spine-c skinned mesh distortion

gwinnell

Hi all,

I'm not sure if it's a bug in my code or a bug in the spine-c runtime, but it seems the further away from (0, 0) a mesh gets, the more distorted it gets.

For example, check out the knees on the characters here. The one on the left is relatively straight (as intended) but the one on the right is dangerously spikey.
Loading Image

I wasn't sure if this was specific to the characters idle/run animations or how the legs were put together in Spine, so I tried a bigger animation.

Close to (0, 0):
Loading Image

Far from (0, 0):
Loading Image

As you can see, bits of the mesh (chin, horn, beardybits) gets extruded (or possibly rounded) towards (0, 0).

Here are the exported atlas/json/png files:
http://forceofhab.it/files/temp/chudAvatar.atlas
http://forceofhab.it/files/temp/chudAvatar.json
http://forceofhab.it/_files/temp/chudAvatar.png

I tried to test these files with spine-js (easiest one to test for me besides spine-c) but that doesn't have the new meshes/ffd stuff so alas no succcess.

Here is the render code for the Skeletons. It's pretty much the spine-sfml rendering code:

void Skeleton::render() {

     unsigned int BLEND_ADDITIVE = Renderer::BLEND_ADDITIVE;
     unsigned int BLEND_SPINE = Renderer::BLEND_NORMAL;

     Renderer* r = ARK2D::getRenderer();
     r->setDrawColor(Color::white);
     float worldVertices[SPINE_MESH_VERTEX_COUNT_MAX];
     for (int i = 0; i < m_skeleton->slotCount; ++i) 
     {
        spSlot* slot = m_skeleton->drawOrder[i];
        spSlotData* slotdata = slot->data;
        
        spAttachment* attachment = slot->attachment;
        if (!attachment) { continue; } 

        unsigned int blend = slot->data->additiveBlending ? BLEND_ADDITIVE  : BLEND_SPINE;
        r->setBlendMode(blend);

        if (attachment->type == SP_ATTACHMENT_REGION) {

           spRegionAttachment* regionAttachment = (spRegionAttachment*)attachment;
           spRegionAttachment_computeWorldVertices(regionAttachment, slot->skeleton->x, slot->skeleton->y, slot->bone, worldVertices);

           spAtlasRegion* spatreg = (spAtlasRegion*)regionAttachment->rendererObject;
           Image* img = (Image*) spatreg->page->rendererObject;
           unsigned int texId = img->getTexture()->getId();
           float sx = img->getTextureW();
           float sy = img->getTextureH();
           
           float rawVertices[] = {
              worldVertices[SP_VERTEX_X1], worldVertices[SP_VERTEX_Y1],
              worldVertices[SP_VERTEX_X2], worldVertices[SP_VERTEX_Y2],
              worldVertices[SP_VERTEX_X4], worldVertices[SP_VERTEX_Y4],
              worldVertices[SP_VERTEX_X4], worldVertices[SP_VERTEX_Y4],
              worldVertices[SP_VERTEX_X2], worldVertices[SP_VERTEX_Y2],
              worldVertices[SP_VERTEX_X3], worldVertices[SP_VERTEX_Y3]
           };
           float rawTexCoords[] = {
              regionAttachment->uvs[SP_VERTEX_X1] * sx, regionAttachment->uvs[SP_VERTEX_Y1] * sy,
              regionAttachment->uvs[SP_VERTEX_X2] * sx, regionAttachment->uvs[SP_VERTEX_Y2] * sy,
              regionAttachment->uvs[SP_VERTEX_X4] * sx, regionAttachment->uvs[SP_VERTEX_Y4] * sy,
              regionAttachment->uvs[SP_VERTEX_X4] * sx, regionAttachment->uvs[SP_VERTEX_Y4] * sy,
              regionAttachment->uvs[SP_VERTEX_X2] * sx, regionAttachment->uvs[SP_VERTEX_Y2] * sy,
              regionAttachment->uvs[SP_VERTEX_X3] * sx, regionAttachment->uvs[SP_VERTEX_Y3] * sy
           };
           unsigned char re = (m_skeleton->r * slot->r * regionAttachment->r) * 255;
           unsigned char g =  (m_skeleton->g * slot->g * regionAttachment->g) * 255;
           unsigned char b =  (m_skeleton->b * slot->b * regionAttachment->b) * 255;
           unsigned char a =  (m_skeleton->a * slot->a * regionAttachment->a) * 255;
           unsigned char rawColors[] = {
              re, g, b, a,
              re, g, b, a,
              re, g, b, a,
              re, g, b, a,
              re, g, b, a,
              re, g, b, a
           };

           r->texturedQuads(texId, &rawVertices[0], &rawTexCoords[0], &rawColors[0], 1);
           
