bounding box collisions

j0e

I get the following 5 errors with my code when trying to build in VB.

Error 1 error C2065: 'g_boundingBox' : undeclared identifier c:\Documents and Settings\user\Desktop\lab 7\Template\Box.cpp 355
Error 2 error C2228: left of '.min' must have class/struct/union c:\Documents and Settings\user\Desktop\lab 7\Template\Box.cpp 398
Error 3 error C2228: left of '.max' must have class/struct/union c:\Documents and Settings\user\Desktop\lab 7\Template\Box.cpp 399
Error 4 error C2228: left of '.min' must have class/struct/union c:\Documents and Settings\user\Desktop\lab 7\Template\Box.cpp 400
Error 5 error C2228: left of '.max' must have class/struct/union c:\Documents and Settings\user\Desktop\lab 7\Template\Box.cpp 401

problem is I'm not sure what to declare the g_boundingBox as tried a few guesses of float, void but to no avail. The rest of the errors i am unsure of.

code below

#include <d3d9.h>
#include <d3dx9.h>
#include <stdio.h>

#pragma comment (lib, "d3d9.lib")
#pragma comment (lib, "d3dx9.lib")

#define WINDOW_CLASS "COM428M1 LAB1"
#define WINDOW_NAME "Direct 3D Blank display"
#define WINDOW_WIDTH 640
#define WINDOW_HEIGHT 480

// Global variables
LPDIRECT3D9 g_D3D = NULL; // Used to create the D3DDevice
LPDIRECT3DDEVICE9 g_D3DDevice = NULL; // Our rendering device

struct stBoundingBox
{
stBoundingBox () {min[0] = min[1] = min[2] =
max[0] = max[1] = max[2] = 0;}
float min[3];
float max[3];
};//End stBoundingBox


//Amounts to move the objects
float g_obj1XPos = -1;
float g_obj1MoveAmt = 0;
float g_obj1Dir = -0.02f;

float g_obj2XPos = 1;
float g_obj2MoveAmt = 0;
float g_obj2Dir = 0.02f;


//Test if collision occurred, false if not
bool g_collision = false;

//DirectX font object
LPD3DXFONT g_Font = NULL;

//Create a RECT to position the text onscreen
RECT g_fontPos = {0, 125, 480, 640};
char g_str[64] = {0};

//Vertexbuffer to hold the geometry
LPDIRECT3DVERTEXBUFFER9 g_VertexBuffer = NULL;

//A structure for our custom vertex type
struct stD3DVertex
{
float x,y,z;
unsigned long colour;
};//End stD3DVertex

//Our custom FVF describing the vertex structure
#define D3DFVF_VERTEX (D3DFVF_XYZ | D3DFVF_DIFFUSE)


// Matrices.
D3DXMATRIX g_Projection;
D3DXMATRIX g_ViewMatrix;
D3DXMATRIX g_WorldMatrix;

//Forward function declarations
LRESULT WINAPI MsgProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
void Render();
void CleanUp();
bool InitialiseD3D(HWND hWnd, bool fullscreen);
bool InitialiseObjects();
void CreateCamera();
void CalculateBoundingBox(stD3DVertex *vList, int totalVerts, stBoundingBox *bb);
bool OnCollision();
bool CreateGeometry();
void SetLighting();
void UpdateObjects();

int WINAPI WinMain(HINSTANCE hInst, HINSTANCE prevhInst, LPSTR cmdLine, int show)
{
// Register the window class
WNDCLASSEX wc = { sizeof(WNDCLASSEX), CS_CLASSDC, MsgProc, 0, 0,
hInst, NULL, NULL, NULL, NULL,
WINDOW_CLASS, NULL };
RegisterClassEx(&wc);

// Create the application's window
HWND hWnd = CreateWindow(WINDOW_CLASS, WINDOW_NAME, WS_OVERLAPPEDWINDOW,
100, 100, WINDOW_WIDTH, WINDOW_HEIGHT, GetDesktopWindow(), NULL,
wc.hInstance, NULL);

if(InitialiseD3D(hWnd, false))
{
// Show the window
ShowWindow(hWnd, SW_SHOWDEFAULT);
UpdateWindow(hWnd);

// Enter the message loop
MSG msg;
ZeroMemory(&msg, sizeof(msg));

while(msg.message != WM_QUIT)
{
if(PeekMessage(&msg, NULL, 0U, 0U, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}//End the if
else
Render();
}//End the while
}//End the if

// Release any and all resources.
CleanUp();

// Unregister our window.
UnregisterClass(WINDOW_CLASS, wc.hInstance);
return 0;
}//End WinMain function


//The MsgProc function handles incoming messages from the OS
LRESULT WINAPI MsgProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_DESTROY:
PostQuitMessage(0);
return 0;
break;

case WM_KEYUP:
if(wParam == VK_ESCAPE) PostQuitMessage(0);
break;
}//End the switch

return DefWindowProc(hWnd, msg, wParam, lParam);
}//End MsgProc function

bool InitialiseD3D(HWND hWnd, bool fullscreen)
{
D3DDISPLAYMODE displayMode;

// Create the D3D object.
g_D3D = Direct3DCreate9(D3D_SDK_VERSION);
if(g_D3D == NULL) return false;

// Get the desktop display mode.
if(FAILED(g_D3D->GetAdapterDisplayMode(D3DADAPTER_DEFAULT,
&displayMode))) return false;

// Set up the structure used to create the D3DDevice
D3DPRESENT_PARAMETERS d3dpp;
ZeroMemory(&d3dpp, sizeof(d3dpp));

if(fullscreen)
{
d3dpp.Windowed = FALSE;
d3dpp.BackBufferWidth = WINDOW_WIDTH;
d3dpp.BackBufferHeight = WINDOW_HEIGHT;
}
else
d3dpp.Windowed = TRUE;
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
d3dpp.BackBufferFormat = displayMode.Format;

// //Create the D3DDevice
if(FAILED(g_D3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL,
hWnd, D3DCREATE_HARDWARE_VERTEXPROCESSING,
&d3dpp, &g_D3DDevice)))
{
//We have failed to create a hardware supported device, so attempt software rendering
if(FAILED(g_D3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL,
hWnd, D3DCREATE_SOFTWARE_VERTEXPROCESSING, &d3dpp, &g_D3DDevice)))
{
//DirectX must not be installed
MessageBox(NULL, "CreateDevice() failed! Make sure you have DirectX 9 installed.", "Error!", MB_OK);
return false;
}
}//End if




// Create any objects we will be displaying.
if(!InitialiseObjects()) return false;

return true;
}//End InitialiseD3D

void Render()
{
// Clear the backbuffer.
g_D3DDevice->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0,0,0), 1.0f, 0);

// Begin the scene. Start rendering.
g_D3DDevice->BeginScene();

// Display if collision occurred.
g_Font->DrawText(NULL, g_str, -1, &g_fontPos, DT_CENTER, D3DCOLOR_XRGB(255,255,255));
// Apply the view (camera).
g_D3DDevice->SetTransform(D3DTS_VIEW, &g_ViewMatrix);


// Set stream.
g_D3DDevice->SetStreamSource(0, g_VertexBuffer, 0, sizeof(stD3DVertex));
// Draw square 1.
D3DXMatrixTranslation(&g_WorldMatrix, g_obj1XPos + g_obj1MoveAmt, 0, 0);
g_D3DDevice->SetTransform(D3DTS_WORLD, &g_WorldMatrix);
g_D3DDevice->SetFVF(D3DFVF_VERTEX);
g_D3DDevice->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 2);

// Draw square 2.
D3DXMatrixTranslation(&g_WorldMatrix, g_obj2XPos + g_obj2MoveAmt, 0, 0);
g_D3DDevice->SetTransform(D3DTS_WORLD, &g_WorldMatrix);
g_D3DDevice->SetFVF(D3DFVF_VERTEX);
g_D3DDevice->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 2);



// End the scene. Stop rendering.
g_D3DDevice->EndScene();

// Display the scene.
g_D3DDevice->Present(NULL, NULL, NULL, NULL);

}//End the render function

//CleanUp - Releases any resources we used
void CleanUp()
{
if( g_D3DDevice != NULL)
g_D3DDevice->Release();

if( g_D3D != NULL)
g_D3D->Release();

if( g_VertexBuffer != NULL)
g_VertexBuffer->Release();

if( g_Font != NULL)
g_Font->Release();

g_VertexBuffer = NULL;
g_Font = NULL;
g_D3DDevice = NULL;
g_D3D = NULL;

}//End Cleanup function

bool InitialiseObjects()
{
CreateGeometry();
SetLighting();
CreateCamera();
return true;
}


void CreateCamera()
{
// Set the projection matrix.
D3DXMatrixPerspectiveFovLH(&g_Projection, 45.0f, WINDOW_WIDTH/WINDOW_HEIGHT, 0.1f, 1000.0f);
g_D3DDevice->SetTransform(D3DTS_PROJECTION, &g_Projection);

// Define camera information.
D3DXVECTOR3 cameraPos(0.0f, 0.0f, -5.0f);
D3DXVECTOR3 lookAtPos(0.0f, 0.0f, 0.0f);
D3DXVECTOR3 upDir(0.0f, 1.0f, 0.0f);

// Build view matrix.
D3DXMatrixLookAtLH(&g_ViewMatrix, &cameraPos, &lookAtPos, &upDir);

}//End CreateCamera


void CalculateBoundingBox(stD3DVertex *vList, int totalVerts, stBoundingBox *bb)
{
if(!vList || totalVerts <=0 || !bb)
return;

for (int i = 0; i < totalVerts; i++)
{
//Check to see if the x,y and z values of the current vert are
// smaller than the current min or greater than the current max values
if(vList.x < bb->min[0]) bb->min[0] = vList.x;
if(vList.x > bb->max[0]) bb->min[0] = vList.x;

if(vList.y < bb->min[1]) bb->min[1] = vList.y;
if(vList.y > bb->max[1]) bb->min[1] = vList.y;

if(vList.z < bb->min[2]) bb->min[2] = vList.z;
if(vList.z > bb->max[2]) bb->min[2] = vList.z;
}//End for
}//End CalculateBoundingBox

bool OnCollision(stBoundingBox bb, float x, float y, float z)
{
if(bb.max[0] <= x) return false;
if(bb.min[0] >= x) return false;

if(bb.max[0] <= y) return false;
if(bb.min[0] >= y) return false;

if(bb.max[0] <= z) return false;
if(bb.min[0] >= z) return false;

