draw: draw_distance for 3d spaces, proper positioning of skybox according to it, scenery demo on circle rasters

apps/demos/scenery/scenes/ingame.c

@@ -12,10 +12,13 @@
 
 
 #define TERRAIN_FREQUENCY 0.15f
-#define TERRAIN_DISTANCE 128
+#define TERRAIN_RADIUS 128
+#define GRASS_RADIUS 16
+#define TERRAIN_DISTANCE (TERRAIN_RADIUS * 2)
 #define HALF_TERRAIN_DISTANCE ((float)TERRAIN_DISTANCE / 2)
 #define PLAYER_HEIGHT 0.6f
 
+/* TODO: pregenerate grid of levels of detail */
 static float heightmap[TERRAIN_DISTANCE][TERRAIN_DISTANCE];
 
 
@@ -23,7 +26,7 @@ static void process_fly_mode(State *state) {
     SceneIngame *scn = (SceneIngame *)state->scene;
 
     DrawCameraFromPrincipalAxesResult dir_and_up =
-        draw_camera_from_principal_axes(scn->pos, scn->roll, scn->pitch, scn->yaw, (float)M_PI_2 * 0.8f, 1);
+        draw_camera_from_principal_axes(scn->pos, scn->roll, scn->pitch, scn->yaw, (float)M_PI_2 * 0.8f, 1, TERRAIN_RADIUS * M_SQRT2f);
 
     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 */
@@ -80,7 +83,7 @@ static void process_ground_mode(State *state) {
     SceneIngame *scn = (SceneIngame *)state->scene;
 
     DrawCameraFromPrincipalAxesResult dir_and_up =
-        draw_camera_from_principal_axes(scn->pos, scn->roll, scn->pitch, scn->yaw, (float)M_PI_2 * 0.8f, 1);
+        draw_camera_from_principal_axes(scn->pos, scn->roll, scn->pitch, scn->yaw, (float)M_PI_2 * 0.8f, 1, TERRAIN_RADIUS * M_SQRT2f);
 
     dir_and_up.direction.y = 0;
     dir_and_up.direction = vec3_norm(dir_and_up.direction);
@@ -134,7 +137,7 @@ static void generate_terrain(SceneIngame *scn) {
             float y = floorf(scn->pos.z - HALF_TERRAIN_DISTANCE + (float)ly);
 
             float height = stb_perlin_noise3((float)x * TERRAIN_FREQUENCY, (float)y * TERRAIN_FREQUENCY, 0, 0, 0, 0) * 3 - 1;
-            height += stb_perlin_noise3((float)x * TERRAIN_FREQUENCY / 10, (float)y * TERRAIN_FREQUENCY / 10, 0, 0, 0, 0) * 10 - 1;
+            height += stb_perlin_noise3((float)x * TERRAIN_FREQUENCY / 10, (float)y * TERRAIN_FREQUENCY / 10, 0, 0, 0, 0) * 20 - 1;
 
             heightmap[lx][ly] = height;
         }
@@ -142,9 +145,23 @@ static void generate_terrain(SceneIngame *scn) {
 }
 
 
+static int32_t ceil_sqrt(int32_t const n) {
+    int32_t res = 1;
+    while(res * res < n)
+        res++;
+    return res;
+}
+
+
 static void draw_terrain(SceneIngame *scn) {
-    for (int ly = TERRAIN_DISTANCE - 1; ly > 0; ly--) {
+    /* draw terrain in circle */
-        for (int lx = 0; lx < TERRAIN_DISTANCE - 1; lx++) {
+    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) {
+        int32_t const dx = ceil_sqrt(rsi - (iy + (iy <= 0)) * (iy + (iy <= 0)));
+        for (int32_t ix = -dx; ix < dx; ++ix) {
+            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));
             int32_t y = (int32_t)(floorf(scn->pos.z - HALF_TERRAIN_DISTANCE + (float)ly));
 
