Merge pull request #10 from omnisci3nce/cel-41-port-over-a-basic-3d-scene-example

Cel 41 port over a basic 3d scene example

11 files changed, 406 insertions, 16 deletions

diff --git a/examples/gltf_loading/ex_gltf_loading.c b/examples/gltf_loading/ex_gltf_loading.c
index 867ddb2..98654d6 100644
--- a/examples/gltf_loading/ex_gltf_loading.c
+++ b/examples/gltf_loading/ex_gltf_loading.c
@@ -70,7 +70,8 @@ int main() {
     angle += (rot_speed * deltaTime);
     transform model_tf = transform_create(vec3(0.0, 0.1, -0.1), rot,
                                           1.8);  // make the backpack a bit bigger
-    draw_model(&core->renderer, &cam, cube, model_tf, &our_scene);
+    mat4 model = transform_to_mat(&model_tf);
+    draw_model(&core->renderer, &cam, cube, &model, &our_scene);
 
     render_frame_end(&core->renderer);
   }
diff --git a/examples/obj_loading/ex_obj_loading.c b/examples/obj_loading/ex_obj_loading.c
index 6e63938..e225cb2 100644
--- a/examples/obj_loading/ex_obj_loading.c
+++ b/examples/obj_loading/ex_obj_loading.c
@@ -62,7 +62,8 @@ int main() {
     // Draw the backpack
     transform model_tf = transform_create(vec3(0.0, -0.4, 0.0), quat_ident(),
                                           1.8);  // make the backpack a bit bigger
-    draw_model(&core->renderer, &cam, backpack, model_tf, &our_scene);
+    mat4 model_matrix = transform_to_mat(&model_tf);
+    draw_model(&core->renderer, &cam, backpack, &model_matrix, &our_scene);
 
