From: hgn <hgodden00@gmail.com>
Date: Thu, 8 Sep 2022 15:09:43 +0000 (+0100)
Subject: much better implicit IK solver
X-Git-Url: https://skaterift.com/git/?a=commitdiff_plain;h=3d5597be2fd4b5d9ea3bf8863e15cc9bc8123755;p=carveJwlIkooP6JGAAIwe30JlM.git

much better implicit IK solver
---

diff --git a/anim_test.h b/anim_test.h
index 5ece5f5..c2f3eae 100644
--- a/anim_test.h
+++ b/anim_test.h
@@ -3,11 +3,14 @@
 
 #include "player.h"
 #include "skeleton.h"
+#include "shaders/viewchar.h"
 
 static struct 
 {
    struct skeleton skele;
    struct skeleton_anim *yay;
+
+   glmesh mesh;
 }
 animtest;
 
@@ -15,7 +18,8 @@ static void anim_test_start(void)
 {
    mdl_header *johannes = mdl_load( "models/ch_new.mdl" );
    skeleton_setup( &animtest.skele, johannes );
-   animtest.yay = skeleton_get_anim( &animtest.skele, "yay" );
+   animtest.yay = skeleton_get_anim( &animtest.skele, "pose_stand" );
+   mdl_unpack_glmesh( johannes, &animtest.mesh );
 
    free( johannes );
 }
@@ -27,12 +31,18 @@ static void anim_test_update(void)
    
    m4x3f transform;
    m4x3_identity( transform );
+   
+   v4f qt;
+   q_axis_angle( qt, (v3f){0.0f,1.0f,0.0f}, vg_time*1.2f );
+   q_m3x3( qt, transform );
+
    skeleton_apply_frame( transform, &animtest.skele, animtest.yay, vg_time );
+   skeleton_apply_ik_pass( &animtest.skele );
 
    skeleton_debug( &animtest.skele );
 }
 
-static void anim_test_render(void)
+static void anim_test_render( vg_tex2d *tex )
 {
    m4x4f world_4x4;
    m4x3_expand( player.camera_inverse, world_4x4 );
@@ -45,6 +55,18 @@ static void anim_test_render(void)
    m4x4_mul( vg_pv, world_4x4, vg_pv );
    glEnable( GL_DEPTH_TEST );
 
+   shader_viewchar_use();
+   vg_tex2d_bind( tex, 0 );
+   shader_viewchar_uTexMain( 0 );
+   shader_viewchar_uPv( vg_pv );
+   glUniformMatrix4x3fv( _uniform_viewchar_uTransforms, 
+                         animtest.skele.bone_count,
+                         0,
+                         (float *)animtest.skele.final_transforms );
+   
+   mesh_bind( &animtest.mesh );
+   mesh_draw( &animtest.mesh );
+
    glDisable( GL_DEPTH_TEST );
    vg_lines_drawall( (float *)vg_pv );
 }
diff --git a/blender_export.py b/blender_export.py
index d43d4af..3f2dd79 100644
--- a/blender_export.py
+++ b/blender_export.py
@@ -143,6 +143,7 @@ class classtype_skin(Structure):
 class classtype_skeleton(Structure):
    _pack_ = 1
    _fields_ = [("channels",c_uint32),
+               ("ik_count",c_uint32),
                ("anim_start",c_uint32),
                ("anim_count",c_uint32)]
 
@@ -150,6 +151,12 @@ class classtype_bone(Structure):
    _pack_ = 1
    _fields_ = [("deform",c_uint32)]
 
+class classtype_ik_bone(Structure):
+   _pack_ = 1
+   _fields_ = [("deform",c_uint32),
+               ("target",c_uint32),
+               ("pole",c_uint32)]
+
 # Exporter
 # ==============================================================================
 
@@ -273,6 +280,7 @@ def write_model(collection_name):
 
             if n.type == 'ARMATURE':
                tree["bones"] = [None] # None is the root transform
+               tree["ik_count"] = 0
 
                def _extendb( p, n, d ):
                   nonlocal tree
@@ -283,13 +291,17 @@ def write_model(collection_name):
                   btree["children"] = []
                   btree["depth"] = d
                   btree["parent"] = p
-
-                  if n.use_deform:
-                     tree["bones"] += [n.name]
+                  tree["bones"] += [n.name]
 
                   for c in n.children:
                      _extendb( btree, c, d+1 )
 
