a-game

commit c1fc73a188a95355ee47a30feccbe5bcfd8c92c4
parent 5ae8724e047c415f75d1c615b3bbb3f27b121b47
Author: amin <dev@aminmesbah.com>
Date:   Fri, 19 Apr 2019 23:17:57 +0000

Do hilarious inverted AABB collision detection

FossilOrigin-Name: 95afb325c226d1199f8fc758ee429b7b2d197423d8cd71d2380d06b3407fb740
Diffstat:
M
src/game.c
 | 
52
+++++++++++++++++++++++++---------------------------
M
src/game.h
 | 
2
+-
M
src/glmth.h
 | 
9
+++++++++

3 files changed, 35 insertions(+), 28 deletions(-)
diff --git a/src/game.c b/src/game.c
@@ -14,7 +14,11 @@ internal void game_init(struct GameMemory *game_memory, v2u framebuffer)
     struct GameState *game_state = game_memory->game_state;
 
     // init player
-    game_state->player.pos = (v2) { 1.0f, 1.0f };
+    game_state->player.pos = (v2) {1.0f, 1.0f};
+
+    // In Knytt, the player is 9 by 14 texels and a tile is 24 by 24 texels.
+    // These dimensions are relative to a square 'meter', one tile
+    game_state->player.dimensions = (v2) {0.375f, 0.583f};
 
     // set up and load tiles
     {
@@ -56,7 +60,6 @@ internal void game_init(struct GameMemory *game_memory, v2u framebuffer)
         game_state->tiles.vao = vao;
         game_state->tiles.vbo = vbo;
         game_state->tiles.ebo = vbo;
-        game_state->tiles.count = 1;
     }
 
     {
@@ -165,13 +168,6 @@ void game_update_and_render(struct GameMemory *game_memory, struct GameInput *ga
         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
@@ -224,20 +220,25 @@ void game_update_and_render(struct GameMemory *game_memory, struct GameInput *ga
                     color = (v3) {0.3f, 0.3f, 0.3f};
                 }
 
-                v2 player_pos = game_state->player.pos;
-                bool player_is_in_tile = (
-                    player_pos.x >= tile_pos.x
-                    && player_pos.x <= tile_pos.x + tile_size
-                    && player_pos.y >= tile_pos.y
-                    && player_pos.y <= tile_pos.y + tile_size
-                );
-                if (player_is_in_tile)
-                {
-                    color = (v3) {0.4f, 0.8f, 0.4f};
-                }
-                if (player_is_in_tile && tile_id > 0)
                 {
-                    color = (v3) {0.8f, 0.4f, 0.4f};
+                    struct Entity player = game_state->player;
+                    rect player_aabb = {
+                        .min = {player.pos.x - (0.5f * player.dimensions.width), player.pos.y - (0.5f * player.dimensions.height)},
+                        .max = {player.pos.x + (0.5f * player.dimensions.width), player.pos.y + (0.5f * player.dimensions.height)},
+                    };
+                    rect tile_aabb = {
+                        .min = tile_pos,
+                        .max = {tile_pos.x + tile_size, tile_pos.y + tile_size},
+                    };
+                    bool player_is_in_tile = glmth_aabb_intersect(player_aabb, tile_aabb);
+                    if (player_is_in_tile)
+                    {
+                        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);
@@ -254,16 +255,13 @@ void game_update_and_render(struct GameMemory *game_memory, struct GameInput *ga
     // render player
     {
         shader_use(&game_state->player.shader);
-        struct Entity player = game_state->player;
         glBindVertexArray(game_state->tiles.vao);
+        struct Entity player = game_state->player;
 
-        // In Knytt, the player is 9 by 14 texels and a tile is 24 by 24 texels
-        // these dimensions are relative to a square 'meter', one tile
-        v2 player_dim = { 0.375f, 0.583f };
 
         m4 model = glmth_m4_init_id();
         model = glmth_translate(model, (v3) {player.pos.x, player.pos.y, 0.0f});
-        model = glmth_scale(model, (v3) {player_dim.x, player_dim.y, 1.0f});
+        model = glmth_scale(model, (v3) {player.dimensions.x, player.dimensions.y, 1.0f});
 
         v3 color = (v3) { 1.0f, 0.0f, 1.0f };
 
diff --git a/src/game.h b/src/game.h
@@ -21,7 +21,6 @@ struct Tiles
     GLuint vao;
     GLuint vbo;
     GLuint ebo;
-    u32 count;
     struct Shader shader;
 };
 
@@ -30,6 +29,7 @@ struct Entity
     v2 acceleration;
     v2 velocity;
     v2 pos;
+    v2 dimensions;
     struct Shader shader;
 };
 
diff --git a/src/glmth.h b/src/glmth.h
@@ -5,6 +5,15 @@
 // TODO: make sure these functions are inlineable and that the compiler does
 // indeed inline them.
 
+internal inline bool glmth_aabb_intersect(rect r1, rect r2)
+{
+    bool aabbs_do_indeed_intersect = (
+        (r1.min.x >= r2.max.x && r1.min.y >= r2.max.y)
+        || (r2.min.x >= r1.max.x && r2.min.y >= r1.max.y)
+    );
+    return aabbs_do_indeed_intersect;
+}
+
 internal inline f32 glmth_wrap(f32 n, f32 min, f32 max)
 {
     if (n > max)