     render_frame_end(&core->renderer);
   }
diff --git a/examples/transforms/ex_transforms.c b/examples/transforms/ex_transforms.c
new file mode 100644
index 0000000..689c49d
--- /dev/null
+++ b/examples/transforms/ex_transforms.c
@@ -0,0 +1,88 @@
+#include <glfw3.h>
+
+#include "core.h"
+#include "maths.h"
+#include "maths_types.h"
+#include "mem.h"
+#include "render.h"
+#include "render_types.h"
+#include "transform_hierarchy.h"
+
+const vec3 pointlight_positions[4] = {
+  { 0.7, 0.2, 2.0 },
+  { 2.3, -3.3, -4.0 },
+  { -4.0, 2.0, -12.0 },
+  { 0.0, 0.0, -3.0 },
+};
+point_light point_lights[4];
+
+int main() {
+  core* core = core_bringup();
+
+  // Set up scene
+  vec3 camera_pos = vec3(3., 4., 10.);
+  vec3 camera_front = vec3_normalise(vec3_negate(camera_pos));
+  camera cam = camera_create(camera_pos, camera_front, VEC3_Y, deg_to_rad(45.0));
+
+  model_handle cube_handle = model_load_obj(core, "assets/models/obj/cube/cube.obj", true);
+  model* cube = &core->models->data[cube_handle.raw];
+  model_upload_meshes(&core->renderer, cube);
+
+  directional_light dir_light = { .direction = (vec3){ -0.2, -1.0, -0.3 },
+                                  .ambient = (vec3){ 0.2, 0.2, 0.2 },
+                                  .diffuse = (vec3){ 0.5, 0.5, 0.5 },
+                                  .specular = (vec3){ 1.0, 1.0, 1.0 } };
+  // point lights setup
+  for (int i = 0; i < 4; i++) {
+    point_lights[i].position = pointlight_positions[i];
+    point_lights[i].ambient = (vec3){ 0.05, 0.05, 0.05 };
+    point_lights[i].diffuse = (vec3){ 0.8, 0.8, 0.8 };
+    point_lights[i].specular = (vec3){ 1.0, 1.0, 1.0 };
+    point_lights[i].constant = 1.0;
+    point_lights[i].linear = 0.09;
+    point_lights[i].quadratic = 0.032;
+  }
+
+  scene our_scene = { .dir_light = dir_light, .n_point_lights = 4 };
+  memcpy(&our_scene.point_lights, &point_lights, sizeof(point_light[4]));
+
+  // Create transform hierarchy
+  transform_hierarchy* transform_tree = transform_hierarchy_create();
+  transform_node* root_node = transform_hierarchy_root_node(transform_tree);
+  // Add nodes
+  // -- 4 cubes
+  transform cube1 = transform_create(vec3(0.0, -2.0, 0.0), quat_ident(), 0.8);
+  transform cube2 = transform_create(vec3(0.0, 1.0, 0.0), quat_ident(), 1.0);
+  transform cube3 = transform_create(vec3(0.0, 1.0, 0.0), quat_ident(), 1.0);
+  transform cube4 = transform_create(vec3(0.0, 1.0, 0.0), quat_ident(), 1.0);
+  transform_node* node1 = transform_hierarchy_add_node(root_node, cube_handle, cube1);
+  transform_node* node2 = transform_hierarchy_add_node(node1, cube_handle, cube2);
+  transform_node* node3 = transform_hierarchy_add_node(node2, cube_handle, cube3);
+  transform_node* node4 = transform_hierarchy_add_node(node3, cube_handle, cube4);
+
+  transform_hierarchy_debug_print(root_node, core);
+
+  char* frame_allocator_storage = malloc(1024 * 1024 * 64);
+  arena frame_arena = arena_create(frame_allocator_storage, 1024 * 1024 * 64);
+
+  // Main loop
+  while (!glfwWindowShouldClose(core->renderer.window)) {
+    input_update(&core->input);
+    threadpool_process_results(&core->threadpool, 1);
+
+    render_frame_begin(&core->renderer);
+    transform_hierarchy_propagate_transforms(transform_tree);
+
+    // TODO: Add setters to transform API
+    node1->tf.position.x += 0.004;
+    node1->tf.is_dirty = true;
+    draw_scene(&frame_arena, core->models, &core->renderer, &cam, transform_tree, &our_scene);
+
+    render_frame_end(&core->renderer);
+    arena_free_all(&frame_arena);
+  }
+
+  transform_hierarchy_free(transform_tree);
+
+  return 0;
+}
diff --git a/src/maths/maths.h b/src/maths/maths.h
index 57d575d..3301634 100644
--- a/src/maths/maths.h
+++ b/src/maths/maths.h
@@ -215,12 +215,14 @@ static inline mat4 mat4_look_at(vec3 position, vec3 target, vec3 up) {
                 .is_dirty = false })
 
 static transform transform_create(vec3 pos, quat rot, f32 scale) {
-  return (transform){ .position = pos, .rotation = rot, .scale = scale, .is_dirty = false };
+  return (transform){ .position = pos, .rotation = rot, .scale = scale, .is_dirty = true };
 }
 
 static inline mat4 transform_to_mat(transform *tf) {
-  // TODO: rotation
-  return mat4_mult(mat4_translation(tf->position), mat4_scale(tf->scale));
+  mat4 trans = mat4_translation(tf->position);
+  mat4 rot = mat4_rotation(tf->rotation);
+  mat4 scale = mat4_scale(tf->scale);
+  return mat4_mult(trans, mat4_mult(rot, scale));
 }
 
 // --- Sizing asserts
diff --git a/src/renderer/render.c b/src/renderer/render.c
index 9d250c6..ac6b80a 100644
--- a/src/renderer/render.c
+++ b/src/renderer/render.c
@@ -1,3 +1,6 @@
+#include <stdlib.h>
+#include "mem.h"
+#include "transform_hierarchy.h"
 #define STB_IMAGE_IMPLEMENTATION
 #include <stb_image.h>
 
