Displaying mesh using DirectX 9 - c++

Question

#include <windows.h>
#include <d3d9.h>
#include <D3DX9Mesh.h>
#define THROW_ERROR_AND_EXIT(x) { \
MessageBox(0,x,0,0); \
return -1; \
}
LRESULT CALLBACK WndProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam )
{
// Handle close event
switch( msg )
{
case WM_DESTROY:
PostQuitMessage( 0 );
return 0;
}
return DefWindowProc( hWnd, msg, wParam, lParam );
}
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
// Registering class
WNDCLASSEX wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style= CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc= (WNDPROC)WndProc;
wcex.cbClsExtra= 0;
wcex.cbWndExtra= 0;
wcex.hInstance= hInstance;
wcex.hIcon= 0;
wcex.hCursor= LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground= (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName= 0;
wcex.lpszClassName= "MyMeshViewer";
wcex.hIconSm= 0;
RegisterClassEx(&wcex);
// Creating Window
HWND hWnd = CreateWindow("MyMeshViewer", "MyMeshViewer", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL);
// Creating Direct3D object
LPDIRECT3D9 d3dObject=NULL;
LPDIRECT3DDEVICE9 d3dDevice=NULL;
d3dObject=Direct3DCreate9(D3D_SDK_VERSION);
// Creating Direct3D device
if(NULL == d3dObject)
THROW_ERROR_AND_EXIT("NULL == d3dObject");
D3DPRESENT_PARAMETERS presParams;
ZeroMemory(&presParams,sizeof(presParams));
presParams.Windowed=TRUE;
presParams.SwapEffect=D3DSWAPEFFECT_DISCARD;
presParams.BackBufferFormat=D3DFMT_UNKNOWN;
presParams.PresentationInterval=D3DPRESENT_INTERVAL_ONE;
HRESULT hr=d3dObject->CreateDevice(D3DADAPTER_DEFAULT,D3DDEVTYPE_HAL,hWnd, D3DCREATE_HARDWARE_VERTEXPROCESSING, &presParams, &d3dDevice);
if(FAILED(hr))
THROW_ERROR_AND_EXIT("d3dObject->CreateDevice");
// Rendering
d3dDevice->Clear(0,NULL,D3DCLEAR_TARGET, D3DCOLOR_XRGB(0,255,0),1.0f,0);
d3dDevice->BeginScene();
// Loading the mesh
LPD3DXBUFFER materialBuffer = NULL;
DWORD numMaterials = 0;
LPD3DXMESH mesh = NULL;
hr=D3DXLoadMeshFromX("tiger.x", D3DXMESH_SYSTEMMEM,
d3dDevice, NULL,
&materialBuffer,NULL, &numMaterials,
&mesh );
if(FAILED(hr))
THROW_ERROR_AND_EXIT("hr=D3DXLoadMeshFromX");
// Loading the material buffer
D3DXMATERIAL* d3dxMaterials = (D3DXMATERIAL*)materialBuffer->GetBufferPointer();
// Holding material and texture pointers
D3DMATERIAL9 *meshMaterials = new D3DMATERIAL9[numMaterials];
LPDIRECT3DTEXTURE9 *meshTextures = new LPDIRECT3DTEXTURE9[numMaterials];
// Filling material and texture arrays
for (DWORD i=0; i<numMaterials; i++)
{
// Copy the material
meshMaterials[i] = d3dxMaterials[i].MatD3D;
// Set the ambient color for the material (D3DX does not do this)
meshMaterials[i].Ambient = meshMaterials[i].Diffuse;
// Create the texture if it exists - it may not
meshTextures[i] = NULL;
if (d3dxMaterials[i].pTextureFilename)
D3DXCreateTextureFromFile(d3dDevice, d3dxMaterials[i].pTextureFilename, &meshTextures[i]);
}
materialBuffer->Release();
for (DWORD i=0; i<numMaterials; i++)
{
// Set the material and texture for this subset
d3dDevice->SetMaterial(&meshMaterials[i]);
d3dDevice->SetTexture(0,meshTextures[i]);
// Draw the mesh subset
mesh->DrawSubset( i );
}
d3dDevice->EndScene();
d3dDevice->Present(NULL, NULL, NULL, NULL);
// Show Window
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
// Handle messages
MSG msg;
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return (int)msg.wParam;
}
This is my program to load a mesh tiger.x and display it. But it is not getting displayed. The value of the variable numMaterials remains 1 all the time. I guess there is some issue with my program. Someone please help me to figure it out. Thanks.
The tiger.x mesh file below
http://pastebin.com/DuvpS4mh

Answer 1

The problem is that you are rendering to the window and then calling UpdateWindow which forces a re-paint, thus erasing the drawing.
I suggest you download the DirectX SDK and look at the samples to see how to build a 'correct' rendering loop.

Answer 2

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_PAINT:
{
// Rendering
d3dDevice->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 255, 0), 1.0f, 0);
d3dDevice->BeginScene();
for (DWORD i = 0; i < numMaterials; i++)
{
// Set the material and texture for this subset
d3dDevice->SetMaterial(&meshMaterials[i]);
d3dDevice->SetTexture(0, meshTextures[i]);
// Draw the mesh subset
mesh->DrawSubset(i);
}
d3dDevice->EndScene();
d3dDevice->Present(NULL, NULL, NULL, NULL);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
You have to handle the WM_PAINT event.