c++ - DirectX 11 Vertices Coordinates -

i'm working on first c++ , directx 11 project current goal draw colored triangle on screen. has worked without problems. however, there's 1 part change, don't know how. i've tried searching solution havn't found yet, , guess reason because don't know should search for.

currently set triangles 3 vertices this:

vertexpos vertices[] = {     { xmfloat3(  0.5f,  0.5f, 1.0f )},     { xmfloat3(  0.5f, -0.5f, 1.0f )},     { xmfloat3( -0.5f, -0.5f, 1.0f )}, } 

where vertexpos defined this:

struct vertexpos {     xmfloat3 pos; }; 

currenty, vertices position set range -1.0f 1.0f, 0.0f center. how can change can position vertices using "real" coordinates this:

vertexpos vertices[] = {     { xmfloat3(  100.0f,  300.0f, 1.0f )},     { xmfloat3(  200.0f,  200.0f, 1.0f )},     { xmfloat3(  200.0f,  300.0f, 1.0f )}, } 

1. usual way:

   • create orthogonal projection matrix (xmmatrixorthographiclh() if using xmmath)
   • create constant buffer matrix on cpu side (c++ code) , on gpu size (vertex shader)
   • multiply vertex positions orthogonal projection matrix in vertex shader

2. simpler way (from f.luna book):

   xmfloat3 spritebatch::pointtondc(int x, int y, float z) {     xmfloat3 p;      p.x = 2.0f*(float)x/mscreenwidth - 1.0f;     p.y = 1.0f - 2.0f*(float)y/mscreenheight;     p.z = z;      return p; } 

   almost same, on cpu side. of course, can move code shader too.

p.s. book/manual/tutorials learn little later. so, better trust , flow step-by step.

happy coding! =)