@@ -82,7 +85,31 @@ void default_material_init() {
   texture_data_upload(&DEFAULT_MATERIAL.specular_texture);
 }
 
-void draw_model(renderer* ren, camera* camera, model* model, transform tf, scene* scene) {
+typedef struct draw_ctx {
+  model_darray* models;
+  renderer* ren;
+  camera* cam;
+  scene* scene;
+} draw_ctx;
+bool draw_scene_node(transform_node* node, void* ctx_data) {
+  if (!node || !node->parent) return true;
+  draw_ctx* ctx = ctx_data;
+  model* m = &ctx->models->data[node->model.raw];
+  draw_model(ctx->ren, ctx->cam, m, &node->world_matrix_tf, ctx->scene);
+  return true;
+}
+
+void draw_scene(arena* frame, model_darray* models, renderer* ren, camera* camera,
+                transform_hierarchy* tfh, scene* scene) {
+  draw_ctx* ctx = arena_alloc(frame, sizeof(draw_ctx));
+  ctx->models = models;
+  ctx->ren = ren;
+  ctx->cam = camera;
+  ctx->scene = scene;
+  transform_hierarchy_dfs(transform_hierarchy_root_node(tfh), draw_scene_node, true, ctx);
+}
+
+void draw_model(renderer* ren, camera* camera, model* model, mat4* model_tf, scene* scene) {
   // TRACE("Drawing model: %s", model->name);
   mat4 view;
   mat4 proj;
@@ -105,11 +132,11 @@ void draw_model(renderer* ren, camera* camera, model* model, transform tf, scene
     }
     // TRACE("Drawing mesh %d", i);
     material* mat = &model->materials->data[m->material_index];
-    draw_mesh(ren, m, tf, mat, &view, &proj);
+    draw_mesh(ren, m, model_tf, mat, &view, &proj);
   }
 }
 
-void draw_mesh(renderer* ren, mesh* mesh, transform tf, material* mat, mat4* view, mat4* proj) {
+void draw_mesh(renderer* ren, mesh* mesh, mat4* model_tf, material* mat, mat4* view, mat4* proj) {
   shader lighting_shader = ren->blinn_phong;
 
   // bind buffer
@@ -121,12 +148,12 @@ void draw_mesh(renderer* ren, mesh* mesh, transform tf, material* mat, mat4* vie
   uniform_f32(lighting_shader.program_id, "material.shininess", 32.);
 
   // upload model transform
-  mat4 trans = mat4_translation(tf.position);
-  mat4 rot = mat4_rotation(tf.rotation);
-  mat4 scale = mat4_scale(tf.scale);
-  mat4 model_tf = mat4_mult(trans, mat4_mult(rot, scale));
+  // mat4 trans = mat4_translation(tf.position);
+  // mat4 rot = mat4_rotation(tf.rotation);
+  // mat4 scale = mat4_scale(tf.scale);
+  // mat4 model_tf = mat4_mult(trans, mat4_mult(rot, scale));
 
-  uniform_mat4f(lighting_shader.program_id, "model", &model_tf);
+  uniform_mat4f(lighting_shader.program_id, "model", model_tf);
   // upload view & projection matrices
   uniform_mat4f(lighting_shader.program_id, "view", view);
   uniform_mat4f(lighting_shader.program_id, "projection", proj);
diff --git a/src/renderer/render.h b/src/renderer/render.h
index 10702e3..1a35488 100644
--- a/src/renderer/render.h
+++ b/src/renderer/render.h
@@ -3,6 +3,7 @@
 #include "camera.h"
 #include "loaders.h"
 #include "render_types.h"
+#include "transform_hierarchy.h"
 
 // --- Lifecycle
 /** @brief initialise the render system frontend */
@@ -17,8 +18,10 @@ void render_frame_end(renderer* ren);
 