           
        } else if (attachment->type == SP_ATTACHMENT_MESH) {
           //spRegionAttachment* regionAttachment = (spRegionAttachment*)attachment;
           spMeshAttachment* mesh = (spMeshAttachment*) attachment;
           if (mesh->uvsCount > SPINE_MESH_VERTEX_COUNT_MAX) { continue; }

           spAtlasRegion* spatreg = (spAtlasRegion*) mesh->rendererObject;
           Image* img = (Image*) spatreg->page->rendererObject;
           unsigned int texId = img->getTexture()->getId();
           float sx = img->getTextureW();
           float sy = img->getTextureH();

           spMeshAttachment_computeWorldVertices(mesh, slot->skeleton->x, slot->skeleton->y, slot, worldVertices);

           float re_f = m_skeleton->r * slot->r * mesh->r;
           float g_f  = m_skeleton->g * slot->g * mesh->g;
           float b_f  = m_skeleton->b * slot->b * mesh->b;
           float a_f  = m_skeleton->a * slot->a * mesh->a;

           unsigned char re = (unsigned char) (re_f * 255.0f);
           unsigned char g =  (unsigned char) (g_f  * 255.0f);
           unsigned char b =  (unsigned char) (b_f  * 255.0f);
           unsigned char a =  (unsigned char) (a_f  * 255.0f);
           
           #ifdef ARK2D_WINDOWS_VS
              float* rawVertices = (float*)alloca((mesh->trianglesCount * 2) * sizeof(float));
              float* rawTexCoords = (float*)alloca((mesh->trianglesCount * 2) * sizeof(float));
              unsigned char* rawColors = (unsigned char*)alloca((mesh->trianglesCount * 4) * sizeof(unsigned char));
           #else
              float rawVertices[mesh->trianglesCount*2];
              float rawTexCoords[mesh->trianglesCount*2];
              unsigned char rawColors[mesh->trianglesCount*4];
           #endif

           /*string thisc = string("r: ");
           thisc += Cast::toString<float>(re_f); 
           thisc += string(", g: ");
           thisc += Cast::toString<float>(g_f);
           thisc += string(", b: ");
           thisc += Cast::toString<float>(b_f);
           thisc += string(", a: ");
           thisc += Cast::toString<float>(a_f);
           ARK2D::getLog()->w(thisc); */

           int k = 0;
           int l = 0;
           for (int j = 0; j < mesh->trianglesCount; ++j) {
              int index = mesh->triangles[j] << 1;
              
              rawVertices[k] = worldVertices[index];
              rawVertices[k+1] = worldVertices[index+1];
              rawTexCoords[k] = mesh->uvs[index] * sx;
              rawTexCoords[k+1] = mesh->uvs[index + 1] * sy;
              rawColors[l] = re;
              rawColors[l+1] = g;
              rawColors[l+2] = b;
              rawColors[l+3] = a; 
              k += 2;
              l += 4;
           }
           r->texturedTriangles(texId, &rawVertices[0], &rawTexCoords[0], &rawColors[0], mesh->trianglesCount/3);

        } else if (attachment->type == SP_ATTACHMENT_SKINNED_MESH) {
           spSkinnedMeshAttachment* mesh = (spSkinnedMeshAttachment*) attachment;
           if (mesh->uvsCount > SPINE_MESH_VERTEX_COUNT_MAX) { continue; } 

           spAtlasRegion* spatreg = (spAtlasRegion*)mesh->rendererObject;
           Image* img = (Image*) spatreg->page->rendererObject;
           unsigned int texId = img->getTexture()->getId();
           float sx = img->getTextureW();
           float sy = img->getTextureH();
           spSkinnedMeshAttachment_computeWorldVertices(mesh, slot->skeleton->x, slot->skeleton->y, slot, worldVertices);

           float re_f = m_skeleton->r * slot->r * mesh->r;
           float g_f  = m_skeleton->g * slot->g * mesh->g;
           float b_f  = m_skeleton->b * slot->b * mesh->b;
           float a_f  = m_skeleton->a * slot->a * mesh->a;

           unsigned char re = (unsigned char) (re_f * 255.0f);
           unsigned char g =  (unsigned char) (g_f  * 255.0f);
           unsigned char b =  (unsigned char) (b_f  * 255.0f);
           unsigned char a =  (unsigned char) (a_f  * 255.0f);

