Drawing point cloud + planes on Canvas

Java-only version of SkAR: drawing on android Canvas

Bug: skia:
Change-Id: I76285aa85c7523ad9ae213d32a159b671d8aa30f
Reviewed-on: https://skia-review.googlesource.com/141048
Reviewed-by: Mike Reed <reed@google.com>

1 files changed, 58 insertions, 98 deletions

diff --git a/platform_tools/android/apps/skar_java/src/main/java/com/google/skar/SkARMatrix.java b/platform_tools/android/apps/skar_java/src/main/java/com/google/skar/SkARMatrix.java
index fc9333c6df..13c249ce36 100644
--- a/platform_tools/android/apps/skar_java/src/main/java/com/google/skar/SkARMatrix.java
+++ b/platform_tools/android/apps/skar_java/src/main/java/com/google/skar/SkARMatrix.java
@@ -1,6 +1,7 @@
 package com.google.skar;
 
 import android.graphics.Matrix;
+import android.graphics.PointF;
 
 /**
  * Provides static methods for matrix manipulation. Input matrices are assumed to be 4x4
@@ -10,70 +11,8 @@ import android.graphics.Matrix;
  */
 
 public class SkARMatrix {
-    /**
-     * Returns an android.graphics.Matrix that can be used on a Canvas to draw a 2D object in
-     * perspective. Objects will be rotated towards the XZ plane. Undefined behavior when any of
-     * the matrices are not of size 16, or are null.
-     *
-     * @param model      4x4 model matrix of the object to be drawn (global/world)
-     * @param view       4x4 camera view matrix (brings objects to camera origin and orientation)
-     * @param projection 4x4 projection matrix
-     * @param viewport   4x4 viewport matrix
-     * @return 3x3 matrix that puts a 2D objects in perspective on a Canvas
-     */
-
-    public static Matrix createPerspectiveMatrix(float[] model, float[] view, float[] projection,
-                                                 float[] viewport) {
-        float[] skiaRotation = createXYtoXZRotationMatrix();
-        float[][] matrices = {skiaRotation, model, view, projection, viewport};
-        return createMatrixFrom4x4Array(matrices);
-    }
-
-    /**
-     * Returns an android.graphics.Matrix that can be used on a Canvas to draw a 2D object in
-     * perspective. Undefined behavior when any of the matrices are not of size 16, or are null.
-     *
-     * @param model       4x4 model matrix of the object to be drawn (global/world)
-     * @param view        4x4 camera view matrix (brings objects to camera origin and orientation)
-     * @param projection  4x4 projection matrix
-     * @param viewport    4x4 viewport matrix
-     * @param rotatePlane specifies if object should be from the XY plane to the XZ plane
-     * @return 3x3 matrix that puts a 2D objects in perspective on a Canvas
-     */
-
-    public static Matrix createPerspectiveMatrix(float[] model, float[] view, float[] projection,
-                                                 float[] viewport, boolean rotatePlane) {
-        if (rotatePlane) {
-            return createPerspectiveMatrix(model, view, projection, viewport);
-        } else {
-            float[][] matrices = {model, view, projection, viewport};
-            return createMatrixFrom4x4Array(matrices);
-        }
-    }
-
-    /**
-     * Returns an android.graphics.Matrix that can be used on a Canvas to draw a 2D object in
-     * perspective. Undefined behavior when any of the matrices are not of size 16, or are null.
-     *
-     * @param model          4x4 model matrix of the object to be drawn (global/world)
-     * @param view           4x4 camera view matrix (brings objects to camera origin and orientation)
-     * @param projection     4x4 projection matrix
-     * @param viewPortWidth  width of viewport of GLSurfaceView
-     * @param viewPortHeight height of viewport of GLSurfaceView
-     * @param rotatePlane    specifies if object should be from the XY plane to the XZ plane
-     * @return 3x3 matrix that puts a 2D objects in perspective on a Canvas
-     */
 
-    public static Matrix createPerspectiveMatrix(float[] model, float[] view, float[] projection,
-                                                 float viewPortWidth, float viewPortHeight, boolean rotatePlane) {
-        if (rotatePlane) {
-            return createPerspectiveMatrix(model, view, projection, viewPortWidth, viewPortHeight);
-        } else {
-            float[] viewPort = createViewportMatrix(viewPortWidth, viewPortHeight);
-            float[][] matrices = {model, view, projection, viewPort};
-            return createMatrixFrom4x4Array(matrices);
-        }
-    }
+    /******************* PUBLIC FUNCTIONS ***********************/
 
     /**
      * Returns an android.graphics.Matrix that can be used on a Canvas to draw a 2D object in
@@ -119,31 +58,19 @@ public class SkARMatrix {
      * to rotate them from the XY plane to the XZ plane.
      */
 