 // --- models meshes
 void model_upload_meshes(renderer* ren, model* model);
-void draw_model(renderer* ren, camera* camera, model* model, transform tf, scene* scene);
-void draw_mesh(renderer* ren, mesh* mesh, transform tf, material* mat, mat4* view, mat4* proj);
+void draw_model(renderer* ren, camera* camera, model* model, mat4* tf, scene* scene);
+void draw_mesh(renderer* ren, mesh* mesh, mat4* tf, material* mat, mat4* view, mat4* proj);
+void draw_scene(arena* frame, model_darray* models, renderer* ren, camera* camera,
+                transform_hierarchy* tfh, scene* scene);
 
 // ---
 texture texture_data_load(const char* path, bool invert_y);  // #frontend
diff --git a/src/renderer/render_types.h b/src/renderer/render_types.h
index 483e392..aed18db 100644
--- a/src/renderer/render_types.h
+++ b/src/renderer/render_types.h
@@ -18,6 +18,7 @@ struct GLFWwindow;
 
 #ifndef RESOURCE_HANDLE_DEFS
 CORE_DEFINE_HANDLE(model_handle);
+#define ABSENT_MODEL_HANDLE 999999999
 CORE_DEFINE_HANDLE(texture_handle);
 #define RESOURCE_HANDLE_DEFS
 #endif
diff --git a/src/std/mem.c b/src/std/mem.c
index d7c0f4c..00f9c39 100644
--- a/src/std/mem.c
+++ b/src/std/mem.c
@@ -11,7 +11,7 @@
 void* arena_alloc_align(arena* a, size_t size, size_t align) {
   ptrdiff_t padding = -(uintptr_t)a->curr & (align - 1);
   ptrdiff_t available = a->end - a->curr - padding;
-  TRACE("Padding %td available %td", padding, available);
+  // TRACE("Padding %td available %td", padding, available);
   if (available < 0 || (ptrdiff_t)size > available) {
     ERROR_EXIT("Arena ran out of memory\n");
   }
diff --git a/src/transform_hierarchy.c b/src/transform_hierarchy.c
new file mode 100644
index 0000000..f1c859a
--- /dev/null
+++ b/src/transform_hierarchy.c
@@ -0,0 +1,184 @@
+
+/**
+ * @file transform_hierarchy.h
+ */
+#pragma once
+#include "transform_hierarchy.h"
+#include <stdlib.h>
+#include <string.h>
+
+#include "core.h"
+#include "log.h"
+#include "maths.h"
+#include "maths_types.h"
+#include "render_types.h"
+
+struct transform_hierarchy {
+  transform_node root;
+};
+
+transform_hierarchy* transform_hierarchy_create() {
+  transform_hierarchy* tfh = malloc(sizeof(struct transform_hierarchy));
+
+  tfh->root = (transform_node){ .model = { ABSENT_MODEL_HANDLE },
+                                .tf = TRANSFORM_DEFAULT,
+                                .local_matrix_tf = mat4_ident(),
+                                .world_matrix_tf = mat4_ident(),
+                                .parent = NULL,
+                                .children = { 0 },
+                                .n_children = 0,
+                                .tfh = tfh };
+  return tfh;
+}
+
+bool free_node(transform_node* node, void* _ctx_data) {
+  if (!node) return true;  // leaf node
+  if (node == &node->tfh->root) {
+    WARN("You can't free the root node!");
+    return false;
+  }
+
+  printf("Freed node\n");
+  free(node);
+  return true;
+}
+
+void transform_hierarchy_free(transform_hierarchy* tfh) {
+  transform_hierarchy_dfs(&tfh->root, free_node, false, NULL);
+  free(tfh);
+}
+
+transform_node* transform_hierarchy_root_node(transform_hierarchy* tfh) { return &tfh->root; }
+
+transform_node* transform_hierarchy_add_node(transform_node* parent, model_handle model,
+                                             transform tf) {
+  if (!parent) {
+    WARN("You tried to add a node to a bad parent (NULL?)");
+    return NULL;
+  }
+  transform_node* node = malloc(sizeof(transform_node));
+  node->model = model;
+  node->tf = tf;