+                  for c in tree['obj'].pose.bones[n.name].constraints:
+                     if c.type == 'IK':
+                        btree["target"] = c.subtarget
+                        btree["pole"] = c.pole_subtarget
+                        tree["ik_count"] += 1
+
                   btree['deform'] = n.use_deform
                   p['children'] += [btree]
 
@@ -359,7 +371,10 @@ def write_model(collection_name):
          node.parent = node_def["parent"]["uid"]
 
       if objt == 'BONE':
-         classtype = 'k_classtype_bone'
+         if 'target' in node_def:
+            classtype = 'k_classtype_ik_bone'
+         else:
+            classtype = 'k_classtype_bone'
       elif objt == 'ARMATURE':
          classtype = 'k_classtype_skeleton'
       else:
@@ -384,6 +399,7 @@ def write_model(collection_name):
             if mod.type == 'ARMATURE':
                classtype = 'k_classtype_skin'
                armature_def = graph_lookup[mod.object]
+               armature_def['obj'].data.pose_position = 'REST'
 
          if can_use_cache and obj.data.name in mesh_cache:
             ref = mesh_cache[obj.data.name]
@@ -564,9 +580,10 @@ def write_model(collection_name):
       s005 = ""
 
       if classtype == 'k_classtype_skin':
+         armature_def['obj'].data.pose_position = 'POSE'
          s005 = F" [armature -> {armature_def['obj'].cv_data.uid}]"
 
-      scmp = F"{s002:<32} {s003:<16} {s004} {s005}"
+      scmp = F"{s002:<32} {s003:<22} {s004} {s005}"
       print( scmp )
       
       if classtype == 'k_classtype_INSTANCE' or \
@@ -595,8 +612,8 @@ def write_model(collection_name):
          armature_def = graph_lookup[obj]
          armature = obj
          bones = armature_def['bones']
-         print( bones )
          skeleton.channels = len(bones)
+         skeleton.ik_count = armature_def["ik_count"]
          
          if armature.animation_data:
             previous_frame = bpy.context.scene.frame_current
@@ -646,9 +663,9 @@ def write_model(collection_name):
                               rq = lc_m.to_quaternion()
 
                               kf = mdl_keyframe()
-                              kf.co[0] =  loc[0]
-                              kf.co[1] =  loc[2]
-                              kf.co[2] = -loc[1]
+                              kf.co[0] =  final_pos[0]
+                              kf.co[1] =  final_pos[1]
+                              kf.co[2] =  final_pos[2]
 
                               kf.q[0] =  rq[1]
                               kf.q[1] =  rq[3]
@@ -680,9 +697,20 @@ def write_model(collection_name):
          entdata_length += sizeof( classtype_bone )
          
          bone = classtype_bone()
-         bone.use_deform = node_def['deform']
+         bone.deform = node_def['deform']
          entdata_buffer += [bone]
 
+      elif classtype == 'k_classtype_ik_bone':
+         node.classtype = 13
+         entdata_length += sizeof( classtype_ik_bone )
+         
+         ikbone = classtype_ik_bone()
+         ikbone.target = armature_def['bones'].index( node_def['target'] )
+         ikbone.pole   = armature_def['bones'].index( node_def['pole'] )
+         ikbone.deform = node_def['deform']
+
+         entdata_buffer += [ikbone]
+
       elif classtype == 'k_classtype_gate':
          node.classtype = 1
          entdata_length += sizeof( classtype_gate )
diff --git a/common.h b/common.h
index afa32fd..efe9a88 100644
--- a/common.h
+++ b/common.h
@@ -22,7 +22,9 @@ enum classtype
    k_classtype_route_node = 8,
    k_classtype_route = 9,
    k_classtype_bone = 10,
-   k_classtype_skeleton = 11
+   k_classtype_skeleton = 11,
+   k_classtype_skin = 12,
+   k_classtype_ik_bone = 13
 };
 
 /* TODO: he needs a home somewhere */
diff --git a/main.c b/main.c
index 6e94231..2ae90c8 100644
--- a/main.c
+++ b/main.c
@@ -55,6 +55,7 @@ void vg_register(void)
    shader_standard_register();
    shader_vblend_register();
    shader_unlit_register();
+   shader_viewchar_register();
 
    world_register();
    character_register();
@@ -357,7 +358,7 @@ void vg_render(void)
    }
    else if( sv_scene == 2 )
    {
-      anim_test_render();
+      anim_test_render( &tex_pallet );
    }
 #endif
 }
diff --git a/model.h b/model.h
index 5091301..54874bd 100644
--- a/model.h
+++ b/model.h
@@ -152,9 +152,17 @@ struct classtype_bone
    u32 deform;
 };
 