@@ -160,8 +177,21 @@ static void draw_terrain(SceneIngame *scn) {
                             (Vec3){ (float)x,     d3, (float)y - 1 },
                             (Rect){ .w = 128, .h = 128 },
                             (Color){255, 255, 255, 255});
+            }
+    }
+
+    int32_t const rsi_g = (int32_t)GRASS_RADIUS * (int32_t)GRASS_RADIUS;
+    for (int32_t iy = -(int32_t)GRASS_RADIUS; iy <= (int32_t)GRASS_RADIUS - 1; ++iy) {
+        int32_t const dx = ceil_sqrt(rsi_g - (iy + (iy <= 0)) * (iy + (iy <= 0)));
+        for (int32_t ix = -dx; ix < dx; ++ix) {
+            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));
+            int32_t y = (int32_t)(floorf(scn->pos.z - HALF_TERRAIN_DISTANCE + (float)ly));
+
+            float d0 = heightmap[lx][ly];
 
-            /* TODO: only draw upclose */
             draw_billboard("/assets/grasses/10.png",
                           (Vec3){ (float)x, d0 + 0.15f, (float)y },
                           (Vec2){0.3f, 0.3f},
@@ -216,7 +246,7 @@ static void ingame_tick(State *state) {
     draw_skybox("/assets/miramar/miramar_*.tga");
 
     ctx.fog_color = (Color){ 140, 147, 160, 255 };
-    ctx.fog_density = 0.03f;
+    ctx.fog_density = 0.02f;
 }
 
 

include/twn_draw.h

@@ -86,11 +86,12 @@ TWN_API void draw_camera_2d(Vec2 position,      /* optional, default: (0, 0) */
 
 /* sets a perspective 3d camera to be used for all 3d commands */
 /* fov = 0 corresponds to orthographic projection */
-TWN_API void draw_camera(Vec3 position,
+TWN_API void draw_camera(Vec3 position,         /* optional, default: (0, 0, 0) */
                          Vec3 direction,        /* optional, default: (0, 0, -1) */
                          Vec3 up,               /* optional, default: (0, 1, 0) */
                          float fov,             /* optional, default: PI / 6 * 3 (90 degrees) */
-                         float zoom);           /* optional, default: 1 */
+                         float zoom,            /* optional, default: 1 */
+                         float draw_distance);  /* optional, default: 100 */
 
 /* same as draw_camera(), but with first person controller in mind */
 /* direction and up vectors are inferred from roll, pitch and yaw parameters (in radians) */
@@ -100,12 +101,13 @@ typedef struct DrawCameraFromPrincipalAxesResult {
     Vec3 up;
 } DrawCameraFromPrincipalAxesResult;
 TWN_API DrawCameraFromPrincipalAxesResult
-draw_camera_from_principal_axes(Vec3 position,
+draw_camera_from_principal_axes(Vec3 position,          /* optional, default: (0, 0, 0) */
                                 float roll,             /* optional, default: 0 */
                                 float pitch,            /* optional, default: 0 */
                                 float yaw,              /* optional, default: 0 */
                                 float fov,              /* optional, default: PI / 6 * 3 (90 degrees) */
-                                float zoom);  /* optional, default: 1 */
+                                float zoom,             /* optional, default: 1 */
+                                float draw_distance);   /* optional, default: 100 */
 
 /* expects '*' masks that will be expanded to 6 names: 'up', 'down', 'east', 'west', 'north' and 'south' */
 TWN_API void draw_skybox(const char *textures);

share/twn_api.json

@@ -207,11 +207,12 @@
             "symbol": "camera",
             "header": "twn_draw.h",
             "params": [
-                { "name": "position", "type": "Vec3" },
+                { "name": "position", "type": "Vec3", "default": { "x": 0, "y": 0, "z": 0 } },
                 { "name": "direction", "type": "Vec3", "default": { "x": 0, "y": 0, "z": -1 } },
                 { "name": "up", "type": "Vec3", "default": { "x": 0, "y": 1, "z": 0 } },
                 { "name": "fov", "type": "float", "default": 1.57079632679 },
-                { "name": "zoom", "type": "float", "default": 1 }
+                { "name": "zoom", "type": "float", "default": 1 },
+                { "name": "draw_distance", "type": "float", "default": 100 }
             ]
         },
 
