/apps/demos/scenery: culling

apps/demos/scenery/scenes/ingame.c

@@ -17,7 +17,7 @@
 #define TERRAIN_DISTANCE (TERRAIN_RADIUS * 2)
 #define HALF_TERRAIN_DISTANCE ((float)TERRAIN_DISTANCE / 2)
 #define PLAYER_HEIGHT 0.6f
-#define TREE_DENSITY 0.02f
+#define TREE_DENSITY 0.03f
 
 /* TODO: pregenerate grid of levels of detail */
 static float heightmap[TERRAIN_DISTANCE][TERRAIN_DISTANCE];
@@ -29,6 +29,8 @@ static void process_fly_mode(State *state) {
     DrawCameraFromPrincipalAxesResult dir_and_up =
         draw_camera_from_principal_axes(scn->pos, scn->roll, scn->pitch, scn->yaw, (float)M_PI_2 * 0.8f, 1, TERRAIN_RADIUS * sqrtf(3));
 
+    scn->looking_direction = dir_and_up.direction;
+
     const Vec3 right = m_vec_norm(m_vec_cross(dir_and_up.direction, dir_and_up.up));
     const float speed = 0.04f; /* TODO: put this in a better place */
     if (input_action_pressed("player_left"))
@@ -86,6 +88,8 @@ static void process_ground_mode(State *state) {
     DrawCameraFromPrincipalAxesResult dir_and_up =
         draw_camera_from_principal_axes(scn->pos, scn->roll, scn->pitch, scn->yaw, (float)M_PI_2 * 0.8f, 1, TERRAIN_RADIUS * sqrtf(3));
 
+    scn->looking_direction = dir_and_up.direction;
+
     dir_and_up.direction.y = 0;
     dir_and_up.direction = vec3_norm(dir_and_up.direction);
 
@@ -169,6 +173,10 @@ static uint32_t adler32(const void *buf, size_t buflength) {
 
 
 static void draw_terrain(SceneIngame *scn) {
+    /* used to cull invisible tiles over field of view (to horizon) */
+    Vec2 const d = vec2_norm((Vec2){ .x = scn->looking_direction.x, .y = scn->looking_direction.z });
+    float const c = cosf((float)M_PI_2 * 0.8f);
+
     /* draw terrain in circle */
     int32_t const rsi = (int32_t)TERRAIN_RADIUS * (int32_t)TERRAIN_RADIUS;
     for (int32_t iy = -(int32_t)TERRAIN_RADIUS; iy <= (int32_t)TERRAIN_RADIUS - 1; ++iy) {
@@ -177,8 +185,12 @@ static void draw_terrain(SceneIngame *scn) {
             int32_t lx = ix + TERRAIN_RADIUS;
             int32_t ly = iy + TERRAIN_RADIUS;
 
-            int32_t x = (int32_t)(floorf(scn->pos.x - HALF_TERRAIN_DISTANCE + (float)lx));
+            float x = (float)(floorf(scn->pos.x - HALF_TERRAIN_DISTANCE + (float)lx));
-            int32_t y = (int32_t)(floorf(scn->pos.z - HALF_TERRAIN_DISTANCE + (float)ly));
+            float y = (float)(floorf(scn->pos.z - HALF_TERRAIN_DISTANCE + (float)ly));
+
+            /* cull tiles outside of vision */
+            if (vec2_dot(vec2_norm((Vec2){x - scn->pos.x + d.x * 2, y - scn->pos.z + d.y * 2}), d) < c)
+                continue;
 
             float d0 = heightmap[lx][ly];
             float d1 = heightmap[lx + 1][ly];
@@ -209,8 +221,8 @@ static void draw_terrain(SceneIngame *scn) {
             int32_t lx = ix + TERRAIN_RADIUS;
             int32_t ly = iy + TERRAIN_RADIUS;
 
-            int32_t x = (int32_t)(floorf(scn->pos.x - HALF_TERRAIN_DISTANCE + (float)lx));
+            float x = (float)(floorf(scn->pos.x - HALF_TERRAIN_DISTANCE + (float)lx));
-            int32_t y = (int32_t)(floorf(scn->pos.z - HALF_TERRAIN_DISTANCE + (float)ly));
+            float y = (float)(floorf(scn->pos.z - HALF_TERRAIN_DISTANCE + (float)ly));
 
             float d0 = heightmap[lx][ly];
 
@@ -268,7 +280,7 @@ static void ingame_tick(State *state) {
     draw_skybox("/assets/miramar/miramar_*.tga");
 
     ctx.fog_color = (Color){ 140, 147, 160, 255 };
-    ctx.fog_density = 0.02f;
+    ctx.fog_density = 0.015f;
 }
 
 

apps/demos/scenery/scenes/ingame.h

@@ -12,6 +12,8 @@
 typedef struct SceneIngame {
     Scene base;
 
+    Vec3 looking_direction;
+
     Vec3 pos;
     float yaw;
     float pitch;

include/twn_vec.h

@@ -29,10 +29,20 @@ static inline Vec2 vec2_scale(Vec2 a, float s) {
     return (Vec2) { a.x * s, a.y * s };
 }
 
+static inline float vec2_dot(Vec2 a, Vec2 b) {
+    return a.x * b.x + a.y * b.y;
+}
+
 static inline float vec2_length(Vec2 a) {
     return sqrtf(a.x * a.x + a.y * a.y);
 }
 
+static inline Vec2 vec2_norm(Vec2 a) {
+    const float n = sqrtf(vec2_dot(a, a));
+    /* TODO: do we need truncating over epsilon as cglm does? */
+    return vec2_scale(a, 1.0f / n);
+}
+
 static inline Vec3 vec3_add(Vec3 a, Vec3 b) {
     return (Vec3) { a.x + b.x, a.y + b.y, a.z + b.z };
 }