+struct classtype_ik_bone
+{
+   u32 deform,
+       target,
+       pole;
+};
+
 struct classtype_skeleton
 {
    u32 channels,
+       ik_count,
        anim_start,
        anim_count;
 };
diff --git a/models_src/ch_new.mdl b/models_src/ch_new.mdl
index b0b82a0..d4cf5c7 100644
Binary files a/models_src/ch_new.mdl and b/models_src/ch_new.mdl differ
diff --git a/shaders.sh b/shaders.sh
index b02bacc..e958679 100755
--- a/shaders.sh
+++ b/shaders.sh
@@ -27,6 +27,7 @@ shader gpos standard.vs gpos.fs
 shader route standard.vs route.fs
 shader scoretext scoretext.vs vblend.fs
 shader routeui routeui.vs routeui.fs
+shader viewchar standard_skinned.vs viewchar.fs
 
 cd shaders
 ../bin/linux/tools/shader $target_shaders
diff --git a/shaders/standard_skinned.vs b/shaders/standard_skinned.vs
new file mode 100644
index 0000000..5c959a0
--- /dev/null
+++ b/shaders/standard_skinned.vs
@@ -0,0 +1,31 @@
+#include "vertex_standard.glsl"
+
+uniform mat4 uPv;
+uniform mat4x3 uTransforms[32];
+
+out vec4 aColour;
+out vec2 aUv;
+out vec3 aNorm;
+out vec3 aCo;
+out vec3 aWorldCo;
+
+void main()
+{
+   vec4 co_local = vec4( a_co, 1.0 );
+   vec3 co0 = uTransforms[ a_groups[0] ] * co_local;
+   vec3 co1 = uTransforms[ a_groups[1] ] * co_local;
+   vec3 co2 = uTransforms[ a_groups[2] ] * co_local;
+   vec3 n0  = mat3(uTransforms[ a_groups[0] ]) * a_norm;
+   vec3 n1  = mat3(uTransforms[ a_groups[1] ]) * a_norm;
+   vec3 n2  = mat3(uTransforms[ a_groups[2] ]) * a_norm;
+
+   vec3 world_pos = co0*a_weights[0] + co1*a_weights[1] + co2*a_weights[2];
+   vec3 world_normal = n0*a_weights[0] + n1*a_weights[1] + n2*a_weights[2];
+   
+   gl_Position = uPv * vec4( world_pos, 1.0 );
+   aColour = a_colour;
+   aUv = a_uv;
+   aNorm = world_normal;
+   aCo = a_co;
+   aWorldCo = world_pos;
+}
diff --git a/shaders/viewchar.fs b/shaders/viewchar.fs
new file mode 100644
index 0000000..ffc969d
--- /dev/null
+++ b/shaders/viewchar.fs
@@ -0,0 +1,28 @@
+out vec4 FragColor;
+
+uniform sampler2D uTexMain;
+
+in vec4 aColour;
+in vec2 aUv;
+in vec3 aNorm;
+in vec3 aCo;
+in vec3 aWorldCo;
+
+#include "common_world.glsl"
+
+void main()
+{
+   vec3 vfrag = texture( uTexMain, aUv ).rgb;
+
+   // Lighting
+   //vec3 halfview = uCamera - aWorldCo;
+   //float fdist = length( halfview );
+   //halfview /= fdist;
+
+   //vfrag = do_light_diffuse( vfrag, aNorm );
+   //vfrag = do_light_spec( vfrag, aNorm, halfview, 0.1 );
+   //vfrag = do_light_shadowing( vfrag );
+   //vfrag = apply_fog( vfrag, fdist );
+
+   FragColor = vec4(aNorm,1.0);
+}
diff --git a/shaders/viewchar.h b/shaders/viewchar.h
new file mode 100644
index 0000000..23cb8b7
--- /dev/null
+++ b/shaders/viewchar.h
@@ -0,0 +1,207 @@
+#ifndef SHADER_viewchar_H
+#define SHADER_viewchar_H
+static void shader_viewchar_link(void);
+static void shader_viewchar_register(void);
+static struct vg_shader _shader_viewchar = {
+   .name = "viewchar",
+   .link = shader_viewchar_link,
+   .vs = 
+{
+.orig_file = "../../shaders/standard_skinned.vs",
+.static_src = 
+"layout (location=0) in vec3 a_co;\n"
+"layout (location=1) in vec3 a_norm;\n"
+"layout (location=2) in vec2 a_uv;\n"
+"layout (location=3) in vec4 a_colour;\n"
+"layout (location=4) in vec4 a_weights;\n"
+"layout (location=5) in ivec4 a_groups;\n"
+"\n"
+"#line      2        0 \n"
+"\n"
+"uniform mat4 uPv;\n"
+"uniform mat4x3 uTransforms[32];\n"