@@ -220,12 +221,13 @@
             "symbol": "camera_from_principal_axes",
             "header": "twn_draw.h",
             "params": [
-                { "name": "position", "type": "Vec3" },
+                { "name": "position", "type": "Vec3", "default": { "x": 0, "y": 0, "z": 0 } },
                 { "name": "roll", "type": "float", "default": 0 },
                 { "name": "pitch", "type": "float", "default": 0 },
                 { "name": "yaw", "type": "float", "default": 0 },
                 { "name": "fov", "type": "float", "default": 1.57079632679 },
-                { "name": "zoom", "type": "float", "default": 1 }
+                { "name": "zoom", "type": "float", "default": 1 },
+                { "name": "draw_distance", "type": "float", "default": 100 }
             ],
             "return": {
                 "fields": [

src/rendering/twn_draw.c

@@ -20,6 +20,7 @@ DeferredCommand *deferred_commands;
 /* TODO: with buffered render, don't we use camera of wrong frame right now ? */
 Matrix4 camera_projection_matrix;
 Matrix4 camera_look_at_matrix;
+float camera_far_z;
 
 float camera_2d_rotation;
 Vec2 camera_2d_position;
@@ -36,7 +37,7 @@ static void reset_camera_2d(void) {
 
 
 void render_clear(void) {
-    draw_camera((Vec3){0, 0, 0}, (Vec3){0, 0, 1}, (Vec3){0, 1, 0}, 1.57079632679f, 1);
+    draw_camera((Vec3){0, 0, 0}, (Vec3){0, 0, 1}, (Vec3){0, 1, 0}, 1.57079632679f, 1, 100);
     reset_camera_2d();
 
     text_cache_reset_arena(&ctx.text_cache);
@@ -423,7 +424,7 @@ TWN_API void draw_camera_2d(Vec2 position,
 }
 
 /* TODO: check for NaNs and alike */
-void draw_camera(Vec3 position, Vec3 direction, Vec3 up, float fov, float zoom) {
+void draw_camera(Vec3 position, Vec3 direction, Vec3 up, float fov, float zoom, float draw_distance) {
     bool const orthographic = fabsf(0.0f - fov) < 0.00001f;
     if (!orthographic && fov >= (float)(M_PI))
         log_warn("Invalid fov given (%f)", (double)fov);
@@ -437,6 +438,7 @@ void draw_camera(Vec3 position, Vec3 direction, Vec3 up, float fov, float zoom)
             (Vec2){ 1/-zoom, 1/zoom },
             (Vec2){ 1/zoom, 1/-zoom }
         },
+        .far_z = draw_distance
     };
 
     if (!orthographic)
@@ -444,6 +446,8 @@ void draw_camera(Vec3 position, Vec3 direction, Vec3 up, float fov, float zoom)
     else
         camera_projection_matrix = camera_orthographic(&camera);
 
+    camera_far_z = draw_distance;
+
     camera_look_at_matrix = camera_look_at(&camera);
 }
 
@@ -455,7 +459,8 @@ DrawCameraFromPrincipalAxesResult draw_camera_from_principal_axes(Vec3 position,
                                                                   float pitch,
                                                                   float yaw,
                                                                   float fov,
-                                                                  float zoom)
+                                                                  float zoom,
+                                                                  float draw_distance)
 {
     bool const orthographic = fabsf(0.0f - fov) < 0.00001f;
     if (!orthographic && fov >= (float)(M_PI))
@@ -476,7 +481,7 @@ DrawCameraFromPrincipalAxesResult draw_camera_from_principal_axes(Vec3 position,
 
     Vec3 const up = (Vec3){0, 1, 0};
 
-    draw_camera(position, direction, up, fov, zoom);
+    draw_camera(position, direction, up, fov, zoom, draw_distance);
 
     return (DrawCameraFromPrincipalAxesResult) {
         .direction = direction,

src/rendering/twn_draw_c.h

@@ -16,6 +16,7 @@
 
 extern Matrix4 camera_projection_matrix;
 extern Matrix4 camera_look_at_matrix;
+extern float camera_far_z;
 
 extern float camera_2d_rotation;
 extern Vec2 camera_2d_position;

src/rendering/twn_gl_15_rendering.c

@@ -441,66 +441,68 @@ void finally_render_skybox(DeferredCommandDrawSkybox command) {
                 glEnable(GL_DEPTH_CLAMP);
         #endif
 