+  node->local_matrix_tf = mat4_ident();
+  node->world_matrix_tf = mat4_ident();
+  node->parent = parent;
+  memset(node->children, 0, sizeof(node->children));
+  node->n_children = 0;
+  node->tfh = parent->tfh;
+
+  // push into parent's children array
+  u32 next_index = parent->n_children;
+  if (next_index == MAX_TF_NODE_CHILDREN) {
+    ERROR("This transform hierarchy node already has MAX children. Dropping.");
+    free(node);
+  } else {
+    parent->children[next_index] = node;
+    parent->n_children++;
+  }
+
+  return node;
+}
+
+void transform_hierarchy_delete_node(transform_node* node) {
+  // delete all children
+  for (u32 i = 0; i < node->n_children; i++) {
+    transform_node* child = node->children[i];
+    transform_hierarchy_dfs(child, free_node, false, NULL);
+  }
+
+  if (node->parent) {
+    for (u32 i = 0; i < node->parent->n_children; i++) {
+      transform_node* child = node->parent->children[i];
+      if (child == node) {
+        node->parent->children[i] = NULL;  // HACK: this will leave behind empty slots in the
+                                           // children array of the parent. oh well.
+      }
+    }
+  }
+
+  free(node);
+}
+
+void transform_hierarchy_dfs(transform_node* start_node,
+                             bool (*visit_node)(transform_node* node, void* ctx_data),
+                             bool is_pre_order, void* ctx_data) {
+  if (!start_node) return;
+
+  bool continue_traversal = true;
+  if (is_pre_order) {
+    continue_traversal = visit_node(start_node, ctx_data);
+  }
+
+  if (continue_traversal) {
+    for (u32 i = 0; i < start_node->n_children; i++) {
+      transform_node* child = start_node->children[i];
+      transform_hierarchy_dfs(child, visit_node, is_pre_order, ctx_data);
+    }
+  }
+
+  if (!is_pre_order) {
+    // post-order
+    visit_node(start_node, ctx_data);
+  }
+}
+
+// Update matrix for the current node
+bool update_matrix(transform_node* node, void* _ctx_data) {
+  if (!node) return true;  // leaf node
+
+  if (node->parent && node->parent->tf.is_dirty) {
+    node->tf.is_dirty = true;
+  }
+
+  if (node->tf.is_dirty) {
+    // invalidates children
+    mat4 updated_local_transform = transform_to_mat(&node->tf);
+    node->local_matrix_tf = updated_local_transform;
+    if (node->parent) {
+      mat4 updated_world_transform =
+          mat4_mult(node->parent->world_matrix_tf, updated_local_transform);
+      node->world_matrix_tf = updated_world_transform;
+    }
+  }
+
+  return true;
+}
+
+void transform_hierarchy_propagate_transforms(transform_hierarchy* tfh) {
+  // kickoff traversal
+  transform_hierarchy_dfs(&tfh->root, update_matrix, false, NULL);
+}
+
+struct print_ctx {
+  core* core;
+  u32 indentation_lvl;
+};
+
+bool print_node(transform_node* node, void* ctx_data) {
+  struct print_ctx* ctx = (struct print_ctx*)ctx_data;
+
+  if (!node) return true;
+  if (!node->parent) {
+    printf("Root Node\n");
+    ctx->indentation_lvl++;
+    return true;
+  }
+
+  // Grab the model
+  model m = ctx->core->models->data[node->model.raw];
+  for (int i = 0; i < ctx->indentation_lvl; i++) {
+    printf("  ");
+  }
+  printf("Node %s\n", m.name.buf);
+  ctx->indentation_lvl++;
+
+  return true;
+}
+
+void transform_hierarchy_debug_print(transform_node* start_node, core* core) {
+  struct print_ctx* ctx = malloc(sizeof(struct print_ctx));
+  ctx->core = core;
+  ctx->indentation_lvl = 0;
+  transform_hierarchy_dfs(start_node, print_node, true, (void*)ctx);
+  free(ctx);
+}
\ No newline at end of file