+"\n"
+"out vec4 aColour;\n"
+"out vec2 aUv;\n"
+"out vec3 aNorm;\n"
+"out vec3 aCo;\n"
+"out vec3 aWorldCo;\n"
+"\n"
+"void main()\n"
+"{\n"
+"   vec4 co_local = vec4( a_co, 1.0 );\n"
+"   vec3 co0 = uTransforms[ a_groups[0] ] * co_local;\n"
+"   vec3 co1 = uTransforms[ a_groups[1] ] * co_local;\n"
+"   vec3 co2 = uTransforms[ a_groups[2] ] * co_local;\n"
+"   vec3 n0  = mat3(uTransforms[ a_groups[0] ]) * a_norm;\n"
+"   vec3 n1  = mat3(uTransforms[ a_groups[1] ]) * a_norm;\n"
+"   vec3 n2  = mat3(uTransforms[ a_groups[2] ]) * a_norm;\n"
+"\n"
+"   vec3 world_pos = co0*a_weights[0] + co1*a_weights[1] + co2*a_weights[2];\n"
+"   vec3 world_normal = n0*a_weights[0] + n1*a_weights[1] + n2*a_weights[2];\n"
+"\n"
+"   gl_Position = uPv * vec4( world_pos, 1.0 );\n"
+"   aColour = a_colour;\n"
+"   aUv = a_uv;\n"
+"   aNorm = world_normal;\n"
+"   aCo = a_co;\n"
+"   aWorldCo = world_pos;\n"
+"}\n"
+""},
+   .fs = 
+{
+.orig_file = "../../shaders/viewchar.fs",
+.static_src = 
+"out vec4 FragColor;\n"
+"\n"
+"uniform sampler2D uTexMain;\n"
+"\n"
+"in vec4 aColour;\n"
+"in vec2 aUv;\n"
+"in vec3 aNorm;\n"
+"in vec3 aCo;\n"
+"in vec3 aWorldCo;\n"
+"\n"
+"#line       1        1 \n"
+"layout (std140) uniform ub_world_lighting\n"
+"{\n"
+"   vec4 g_light_colours[3];\n"
+"   vec4 g_light_directions[3];\n"
+"   vec4 g_ambient_colour;\n"
+"\n"
+"   vec4 g_water_plane;\n"
+"   vec4 g_depth_bounds;\n"
+"   float g_water_fog;\n"
+"   int g_light_count;\n"
+"   int g_light_preview;\n"
+"};\n"
+"\n"
+"uniform sampler2D g_world_depth;\n"
+"\n"
+"// Standard diffuse + spec models\n"
+"// ==============================\n"
+"\n"
+"vec3 do_light_diffuse( vec3 vfrag, vec3 wnormal )\n"
+"{\n"
+"   vec3 vtotal = g_ambient_colour.rgb;\n"
+"\n"
+"   for( int i=0; i<g_light_count; i++ )\n"
+"   {\n"
+"      vec3 vcolour = g_light_colours[i].rgb;\n"
+"      vec3 vdir = g_light_directions[i].xyz;\n"
+"\n"
+"      float flight = max(dot( vdir, wnormal )*0.75+0.25,0.0);\n"
+"      vtotal += vcolour*flight;\n"
+"   }\n"
+"\n"
+"   return vfrag * vtotal;\n"
+"}\n"
+"\n"
+"vec3 do_light_spec( vec3 vfrag, vec3 wnormal, vec3 halfview, float fintensity )\n"
+"{\n"
+"   vec3 vcolour = g_light_colours[0].rgb;\n"
+"   vec3 vdir = g_light_directions[0].xyz;\n"
+"\n"
+"   vec3 specdir = reflect( -vdir, wnormal );\n"
+"   float spec = pow(max(dot( halfview, specdir ), 0.0), 10.0);\n"
+"   return vfrag + vcolour*spec*fintensity;\n"
+"}\n"
+"\n"
+"float world_depth_sample( vec3 pos )\n"
+"{\n"
+"   vec2 depth_coord = (pos.xz - g_depth_bounds.xy) * g_depth_bounds.zw; \n"
+"   return texture( g_world_depth, depth_coord ).r;\n"
+"}\n"
+"\n"
+"float shadow_sample( vec3 vdir )\n"
+"{\n"
+"   vec3 sample_pos = aWorldCo + vdir;\n"
+"   float height_sample = world_depth_sample( sample_pos );\n"
+"\n"
+"   float fdelta = height_sample - sample_pos.y;\n"
+"   return clamp( fdelta, 0.1, 0.2 )-0.1;\n"
+"}\n"
+"\n"
+"vec3 do_light_shadowing_old( vec3 vfrag )\n"
+"{\n"
+"   float faccum = 0.0;\n"
+"   faccum += shadow_sample( vec3( 0.0, 0.5, 0.0 ));\n"
+"   faccum += shadow_sample( vec3( 2.0, 0.3, 0.0 ));\n"
+"   faccum += shadow_sample( vec3( 3.0, 1.0, 0.0 ));\n"
+"   faccum += shadow_sample( vec3( 5.0, 1.0, 0.0 ));\n"
+"   faccum += shadow_sample( vec3( 0.0, 0.5, 0.0 )*1.5);\n"
+"   faccum += shadow_sample( vec3( 2.0, 0.3, 0.0 )*1.5);\n"
