add collision w/ walls

src/lua/pxl8.lua

@@ -143,6 +143,8 @@ pxl8.world_unload = world.unload
 pxl8.world_is_loaded = world.is_loaded
 pxl8.world_generate = world.generate
 pxl8.world_apply_textures = world.apply_textures
+pxl8.world_check_collision = world.check_collision
+pxl8.world_resolve_collision = world.resolve_collision
 pxl8.procgen_tex = world.procgen_tex
 pxl8.PROCGEN_ROOMS = world.PROCGEN_ROOMS
 pxl8.PROCGEN_TERRAIN = world.PROCGEN_TERRAIN

src/lua/pxl8/world.lua

@@ -95,4 +95,16 @@ function world.apply_textures(w, texture_defs)
     return result
 end
 
+function world.check_collision(w, x, y, z, radius)
+    local pos = ffi.new("pxl8_vec3", {x = x, y = y, z = z})
+    return C.pxl8_world_check_collision(w, pos, radius)
+end
+
+function world.resolve_collision(w, from_x, from_y, from_z, to_x, to_y, to_z, radius)
+    local from = ffi.new("pxl8_vec3", {x = from_x, y = from_y, z = from_z})
+    local to = ffi.new("pxl8_vec3", {x = to_x, y = to_y, z = to_z})
+    local result = C.pxl8_world_resolve_collision(w, from, to, radius)
+    return result.x, result.y, result.z
+end
+
 return world

src/pxl8_script.c

@@ -302,11 +302,13 @@ static const char* pxl8_ffi_cdefs =
 "pxl8_world* pxl8_world_create(void);\n"
 "void pxl8_world_destroy(pxl8_world* world);\n"
 "int pxl8_world_generate(pxl8_world* world, pxl8_gfx* gfx, const pxl8_procgen_params* params);\n"
-"int pxl8_world_apply_textures(pxl8_world* world, const pxl8_world_texture* textures, unsigned int count);\n"
-"bool pxl8_world_is_loaded(const pxl8_world* world);\n"
 "int pxl8_world_load(pxl8_world* world, const char* path);\n"
-"void pxl8_world_render(pxl8_world* world, pxl8_gfx* gfx, pxl8_vec3 camera_pos);\n"
 "void pxl8_world_unload(pxl8_world* world);\n"
+"int pxl8_world_apply_textures(pxl8_world* world, const pxl8_world_texture* textures, unsigned int count);\n"
+"bool pxl8_world_check_collision(const pxl8_world* world, pxl8_vec3 pos, float radius);\n"
+"bool pxl8_world_is_loaded(const pxl8_world* world);\n"
+"void pxl8_world_render(pxl8_world* world, pxl8_gfx* gfx, pxl8_vec3 camera_pos);\n"
+"pxl8_vec3 pxl8_world_resolve_collision(const pxl8_world* world, pxl8_vec3 from, pxl8_vec3 to, float radius);\n"
 "\n"
 "typedef struct { i32 cursor_x; i32 cursor_y; bool cursor_down; bool cursor_clicked; u32 hot_id; u32 active_id; } pxl8_gui_state;\n"
 "pxl8_gui_state* pxl8_gui_state_create(void);\n"

src/pxl8_world.c

@@ -38,8 +38,6 @@ void pxl8_world_destroy(pxl8_world* world) {
 }
 
 pxl8_result pxl8_world_generate(pxl8_world* world, pxl8_gfx* gfx, const pxl8_procgen_params* params) {
-    pxl8_debug("pxl8_world_generate called");
-
     if (!world || !gfx || !params) {
         pxl8_error("Invalid arguments to pxl8_world_generate");
         return PXL8_ERROR_INVALID_ARGUMENT;
@@ -63,6 +61,35 @@ pxl8_result pxl8_world_generate(pxl8_world* world, pxl8_gfx* gfx, const pxl8_pro
     return PXL8_OK;
 }
 
