1 files changed, 420 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..1c017f0
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,420 @@
+#include <model.h>
+
+#include <filesystem.h>
+// TODO: Update math/camera to explicitly expose ortho/perspective camera parameters,
+//  not just a baked matrix.
+//#include <math/camera.h>
+#include <math/spatial3.h>
+#include <math/vec2.h>
+#include <swgfx.h>
+#include <SDL3/SDL.h>
+#include <SDL3/SDL_timer.h>
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static constexpr int     BufferWidth  = 160;
+static constexpr int     BufferHeight = 120;
+static constexpr sgVec2i BufferDims   = (sgVec2i){.x = BufferWidth, .y = BufferHeight};
+static constexpr R       Aspect       = (R)BufferWidth / (R)BufferHeight;
+
+static const char*   WindowTitle  = "GAME";
+// Window dimensions must be an integer scaling of buffer dimensions.
+// TODO: Make window dimensions a function of DPI.
+static constexpr int     WindowWidth  = 640;
+static constexpr int     WindowHeight = 480;
+static constexpr sgVec2i WindowDims   = (sgVec2i){.x = WindowWidth, .y = WindowHeight};
+
+static const R Fovy = (R)(90 * TO_RAD);
+
+#define DEBUG_EVENT_LOOP 1
+
+#ifdef DEBUG_EVENT_LOOP
+#define EVENT_LOOP_PRINT printf
+#else
+#define EVENT_LOOP_PRINT(...)
+#endif // DEBUG_EVENT_LOOP
+
+typedef struct CameraCommand {
+  bool CameraMoveLeft     : 1;
+  bool CameraMoveRight    : 1;
+  bool CameraMoveForward  : 1;
+  bool CameraMoveBackward : 1;
+  bool CameraSlow         : 1; // When true, move more slowly.
+  bool CameraRotate       : 1; // When true, subsequent mouse movements cause
+                               // the camera to rotate.
+} CameraCommand;
+
+typedef struct CameraController {
+  R speed;          // Camera movement speed.
+  R rotation_speed; // Controls the degree with which mouse movements rotate
+                    // the camera.
+  vec2 prev_mouse_position; // Mouse position in the previous frame.
+} CameraController;
+
+typedef struct Camera {
+  Spatial3 spatial;
+  R        fovy;
+  R        aspect;
+  R        near;
+  R        far;
+} Camera;
+
+typedef struct State {
+  SDL_Window*      window;
+  swgfx*           gfx;
+  sgPixel*         colour;
+  Model*           model;
+  Camera           camera;
+  CameraController camera_controller;
+  Uint64           last_tick;
+} State;
+
+static sgVec3 SgVec3FromMathVec3(vec3 v) {
+  return (sgVec3){v.x, v.y, v.z};
+}
+
+static CameraCommand CameraCommandFromInput(
+    const bool* keyboard_state, const SDL_MouseButtonFlags mouse_flags) {
+  assert(keyboard_state);
+  if (keyboard_state[SDL_SCANCODE_W]) {
+    printf("W: %d\n", keyboard_state[SDL_SCANCODE_W]);
+  }
+  return (CameraCommand){
+    .CameraMoveLeft     = keyboard_state[SDL_SCANCODE_A],
+    .CameraMoveRight    = keyboard_state[SDL_SCANCODE_D],
+    .CameraMoveForward  = keyboard_state[SDL_SCANCODE_W],
+    .CameraMoveBackward = keyboard_state[SDL_SCANCODE_S],
+    .CameraSlow         = keyboard_state[SDL_SCANCODE_LSHIFT],
+    .CameraRotate       = mouse_flags & SDL_BUTTON_MASK(SDL_BUTTON_LEFT),
+  };
+}
+
+static void UpdateCamera(
+    CameraController* controller, R dt, vec2 mouse_position,
+    CameraCommand command, Camera* camera) {
+  assert(controller);
+  assert(camera);
+
+  Spatial3* cam = &camera->spatial;
+
+  // Translation.