diff --git a/src/transform_hierarchy.h b/src/transform_hierarchy.h
new file mode 100644
index 0000000..af77ee1
--- /dev/null
+++ b/src/transform_hierarchy.h
@@ -0,0 +1,76 @@
+/**
+ * @file transform_hierarchy.h
+ */
+#pragma once
+
+#include "maths_types.h"
+#include "render_types.h"
+
+#define MAX_TF_NODE_CHILDREN \
+  32 /** TEMP: Make it simpler to manage children in `transform_node`s　*/
+
+typedef struct transform_hierarchy transform_hierarchy;
+
+struct transform_node {
+  model_handle model; /** A handle back to what model this node represents */
+  transform tf;
+  mat4 local_matrix_tf; /** cached local affine transform */
+  mat4 world_matrix_tf; /** cached world-space affine transform */
+
+  struct transform_node* parent;
+  struct transform_node* children[MAX_TF_NODE_CHILDREN];
+  u32 n_children;
+  struct transform_hierarchy* tfh;
+};
+typedef struct transform_node transform_node;
+
+// --- Lifecycle
+
+/** @brief Allocates and returns an empty transform hierarchy with a root node */
+transform_hierarchy* transform_hierarchy_create();
+
+/**
+ * @brief recursively frees all the children and then finally itself
+ * @note in the future we can use an object pool for the nodes
+ */
+void transform_hierarchy_free(transform_hierarchy* tfh);
+
+// --- Main usecase
+
+/** @brief Updates matrices of any invalidated nodes based on the `is_dirty` flag inside `transform`
+ */
+void transform_hierarchy_propagate_transforms(transform_hierarchy* tfh);
+
+// --- Queries
+
+/** @brief Get a pointer to the root node */
+transform_node* transform_hierarchy_root_node(transform_hierarchy* tfh);
+
+// --- Mutations
+transform_node* transform_hierarchy_add_node(transform_node* parent, model_handle model,
+                                             transform tf);
+void transform_hierarchy_delete_node(transform_node* node);
+
+// --- Traversal
+
+/**
+ * @brief Perform a depth-first search traversal starting from `start_node`.
+ * @param start_node The starting node of the traversal.
+ * @param visit_node The function to call for each node visited. The callback should return false to
+ stop the traversal early.
+ * @param is_pre_order Indicates whether to do pre-order or post-order traversal i.e. when to call
+ the `visit_node` function.
+ * @param ctx_data An optional pointer to data that is be passed on each call to `visit_node`. Can
+ be used to carry additional information or context.
+ *
+ * @note The main use-cases are:
+            1. traversing the whole tree to update cached 4x4 affine transform matrices (post-order)
+            2. freeing child nodes after deleting a node in the tree (post-order)
+            3. debug pretty printing the whole tree (post-order)
+ */
+void transform_hierarchy_dfs(transform_node* start_node,
+                             bool (*visit_node)(transform_node* node, void* ctx_data),
+                             bool is_pre_order, void* ctx_data);
+
+struct core;
+void transform_hierarchy_debug_print(transform_node* start_node, struct core* core);
\ No newline at end of file
diff --git a/xmake.lua b/xmake.lua
index c18e926..453fb55 100644
--- a/xmake.lua
+++ b/xmake.lua
@@ -126,6 +126,13 @@ target("gltf")
     add_files("examples/gltf_loading/ex_gltf_loading.c")
     set_rundir("$(projectdir)")
 
+target("transforms")
+    set_kind("binary")
+    set_group("examples")
+    add_deps("core_shared")
+    add_files("examples/transforms/ex_transforms.c")
+    set_rundir("$(projectdir)")
+
 target("demo")
     set_kind("binary")
     set_group("examples")