt));
+        player->pos = glmth_v2_a(player->pos, glmth_v2f_m(player->velocity, dt));
+
+        glmth_clamp(&(player->pos.x), 0, ROOM_TILE_DIM_X);
+        glmth_clamp(&(player->pos.y), 0, ROOM_TILE_DIM_Y);
+        printf("A: ");
+        glmth_v2_print(player->acceleration);
+        printf("V: ");
+        glmth_v2_print(player->velocity);
+        printf("P: ");
+        glmth_v2_print(player->pos);
     }
 
     // render tiles
@@ -208,6 +231,10 @@ void game_update_and_render(struct GameMemory *game_memory, struct GameInput *ga
                 {
                     color = (v3) {0.4f, 0.8f, 0.4f};
                 }
+                if (player_is_in_tile && tile_id > 0)
+                {
+                    color = (v3) {0.8f, 0.4f, 0.4f};
+                }
 
                 shader_setv3(&game_state->tiles.shader, "color", &color);
                 shader_setm4(&game_state->tiles.shader, "model", &model);
diff --git a/src/game.h b/src/game.h
@@ -27,6 +27,8 @@ struct Tiles
 
 struct Entity
 {
+    v2 acceleration;
+    v2 velocity;
     v2 pos;
     struct Shader shader;
 };
diff --git a/src/glmth.h b/src/glmth.h
@@ -121,6 +121,12 @@ internal inline v2 glmth_v2_a(v2 vec1, v2 vec2)
     return r;
 }
 
+internal inline v2 glmth_v2f_m(v2 v, f32 s)
+{
+    v2 r = {v.x * s, v.y * s};
+    return r;
+}
+
 internal inline void glmth_v2_print(v2 v)
 {
     printf("( %f, %f )\n", v.x, v.y);