1 files changed, 83 insertions, 5 deletions

diff --git a/examples/cube.c b/examples/cube.c
index 629a570..8fd85de 100644
--- a/examples/cube.c
+++ b/examples/cube.c
@@ -1,8 +1,10 @@
 #include <celeritas.h>
 #include "glfw3.h"
 
+camera cam;
 pipeline_handle draw_pipeline;
 buf_handle cube_vbuf;
+buf_handle transform_buf;
 tex_handle texture;
 
 // transformation data
@@ -12,24 +14,83 @@ typedef struct MVPData {
   mat4 projection;
 } MVPData;
 
+// draw calls for a single frame
 void draw() {
-  // prepare data
-  mat4 translation_matrix = mat4_translation(vec3(0, 0, -1));
-
-  f32 angle_degrees = glfwGetTime() / 2.0 * 45.0;
+  // prepare model data
+  f32 angle_degrees = glfwGetTime() * 45.0;
   f32 angle = angle_degrees * PI / 180.0;
-  mat4 rotation_matrix = mat4_rotation(quat_from_axis_angle(VEC3_Y, angle, true));
+
+  // Move origin to cube center
+  vec3 center_offset = vec3(0.5, 0.5, 0.5);
+  mat4 to_center = mat4_translation(vec3_negate(center_offset));
+  mat4 from_center = mat4_translation(center_offset);
+
+  // Create rotation around Y axis
+  mat4 rotation = mat4_rotation(quat_from_axis_angle(VEC3_Y, angle, true));
+
+  // Print debug info for one frame
+  static bool printed = false;
+  if (!printed) {
+    printf("\nTo Center:\n");
+    for (int i = 0; i < 16; i += 4) {
+      printf("%f %f %f %f\n", to_center.data[i], to_center.data[i + 1], to_center.data[i + 2], to_center.data[i + 3]);
+    }
+    printed = true;
+  }
+
+  // Order: first move to center, then rotate, then move back
+  mat4 cube_transform = mat4_mult(from_center, mat4_mult(rotation, to_center));
+
+  mat4 move = mat4_translation(vec3(-0.5, -0.5, 0));
+  cube_transform = mat4_mult(move, cube_transform);
+
+  // prepare camera data
+  mat4 view, proj;
+  camera_view_proj(cam, 800, 600, &view, &proj);
 
   render_pass_desc d = {};
   gpu_encoder* enc = ral_render_encoder(d);
   ral_encode_bind_pipeline(enc, draw_pipeline);
+  ral_set_default_settings(enc);
+
+  MVPData mvp = { .model = cube_transform, .view = view, .projection = proj };
+
+  ral_buffer_upload_data(transform_buf, sizeof(MVPData), &mvp);
+  ral_bind_buffer(enc, transform_buf, 1);  // bind the transform data buffer to binding 1
   ral_encode_set_vertex_buf(enc, cube_vbuf);
   ral_encode_set_texture(enc, texture, 0);
   ral_encode_draw_tris(enc, 0, 36);
   ral_encoder_finish_and_submit(enc);
 }
 
+void test_matrix_mult() {
+  // Create a simple translation matrix (1 unit in x)
+  mat4 trans1 = mat4_translation(vec3(1, 0, 0));
+  // Create another translation matrix (1 unit in y)
+  mat4 trans2 = mat4_translation(vec3(0, 1, 0));
+
+  printf("Matrix 1 (translate x+1):\n");
+  for (int i = 0; i < 16; i += 4) {
+    printf("%f %f %f %f\n", trans1.data[i], trans1.data[i + 1], trans1.data[i + 2], trans1.data[i + 3]);
+  }
+
+  printf("\nMatrix 2 (translate y+1):\n");
+  for (int i = 0; i < 16; i += 4) {
+    printf("%f %f %f %f\n", trans2.data[i], trans2.data[i + 1], trans2.data[i + 2], trans2.data[i + 3]);
+  }
+
+  mat4 result = mat4_mult(trans1, trans2);
+
+  printf("\nResult matrix:\n");
+  for (int i = 0; i < 16; i += 4) {
+    printf("%f %f %f %f\n", result.data[i], result.data[i + 1], result.data[i + 2], result.data[i + 3]);
+  }
+}
+
 int main() {
+  test_matrix_mult();
+  // exit(1);
+
   core_bringup("Celeritas Example: Triangle", NULL);
 
   // create rendering pipeline
@@ -52,12 +113,29 @@ int main() {
 
   draw_pipeline = ral_gfx_pipeline_create(pipeline_desc);
 
+  // load texture from file
+  texture = ral_texture_load_from_file("assets/textures/mc_grass.jpeg");
+
+  cam = (camera){ .position = vec3(0, 3, 5), .forwards = vec3(0, -3, -5), .fov = 45.0, .up = VEC3_Y };
+
   // create the cube geometry
   geometry cube = geo_cuboid(1.0, 1.0, 1.0);
 
+  // (debug) print out each vertex
+  size_t vertex_stride = cube.data_length / cube.n_vertices;
+  printf("Vertex stride %ld\n", vertex_stride);
+  for (int i = 0; i < cube.n_vertices; i++) {
+    static_3d_vert* vertex = (static_3d_vert*)(cube.vertex_data + vertex_stride * i);
+    print_static_3d_vert(vertex);
+  }
+
   // upload vertex data to the gpu
   cube_vbuf = ral_buffer_create(64 * 36, cube.vertex_data);
 
+  // create a buffer to hold the MVP transforms
+  MVPData d = {};
+  transform_buf = ral_buffer_create(sizeof(MVPData), &d);
+
   while (!app_should_exit()) {
     glfwPollEvents();