Question

I am trying to render a model in Direct3D using DrawIndexedPrimitives. However, I am not able to see it on screen. What are the usual methods used to debug a Direct3D model?

I’ve tried the following:

• Switched off back face culling
• Used PrimitiveType.LineStrip instead of PrimitiveType.TriangleStrip
• Several combinations of View and Projection matrices.
• Used AutoCAD to plot the vertices as tiny spheres

Answer 1

• Make the background color grey; then if it’s white or black you’ll see it.
• Check your transform matrices (world/view/projection). Use a standard math function for view & projection, set world to identity.
• Make sure you setup your viewport; easy to forget this one and have 0 values in the viewport.
• Turn on D3D debugging. Look at the debug spew; lots of people miss that the runtime will tell you what’s going wrong.
• Check your pixel/vertex shader. Use a known setup that works; or fixed function.
• Check render state. Turn of Z buffering, Z test, Z write, etc in case you have depth setup problems. Check your color write masks are on. There are lots of states, look for ones you changed that might cause problems.
• Check your call to DrawIP – you might have parameter problems such as specifiying the wrong number of vertices, faces, etc. Try drawing the first triangle in the list, and no others; get one to work before you draw them all…