close.

7 files changed, 149 insertions, 17 deletions

diff --git a/src/animation.c b/src/animation.c
index e69de29..f6741e8 100644
--- a/src/animation.c
+++ b/src/animation.c
@@ -0,0 +1,38 @@
+#include "animation.h"
+#include "maths.h"
+#include "log.h"
+
+keyframe animation_sample(animation_sampler *sampler, f32 t) {
+  size_t previous_index = 0;
+  f32 previous_time = 0.0;
+  // look forwards
+  DEBUG("%d\n", sampler->animation.values.kind);
+  TRACE("Here %d", sampler->animation.n_timestamps);
+  for (u32 i = 1; i < sampler->animation.n_timestamps; i++) {
+    f32 current_time = sampler->animation.timestamps[i];
+    if (current_time > t) {
+      break;
+    }
+    previous_time = current_time;
+    previous_index = i;
+    
+  }
+
+  size_t next_index = (previous_index + 1) % sampler->animation.n_timestamps;
+  f32 next_time = sampler->animation.timestamps[next_index];
+  printf("%d %f %d %f\n", previous_index, previous_time, next_index, next_time);
+
+  keyframe prev_value = sampler->animation.values.values[previous_index];
+  keyframe next_value = sampler->animation.values.values[next_index];
+
+  printf("%d %d\n", previous_index, next_index);
+   
+      f32 time_diff = sampler->animation.timestamps[next_index] - sampler->animation.timestamps[previous_index
+      ];
+      f32 percent = (t - sampler->animation.timestamps[next_index]) / time_diff;
+
+      quat interpolated_rot = quat_slerp(sampler->animation.values.values[previous_index].rotation,
+                                         sampler->animation.values.values[next_index].rotation, percent);
+
+     return  (keyframe){ .rotation = interpolated_rot };
+}
\ No newline at end of file
diff --git a/src/animation.h b/src/animation.h
index b7c8ca4..81e150a 100644
--- a/src/animation.h
+++ b/src/animation.h
@@ -29,18 +29,21 @@ typedef struct keyframes {
 } keyframes;
 
 typedef struct animation_spline {
-  f32_darray timestamps;
+  f32* timestamps;
+  size_t n_timestamps;
   keyframes values;
   interpolation interpolation;
 } animation_spline;
 
 typedef struct animation_sampler {
   int current_index;
+  f32 min;
+  f32 max;
   animation_spline animation;
 } animation_sampler;
 
 /** @brief Sample an animation at a given time `t` */
-keyframe animation_sample(animation_sampler sampler, f32 t);
+keyframe animation_sample(animation_sampler* sampler, f32 t);
 
 typedef struct animation_clip {
   // A clip contains one or more animation curves
@@ -50,4 +53,6 @@ typedef struct animation_clip {
   animation_sampler* translation;
   animation_sampler* scale;
   animation_sampler* weights;
-} animation_clip;
\ No newline at end of file
+} animation_clip;
+
+void animation_play(animation_clip* clip);
\ No newline at end of file
diff --git a/src/defines.h b/src/defines.h
index 52aa7b0..5110f5a 100644
--- a/src/defines.h
+++ b/src/defines.h
@@ -71,6 +71,6 @@ Renderer backend defines:
 #endif
 
 #if defined(CEL_PLATFORM_MAC)
-#define CEL_REND_BACKEND_METAL 1
-// #define CEL_REND_BACKEND_OPENGL 1
+// #define CEL_REND_BACKEND_METAL 1
+#define CEL_REND_BACKEND_OPENGL 1
 #endif
\ No newline at end of file
diff --git a/src/maths/maths.h b/src/maths/maths.h
index a16a6b4..76531f2 100644
--- a/src/maths/maths.h
+++ b/src/maths/maths.h
@@ -83,6 +83,55 @@ static quat quat_from_axis_angle(vec3 axis, f32 angle, bool normalize) {
   return q;
 }
 