+"   faccum += shadow_sample( vec3( 3.0, 1.0, 0.0 )*1.5);\n"
+"   faccum += shadow_sample( vec3( 5.0, 1.0, 0.0 )*1.5);\n"
+"   return mix( vfrag, g_ambient_colour.rgb, faccum );\n"
+"}\n"
+"\n"
+"vec3 do_light_shadowing( vec3 vfrag )\n"
+"{\n"
+"   float fspread = g_light_colours[0].w;\n"
+"   vec3  vdir = g_light_directions[0].xyz;\n"
+"   float flength = g_light_directions[0].w;\n"
+"\n"
+"   float famt = 0.0;\n"
+"   famt+=shadow_sample((vdir+vec3(-0.563, 0.550, 0.307)*fspread)*flength*0.1);\n"
+"   famt+=shadow_sample((vdir+vec3( 0.808, 0.686, 0.346)*fspread)*flength*0.2);\n"
+"   famt+=shadow_sample((vdir+vec3( 0.787, 0.074,-0.065)*fspread)*flength*0.3);\n"
+"   famt+=shadow_sample((vdir+vec3(-0.593, 0.071,-0.425)*fspread)*flength*0.4);\n"
+"   famt+=shadow_sample((vdir+vec3(-0.790,-0.933,-0.875)*fspread)*flength*0.5);\n"
+"   famt+=shadow_sample((vdir+vec3( 0.807,-0.690, 0.472)*fspread)*flength*0.6);\n"
+"   famt+=shadow_sample((vdir+vec3( 0.522,-0.379, 0.350)*fspread)*flength*0.7);\n"
+"   famt+=shadow_sample((vdir+vec3( 0.483, 0.201, 0.306)*fspread)*flength*0.8);\n"
+"   return mix( vfrag, g_ambient_colour.rgb, famt );\n"
+"}\n"
+"\n"
+"vec3 apply_fog( vec3 vfrag, float fdist )\n"
+"{\n"
+"   float dist = pow(fdist*0.0008,1.2);\n"
+"   return mix( vfrag, vec3(0.55,0.76,1.0), min( 1.0, dist ) );\n"
+"}\n"
+"\n"
+"#line     12        0 \n"
+"\n"
+"void main()\n"
+"{\n"
+"   vec3 vfrag = texture( uTexMain, aUv ).rgb;\n"
+"\n"
+"   // Lighting\n"
+"   //vec3 halfview = uCamera - aWorldCo;\n"
+"   //float fdist = length( halfview );\n"
+"   //halfview /= fdist;\n"
+"\n"
+"   //vfrag = do_light_diffuse( vfrag, aNorm );\n"
+"   //vfrag = do_light_spec( vfrag, aNorm, halfview, 0.1 );\n"
+"   //vfrag = do_light_shadowing( vfrag );\n"
+"   //vfrag = apply_fog( vfrag, fdist );\n"
+"\n"
+"   FragColor = vec4(vfrag,1.0);\n"
+"}\n"
+""},
+};
+
+static GLuint _uniform_viewchar_uPv;
+static GLuint _uniform_viewchar_uTransforms;
+static GLuint _uniform_viewchar_uTexMain;
+static GLuint _uniform_viewchar_g_world_depth;
+static void shader_viewchar_uPv(m4x4f m){
+   glUniformMatrix4fv( _uniform_viewchar_uPv, 1, GL_FALSE, (float *)m );
+}
+static void shader_viewchar_uTexMain(int i){
+   glUniform1i( _uniform_viewchar_uTexMain, i );
+}
+static void shader_viewchar_g_world_depth(int i){
+   glUniform1i( _uniform_viewchar_g_world_depth, i );
+}
+static void shader_viewchar_register(void){
+   vg_shader_register( &_shader_viewchar );
+}
+static void shader_viewchar_use(void){ glUseProgram(_shader_viewchar.id); }
+static void shader_viewchar_link(void){
+   _uniform_viewchar_uPv = glGetUniformLocation( _shader_viewchar.id, "uPv" );
+   _uniform_viewchar_uTransforms = glGetUniformLocation( _shader_viewchar.id, "uTransforms" );
+   _uniform_viewchar_uTexMain = glGetUniformLocation( _shader_viewchar.id, "uTexMain" );
+   _uniform_viewchar_g_world_depth = glGetUniformLocation( _shader_viewchar.id, "g_world_depth" );
+}
+#endif /* SHADER_viewchar_H */
diff --git a/skeleton.h b/skeleton.h
index 4fb3098..ace80e6 100644
--- a/skeleton.h
+++ b/skeleton.h
@@ -8,14 +8,22 @@ struct skeleton
    struct skeleton_bone
    {
       v3f co, end;
-      u32 children; /* maybe remove */
       u32 parent;
-      
+
+      /* info, not real */
+      int deform, ik;
+
       mdl_keyframe kf;
    }
    *bones;
    m4x3f *final_transforms;
 
