# DX11 Bottleneck in MD5 animation

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Well met,

I have implemented animation into my 3d engine [dx11]. I chose the md5 format, known from doom 3 I think, because it appeared

to be the most simple format for bonebased animations (correct me, if im wrong on this).

Anyway, I manage to make it work, but appearently I created a bottleneck somewhere, because even a very simple anymation with 3 bones and like 50 polys makes everything slow as hell when played more than 10 times at once on the screen.

I doublechecked the code for the animation itself, im not allocating memory every frame or something like that. So my best guess is that it has to do with the passing from CPU to GPU, which is done like this:


D3D11_MAPPED_SUBRESOURCE mappedResource;
cbPerObject* dataPtr;
dataPtr = (cbPerObject*)mappedResource.pData;
dataPtr->worldMatrix = World;
dataPtr->viewMatrix = camView;
dataPtr->projectionMatrix = camProjection;
d3d11DevCon->Unmap(matrixBuffer, 0);
d3d11DevCon->VSSetConstantBuffers(0, 1, &matrixBuffer);

for(int i=0;i<numSubsets;i++){

d3d11DevCon->IASetIndexBuffer(subsets[i].indexBuff, DXGI_FORMAT_R32_UINT, 0);
d3d11DevCon->IASetVertexBuffers( 0, 1, &subsets[i].vertBuff, &stride, &offset );
d3d11DevCon->DrawIndexed(subsets[i].indices.size(), 0, 0 );

}


I am only using Vertex and Pixelshader, both very basic.

EDIT: After further inverstigation, I figured that this part is the slow one, not the actual rendering. It's the update for the vertices using the bones.

EDIT2: Okey, I managed to narrow down the problem - using more-poly objects makes me lose more performace. Therefore, the problem lies not in something nasty called per object, but something called per vertex/joint .... Or MD5 is just a really slow format, but I can't see why this would be the case. Someone please enlighten me :(


struct Weight{
int jointID;
float bias;
D3DXVECTOR3 normal;
D3DXVECTOR3 pos;
};

struct ModelSubset{

int numTriangles;

vector<Vertex> vertices;
vector<DWORD> indices;
vector<Weight> weights;

vector<D3DXVECTOR3> positions;
VertexPosNormalTex *verts;
unsigned long *indis;

ID3D11Buffer* vertBuff;
ID3D11Buffer* indexBuff;
};

void animatedModel::updateWithAnimation(float deltaTime, int animationID){

currentAnimationID = animationID;
animations[animationID].currAnimTime += deltaTime; // Update the current animation time

if(animations[animationID].currAnimTime > animations[animationID].totalAnimTime){animations[animationID].currAnimTime = 0.0f;}

// Which frame are we on
float currentFrame = animations[animationID].currAnimTime * animations[animationID].frameRate;
int frame0 = floorf( currentFrame );
int frame1 = frame0 + 1;

// Make sure we don't go over the number of frames
if(frame0 == animations[animationID].numFrames-1){frame1 = 0;}

float interpolation = currentFrame - frame0; // Get the remainder (in time) between frame0 and frame1 to use as interpolation factor

vector<joint> interpolatedSkeleton; // Create a frame skeleton to store the interpolated skeletons in

// Compute the interpolated skeleton
for( int i = 0; i < animations[animationID].numJoints; i++){
joint tempJoint;
joint joint0 = animations[animationID].frameSkeleton[frame0][i]; // Get the i'th joint of frame0's skeleton
joint joint1 = animations[animationID].frameSkeleton[frame1][i]; // Get the i'th joint of frame1's skeleton

tempJoint.parentID = joint0.parentID; // Set the tempJoints parent id

// Turn the two quaternions into XMVECTORs for easy computations
D3DXQUATERNION joint0Orient = D3DXQUATERNION(joint0.orientation.x, joint0.orientation.y, joint0.orientation.z, joint0.orientation.w);
D3DXQUATERNION joint1Orient = D3DXQUATERNION(joint1.orientation.x, joint1.orientation.y, joint1.orientation.z, joint1.orientation.w);

// Interpolate positions
tempJoint.pos.x = joint0.pos.x + (interpolation * (joint1.pos.x - joint0.pos.x));
tempJoint.pos.y = joint0.pos.y + (interpolation * (joint1.pos.y - joint0.pos.y));
tempJoint.pos.z = joint0.pos.z + (interpolation * (joint1.pos.z - joint0.pos.z));

