private bool UpdateBuffers(DeviceContext deviceContext, int positionX, int positionY)
{
// If the position we rendering this bitmap to has not changed then don't update the vertex buffer since it.
if (positionX == PreviousPosX && positionY == PreviousPosY)
return true;
// If it has changed then update the position it is being rendered to.
PreviousPosX = positionX;
PreviousPosY = positionY;
// Calculate the screen coordinates of the left side of the bitmap.
var left = (-(ScreenWidth >> 1)) + (float)positionX;
// Calculate the screen coordinates of the right side of the bitmap.
var right = left + BitmapWidth;
// Calculate the screen coordinates of the top of the bitmap.
var top = (ScreenHeight >> 1) - (float)positionY;
// Calculate the screen coordinates of the bottom of the bitmap.
var bottom = top - BitmapHeight;
// Create and load the vertex array.
var vertices = new[]
{
new TextureShader.Vertex()
{
position = new Vector3(left, top, 0),
texture = new Vector2(0, 0)
},
new TextureShader.Vertex()
{
position = new Vector3(right, bottom, 0),
texture = new Vector2(1, 1)
},
new TextureShader.Vertex()
{
position = new Vector3(left, bottom, 0),
texture = new Vector2(0, 1)
},
new TextureShader.Vertex()
{
position = new Vector3(left, top, 0),
texture = new Vector2(0, 0)
},
new TextureShader.Vertex()
{
position = new Vector3(right, top, 0),
texture = new Vector2(1, 0)
},
new TextureShader.Vertex()
{
position = new Vector3(right, bottom, 0),
texture = new Vector2(1, 1)
}
};
DataStream mappedResource;
#region Vertex Buffer
// Lock the vertex buffer so it can be written to.
deviceContext.MapSubresource(VertexBuffer, MapMode.WriteDiscard, SharpDX.Direct3D11.MapFlags.None, out mappedResource);
// Copy the data into the vertex buffer.
mappedResource.WriteRange<TextureShader.Vertex>(vertices);
// Unlock the vertex buffer.
deviceContext.UnmapSubresource(VertexBuffer, 0);
#endregion
return true;
}
private void CalculateTangentBinormal(TempVertex vertex1, TempVertex vertex2, TempVertex vertex3, out Vector tangent, out Vector binormal)
{
// Calculate the two vectors for the this face.
var vector1 = new[] { vertex2.x - vertex1.x, vertex2.y - vertex1.y, vertex2.z - vertex1.z };
var vector2 = new[] { vertex3.x - vertex1.x, vertex3.y - vertex1.y, vertex3.z - vertex1.z };
// Calculate the tu and tv texture space vectors.
var tuVector = new[] { vertex2.tu - vertex1.tu, vertex3.tu - vertex1.tu };
var tvVector = new[] { vertex2.tv - vertex1.tv, vertex3.tv - vertex1.tv };
// Calculate the denominator of the tangent / binormal equation.
var den = 1.0f / (tuVector[0] * tvVector[1] - tuVector[1] * tvVector[0]);
// Calculate the cross products and multiply by the coefficient to get the tangent and binormal.
tangent.x = (tvVector[1] * vector1[0] - tvVector[0] * vector2[0]) * den;
tangent.y = (tvVector[1] * vector1[1] - tvVector[0] * vector2[1]) * den;
tangent.z = (tvVector[1] * vector1[2] - tvVector[0] * vector2[2]) * den;
binormal.x = (tuVector[0] * vector2[0] - tuVector[1] * vector1[0]) * den;
binormal.y = (tuVector[0] * vector2[1] - tuVector[1] * vector1[1]) * den;
binormal.z = (tuVector[0] * vector2[2] - tuVector[1] * vector1[2]) * den;
// Calculate the length of this normal.
var length = (float)Math.Sqrt(tangent.x * tangent.x + tangent.y * tangent.y + tangent.z * tangent.z);
// Normalize the normal and the store it.
tangent.x = tangent.x / length;
tangent.y = tangent.y / length;
tangent.z = tangent.z / length;
// Calculate the length of this normal.
length = (float)Math.Sqrt(binormal.x * binormal.x + binormal.y * binormal.y + binormal.z * binormal.z);
// Normalize the normal and the store it.
binormal.x = binormal.x / length;
binormal.y = binormal.y / length;
binormal.z = binormal.z / length;
}