+pxl8_result pxl8_world_load(pxl8_world* world, const char* path) {
+    if (!world || !path) return PXL8_ERROR_INVALID_ARGUMENT;
+
+    if (world->loaded) {
+        pxl8_bsp_destroy(&world->bsp);
+        world->loaded = false;
+    }
+
+    memset(&world->bsp, 0, sizeof(pxl8_bsp));
+
+    pxl8_result result = pxl8_bsp_load(path, &world->bsp);
+    if (result != PXL8_OK) {
+        pxl8_error("Failed to load world: %s", path);
+        return result;
+    }
+
+    world->loaded = true;
+    pxl8_info("Loaded world: %s", path);
+
+    return PXL8_OK;
+}
+
+void pxl8_world_unload(pxl8_world* world) {
+    if (!world || !world->loaded) return;
+
+    pxl8_bsp_destroy(&world->bsp);
+    world->loaded = false;
+}
+
 pxl8_result pxl8_world_apply_textures(pxl8_world* world, const pxl8_world_texture* textures, u32 count) {
     if (!world || !world->loaded || !textures || count == 0) {
         return PXL8_ERROR_INVALID_ARGUMENT;
@@ -151,26 +178,229 @@ pxl8_result pxl8_world_apply_textures(pxl8_world* world, const pxl8_world_textur
     return PXL8_OK;
 }
 
-pxl8_result pxl8_world_load(pxl8_world* world, const char* path) {
+bool pxl8_world_check_collision(const pxl8_world* world, pxl8_vec3 pos, f32 radius) {
-    if (!world || !path) return PXL8_ERROR_INVALID_ARGUMENT;
+    if (!world || !world->loaded) return false;
 
-    if (world->loaded) {
+    const pxl8_bsp* bsp = &world->bsp;
-        pxl8_bsp_destroy(&world->bsp);
+
-        world->loaded = false;
+    for (u32 i = 0; i < bsp->num_faces; i++) {
+        const pxl8_bsp_face* face = &bsp->faces[i];
+        const pxl8_bsp_plane* plane = &bsp->planes[face->plane_id];
+
+        if (fabsf(plane->normal.y) > 0.7f) {
+            continue;
+        }
+
+        f32 dist = plane->normal.x * pos.x +
+                   plane->normal.y * pos.y +
+                   plane->normal.z * pos.z - plane->dist;
+
+        if (fabsf(dist) > radius) {
+            continue;
+        }
+
+        pxl8_vec3 closest_point = {
+            pos.x - plane->normal.x * dist,
+            pos.y - plane->normal.y * dist,
+            pos.z - plane->normal.z * dist
+        };
+
+        if (closest_point.x < face->aabb_min.x - radius || closest_point.x > face->aabb_max.x + radius ||
+            closest_point.y < face->aabb_min.y - radius || closest_point.y > face->aabb_max.y + radius ||
+            closest_point.z < face->aabb_min.z - radius || closest_point.z > face->aabb_max.z + radius) {
+            continue;
+        }
+
+        return true;
     }
 