+   struct skeleton_ik
+   {
+      u32 lower, upper, target, pole;
+   }
+   *ik;
+
    struct skeleton_anim
    {
       float rate;
@@ -26,7 +34,11 @@ struct skeleton
    *anims;
 
    u32 bone_count,
-       anim_count;
+       ik_count,
+       anim_count,
+       bindable_count;  /* TODO: try to place IK last in the rig from export
+                                 so that we dont always upload transforms for
+                                 useless cpu IK bones. */
 };
 
 static void skeleton_apply_frame( m4x3f transform,
@@ -34,10 +46,16 @@ static void skeleton_apply_frame( m4x3f transform,
                                   struct skeleton_anim *anim, 
                                   float time )
 {
-   u32 frame = time*anim->rate;
-   frame = frame % anim->length;
+   float animtime = time*anim->rate;
+
+   u32 frame = ((u32)animtime) % anim->length,
+       next  = (frame+1) % anim->length;
+
+   float t = vg_fractf( animtime );
+
+   mdl_keyframe *base  = anim->anim_data + (skele->bone_count-1)*frame,
+                *nbase = anim->anim_data + (skele->bone_count-1)*next;
 
-   mdl_keyframe *base = anim->anim_data + (skele->bone_count-1)*frame;
    m4x3_copy( transform, skele->final_transforms[0] );
 
    for( int i=1; i<skele->bone_count; i++ )
@@ -50,12 +68,20 @@ static void skeleton_apply_frame( m4x3f transform,
       v3f temp_delta;
       v3_sub( skele->bones[i].co, skele->bones[sb->parent].co, temp_delta );
 
-
       /* pose matrix */
-      mdl_keyframe *kf = base+i-1;
+      mdl_keyframe *kf  = base+i-1,
+                   *nkf = nbase+i-1;
+
+      v3f co;
+      v4f q;
+      v3f s;
 
-      q_m3x3( kf->q, posemtx );
-      v3_copy( kf->co, posemtx[3] );
+      v3_lerp( kf->co, nkf->co, t, co );
+      q_nlerp( kf->q, nkf->q, t, q );
+      v3_lerp( kf->s, nkf->s, t, s );
+
+      q_m3x3( q, posemtx );
+      v3_copy( co, posemtx[3] );
       v3_add( temp_delta, posemtx[3], posemtx[3] );
 
       /* final matrix */
@@ -74,6 +100,119 @@ static void skeleton_apply_frame( m4x3f transform,
    }
 }
 
