Temperamental ID3D10EffectVectorVariable

Question

I set the HLSL effect variable as follows in several places.

extern ID3D10EffectVectorVariable* pColour; pColour = pEffect->GetVariableByName("Colour")->AsVector(); pColour->SetFloatVector(temporaryLines[i].colour); 

In one of the places that it is specified in the loop, each line in the temporaryLines vector has a D3DXCOLOR variable associated with it. The most unpleasant thing about this problem is that it really works in rare cases, but most of the time it does not. Are there any known issues with this code?

Here it works:

 void GameObject::Draw(D3DMATRIX matView, D3DMATRIX matProjection) { device->IASetInputLayout(pVertexLayout); mesh.SetTopology();//TODO should not be done multiple times // select which vertex buffer and index buffer to display UINT stride = sizeof(VERTEX); UINT offset = 0; device->IASetVertexBuffers(0, 1, mesh.PBuffer(), &stride, &offset); device->IASetIndexBuffer(mesh.IBuffer(), DXGI_FORMAT_R32_UINT, 0); pColour->SetFloatVector(colour); // create a scale matrix D3DXMatrixScaling(&matScale, scale.x, scale.y, scale.z); // create a rotation matrix D3DXMatrixRotationYawPitchRoll(&matRotate, rotation.y, rotation.x, rotation.z); // create a position matrix D3DXMatrixTranslation(&matTranslation, position.x, position.y, position.z); // combine the matrices and render matFinal = matScale * matRotate * matTranslation * matView * matProjection; pTransform->SetMatrix(&matFinal._11); pRotation->SetMatrix(&matRotate._11); // set the rotation matrix in the effect pPass->Apply(0); device->DrawIndexed(mesh.Indices(), 0, 0); //input specific } 

It sometimes works here:

 void BatchLineRenderer::RenderLines(D3DXMATRIX matView, D3DXMATRIX matProjection) { device->IASetInputLayout(pVertexLayout); device->IASetPrimitiveTopology(D3D10_PRIMITIVE_TOPOLOGY_LINESTRIP); // select which vertex buffer and index buffer to display UINT stride = sizeof(LINE); UINT offset = 0; device->IASetVertexBuffers(0, 1, &pBuffer, &stride, &offset); device->IASetIndexBuffer(iBuffer, DXGI_FORMAT_R32_UINT, 0); allLines = temporaryLines.size(); for(int i = 0; i < allLines; i++) { pColour->SetFloatVector(temporaryLines[i].colour); // in the line loop too? // combine the matrices and render D3DXMATRIX matFinal = temporaryLines[i].scale * temporaryLines[i].rotation * temporaryLines[i].position * matView * matProjection; pTransform->SetMatrix(&matFinal._11); pRotation->SetMatrix(&temporaryLines[i].rotation._11); // set the rotation matrix in the effect pPass->Apply(0); device->DrawIndexed(2, 0, 0); } temporaryLines.clear(); } 

effect file:

 float4x4 Transform; // a matrix to store the transform float4x4 Rotation; // a matrix to store the rotation transform float4 LightVec = {0.612f, 0.3535f, 0.612f, 0.0f}; // the light vector float4 LightCol = {1.0f, 1.0f, 1.0f, 1.0f}; // the light color float4 AmbientCol = {0.3f, 0.3f, 0.3f, 1.0f}; // the ambient light color float4 Colour; // a struct for the vertex shader return value struct VSOut { float4 Col : COLOR; // vertex normal float4 Pos : SV_POSITION; // vertex screen coordinates }; // the vertex shader VSOut VS(float4 Norm : NORMAL, float4 Pos : POSITION) { VSOut Output; Output.Pos = mul(Pos, Transform); // transform the vertex from 3D to 2D Output.Col = AmbientCol; // set the vertex color to the input color float4 Normal = mul(Norm, Rotation); Output.Col += saturate(dot(Normal, LightVec)) * LightCol * Colour; // add the diffuse and passed in light return Output; // send the modified vertex data to the Rasterizer Stage } // the pixel shader float4 PS(float4 Col : COLOR) : SV_TARGET { return Col; // set the pixel color to the color passed in by the Rasterizer Stage } // the primary technique technique10 Technique_0 { // the primary pass pass Pass_0 { SetVertexShader(CompileShader(vs_4_0, VS())); SetGeometryShader(NULL); SetPixelShader(CompileShader(ps_4_0, PS())); } } 

Answer 1

Thus, the Color HLSL variable was not defined inside ConstantBuffer, just an ordinary shader variable. Perhaps the variable should be defined in the constant buffer, updateblae per frame? Similar to how the matrices of the world and representations should be defined. At least then the GPU knows that you want to update the color variable every time you render. (Since you are updating the value before you draw).

 cbuffer cbChangesEveryFrame { //The MVP matrices. matrix World; matrix View; float4 Colour; } 

Another point I would like to consider is to get a pointer to the desc method every time before calling draw (or go through the loop), and not reusing it also seems to make a difference.

 //Initiate the pass through loop for the shader effect. technique->GetDesc(&desc); for (UINT p=0; p<desc.Passes; p++) { //Apply this pass through. technique->GetPassByIndex(p)->Apply(0); //draw indexed, instanced. device->device->DrawIndexedInstanced(indicesCount, (UINT) instanceCount, 0, 0, 0); }