-    memset(&world->bsp, 0, sizeof(pxl8_bsp));
+    return false;
+}
 
-    pxl8_result result = pxl8_bsp_load(path, &world->bsp);
+bool pxl8_world_is_loaded(const pxl8_world* world) {
-    if (result != PXL8_OK) {
+    return world && world->loaded;
-        pxl8_error("Failed to load world: %s", path);
+}
-        return result;
+
+static inline f32 vec3_dot(pxl8_vec3 a, pxl8_vec3 b) {
+    return a.x * b.x + a.y * b.y + a.z * b.z;
+}
+
+static inline pxl8_vec3 vec3_cross(pxl8_vec3 a, pxl8_vec3 b) {
+    return (pxl8_vec3){
+        a.y * b.z - a.z * b.y,
+        a.z * b.x - a.x * b.z,
+        a.x * b.y - a.y * b.x
+    };
+}
+
+static inline f32 vec3_length(pxl8_vec3 v) {
+    return sqrtf(v.x * v.x + v.y * v.y + v.z * v.z);
+}
+
+pxl8_vec3 pxl8_world_resolve_collision(const pxl8_world* world, pxl8_vec3 from, pxl8_vec3 to, f32 radius) {
+    if (!world || !world->loaded) return to;
+
+    const pxl8_bsp* bsp = &world->bsp;
+    pxl8_vec3 pos = to;
+    pxl8_vec3 original_velocity = {to.x - from.x, to.y - from.y, to.z - from.z};
+
+    pxl8_vec3 clip_planes[5];
+    u32 num_planes = 0;
+
+    const f32 edge_epsilon = 1.2f;
+    const f32 radius_min = -radius + edge_epsilon;
+    const f32 radius_max = radius - edge_epsilon;
+
+    for (i32 iteration = 0; iteration < 4; iteration++) {
+        bool collided = false;
+
+        for (u32 i = 0; i < bsp->num_faces; i++) {
+            const pxl8_bsp_face* face = &bsp->faces[i];
+            const pxl8_bsp_plane* plane = &bsp->planes[face->plane_id];
+
+            if (fabsf(plane->normal.y) > 0.7f) continue;
+
+            f32 dist = plane->normal.x * pos.x +
+                       plane->normal.y * pos.y +
+                       plane->normal.z * pos.z - plane->dist;
+
+            f32 abs_dist = fabsf(dist);
+            if (abs_dist > radius) continue;
+
+            pxl8_vec3 closest_point = {
+                pos.x - plane->normal.x * dist,
+                pos.y - plane->normal.y * dist,
+                pos.z - plane->normal.z * dist
+            };
+
+            if (closest_point.x < face->aabb_min.x + radius_min || closest_point.x > face->aabb_max.x + radius_max ||
+                closest_point.y < face->aabb_min.y + radius_min || closest_point.y > face->aabb_max.y + radius_max ||
+                closest_point.z < face->aabb_min.z + radius_min || closest_point.z > face->aabb_max.z + radius_max) {
+                continue;
+            }
+
+            f32 penetration = radius - abs_dist;
+            if (penetration > 0.01f) {
+                pxl8_vec3 push_dir;
+                if (dist < 0) {
+                    push_dir.x = -plane->normal.x;
+                    push_dir.y = -plane->normal.y;
+                    push_dir.z = -plane->normal.z;
+                } else {
+                    push_dir.x = plane->normal.x;
+                    push_dir.y = plane->normal.y;
+                    push_dir.z = plane->normal.z;
+                }
+
+                bool is_new_plane = true;
+                for (u32 p = 0; p < num_planes; p++) {
+                    if (vec3_dot(push_dir, clip_planes[p]) > 0.99f) {
+                        is_new_plane = false;
+                        break;
+                    }
+                }
+
+                if (is_new_plane && num_planes < 5) {
+                    clip_planes[num_planes++] = push_dir;
+                }
+
+                pos.x += push_dir.x * penetration;
+                pos.y += push_dir.y * penetration;
+                pos.z += push_dir.z * penetration;
+
+                collided = true;
+            }
+        }
+
+        if (!collided) {
+            break;
+        }
+
+        if (num_planes >= 3) {
+            break;
+        }
     }
 
-    world->loaded = true;
+    if (num_planes == 2) {
-    pxl8_info("Loaded world: %s", path);
+        f32 orig_vel_len_sq = original_velocity.x * original_velocity.x +
+                              original_velocity.y * original_velocity.y +
+                              original_velocity.z * original_velocity.z;
 