+  const R move_x = (R)(command.CameraMoveLeft ? -1 : 0) +
+                   (R)(command.CameraMoveRight ? 1 : 0);
+  const R move_y = (R)(command.CameraMoveForward ? 1 : 0) +
+                   (R)(command.CameraMoveBackward ? -1 : 0);
+  const R speed_factor = command.CameraSlow ? 0.3f : 1.f;
+  const vec2 translation  = vec2_scale(
+      vec2_normalize(vec2_make(move_x, move_y)),
+      controller->speed * speed_factor * dt);
+  spatial3_move_right(cam, translation.x);
+  spatial3_move_forwards(cam, translation.y);
+
+  // Rotation.
+  if (command.CameraRotate) {
+    const vec2 mouse_delta =
+        vec2_sub(mouse_position, controller->prev_mouse_position);
+
+    const vec2 rotation =
+        vec2_scale(mouse_delta, controller->rotation_speed * dt);
+
+    spatial3_global_yaw(cam, -rotation.x);
+    spatial3_pitch(cam, -rotation.y);
+  }
+
+  // Update controller state.
+  controller->prev_mouse_position = mouse_position;
+}
+
+static bool Update(State* state, R dt) {
+  assert(state);
+
+  int num_keys = 0;
+  const bool* keyboard_state = SDL_GetKeyboardState(&num_keys);
+
+  vec2 mouse = {0};
+  const SDL_MouseButtonFlags mouse_flags = SDL_GetMouseState(&mouse.x, &mouse.y);
+
+  const CameraCommand cmd = CameraCommandFromInput(keyboard_state, mouse_flags);
+  UpdateCamera(&state->camera_controller, dt, mouse, cmd, &state->camera);
+
+  return true;
+}
+
+static void RenderIndexedModel(swgfx* gfx, const IndexedModel* model) {
+  assert(gfx);
+  assert(model);
+  const sgTriIdx*  tris   = (const sgTriIdx*)(model->data + model->offsetTris);
+  const sgVec3* positions = (const sgVec3*)(model->data + model->offsetPositions);
+  sgTrianglesIndexedNonUniform(gfx, model->numTris, tris, positions);
+}
+
+static void RenderModel(swgfx* gfx, const Model* model) {
+  assert(gfx);
+  assert(model);
+  switch (model->type) {
+  case ModelTypeIndexed: RenderIndexedModel(gfx, &model->indexed); break;
+  case ModelTypeFlat: /* TODO: Render flat models. */ break;
+  default: assert(false); break;
+  }
+}
+
+static void RenderTriangle2d(swgfx* gfx) {
+  assert(gfx);
+  const sgVec2 p0  = (sgVec2){20, 20};
+  const sgVec2 p1  = (sgVec2){80, 20};
+  const sgVec2 p2  = (sgVec2){50, 50};
+  const sgTri2 tri = (sgTri2){p0, p1, p2};
+  sgTriangles2(gfx, 1, &tri);
+}
+
+static void Checkerboard(swgfx* gfx, int width, int height) {
+  assert(gfx);
+  const sgPixel colour = (sgPixel){255, 0, 255, 255};
+  for (int y = 0; y < height; ++y) {
+    for (int x = 0; x < width; ++x) {
+      if (((x ^ y) & 1) == 1) {
+        const sgVec2i position = (sgVec2i){x, y};
+        sgPixels(gfx, 1, &position, colour);
+      }
+    }
+  }
+}
+
+static bool Render(State* state) {
+  assert(state);
+  assert(state->window);
+  assert(state->gfx);
+
+  // Locking/unlocking SDL software surfaces is not necessary.
+  // Probably also best to avoid SDL_BlitSurface(); it does pixel format
+  // conversion while blitting one pixel at a time. Instead, make the UI pixel
+  // format match the SDL window's and write to SDL's back buffer directly.