           #ifdef ARK2D_WINDOWS_VS
              float* rawVertices = (float*)alloca((mesh->trianglesCount * 6) * sizeof(float));
              float* rawTexCoords = (float*)alloca((mesh->trianglesCount * 6) * sizeof(float));
              unsigned char* rawColors = (unsigned char*)alloca((mesh->trianglesCount * 12) * sizeof(unsigned char));
           #else
              float rawVertices[mesh->trianglesCount * 2];
              float rawTexCoords[mesh->trianglesCount * 2];
              unsigned char rawColors[mesh->trianglesCount * 4];
           #endif

           int k = 0;
           int l = 0;
           for (int j = 0; j < mesh->trianglesCount; ++j) {
              int index = mesh->triangles[j] << 1;
              
              rawVertices[k] = worldVertices[index];
              rawVertices[k+1] = worldVertices[index+1];
              rawTexCoords[k] = mesh->uvs[index] * sx;
              rawTexCoords[k+1] = mesh->uvs[index + 1] * sy;
              rawColors[l] = re;
              rawColors[l+1] = g;
              rawColors[l+2] = b;
              rawColors[l+3] = a;
              k += 2;
              l += 4;

           }
           
           r->texturedTriangles(texId, &rawVertices[0], &rawTexCoords[0], &rawColors[0], mesh->trianglesCount/3);

        } /*else if (attachment->type == SP_ATTACHMENT_BOUNDING_BOX) {

           
           spBoundingBoxAttachment* boxAttachment = (spBoundingBoxAttachment*) attachment;
           spBoundingBoxAttachment_computeWorldVertices (boxAttachment, slot->skeleton->x, slot->skeleton->y, slot->bone, worldVertices);

           r->setDrawColor(Color::white);
           r->drawLine(worldVertices[SP_VERTEX_X1], worldVertices[SP_VERTEX_Y1], worldVertices[SP_VERTEX_X2], worldVertices[SP_VERTEX_Y2]);
           r->drawLine(worldVertices[SP_VERTEX_X2], worldVertices[SP_VERTEX_Y2], worldVertices[SP_VERTEX_X3], worldVertices[SP_VERTEX_Y3]);
           r->drawLine(worldVertices[SP_VERTEX_X3], worldVertices[SP_VERTEX_Y3], worldVertices[SP_VERTEX_X4], worldVertices[SP_VERTEX_Y4]);
           r->drawLine(worldVertices[SP_VERTEX_X4], worldVertices[SP_VERTEX_Y4], worldVertices[SP_VERTEX_X1], worldVertices[SP_VERTEX_Y1]);
           continue;
           
        }*/

     }
     
     r->setBlendMode(Renderer::BLEND_NORMAL);
  }

I've also called spBone_setYDown(1) because my setup has a top-left coordinate space.

Let me know if you need anything else to help solve the problem. 🙂

Many thanks,
Ashley

EDIT:

Quick and dirty mesh outline drawing (glPolygonMode). You an still sort of see it on that lip at the front of the face.
Loading Image
Loading Image

Nate

Sounds bizarre. I'll look at it tomorrow, but a quick test with spine-sfml and there doesn't seem to be an issue:

Loading Image

How do you position your skeleton?

You can avoid the stack allocation, I only do it for SFML because the SFML draw method is const (super annoying). Ideally you'd check and reallocate your heap buffer if it isn't big enough.

gwinnell

Sorry Nate - a bit of a misleading topic name! I think I meant skinning of the free-form deformation type. Goblin guy renders fine here. Possibly worth checking the atlas/json/png files I uploaded in your spine-sfml environment. I'll get the source spine project files uploaded tomorrow (they're currently sitting with Tom, our animator).

Thanks for the swift response!

Sorry for double-post. Here are the zipped up Spine source/project files.
http://forceofhab.it/_files/temp/chudSpine.zip

Nate

I will check it soon, but how do you position your skeleton? Setting skeleton->x/y?

gwinnell

I'm changing the position by setting the root bone x/y and calling spSkeleton_updateWorldTransform(). I have to multiply the y by -1 to get it in the right place because of the negative coordinate space.

EDIT:
I'm setting the position using skeleton->x/y now and it works - wahoo! Thanks Nate. Not sure why it was slightly broken when moving things by the bone coordinates though. 🙂

Nate

Ah. It's more usual to position the skeleton using skeleton->x/y. This way you don't have to waste a bone solely to position the skeleton. I found the problem occurred because of a lack of precision in the JSON output. Fixed in 1.8.35. Cheers! :beer: