Draw triangle using expandable array in DirectX 9 - c++

Question

I'm trying to draw a triangle which did work with the following code using C++ and DirectX:
Renderer.h
#pragma once
#include "DirectX.h"
#include "Camera.h"
#include "OBJMesh.h"
class Renderer : public DirectX
{
public:
Renderer(std::string windowTitle, int x, int y, unsigned int windowWidth, unsigned int windowHeight, bool fullscreen);
~Renderer();
void Update();
void Render();
protected:
OBJMesh* modelMesh;
Camera* camera;
VERTEX vertices[3];
};
Renderer.cpp
#include "Renderer.h"
Renderer::Renderer(std::string windowTitle, int x, int y, unsigned int windowWidth, unsigned int windowHeight, bool fullscreen) : DirectX(windowTitle, x, y, windowWidth, windowHeight, fullscreen)
{
//camera = new Camera(Vector3(0.0f, -100.0f, 5000.0f), 0.0f, 0.0f);
camera = new Camera(0.0f, 0.0f, D3DXVECTOR3(0.0f, 0.0f, 10.0f));
OBJMesh* modelMesh = new OBJMesh("../Models/Tank/destroyedTank.obj");
VERTEX v1, v2, v3;
v1.x = 0.0f;
v1.y = -1.0f;
v1.z = 0.5f;
v1.color = D3DCOLOR_XRGB(0, 0, 255);
v2.x = 1.0f;
v2.y = 1.0f;
v2.z = 0.5f;
v2.color = D3DCOLOR_XRGB(0, 255, 0);
v3.x = -1.0f;
v3.y = 1.0f;
v3.z = 0.5f;
v3.color = D3DCOLOR_XRGB(255, 0, 0);
vertices[0] = v1;
vertices[1] = v2;
vertices[2] = v3;
device->CreateVertexBuffer(3 * sizeof(VERTEX), 0, VERTEXFORMAT, D3DPOOL_MANAGED, &vertexBuffer, NULL);
VOID* lockingAd;
vertexBuffer->Lock(0, 0, (void**)&lockingAd, 0);
memcpy(lockingAd, vertices, sizeof(vertices));
vertexBuffer->Unlock();
device->SetRenderState(D3DRS_LIGHTING, FALSE); //turn off lighting - DirectX needs to know this :(
device->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE); //turns off face culling (for now)
}
Renderer::~Renderer()
{
delete camera;
}
void Renderer::Update()
{
window->Update();
float msec = Window::GetGameTimer()->GetFrameTime();
camera->Update(msec);
}
void Renderer::Render()
{
device->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(40, 40, 40), 1.0f, 0);
device->BeginScene(); //Must be used as it tells DirectX we're starting to draw stuff.
D3DXMATRIX worldMat;
D3DXMatrixTranslation(&worldMat, 0.0f, 0.0f, 0.0f);
device->SetTransform(D3DTS_WORLD, &worldMat);
device->SetTransform(D3DTS_VIEW, &camera->BuildViewMatrix());
D3DXMATRIX projMatrix;
D3DXMatrixPerspectiveFovLH( &projMatrix,
D3DXToRadian(45),
(float)width/(float)height,
1.0f,
10000.0f);
device->SetTransform(D3DTS_PROJECTION, &projMatrix);
device->SetFVF(VERTEXFORMAT);
device->SetStreamSource(0, vertexBuffer, 0, sizeof(VERTEX));
device->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);
device->EndScene(); //Thank you for waiting, I have finished drawing stuff on the screen, please handle the rest Mr DirectX.
device->Present(NULL, NULL, NULL, NULL);
}
However, when I change the vertices array to VERTEX* vertices in my header file and vertices = new VERTEX[3] in my cpp file, it doesn't draw anything... why's that? How can I fix this?

Answer 1

I'm not sure if this is your problem, but this looks like it could be the offending line:
memcpy( lockingAd, vertices, sizeof(vertices) );
Here, this will do different things if vertices is of type VERTEX[3] and VERTEX*. In the first case the sizeof will return the size of the array, whereas in the second case it will simply return the size of a pointer on your machine, to fix this (if you have a fixed number of elements 3) you should change it to the following:
memcpy( lockingAd, vertices, sizeof(VERTEX) * 3 );