+  SDL_Surface* window_surface = SDL_GetWindowSurface(state->window);
+  assert(window_surface);
+  
+  // Until we make the window resizable, assert dimensions for safety.
+  assert(window_surface->w == WindowWidth);
+  assert(window_surface->h == WindowHeight);
+
+#ifdef DEBUG_EVENT_LOOP
+  EVENT_LOOP_PRINT(
+      "Render: window surface: %dx%d\n",
+      window_surface->w, window_surface->h);
+#endif
+
+  const Camera* cam = &state->camera;
+
+  sgColourBuffer(state->gfx, BufferDims, state->colour);
+  sgClear(state->gfx);
+  sgViewport(state->gfx, 0, 0, BufferWidth, BufferHeight);
+  sgCheck(state->gfx);
+  // TODO: For easier debugging, overlay the checkerboard on top of the
+  //  other rendered items with alpha blending.
+  //Checkerboard(state->gfx, BufferWidth, BufferHeight);
+  //RenderTriangle2d(state->gfx);
+  sgModelId(state->gfx);
+  sgView(state->gfx, SgVec3FromMathVec3(cam->spatial.p), SgVec3FromMathVec3(cam->spatial.f));
+  sgPerspective(state->gfx, cam->fovy, cam->aspect, cam->near, cam->far);
+  RenderModel(state->gfx, state->model);
+  /*sgIdx indices[3] = {0, 1, 2};
+  sgVec3 positions[3] = {
+    (sgVec3){0, 0, 0},
+    (sgVec3){5, 2, 0},
+    (sgVec3){8, 8, 0},
+  };
+  sgTrianglesIndexed(state->gfx, 3, indices, positions);*/
+  sgPresent(state->gfx, WindowDims, window_surface->pixels);
+
+  if (!SDL_UpdateWindowSurface(state->window)) {
+    return false;
+  }
+
+  return true;
+}
+
+static bool Resize(State* state) {
+  assert(state);
+
+  // int width, height;
+  // SDL_GetWindowSize(state->window, &width, &height);
+
+  const SDL_Surface* window_surface = SDL_GetWindowSurface(state->window);
+  if (!window_surface) {
+    return false;
+  }
+  const int width  = window_surface->w;
+  const int height = window_surface->h;
+
+  EVENT_LOOP_PRINT("Resize: %dx%d\n", width, height);
+
+  return true;
+}
+
+static bool Initialize(State* state) {
+  assert(state);
+
+  if ((state->window = SDL_CreateWindow(
+         WindowTitle,
+         WindowWidth,
+         WindowHeight,
+         0)) == NULL) {
+    fprintf(stderr, "SDL_CreateWindow failed\n");
+    return false;
+  }
+  
+  if (!(state->gfx = sgNew())) {
+    fprintf(stderr, "sgNew failed\n");
+    return false;
+  }
+  
+  if (!(state->colour = SG_ALIGN_ALLOC(BufferWidth * BufferHeight, sgPixel))) {
+    fprintf(stderr, "Failed to allocate colour buffer\n");
+    return false;
+  }
+  
+  sgColourBuffer(state->gfx, BufferDims, state->colour);
+
+  const char* model_path = "/home/jeanne/blender/box.mdl";
+  if (!(state->model = read_file(model_path))) {
+    fprintf(stderr, "Failed to load model: [%s]\n", model_path);
+    return false;
+  }
+
+  Camera* camera    = &state->camera;
+  camera->fovy      = Fovy;
+  camera->aspect    = Aspect;
+  camera->near      = 0.1f;
+  camera->far       = 1000.f;
+  camera->spatial   = spatial3_make();
+  camera->spatial.p = vec3_make(0, 1, 10);
+
+  state->camera_controller = (CameraController){
+    .speed = 7.f,
+    .rotation_speed = (R)(90 * TO_RAD),
+  };
+
+  state->last_tick = SDL_GetPerformanceCounter();
+
+  return true;
+}
+