-    return PXL8_OK;
+        if (orig_vel_len_sq > 0.000001f) {
+            f32 vdot0 = vec3_dot(original_velocity, clip_planes[0]);
+            f32 vdot1 = vec3_dot(original_velocity, clip_planes[1]);
+            f32 dot0 = fabsf(vdot0);
+            f32 dot1 = fabsf(vdot1);
+
+            pxl8_vec3 slide_vel;
+            if (dot0 < dot1) {
+                slide_vel.x = original_velocity.x - clip_planes[0].x * vdot0;
+                slide_vel.y = original_velocity.y - clip_planes[0].y * vdot0;
+                slide_vel.z = original_velocity.z - clip_planes[0].z * vdot0;
+            } else {
+                slide_vel.x = original_velocity.x - clip_planes[1].x * vdot1;
+                slide_vel.y = original_velocity.y - clip_planes[1].y * vdot1;
+                slide_vel.z = original_velocity.z - clip_planes[1].z * vdot1;
+            }
+
+            f32 slide_len = sqrtf(slide_vel.x * slide_vel.x + slide_vel.y * slide_vel.y + slide_vel.z * slide_vel.z);
+
+            if (slide_len > 0.01f) {
+                pos.x += slide_vel.x;
+                pos.y += slide_vel.y;
+                pos.z += slide_vel.z;
+
+                pxl8_vec3 crease_dir = vec3_cross(clip_planes[0], clip_planes[1]);
+                f32 crease_len = vec3_length(crease_dir);
+                if (crease_len > 0.01f && fabsf(crease_dir.y / crease_len) > 0.9f) {
+                    f32 bias0 = vec3_dot(original_velocity, clip_planes[0]);
+                    f32 bias1 = vec3_dot(original_velocity, clip_planes[1]);
+
+                    if (bias0 < 0 && bias1 < 0) {
+                        const f32 corner_push = 0.1f;
+                        pxl8_vec3 push_away = {
+                            clip_planes[0].x + clip_planes[1].x,
+                            clip_planes[0].y + clip_planes[1].y,
+                            clip_planes[0].z + clip_planes[1].z
+                        };
+                        f32 push_len_sq = push_away.x * push_away.x + push_away.y * push_away.y + push_away.z * push_away.z;
+                        if (push_len_sq > 0.000001f) {
+                            f32 inv_push_len = corner_push / sqrtf(push_len_sq);
+                            pos.x += push_away.x * inv_push_len;
+                            pos.y += push_away.y * inv_push_len;
+                            pos.z += push_away.z * inv_push_len;
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    f32 horizontal_movement_sq = (pos.x - from.x) * (pos.x - from.x) +
+                                  (pos.z - from.z) * (pos.z - from.z);
+    f32 desired_horizontal_sq = (to.x - from.x) * (to.x - from.x) +
+                                 (to.z - from.z) * (to.z - from.z);
+
+    if (desired_horizontal_sq > 0.01f && horizontal_movement_sq < desired_horizontal_sq * 0.25f) {
+        const f32 max_step_height = 0.4f;
+
+        pxl8_vec3 step_up = pos;
+        step_up.y += max_step_height;
+
+        if (!pxl8_world_check_collision(world, step_up, radius)) {
+            pxl8_vec3 step_forward = {
+                step_up.x + (to.x - pos.x),
+                step_up.y,
+                step_up.z + (to.z - pos.z)
+            };
+
+            if (!pxl8_world_check_collision(world, step_forward, radius)) {
+                pos = step_forward;
+            }
+        }
+    }
+
+    return pos;
 }
 
 void pxl8_world_render(pxl8_world* world, pxl8_gfx* gfx, pxl8_vec3 camera_pos) {
@@ -182,14 +412,3 @@ void pxl8_world_render(pxl8_world* world, pxl8_gfx* gfx, pxl8_vec3 camera_pos) {
         pxl8_bsp_render_textured(gfx, &world->bsp, camera_pos);
     }
 }
-
-void pxl8_world_unload(pxl8_world* world) {
-    if (!world || !world->loaded) return;
-
-    pxl8_bsp_destroy(&world->bsp);
-    world->loaded = false;
-}
-
-bool pxl8_world_is_loaded(const pxl8_world* world) {
-    return world && world->loaded;
-}

src/pxl8_world.h

@@ -24,12 +24,15 @@ pxl8_world* pxl8_world_create(void);
 void pxl8_world_destroy(pxl8_world* world);
 
 pxl8_result pxl8_world_generate(pxl8_world* world, pxl8_gfx* gfx, const pxl8_procgen_params* params);
-pxl8_result pxl8_world_apply_textures(pxl8_world* world, const pxl8_world_texture* textures, u32 count);
-bool pxl8_world_is_loaded(const pxl8_world* world);
 pxl8_result pxl8_world_load(pxl8_world* world, const char* path);
-void pxl8_world_render(pxl8_world* world, pxl8_gfx* gfx, pxl8_vec3 camera_pos);
 void pxl8_world_unload(pxl8_world* world);
 
+pxl8_result pxl8_world_apply_textures(pxl8_world* world, const pxl8_world_texture* textures, u32 count);
+bool pxl8_world_check_collision(const pxl8_world* world, pxl8_vec3 pos, f32 radius);
+bool pxl8_world_is_loaded(const pxl8_world* world);
+void pxl8_world_render(pxl8_world* world, pxl8_gfx* gfx, pxl8_vec3 camera_pos);
+pxl8_vec3 pxl8_world_resolve_collision(const pxl8_world* world, pxl8_vec3 from, pxl8_vec3 to, f32 radius);
+
 #ifdef __cplusplus
 }
 #endif