/// <summary>
/// configures a transformed matrix to the vertex component data
/// using the sprite object.
/// </summary>
/// <param name="vertexData">target vertex component data</param>
/// <param name="obj">source sprite object</param>
/// <param name="startIndex">start index of the vertex component data</param>
/// <param name="transformMatrix">transformed matrix</param>
/// <param name="space">3D render space</param>
private static void SetBufferPosition(
ref VertexPositionColorTexture[] vertexData, Sprite3DObject obj,
int startIndex, Matrix transformMatrix, RenderingSpace space)
{
float cx = obj.Width * 0.5f;
float cy = obj.Height * 0.5f;
vertexData[startIndex + 0].Position = new Vector3(-cx, +cy, 0.0f);
vertexData[startIndex + 1].Position = new Vector3(+cx, +cy, 0.0f);
vertexData[startIndex + 2].Position = new Vector3(-cx, -cy, 0.0f);
vertexData[startIndex + 3].Position = new Vector3(+cx, -cy, 0.0f);
for (int i = 0; i < 4; i++)
{
int arrayIndex = startIndex + i;
Vector3.TransformNormal(ref vertexData[arrayIndex].Position,
ref transformMatrix,
out vertexData[arrayIndex].Position);
vertexData[arrayIndex].Position += obj.Center;
if (space == RenderingSpace.Screen)
{
vertexData[arrayIndex].Position =
HelperMath.Make2DCoord(vertexData[arrayIndex].Position);
}
}
}