+// TODO: grok this.
+static inline quat quat_slerp(quat a, quat b, f32 percentage) {
+  quat out_quaternion;
+
+  quat q0 = quat_normalise(a);
+  quat q1 = quat_normalise(b);
+
+  // Compute the cosine of the angle between the two vectors.
+    f32 dot = quat_dot(q0, q1);
+
+    // If the dot product is negative, slerp won't take
+    // the shorter path. Note that v1 and -v1 are equivalent when
+    // the negation is applied to all four components. Fix by
+    // reversing one quaternion.
+    if (dot < 0.0f) {
+        q1.x = -q1.x;
+        q1.y = -q1.y;
+        q1.z = -q1.z;
+        q1.w = -q1.w;
+        dot = -dot;
+    }
+
+    const f32 DOT_THRESHOLD = 0.9995f;
+    if (dot > DOT_THRESHOLD) {
+        // If the inputs are too close for comfort, linearly interpolate
+        // and normalize the result.
+        out_quaternion = (quat){q0.x + ((q1.x - q0.x) * percentage),
+                                q0.y + ((q1.y - q0.y) * percentage),
+                                q0.z + ((q1.z - q0.z) * percentage),
+                                q0.w + ((q1.w - q0.w) * percentage)};
+
+        return quat_normalise(out_quaternion);
+    }
+
+    // Since dot is in range [0, DOT_THRESHOLD], acos is safe
+    f32 theta_0 = cos(dot);          // theta_0 = angle between input vectors
+    f32 theta = theta_0 * percentage;  // theta = angle between v0 and result
+    f32 sin_theta = sin(theta);       // compute this value only once
+    f32 sin_theta_0 = sin(theta_0);   // compute this value only once
+
+    f32 s0 =
+        cos(theta) -
+        dot * sin_theta / sin_theta_0;  // == sin(theta_0 - theta) / sin(theta_0)
+    f32 s1 = sin_theta / sin_theta_0;
+
+    return (quat){(q0.x * s0) + (q1.x * s1), (q0.y * s0) + (q1.y * s1),
+                  (q0.z * s0) + (q1.z * s1), (q0.w * s0) + (q1.w * s1)};
+}
+
 // --- Matrix Implementations
 
 static inline mat4 mat4_ident() {
diff --git a/src/resources/gltf.c b/src/resources/gltf.c
index b6e100f..6081e45 100644
--- a/src/resources/gltf.c
+++ b/src/resources/gltf.c
@@ -10,6 +10,7 @@
 #include "mem.h"
 #include "path.h"
 #include "render.h"
+#include "render_backend.h"
 #include "render_types.h"
 #include "str.h"
 
@@ -236,10 +237,12 @@ bool model_load_gltf_str(const char *file_string, const char *filepath, str8 rel
   size_t num_animations = data->animations_count;
   if (num_animations > 0) {
 // Create an arena for all animation related data
-#define ANIMATION_STORAGE_ARENA_SIZE (1024 * 1024)
+#define ANIMATION_STORAGE_ARENA_SIZE (1024 * 1024 * 1024)
     char *animation_backing_storage = malloc(ANIMATION_STORAGE_ARENA_SIZE);
     // We'll store data on this arena so we can easily free it all at once later
-    arena anim_arena = arena_create(animation_backing_storage, ANIMATION_STORAGE_ARENA_SIZE);
+    out_model->animation_data_arena =
+        arena_create(animation_backing_storage, ANIMATION_STORAGE_ARENA_SIZE);
+    arena *arena = &out_model->animation_data_arena;
 
     if (!out_model->animations) {
       out_model->animations = animation_clip_darray_new(num_animations);
@@ -252,38 +255,74 @@ bool model_load_gltf_str(const char *file_string, const char *filepath, str8 rel
       for (size_t c = 0; c < animation.channels_count; c++) {
         cgltf_animation_channel channel = animation.channels[c];
 
-        animation_sampler *sampler = arena_alloc(&anim_arena, sizeof(animation_sampler));
+        animation_sampler *sampler = arena_alloc(arena, sizeof(animation_sampler));
 