+            float const d = camera_far_z / sqrtf(3);
+
             glBegin(GL_QUADS); {
                 /* up */
-                glTexCoord3f(50.f, 50.f, 50.f);
+                glTexCoord3f(d, d, d);
-                glVertex3f(50.f, 50.f, 50.f);
+                glVertex3f(d, d, d);
-                glTexCoord3f(-50.f, 50.f, 50.f);
+                glTexCoord3f(-d, d, d);
-                glVertex3f(-50.f, 50.f, 50.f);
+                glVertex3f(-d, d, d);
-                glTexCoord3f(-50.f, 50.f, -50.f);
+                glTexCoord3f(-d, d, -d);
-                glVertex3f(-50.f, 50.f, -50.f);
+                glVertex3f(-d, d, -d);
-                glTexCoord3f(50.f, 50.f, -50.f);
+                glTexCoord3f(d, d, -d);
-                glVertex3f(50.f, 50.f, -50.f);
+                glVertex3f(d, d, -d);
 
                 /* down */
-                glTexCoord3f(50.f, -50.f, 50.f);
+                glTexCoord3f(d, -d, d);
-                glVertex3f(50.f, -50.f, 50.f);
+                glVertex3f(d, -d, d);
-                glTexCoord3f(50.f, -50.f, -50.f);
+                glTexCoord3f(d, -d, -d);
-                glVertex3f(50.f, -50.f, -50.f);
+                glVertex3f(d, -d, -d);
-                glTexCoord3f(-50.f, -50.f, -50.f);
+                glTexCoord3f(-d, -d, -d);
-                glVertex3f(-50.f, -50.f, -50.f);
+                glVertex3f(-d, -d, -d);
-                glTexCoord3f(-50.f, -50.f, 50.f);
+                glTexCoord3f(-d, -d, d);
-                glVertex3f(-50.f, -50.f, 50.f);
+                glVertex3f(-d, -d, d);
 
                 /* east */
-                glTexCoord3f(50.f, -50.f, 50.f);
+                glTexCoord3f(d, -d, d);
-                glVertex3f(50.f, -50.f, 50.f);
+                glVertex3f(d, -d, d);
-                glTexCoord3f(50.f, 50.f, 50.f);
+                glTexCoord3f(d, d, d);
-                glVertex3f(50.f, 50.f, 50.f);
+                glVertex3f(d, d, d);
-                glTexCoord3f(50.f, 50.f, -50.f);
+                glTexCoord3f(d, d, -d);
-                glVertex3f(50.f, 50.f, -50.f);
+                glVertex3f(d, d, -d);
-                glTexCoord3f(50.f, -50.f, -50.f);
+                glTexCoord3f(d, -d, -d);
-                glVertex3f(50.f, -50.f, -50.f);
+                glVertex3f(d, -d, -d);
 
                 /* west */
-                glTexCoord3f(-50.f, -50.f, 50.f);
+                glTexCoord3f(-d, -d, d);
-                glVertex3f(-50.f, -50.f, 50.f);
+                glVertex3f(-d, -d, d);
-                glTexCoord3f(-50.f, -50.f, -50.f);
+                glTexCoord3f(-d, -d, -d);
-                glVertex3f(-50.f, -50.f, -50.f);
+                glVertex3f(-d, -d, -d);
-                glTexCoord3f(-50.f, 50.f, -50.f);
+                glTexCoord3f(-d, d, -d);
-                glVertex3f(-50.f, 50.f, -50.f);
+                glVertex3f(-d, d, -d);
-                glTexCoord3f(-50.f, 50.f, 50.f);
+                glTexCoord3f(-d, d, d);
-                glVertex3f(-50.f, 50.f, 50.f);
+                glVertex3f(-d, d, d);
 
                 /* north */
-                glTexCoord3f(-50.f, -50.f, 50.f);
+                glTexCoord3f(-d, -d, d);
-                glVertex3f(-50.f, -50.f, 50.f);
+                glVertex3f(-d, -d, d);
-                glTexCoord3f(-50.f, 50.f, 50.f);
+                glTexCoord3f(-d, d, d);
-                glVertex3f(-50.f, 50.f, 50.f);
+                glVertex3f(-d, d, d);
-                glTexCoord3f(50.f, 50.f, 50.f);
+                glTexCoord3f(d, d, d);
-                glVertex3f(50.f, 50.f, 50.f);
+                glVertex3f(d, d, d);
-                glTexCoord3f(50.f, -50.f, 50.f);
+                glTexCoord3f(d, -d, d);
-                glVertex3f(50.f, -50.f, 50.f);
+                glVertex3f(d, -d, d);
 