// Interpolate orientations using spherical interpolation (Slerp)
D3DXQUATERNION tempO;
D3DXQuaternionSlerp(&tempO, &joint0Orient, &joint1Orient, interpolation);
tempJoint.orientation.x = tempO.x;
tempJoint.orientation.y = tempO.y;
tempJoint.orientation.z = tempO.z;
tempJoint.orientation.w = tempO.w;

interpolatedSkeleton.push_back(tempJoint); // Push the joint back into our interpolated skeleton
}

for ( int k = 0; k < numSubsets; k++){
for ( int i = 0; i < subsets[k].vertices.size(); ++i ){
Vertex tempVert = subsets[k].vertices[i];
tempVert.pos = D3DXVECTOR3(0, 0, 0); // Make sure the vertex's pos is cleared first
tempVert.normal = D3DXVECTOR3(0,0,0); // Clear vertices normal

// Sum up the joints and weights information to get vertex's position and normal
for ( int j = 0; j < tempVert.WeightCount; ++j ){
Weight tempWeight = subsets[k].weights[tempVert.StartWeight + j];
joint tempJoint = interpolatedSkeleton[tempWeight.jointID];

// Convert joint orientation and weight pos to vectors for easier computation
D3DXQUATERNION tempJointOrientation = D3DXQUATERNION(tempJoint.orientation.x, tempJoint.orientation.y, tempJoint.orientation.z, tempJoint.orientation.w);
D3DXQUATERNION tempWeightPos = D3DXQUATERNION(tempWeight.pos.x, tempWeight.pos.y, tempWeight.pos.z, 0.0f);

// We will need to use the conjugate of the joint orientation quaternion
D3DXQUATERNION tempJointOrientationConjugate;
D3DXQuaternionInverse(&tempJointOrientationConjugate, &tempJointOrientation);

// Calculate vertex position (in joint space, eg. rotate the point around (0,0,0)) for this weight using the joint orientation quaternion and its conjugate
// We can rotate a point using a quaternion with the equation "rotatedPoint = quaternion * point * quaternionConjugate"
D3DXVECTOR3 rotatedPoint;
D3DXQUATERNION temp1, temp2;
D3DXQuaternionMultiply(&temp1, &tempJointOrientation, &tempWeightPos);
D3DXQuaternionMultiply(&temp2, &temp1, &tempJointOrientationConjugate);
rotatedPoint.x = temp2.x;rotatedPoint.y = temp2.y;rotatedPoint.z = temp2.z;

// Now move the verices position from joint space (0,0,0) to the joints position in world space, taking the weights bias into account
tempVert.pos.x += ( tempJoint.pos.x + rotatedPoint.x ) * tempWeight.bias;
tempVert.pos.y += ( tempJoint.pos.y + rotatedPoint.y ) * tempWeight.bias;
tempVert.pos.z += ( tempJoint.pos.z + rotatedPoint.z ) * tempWeight.bias;

// Compute the normals for this frames skeleton using the weight normals from before
// We can comput the normals the same way we compute the vertices position, only we don't have to translate them (just rotate)
D3DXQUATERNION tempWeightNormal = D3DXQUATERNION(tempWeight.normal.x, tempWeight.normal.y, tempWeight.normal.z, 0.0f);

// Rotate the normal
D3DXVECTOR3 rotatedPoint2;
D3DXQUATERNION temp3, temp4;
D3DXQuaternionMultiply(&temp3, &tempJointOrientation, &tempWeightPos);
D3DXQuaternionMultiply(&temp4, &temp3, &tempJointOrientationConjugate);
rotatedPoint2.x = temp4.x; rotatedPoint2.y = temp4.y; rotatedPoint2.z = temp4.z;

// Add to vertices normal and ake weight bias into account
tempVert.normal.x -= rotatedPoint2.x * tempWeight.bias;
tempVert.normal.y -= rotatedPoint2.y * tempWeight.bias;
tempVert.normal.z -= rotatedPoint2.z * tempWeight.bias;
}

subsets[k].positions[i] = tempVert.pos; // Store the vertices position in the position vector instead of straight into the vertex vector
subsets[k].vertices[i].normal = tempVert.normal; // Store the vertices normal
D3DXVec3Normalize(&subsets[k].vertices[i].normal, &subsets[k].vertices[i].normal);

}

// Put the positions into the vertices for this subset
for(int i = 0; i < subsets[k].vertices.size(); i++){
subsets[k].vertices[i].pos = subsets[k].positions[i];
subsets[k].verts[i].pos = subsets[k].vertices[i].pos;
subsets[k].verts[i].normal = subsets[k].vertices[i].normal;
subsets[k].verts[i].texcoord = subsets[k].vertices[i].texCoord;
}

D3D11_MAPPED_SUBRESOURCE mappedVertBuff;
VertexPosNormalTex *updatedV; updatedV = (VertexPosNormalTex *)mappedVertBuff.pData;
for(int h=0;h<subsets[k].vertices.size();h++){
updatedV[h].pos = subsets[k].verts[h].pos;
updatedV[h].normal = subsets[k].verts[h].normal;
updatedV[h].texcoord = subsets[k].verts[h].texcoord;
}
d3d11DevCon->Unmap(subsets[k].vertBuff, 0);

}
}

Edited by gnomgrol

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