trying to make a class that makes quads

Da cobra · 2002-08-26T16:21:26

well as the title says I''m trying to make a class so I can make "infinite" quads but here''s my problem, how do I deal with the variables that always need a new name?!? I mean for each quad I need a new pointer to a IDirect3DVertexBuffer8, right. so how do I solve this? here''s my CQuad.h : #include <d3d8.h> // Direct3D header file //class definition of Quad : class CQuad { private: struct my_vertex { FLOAT x, y, z, rhw; // The transformed position for the vertex. DWORD color; // The vertex color. } ; // end of struct public: void DrawQuad() ; void InitQuad(float fStartX, float fStartY, float fEndX, float fEndY, DWORD color) ; void ReleaseQuad() ; } ; // end of class and this is my CQuad.cpp : #include "CQuad.h" IDirect3DVertexBuffer8 *g_square=NULL ; // what to do with this one??? void CQuad::DrawQuad() { #define D3D8T_CUSTOMVERTEX (D3DFVF_XYZRHW | D3DFVF_DIFFUSE) // Vertex shaders are a complex topic, but you can do some amazing things with them // For this example we''re not creating one, so we tell Direct3D that we''re just // using a plain vertex format. g_lpDevice->SetVertexShader(D3D8T_CUSTOMVERTEX); // Set the active stream to be our square. // NOTE: Because of the offsets that DrawPrimitive takes, we could // have built the triangle & square into a single VB and still // drawn them seperately. g_lpDevice->SetStreamSource(0,g_square,sizeof(my_vertex)); // Now we''re drawing a Triangle Strip, 4 vertices to draw 2 triangles. g_lpDevice->DrawPrimitive(D3DPT_TRIANGLESTRIP, 0, 2); } void CQuad::InitQuad(float fStartX, float fStartY, float fEndX, float fEndY, DWORD color) { // Declare a structure to hold a vertex with all the information that we need struct my_vertex { FLOAT x, y, z, rhw ; // The transformed position for the vertex. DWORD color; // The vertex color. } ; // end of struct // A handy little ''macro'' for our definition of the vertex. When we use the vertex data // we have to tell D3D what data we''re passing it. D3DFVF_DIFFUSE specifies that the // vertex will have a colour, the D3DFVF_XYZRHW specifies that the vertex will have // coordinate given in screen space. #define D3D8T_CUSTOMVERTEX (D3DFVF_XYZRHW | D3DFVF_DIFFUSE) my_vertex g_square_vertices[] = { { fStartX, fEndY , 0.5f, 1.0f, color }, // x, y, z, rhw, color { fStartX, fStartY, 0.5f, 1.0f, color }, { fEndX , fEndY , 0.5f, 1.0f, color }, { fEndX , fStartY, 0.5f, 1.0f, color } } ; // end of my_vertex g_square_vertices[] unsigned char *vb_vertices; if(FAILED(g_lpDevice->CreateVertexBuffer(4*sizeof(my_vertex),//Size of memory to be allocated // Number of vertices * size of a vertex D3DUSAGE_WRITEONLY, // We never need to read from it so // we specify write only, it''s faster D3D8T_CUSTOMVERTEX, // Our custom vertex specifier (coordinates & a colour) D3DPOOL_MANAGED, // Tell DirectX to manage the memory of this resource &g_square))) // Pointer to our triangle, after this call // It will point to a valid vertex buffer { Write2Log("Failed to initialize a square") ; } // end of if // Now we go through the same process to fill in our VB for the square. if(FAILED(g_square->Lock(0, //Offset, we want to start at the beginning 0, //SizeToLock, 0 means lock the whole thing &vb_vertices, //If successful, this will point to the data in the VB 0))) //Flags, nothing special { Write2Log("Failed to lock Square") ; } memcpy(vb_vertices, g_square_vertices, sizeof(g_square_vertices)) ; g_square->Unlock() ; } // end of InitASquare void CQuad::ReleaseQuad() { if(g_square) { g_square->Release() ; g_square=NULL ; } } // end of ReleaseSquare() thanx in advance for any tips

For Beginners

Started by Da cobra August 22, 2002 01:33 PM

11 comments, last by Da cobra 22 years, 4 months ago

Da cobra

Author

122

August 26, 2002 05:21 AM

thanx I changed my class again so my pointer to a VB is now a private member and all works fine now

anything I should worry about when using a pointer as a private member?

Colin Jeanne

1,115

August 26, 2002 04:11 PM

As stated in my post above, when dealing with a private member that is a pointer to an external variable you could run into the danger of having the external destroyed, invalidating the private pointer. However, the class would know nothing of the object''s demise and would continue to use the pointer as if it was valid which will cause your program to barf.

In my sprite class I use this method and then just assume that the user of the class will be smart enough to stop using/re-initialize the class when the pointer becomes invalid. I also give the user the option to have the sprite class manage itself instead. While this is less efficient than the former choice (each sprite has it''s own tiny vb), it does give a bit of automation.

So, as always when working with pointers, you just need to be careful.

*Side note*
If you use ATL, there is a class to help manage COM pointers, CComPtr. You may also want to look into that

The hackers must have gotten into the system through the hyperlink!!

Invader''s Realm

UltimaGames

122

August 26, 2002 04:21 PM

Well i see ur problem, and i think the above fix is the best way to go TOTALLY private VertexBuffers... u might get rendering problems tho... i recommend doing the above thing just make sure uve got ur render stuff down pat!

trying to make a class that makes quads

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