/**
* Draws the collection of tracked planes, with closer planes hiding more distant ones.
*
* @param allPlanes The collection of planes to draw.
* @param cameraPose The pose of the camera, as returned by {@link Frame#getPose()}
* @param cameraPerspective The projection matrix, as returned by
* {@link Session#getProjectionMatrix(float[], int, float, float)}
*/
public void DrawPlanes(IEnumerable <Plane> allPlanes, Pose cameraPose, float[] cameraPerspective)
{
// Planes must be sorted by distance from camera so that we draw closer planes first, and
// they occlude the farther planes.
List <SortablePlane> sortedPlanes = new List <SortablePlane>();
float[] normal = new float[3];
float cameraX = cameraPose.Tx();
float cameraY = cameraPose.Ty();
float cameraZ = cameraPose.Tz();
foreach (var plane in allPlanes)
{
if (plane.GetType() != Plane.Type.HorizontalUpwardFacing ||
plane.GetTrackingState() != Plane.TrackingState.Tracking)
{
continue;
}
var center = plane.CenterPose;
// Get transformed Y axis of plane's coordinate system.
center.GetTransformedAxis(1, 1.0f, normal, 0);
// Compute dot product of plane's normal with vector from camera to plane center.
float distance = (cameraX - center.Tx()) * normal[0] +
(cameraY - center.Ty()) * normal[1] + (cameraZ - center.Tz()) * normal[2];
if (distance < 0)
{ // Plane is back-facing.
continue;
}
sortedPlanes.Add(new SortablePlane(distance, plane));
}
sortedPlanes.Sort((x, y) => x.Distance.CompareTo(y.Distance));
var cameraView = new float[16];
cameraPose.Inverse().ToMatrix(cameraView, 0);
// Planes are drawn with additive blending, masked by the alpha channel for occlusion.
// Start by clearing the alpha channel of the color buffer to 1.0.
GLES20.GlClearColor(1, 1, 1, 1);
GLES20.GlColorMask(false, false, false, true);
GLES20.GlClear(GLES20.GlColorBufferBit);
GLES20.GlColorMask(true, true, true, true);
// Disable depth write.
GLES20.GlDepthMask(false);
// Additive blending, masked by alpha chanel, clearing alpha channel.
GLES20.GlEnable(GLES20.GlBlend);
GLES20.GlBlendFuncSeparate(
GLES20.GlDstAlpha, GLES20.GlOne, // RGB (src, dest)
GLES20.GlZero, GLES20.GlOneMinusSrcAlpha); // ALPHA (src, dest)
// Set up the shader.
GLES20.GlUseProgram(mPlaneProgram);
// Attach the texture.
GLES20.GlActiveTexture(GLES20.GlTexture0);
GLES20.GlBindTexture(GLES20.GlTexture2d, mTextures[0]);
GLES20.GlUniform1i(mTextureUniform, 0);
// Shared fragment uniforms.
GLES20.GlUniform4fv(mGridControlUniform, 1, GRID_CONTROL, 0);
// Enable vertex arrays
GLES20.GlEnableVertexAttribArray(mPlaneXZPositionAlphaAttribute);
ShaderUtil.CheckGLError(TAG, "Setting up to draw planes");
foreach (var sortedPlane in sortedPlanes)
{
var plane = sortedPlane.Plane;
float[] planeMatrix = new float[16];
plane.CenterPose.ToMatrix(planeMatrix, 0);
updatePlaneParameters(planeMatrix, plane.ExtentX,
plane.ExtentZ, plane.PlanePolygon);
// Get plane index. Keep a map to assign same indices to same planes.
int planeIndex = -1;
if (!mPlaneIndexMap.TryGetValue(plane, out planeIndex))
{
planeIndex = Java.Lang.Integer.ValueOf(mPlaneIndexMap.Count).IntValue();
mPlaneIndexMap.Add(plane, planeIndex);
}
// Set plane color. Computed deterministically from the Plane index.
int colorIndex = planeIndex % PLANE_COLORS_RGBA.Length;
colorRgbaToFloat(mPlaneColor, PLANE_COLORS_RGBA[colorIndex]);
GLES20.GlUniform4fv(mLineColorUniform, 1, mPlaneColor, 0);
GLES20.GlUniform4fv(mDotColorUniform, 1, mPlaneColor, 0);
// Each plane will have its own angle offset from others, to make them easier to
// distinguish. Compute a 2x2 rotation matrix from the angle.
float angleRadians = planeIndex * 0.144f;
float uScale = DOTS_PER_METER;
float vScale = DOTS_PER_METER * EQUILATERAL_TRIANGLE_SCALE;
mPlaneAngleUvMatrix[0] = +(float)Math.Cos(angleRadians) * uScale;
mPlaneAngleUvMatrix[1] = -(float)Math.Sin(angleRadians) * uScale;
mPlaneAngleUvMatrix[2] = +(float)Math.Sin(angleRadians) * vScale;
mPlaneAngleUvMatrix[3] = +(float)Math.Cos(angleRadians) * vScale;
GLES20.GlUniformMatrix2fv(mPlaneUvMatrixUniform, 1, false, mPlaneAngleUvMatrix, 0);
Draw(cameraView, cameraPerspective);
}
// Clean up the state we set
GLES20.GlDisableVertexAttribArray(mPlaneXZPositionAlphaAttribute);
GLES20.GlBindTexture(GLES20.GlTexture2d, 0);
GLES20.GlDisable(GLES20.GlBlend);
GLES20.GlDepthMask(true);
ShaderUtil.CheckGLError(TAG, "Cleaning up after drawing planes");
}