//We have a collision!
return true;
}//End OnCollision

bool OnCollision(stBoundingBox &bb1, stBoundingBox &bb2)
{
//Test collision between two bounding boxes
if((bb1.min[0] > bb2.max[0]) || (bb2.min[0] > bb1.max[0])) return false;

if((bb1.min[1] > bb2.max[1]) || (bb2.min[1] > bb1.max[1])) return false;

if((bb1.min[2] > bb2.max[2]) || (bb2.min[2] > bb1.max[2])) return false;

//We have a collision!
return true;
}//End OnCollision

bool CreateGeometry()
{
// Create the font.
if(FAILED(D3DXCreateFont(g_D3DDevice, 18, 0, 0, 1, 0,
DEFAULT_CHARSET, OUT_DEFAULT_PRECIS, DEFAULT_QUALITY,
DEFAULT_PITCH | FF_DONTCARE, "Arial", &g_Font)))
return false;


// Fill in our structure to draw an object.
// x, y, z, colour, texture coords.
stD3DVertex objData[] =
{
{-0.3f, -0.4f, 0, D3DCOLOR_XRGB(255,255,255)},
{0.3f, -0.4f, 0, D3DCOLOR_XRGB(255,255,255)},
{0.3f, 0.4f, 0, D3DCOLOR_XRGB(255,255,255)},

{0.3f, 0.4f, 0, D3DCOLOR_XRGB(255,255,255)},
{-0.3f, 0.4f, 0, D3DCOLOR_XRGB(255,255,255)},
{-0.3f, -0.4f, 0, D3DCOLOR_XRGB(255,255,255)}
};//End stD3DVertex objData[] =

CalculateBoundingBox(objData, 6, &g_boundingBox);

// Create the vertex buffer.
if(FAILED(g_D3DDevice->CreateVertexBuffer(sizeof(objData), 0,
D3DFVF_VERTEX, D3DPOOL_DEFAULT,
&g_VertexBuffer, NULL))) return false;

// Fill the vertex buffer.
void *ptr;

if(FAILED(g_VertexBuffer->Lock(0, sizeof(objData),
(void**)&ptr, 0))) return false;

memcpy(ptr, objData, sizeof(objData));

g_VertexBuffer->Unlock();
}//End CreateGeometry

void SetLighting()
{
// Set default rendering states.
g_D3DDevice->SetRenderState(D3DRS_LIGHTING, FALSE);
g_D3DDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);

}//End SetLighting

void UpdateObjects()
{
// Move objects. If position limit is hit, switch directions.
g_obj1MoveAmt += g_obj1Dir;
if(g_obj1MoveAmt > 2) g_obj1Dir *= -1;
if(g_obj1MoveAmt < -2) g_obj1Dir *= -1;

g_obj2MoveAmt += g_obj2Dir;
if(g_obj2MoveAmt > 2) g_obj2Dir *= -1;
if(g_obj2MoveAmt < -2) g_obj2Dir *= -1;

// Get bounding box for each object.
stBoundingBox newBB1, newBB2;
memcpy(&newBB1, &g_boundingBox, sizeof(stBoundingBox));
memcpy(&newBB2, &g_boundingBox, sizeof(stBoundingBox));

// Move boxes for each object along since they have moved.
newBB1.min[0] = g_boundingBox.min[0] + (g_obj1XPos + g_obj1MoveAmt);
newBB1.max[0] = g_boundingBox.max[0] + (g_obj1XPos + g_obj1MoveAmt);
newBB2.min[0] = g_boundingBox.min[0] + (g_obj2XPos + g_obj2MoveAmt);
newBB2.max[0] = g_boundingBox.max[0] + (g_obj2XPos + g_obj2MoveAmt);

// Test for collision and record results.
g_collision = OnCollision(newBB1, newBB2);

// Create string.
if(g_collision) sprintf(g_str, "Collision: TRUE");
else sprintf(g_str, "Collision: FALSE");

}//End UpdateObjects

if you made it this far thanks

Overheal

I dont think youre initializing g_boundingBox anywhere at all. All I see are the min and max calls to it, and it getting passed as a reference: but nowhere is it declared initialized or constructed.

thelordofcheese

g_boundingBox is (most probably) an instance of the struct stBoundingBox, which you havn't initialised anywhere.

As you said yourself you tried to create g_boundingBox but it wouldn't work, may i suggest this

stBoundingBox g_boundingBox;

which should initalise all the values in g_boundingBox to Zero

And then when you do this

memcpy(&newBB1, &g_boundingBox, sizeof(stBoundingBox));

It'll essentially just set all the values in newBB1 to Zero.

Disclaimer: I'm too bone idle to check this out myself so i could be wrong. Hideously wrong