+static void Shutdown(State* state) {
+  assert(state);
+
+  if (state->model) {
+    free(state->model);
+    state->model = nullptr;
+  }
+  
+  if (state->colour) {
+    SG_FREE(&state->colour);
+  }
+  
+  if (state->gfx) {
+    sgDel(&state->gfx);
+  }
+  
+  if (state->window) {
+    SDL_DestroyWindow(state->window);
+    state->window = nullptr;
+  }
+}
+
+static R GetDeltaTime(State* state) {
+  assert(state);
+  constexpr Uint64 NS_IN_SEC = 1'000'000'000;
+  const Uint64 this_tick = SDL_GetPerformanceCounter();
+  const Uint64 freq = SDL_GetPerformanceFrequency();
+  const Uint64 elapsed_ns = (this_tick - state->last_tick) * NS_IN_SEC / freq;
+  const R elapsed_sec = (R)elapsed_ns / (R)NS_IN_SEC;
+  state->last_tick = this_tick;
+  return elapsed_sec;
+}
+
+int main() {
+  bool success = false;
+  // Controls whether we should keep running.
+  bool running = true;
+
+  State state = {0};
+
+  if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS)) {
+    fprintf(stderr, "SDL_Init failed\n");
+    goto cleanup;
+  }
+
+  if (!Initialize(&state)) {
+    fprintf(stderr, "Initialization failed\n");
+    goto cleanup;
+  }
+
+  if (!Resize(&state)) {
+    goto cleanup;
+  }
+  
+  success = true;
+
+  while (success && running) {
+    EVENT_LOOP_PRINT("loop\n");
+
+    // Handle events.
+    SDL_Event event = {0};
+    while (SDL_PollEvent(&event)) {
+      if ((event.type == SDL_EVENT_QUIT) ||
+          (event.type == SDL_EVENT_WINDOW_CLOSE_REQUESTED)) {
+        running = false;
+        break;
+      } else if ((event.window.type == SDL_EVENT_WINDOW_DISPLAY_CHANGED) ||
+                 (event.window.type == SDL_EVENT_WINDOW_RESIZED) ||
+                 (event.window.type == SDL_EVENT_WINDOW_MOVED)) {
+        // When the window is maximized, an SDL_WINDOWEVENT_MOVED comes in
+        // before an SDL_WINDOWEVENT_SIZE_CHANGED with the window already
+        // resized. This is unfortunate because we cannot rely on the latter
+        // event alone to handle resizing.
+        if (!Resize(&state)) {
+          success = false;
+          break;
+        }
+      } else if (event.type == SDL_EVENT_KEY_DOWN) {
+        if (event.key.mod & SDL_KMOD_LCTRL) {
+          switch (event.key.key) {
+          // Exit.
+          case SDLK_C:
+          case SDLK_D:
+            running = false;
+            break;
+          default:
+            break;
+          }
+        }
+      } else if (event.type == SDL_EVENT_MOUSE_BUTTON_DOWN) {
+        //
+      } else if (event.type == SDL_EVENT_MOUSE_BUTTON_UP) {
+        //
+      } else if (event.type == SDL_EVENT_MOUSE_WHEEL) {
+        //
+      } else {
+        EVENT_LOOP_PRINT("event.window.type = %d\n", event.window.type);
+      }
+    } // events
+
+    // Draw and update if needed.
+    if (success && running) {
+      const R dt = GetDeltaTime(&state);
+      success = Update(&state, dt);
+    }
+    if (success && running) {
+      success = Render(&state);
+    }
+  } // loop
+
+cleanup:
+  if (!success) {
+    fprintf(stderr, "%s\n", SDL_GetError());
+  }
+  Shutdown(&state);
+  SDL_Quit();
+  return success ? 0 : 1;
+}