private void DrawLabel(float[] cameraViews, float[] cameraProjection)
{
ShaderUtil.CheckGlError(TAG, "Draw label start.");
Matrix.MultiplyMM(modelViewMatrix, 0, cameraViews, 0, modelMatrix, 0);
Matrix.MultiplyMM(modelViewProjectionMatrix, 0, cameraProjection, 0, modelViewMatrix, 0);
float halfWidth = LABEL_WIDTH / 2.0f;
float halfHeight = LABEL_HEIGHT / 2.0f;
float[] vertices =
{
-halfWidth, -halfHeight, 1,
-halfWidth, halfHeight, 1,
halfWidth, halfHeight, 1,
halfWidth, -halfHeight, 1,
};
// The size of each floating point is 4 bits.
FloatBuffer vetBuffer = ByteBuffer.AllocateDirect(4 * vertices.Length)
.Order(ByteOrder.NativeOrder()).AsFloatBuffer();
vetBuffer.Rewind();
for (int i = 0; i < vertices.Length; ++i)
{
vetBuffer.Put(vertices[i]);
}
vetBuffer.Rewind();
// The size of each floating point is 4 bits.
GLES20.GlVertexAttribPointer(glPositionParameter, COORDS_PER_VERTEX, GLES20.GlFloat,
false, 4 * COORDS_PER_VERTEX, vetBuffer);
// Set the sequence of OpenGL drawing points to generate two triangles that form a plane.
short[] indices = { 0, 1, 2, 0, 2, 3 };
// Size of the allocated buffer.
ShortBuffer idxBuffer = ByteBuffer.AllocateDirect(2 * indices.Length)
.Order(ByteOrder.NativeOrder()).AsShortBuffer();
idxBuffer.Rewind();
for (int i = 0; i < indices.Length; ++i)
{
idxBuffer.Put(indices[i]);
}
idxBuffer.Rewind();
GLES20.GlUniformMatrix4fv(glModelViewProjectionMatrix, 1, false, modelViewProjectionMatrix, 0);
GLES20.GlDrawElements(GLES20.GlTriangleStrip, idxBuffer.Limit(), GLES20.GlUnsignedShort, idxBuffer);
ShaderUtil.CheckGlError(TAG, "Draw label end.");
}
/// <summary>
/// Converts a plane polygon from ARCore into a <see cref="Vector3"/> array.
/// </summary>
/// <param name="buffer">The float buffer containing 2D vertices of the polygon</param>
/// <param name="waveVectorArray">The <see cref="Vector3"/> array with the 3D vertices of the polygon</param>
public static void ToWave(this FloatBuffer buffer, ref Vector3[] waveVectorArray)
{
buffer.Rewind();
var boundaryVertices = buffer.Limit() / 2;
if (waveVectorArray == null)
{
waveVectorArray = new Vector3[boundaryVertices];
}
else if (waveVectorArray.Length != boundaryVertices)
{
Array.Resize(ref waveVectorArray, boundaryVertices);
}
for (int i = 0; i < boundaryVertices; i++)
{
waveVectorArray[i].X = buffer.Get();
waveVectorArray[i].Z = buffer.Get();
}
}
/**
* Updates the plane model transform matrix and extents.
*/
private void updatePlaneParameters(float[] planeMatrix, float extentX, float extentZ,
FloatBuffer boundary)
{
Array.Copy(planeMatrix, 0, mModelMatrix, 0, 16);
if (boundary == null)
{
mVertexBuffer.Limit(0);
mIndexBuffer.Limit(0);
return;
}
// Generate a new set of vertices and a corresponding triangle strip index set so that
// the plane boundary polygon has a fading edge. This is done by making a copy of the
// boundary polygon vertices and scaling it down around center to push it inwards. Then
// the index buffer is setup accordingly.
boundary.Rewind();
int boundaryVertices = boundary.Limit() / 2;
int numVertices;
int numIndices;
numVertices = boundaryVertices * VERTS_PER_BOUNDARY_VERT;
// drawn as GL_TRIANGLE_STRIP with 3n-2 triangles (n-2 for fill, 2n for perimeter).
numIndices = boundaryVertices * INDICES_PER_BOUNDARY_VERT;
if (mVertexBuffer.Capacity() < numVertices * COORDS_PER_VERTEX)
{
int size = mVertexBuffer.Capacity();
while (size < numVertices * COORDS_PER_VERTEX)
{
size *= 2;
}
mVertexBuffer = ByteBuffer.AllocateDirect(BYTES_PER_FLOAT * size)
.Order(ByteOrder.NativeOrder()).AsFloatBuffer();
}
mVertexBuffer.Rewind();
mVertexBuffer.Limit(numVertices * COORDS_PER_VERTEX);
if (mIndexBuffer.Capacity() < numIndices)
{
int size = mIndexBuffer.Capacity();
while (size < numIndices)
{
size *= 2;
}
mIndexBuffer = ByteBuffer.AllocateDirect(BYTES_PER_SHORT * size)
.Order(ByteOrder.NativeOrder()).AsShortBuffer();
}
mIndexBuffer.Rewind();
mIndexBuffer.Limit(numIndices);
// Note: when either dimension of the bounding box is smaller than 2*FADE_RADIUS_M we
// generate a bunch of 0-area triangles. These don't get rendered though so it works
// out ok.
float xScale = Math.Max((extentX - 2 * FADE_RADIUS_M) / extentX, 0.0f);
float zScale = Math.Max((extentZ - 2 * FADE_RADIUS_M) / extentZ, 0.0f);
while (boundary.HasRemaining)
{
float x = boundary.Get();
float z = boundary.Get();
mVertexBuffer.Put(x);
mVertexBuffer.Put(z);
mVertexBuffer.Put(0.0f);
mVertexBuffer.Put(x * xScale);
mVertexBuffer.Put(z * zScale);
mVertexBuffer.Put(1.0f);
}
// step 1, perimeter
mIndexBuffer.Put((short)((boundaryVertices - 1) * 2));
for (int i = 0; i < boundaryVertices; ++i)
{
mIndexBuffer.Put((short)(i * 2));
mIndexBuffer.Put((short)(i * 2 + 1));
}
mIndexBuffer.Put((short)1);
// This leaves us on the interior edge of the perimeter between the inset vertices
// for boundary verts n-1 and 0.
// step 2, interior:
for (int i = 1; i < boundaryVertices / 2; ++i)
{
mIndexBuffer.Put((short)((boundaryVertices - 1 - i) * 2 + 1));
mIndexBuffer.Put((short)(i * 2 + 1));
}
if (boundaryVertices % 2 != 0)
{
mIndexBuffer.Put((short)((boundaryVertices / 2) * 2 + 1));
}
}