-        animation_sampler **target_property;
+        // animation_sampler **target_property;
         keyframe_kind data_type;
 
         switch (channel.target_path) {
           case cgltf_animation_path_type_rotation:
-            target_property = &clip.rotation;
+            // target_property = &clip.rotation;
             data_type = KEYFRAME_ROTATION;
             break;
           default:
             WARN("unsupported animation type");
             return false;
         }
-        *target_property = sampler;
+        // *target_property = sampler;
 
         sampler->current_index = 0;
+        printf("1 %d index\n", sampler->current_index);
         sampler->animation.interpolation = INTERPOLATION_LINEAR;
 
         // keyframe times
         size_t n_frames = channel.sampler->input->count;
+        printf("n_frames: %d\n", n_frames);
         assert(channel.sampler->input->component_type == cgltf_component_type_r_32f);
-        // FIXME: CASSERT_MSG function "Expected animation sampler input component to be type f32 (keyframe times)");
-        
-        sampler,
-        
+        // FIXME: CASSERT_MSG function "Expected animation sampler input component to be type f32
+        // (keyframe times)");
+        printf("2 %d index\n", sampler->current_index);
+        f32 *times = arena_alloc(arena, n_frames * sizeof(f32));
+        printf("3 %d index\n", sampler->current_index);
+        sampler->animation.n_timestamps = n_frames;
+        printf("n_timestamps: %d\n", sampler->animation.n_timestamps);
+        sampler->animation.timestamps = times;
+        cgltf_accessor_unpack_floats(channel.sampler->input, times, n_frames);
+      
+        printf("4 %d index\n", sampler->current_index);
+
+        if (channel.target_path == cgltf_animation_path_type_rotation) {
+          assert(channel.sampler->output->component_type == cgltf_component_type_r_32f);
+          assert(channel.sampler->output->type == cgltf_type_vec4);
+        }
+
         // keyframe values
         size_t n_values = channel.sampler->output->count;
         assert(n_frames == n_values);
+        ERROR("N frames %d", n_frames);
 
-        sampler->animation.timestamps
+        keyframes keyframes = { 0 };
+        keyframes.kind = KEYFRAME_ROTATION;
+        keyframes.count = n_values;
+        keyframes.values = arena_alloc(arena, n_values * sizeof(keyframe));
+        for (cgltf_size v = 0; v < channel.sampler->output->count; ++v) {
+          quat rot;
+          cgltf_accessor_read_float(channel.sampler->output, v, &rot.x, 4);
+          printf("Quat %f %f %f %f\n", rot.x, rot.y, rot.z, rot.w);
+          keyframes.values[v].rotation = rot;
+        }
+        sampler->animation.values = keyframes;
+
+        sampler->min = channel.sampler->input->min[0];
+        sampler->max = channel.sampler->input->max[0];
+
+        clip.rotation = sampler;
+        printf("%d timestamps\n", sampler->animation.n_timestamps);
+        printf("%d index\n", sampler->current_index);
       }
+
+      WARN("stuff %ld", clip.rotation->animation.n_timestamps);
+      animation_clip_darray_push(out_model->animations, clip);
     }
   }
 
diff --git a/src/resources/obj.c b/src/resources/obj.c
index c6e9fa6..ea73ffa 100644
--- a/src/resources/obj.c
+++ b/src/resources/obj.c
@@ -18,6 +18,7 @@
 #include "mem.h"
 #include "path.h"
 #include "render.h"
+#include "render_backend.h"
 #include "render_types.h"
 #include "str.h"
 
diff --git a/src/std/mem.c b/src/std/mem.c
index d7c0f4c..25c9563 100644
--- a/src/std/mem.c
+++ b/src/std/mem.c
@@ -15,7 +15,7 @@ void* arena_alloc_align(arena* a, size_t size, size_t align) {
   if (available < 0 || (ptrdiff_t)size > available) {
     ERROR_EXIT("Arena ran out of memory\n");
   }
-  void* p = a->begin + padding;
+  void* p = a->curr + padding;
   a->curr += padding + size;
   return memset(p, 0, size);
 }