Direct3D 11 not rasterizing any vertices

Question

I'm trying to render a simple triangle on screen using Direct3D 11, but nothing shows up. Here are my vertices:

SimpleVertex vertices[ 3 ] =
{
    { XMFLOAT3( -1.0f, -1.0f, 0.0f ) },
    { XMFLOAT3(  1.0f, -1.0f, 0.0f ) },
    { XMFLOAT3( -1.0f,  1.0f, 0.0f ) },
};

The expected output is a triangle with one point in the top left corner of the screen, one point in the top right corner of the screen, and one point in the bottom left corner of the screen. However, nothing is being rendered anywhere.

I'm not performing any matrix transformations, and the vertex shader just passes the input directly to the output. Everything seems to be set up correctly, and when I use the graphics debugger in Visual Studio 2012, the correct vertex position is being passed to the vertex shader. However, it skips directly from the vertex shader stage to the output merger stage in the pipeline. I assume this means that nothing is being sent to the pixel shader, which would again mean that the vectors are being discarded in the rasterizer stage. Why is this happening?

Here is my rasterizer state:

D3D11_RASTERIZER_DESC rasterizerDesc;
rasterizerDesc.AntialiasedLineEnable = false;
rasterizerDesc.CullMode = D3D11_CULL_NONE;
rasterizerDesc.DepthBias = 0;
rasterizerDesc.DepthBiasClamp = 0.0f;
rasterizerDesc.DepthClipEnable = true;
rasterizerDesc.FillMode = D3D11_FILL_SOLID;
rasterizerDesc.FrontCounterClockwise = false;
rasterizerDesc.MultisampleEnable = false;
rasterizerDesc.ScissorEnable = false;
rasterizerDesc.SlopeScaledDepthBias = 0.0f;

And my viewport (width/height are the window client area matching my back buffer, which are set to 1024x576 in my test setup):

D3D11_VIEWPORT viewport;
viewport.Height = static_cast< float >( height );
viewport.MaxDepth = 1.0f;
viewport.MinDepth = 0.0f;
viewport.TopLeftX = 0.0f;
viewport.TopLeftY = 0.0f;
viewport.Width = static_cast< float >( width );

Can anyone see what is making the rasterize stage drop my vertices? Or are there any other parts of my D3D setup that could be causing this?

Rachel Gallen Rachel Gallen · Accepted Answer · 2013-01-19T17:52:24

i found this on the internet .. it took absolulely ages to load so i copied and pasted i have highlighted in bold an interesting point.

The D3D_OVERLOADS constructors defined in row 11 offers a convenient way for C++ programmers to create transformed and lit vertices with D3DTLVERTEX.

_D3DTLVERTEX(const D3DVECTOR& v, float _rhw, D3DCOLOR _color,
         D3DCOLOR _specular, float _tu, float _tv)
{
sx = v.x;
sy = v.y;
sz = v.z;
rhw = _rhw;
color = _color;
specular = _specular;
tu = _tu;
tv = _tv;

}

The system requires a vertex position that has already been transformed. So the x and y values must be in screen coordinates, and z must be the depth value of the pixel, which could be used in a z-buffer (we won't use a z-buffer here). Z values can range from 0.0 to 1.0, where 0.0 is the closest possible position to the viewer, and 1.0 is the farthest position still visible within the viewing area. Immediately following the position, transformed and lit vertices must include an RHW (reciprocal of homogeneous W) value.

Before rasterizing the vertices, they have to be converted from homogeneous vertices to non-homogeneous vertices, because the rasterizer expects them this way. Direct3D converts the homogeneous vertices to non-homogeneous vertices by dividing the x-, y-, and z-coordinates by the w-coordinate, and produces an RHW value by inverting the w-coordinate. This is only done for vertices which are transformed and lit by Direct3D. The RHW value is used in multiple ways: for calculating fog, for performing perspective-correct texture mapping, and for w-buffering (an alternate form of depth buffering).

With D3D_OVERLOADS defined, D3DVECTOR is declared as

_D3DVECTOR(D3DVALUE _x, D3DVALUE _y, D3DVALUE _z);

D3DVALUE is the fundamental Direct3D fractional data type. It's declared in d3dtypes.h as

 typedef float D3DVALUE, *LPD3DVALUE;

The source shows that the x and y values for the D3DVECTOR are always 0.0f (this will be changed in InitDeviceObjects()). rhw is always 0.5f, color is 0xfffffff and specular is set to 0. Only the tu1 and tv1 values are differing between the four vertices. These are the coordinates of the background texture.

In order to map texels onto primitives, Direct3D requires a uniform address range for all texels in all textures. Therefore, it uses a generic addressing scheme in which all texel addresses are in the range of 0.0 to 1.0 inclusive. If, instead, you decide to assign texture coordinates to make Direct3D use the bottom half of the texture, the texture coordinates your application would assign to the vertices of the primitive in this example are (0.0,0.0), (1.0,0.0), (1.0,0.5), and (0.0,0.5). Direct3D will apply the bottom half of the texture as the background.

Note: By assigning texture coordinates outside that range, you can create certain special texturing effects.

You will find the declaration of D3DTextr_CreateTextureFromFile() in the Framework source in d3dtextr.cpp. It creates a local bitmap from a passed file. Textures could be created from *.bmp and *.tga files. Textures are managed in the framework in a linked list, which holds the info per texture, called texture container.

 struct TextureContainer
{
TextureContainer* m_pNext; // Linked list ptr

TCHAR   m_strName[80];  // Name of texture (doubles as image filename)
DWORD   m_dwWidth;
DWORD   m_dwHeight;
DWORD   m_dwStage;      // Texture stage (for multitexture devices)
DWORD   m_dwBPP;
DWORD   m_dwFlags;
BOOL    m_bHasAlpha;

LPDIRECTDRAWSURFACE7 m_pddsSurface;  // Surface of the texture
HBITMAP m_hbmBitmap;                 // Bitmap containing texture image
DWORD*  m_pRGBAData;

public:
HRESULT LoadImageData();
HRESULT LoadBitmapFile( TCHAR* strPathname );
HRESULT LoadTargaFile( TCHAR* strPathname );
HRESULT Restore( LPDIRECT3DDEVICE7 pd3dDevice );
HRESULT CopyBitmapToSurface();
HRESULT CopyRGBADataToSurface();

TextureContainer( TCHAR* strName, DWORD dwStage, DWORD dwFlags );
~TextureContainer();
};

Direct3D 11 not rasterizing any vertices

2 Answers