                 /* south */
-                glTexCoord3f(-50.f, -50.f, -50.f);
+                glTexCoord3f(-d, -d, -d);
-                glVertex3f(-50.f, -50.f, -50.f);
+                glVertex3f(-d, -d, -d);
-                glTexCoord3f(50.f, -50.f, -50.f);
+                glTexCoord3f(d, -d, -d);
-                glVertex3f(50.f, -50.f, -50.f);
+                glVertex3f(d, -d, -d);
-                glTexCoord3f(50.f, 50.f, -50.f);
+                glTexCoord3f(d, d, -d);
-                glVertex3f(50.f, 50.f, -50.f);
+                glVertex3f(d, d, -d);
-                glTexCoord3f(-50.f, 50.f, -50.f);
+                glTexCoord3f(-d, d, -d);
-                glVertex3f(-50.f, 50.f, -50.f);
+                glVertex3f(-d, d, -d);
             } glEnd();
 
         #ifndef __EMSCRIPTEN__

src/twn_camera.c

@@ -6,7 +6,7 @@
 
 
 #define CAMERA_NEAR_Z 0.1f
-#define CAMERA_FAR_Z 1000.0f
+// #define CAMERA_FAR_Z 400.0f
 
 
 Matrix4 camera_look_at(const Camera *const camera) {
@@ -42,13 +42,13 @@ Matrix4 camera_perspective(const Camera *const camera) {
     const float aspect = ((float)ctx.base_render_width / (float)ctx.base_render_height);
 
     const float f  = 1.0f / tanf(camera->fov * 0.5f);
-    const float fn = 1.0f / (CAMERA_NEAR_Z - CAMERA_FAR_Z);
+    const float fn = 1.0f / (CAMERA_NEAR_Z - camera->far_z);
 
     result.row[0].x =  f / aspect;
     result.row[1].y =  f;
-    result.row[2].z =  (CAMERA_NEAR_Z + CAMERA_FAR_Z) * fn;
+    result.row[2].z =  (CAMERA_NEAR_Z + camera->far_z) * fn;
     result.row[2].w = -1.0f;
-    result.row[3].z =  2.0f * CAMERA_NEAR_Z * CAMERA_FAR_Z * fn;
+    result.row[3].z =  2.0f * CAMERA_NEAR_Z * camera->far_z * fn;
 
     return result;
 }
@@ -61,14 +61,14 @@ Matrix4 camera_orthographic(const Camera *const camera) {
 
     const float rl =  1.0f / (camera->viewbox[0].y - camera->viewbox[0].x);
     const float tb =  1.0f / (camera->viewbox[1].x - camera->viewbox[1].y);
-    const float fn = -1.0f / (CAMERA_FAR_Z - -CAMERA_FAR_Z);
+    const float fn = -1.0f / (camera->far_z - -camera->far_z);
 
     result.row[0].x =  2.0f * rl;
     result.row[1].y =  2.0f * tb;
     result.row[2].z =  2.0f * fn;
     result.row[3].x = -(camera->viewbox[0].y + camera->viewbox[0].x)  * rl;
     result.row[3].y = -(camera->viewbox[1].x + camera->viewbox[1].y)  * tb;
-    result.row[3].z =  (CAMERA_FAR_Z + -CAMERA_FAR_Z) * fn;
+    result.row[3].z =  (camera->far_z + -camera->far_z) * fn;
     result.row[3].w =  1.0f;
 
     return result;

src/twn_camera_c.h

@@ -12,8 +12,9 @@ typedef struct Camera {
     Vec3 pos;        /* eye position */
     Vec3 target;     /* normalized target vector */
     Vec3 up;         /* normalized up vector */
-    float fov;       /* field of view, in radians */
     Vec2 viewbox[2]; /* othrographic aabb, ((left, right), (top, bottom)) */
+    float fov;       /* field of view, in radians */
+    float far_z;
 } Camera;
 
 Matrix4 camera_look_at(const Camera *camera);

src/twn_loop.c

@@ -631,7 +631,7 @@ static bool initialize(void) {
 
     input_state_init(&ctx.input);
 
-    ctx.render_double_buffered = true;
+    ctx.render_double_buffered = false;
     ctx.window_mouse_resident = true;
 
     ctx.game.fog_color = (Color){ 255, 255, 255, 255 }; /* TODO: pick some grey? */