+/*
+ * Get transformed position of bone
+ */
+static void skeleton_bone_posepos( struct skeleton *skele, u32 id, v3f co )
+{
+   m4x3_mulv( skele->final_transforms[id], skele->bones[id].co, co );
+}
+
+/* 
+ * creates the reference inverse matrix for an IK bone, as it has an initial 
+ * intrisic rotation based on the direction that the IK is setup..
+ */
+static void skeleton_inverse_for_ik( struct skeleton *skele,
+                                     v3f ivaxis,
+                                     u32 id, m4x3f inverse )
+{
+   v3_copy( ivaxis, inverse[0] );
+   v3_copy( skele->bones[id].end, inverse[1] );
+   v3_normalize( inverse[1] );
+   v3_cross( inverse[0], inverse[1], inverse[2] );
+   v3_copy( skele->bones[id].co, inverse[3] );
+   m4x3_invert_affine( inverse, inverse );
+}
+
+/*
+ * Apply all IK modifiers (2 bone ik reference from blender is supported)
+ */
+static void skeleton_apply_ik_pass( struct skeleton *skele )
+{
+   for( int i=0; i<skele->ik_count; i++ )
+   {
+      struct skeleton_ik *ik = &skele->ik[i];
+      
+      v3f v0, /* base -> target */
+          v1, /* base -> pole */
+          vaxis;
+
+      v3f co_base,
+          co_target,
+          co_pole;
+
+      skeleton_bone_posepos( skele, ik->lower, co_base );
+      skeleton_bone_posepos( skele, ik->target, co_target );
+      skeleton_bone_posepos( skele, ik->pole, co_pole );
+
+      v3_sub( co_target, co_base, v0 );
+      v3_sub( co_pole, co_base, v1 );
+      v3_cross( v0, v1, vaxis );
+      v3_normalize( vaxis );
+      v3_normalize( v0 );
+      v3_cross( vaxis, v0, v1 );
+
+      /* localize problem into [x:v0,y:v1] 2d plane */
+      v2f base = { v3_dot( v0, co_base   ), v3_dot( v1, co_base   ) },
+          end  = { v3_dot( v0, co_target ), v3_dot( v1, co_target ) },
+          knee;
+
+      /* Compute angles (basic trig)*/
+      v2f delta;
+      v2_sub( end, base, delta );
+
+      float 
+         l1 = v3_length( skele->bones[ik->lower].end ),
+         l2 = v3_length( skele->bones[ik->upper].end ),
+         d = vg_clampf( v2_length(delta), fabsf(l1 - l2), l1+l2-0.00001f ),
+         c = acosf( (l1*l1 + d*d - l2*l2) / (2.0f*l1*d) ),
+         rot = atan2f( delta[1], delta[0] ) + c - VG_PIf/2.0f;
+
+      knee[0] = sinf(-rot) * l1;
+      knee[1] = cosf(-rot) * l1;
+
+      m4x3_identity( skele->final_transforms[ik->lower] );
+      m4x3_identity( skele->final_transforms[ik->upper] );
+
+      /* inverse matrix axis '(^axis,^bone,...)[base] */
+      m4x3f inverse;
+      v3f iv0, iv1, ivaxis;
+      v3_sub( skele->bones[ik->target].co, skele->bones[ik->lower].co, iv0 );
+      v3_sub( skele->bones[ik->pole].co, skele->bones[ik->lower].co, iv1 );
+      v3_cross( iv0, iv1, ivaxis );
+      v3_normalize( ivaxis );
+
+      skeleton_inverse_for_ik( skele, ivaxis, ik->lower, inverse );
+
+      /* create rotation matrix */
+      v3f co_knee;
+      v3_muladds( co_base, v0, knee[0], co_knee );
+      v3_muladds( co_knee, v1, knee[1], co_knee );
+      vg_line( co_base, co_knee, 0xff00ff00 );
+
+      m4x3f transform;
+      v3_copy( vaxis, transform[0] );
+      v3_muls( v0, knee[0], transform[1] );
+      v3_muladds( transform[1], v1, knee[1], transform[1] );
+      v3_normalize( transform[1] );
+      v3_cross( transform[0], transform[1], transform[2] );
+      v3_copy( co_base, transform[3] );
+
+      m4x3_mul( transform, inverse, skele->final_transforms[ik->lower] );
+
+      /* 'upper' or knee bone */
+      skeleton_inverse_for_ik( skele, ivaxis, ik->upper, inverse );
+
+      v3_copy( vaxis, transform[0] );
+      v3_sub( co_target, co_knee, transform[1] );
+      v3_normalize( transform[1] );
+      v3_cross( transform[0], transform[1], transform[2] );
+      v3_copy( co_knee, transform[3] );
+
+      m4x3_mul( transform, inverse, skele->final_transforms[ik->upper] );
+   }
+}
+
 static struct skeleton_anim *skeleton_get_anim( struct skeleton *skele,
                                                 const char *name )
 {
@@ -91,7 +230,7 @@ static struct skeleton_anim *skeleton_get_anim( struct skeleton *skele,
 /* Setup an animated skeleton from model */
 static int skeleton_setup( struct skeleton *skele, mdl_header *mdl )
 {
-   u32 bone_count = 1, skeleton_root = 0;
+   u32 bone_count = 1, skeleton_root = 0, ik_count = 0;
    skele->bone_count = 0;
    skele->bones = NULL;
    skele->final_transforms = NULL;
@@ -109,22 +248,64 @@ static int skeleton_setup( struct skeleton *skele, mdl_header *mdl )
          if( skele->bone_count )
          {
             vg_error( "Multiple skeletons in model file\n" );
-            free( skele->bones );
-            return 0;
+            goto error_dealloc;
          }
          
          skele->bone_count = inf->channels;
+         skele->ik_count = inf->ik_count;
          skele->bones = malloc(sizeof(struct skeleton_bone)*skele->bone_count);
+         skele->ik = malloc(sizeof(struct skeleton_ik)*skele->ik_count);
          skeleton_root = i;
       }
       else if( skele->bone_count )
       {
-         if( pnode->classtype == k_classtype_bone )
+         int is_ik   =  pnode->classtype == k_classtype_ik_bone,
+             is_bone = (pnode->classtype == k_classtype_bone) || is_ik;
+
+         if( is_bone )
          {
-            struct skeleton_bone *sb = &skele->bones[bone_count ++];
+            if( bone_count == skele->bone_count )
+            {
+               vg_error( "too many bones (%u/%u) @%s!\n", 
+                           bone_count, skele->bone_count,
+                           mdl_pstr( mdl, pnode->pstr_name ));
+
+               goto error_dealloc;
+            }
+
+            struct skeleton_bone *sb = &skele->bones[bone_count];
+
             v3_copy( pnode->co, sb->co );
             v3_copy( pnode->s, sb->end );
             sb->parent = pnode->parent-skeleton_root;
+
+            if( is_ik )
+            {
+               struct classtype_ik_bone *ik_inf = mdl_get_entdata( mdl, pnode );
+               sb->deform = ik_inf->deform;
+               sb->ik = 1; /* TODO: place into new IK array */
+               skele->bones[ sb->parent ].ik = 1;
+               
+               if( ik_count == skele->ik_count )
+               {
+                  vg_error( "Too many ik bones, corrupt model file\n" );
+                  goto error_dealloc;
+               }
+
+               struct skeleton_ik *ik = &skele->ik[ ik_count ++ ];
+               ik->upper = bone_count;
+               ik->lower = sb->parent;
+               ik->target = ik_inf->target;
+               ik->pole = ik_inf->pole;
+            }
+            else
+            {
+               struct classtype_bone *bone_inf = mdl_get_entdata( mdl, pnode );
+               sb->deform = bone_inf->deform;
+               sb->ik = 0;
+            }
+
+            bone_count ++;
          }
          else
          {
@@ -142,7 +323,13 @@ static int skeleton_setup( struct skeleton *skele, mdl_header *mdl )
    if( bone_count != skele->bone_count )
    {
       vg_error( "Loaded %u bones out of %u\n", bone_count, skele->bone_count );
-      return 0;
+      goto error_dealloc;
+   }
+
+   if( ik_count != skele->ik_count )
+   {
+      vg_error( "Loaded %u ik bones out of %u\n", ik_count, skele->ik_count );
+      goto error_dealloc;
    }
 
    /* fill in implicit root bone */
@@ -173,6 +360,11 @@ static int skeleton_setup( struct skeleton *skele, mdl_header *mdl )
 
    vg_success( "Loaded skeleton with %u bones\n", skele->bone_count );
    return 1;
+
+error_dealloc:
+   free( skele->bones );
+   free( skele->ik );
+   return 0;
 }
 
 static void skeleton_debug( struct skeleton *skele )
@@ -184,11 +376,24 @@ static void skeleton_debug( struct skeleton *skele )
       v3f p0, p1;
       v3_copy( sb->co, p0 );
       v3_add( p0, sb->end, p1 );
-      vg_line( p0, p1, 0xffffffff );
+      //vg_line( p0, p1, 0xffffffff );
 
       m4x3_mulv( skele->final_transforms[i], p0, p0 );
       m4x3_mulv( skele->final_transforms[i], p1, p1 );
-      vg_line( p0, p1, 0xff0000ff );
+
+      if( sb->deform )
+      {
+         if( sb->ik )
+         {
+            vg_line( p0, p1, 0xff0000ff );
+         }
+         else
+         {
+            vg_line( p0, p1, 0xffcccccc );
+         }
+      }
+      else
+         vg_line( p0, p1, 0xff00ffff );
    }
 }