-    private static float[] createXYtoXZRotationMatrix() {
+    public static float[] createXYtoXZRotationMatrix() {
         float[] rotation = new float[16];
         android.opengl.Matrix.setIdentityM(rotation, 0);
         android.opengl.Matrix.rotateM(rotation, 0, 90, 1, 0, 0);
         return rotation;
     }
 
-    /**
-     * Returns an android.graphics.Matrix resulting from a 9-float matrix array in row-major order.
-     * Undefined behavior when the array is not of size 9 or is null.
-     *
-     * @param m3 9-float matrix array in row-major order
-     */
-
-    public static Matrix createMatrixFrom3x3(float[] m3) {
-        Matrix m = new Matrix();
-        m.setValues(m3);
-        return m;
-    }
 
     /**
      * Returns an android.graphics.Matrix resulting from a 16-float matrix array in column-major order
      * Undefined behavior when the array is not of size 16 or is null.
      *
-     * @param m4
+     * @param m4 16-float matrix in column-major order
      */
 
     public static Matrix createMatrixFrom4x4(float[] m4) {
@@ -152,6 +79,46 @@ public class SkARMatrix {
     }
 
     /**
+     * Returns an android.graphics.PointF resulting from the multiplication of a Vector of 4 floats
+     * with a 4x4 float Matrix. The return PointF is the (x, y) values of m4 * v4
+     * @param m4                16-float matrix in column-major order
+     * @param v4                4-float vector
+     * @param perspectiveDivide if true, divide return value by the w-coordinate
+     * @return                  PointF resulting from taking the (x, y) values of m4 * v4
+     */
+    public static PointF multiplyMatrixVector(float[] m4, float[] v4, boolean perspectiveDivide) {
+        float[] result = new float[4];
+        android.opengl.Matrix.multiplyMV(result, 0, m4, 0, v4, 0);
+        if (perspectiveDivide) {
+            return new PointF(result[0] / result[3], result[1] / result[3]);
+        }
+
+        return new PointF(result[0], result[1]);
+    }
+
+    /**
+     * Returns a 16-float matrix in column-major order resulting from the multiplication of matrices.
+     * e.g: m4Array = {m1, m2, m3} --> returns m = m3 * m2 * m1
+     * Undefined behavior when the array is empty, null, or contains arrays not of size 9 (or null)
+     *
+     * @param m4Array array of 16-float matrices in column-major order
+     */
+
+    public static float[] multiplyMatrices4x4(float[][] m4Array) {
+        float[] result = new float[16];
+        android.opengl.Matrix.setIdentityM(result, 0);
+        float[] rhs = result;
+        for (int i = 0; i < m4Array.length; i++) {
+            float[] lhs = m4Array[i];
+            android.opengl.Matrix.multiplyMM(result, 0, lhs, 0, rhs, 0);
+            rhs = result;
+        }
+        return result;
+    }
+
+    /******************* PRIVATE FUNCTIONS ***********************/
+
+    /**
      * Returns an android.graphics.Matrix resulting from the concatenation of 16-float matrices
      * in column-major order from left to right.
      * e.g: m4Array = {m1, m2, m3} --> returns m = m3 * m2 * m1
@@ -160,12 +127,25 @@ public class SkARMatrix {
      * @param m4Array array of 16-float matrices in column-major order
      */
 
-    public static Matrix createMatrixFrom4x4Array(float[][] m4Array) {
+    private static Matrix createMatrixFrom4x4Array(float[][] m4Array) {
         float[] result = multiplyMatrices4x4(m4Array);
         return createMatrixFrom4x4(result);
     }
 
     /**
+     * Returns an android.graphics.Matrix resulting from a 9-float matrix array in row-major order.
+     * Undefined behavior when the array is not of size 9 or is null.
+     *
+     * @param m3 9-float matrix array in row-major order
+     */
+
+    private static Matrix createMatrixFrom3x3(float[] m3) {
+        Matrix m = new Matrix();
+        m.setValues(m3);
+        return m;
+    }
+
+    /**
      * Returns a 9-float matrix in row-major order given a 16-float matrix in column-major order.
      * This will drop the Z column and row.
      * Undefined behavior when the array is not of size 9 or is null.
@@ -188,24 +168,4 @@ public class SkARMatrix {
         }
         return m3;
     }
-
-    /**
-     * Returns a 16-float matrix in column-major order resulting from the multiplication of matrices.
-     * e.g: m4Array = {m1, m2, m3} --> returns m = m3 * m2 * m1
-     * Undefined behavior when the array is empty, null, or contains arrays not of size 9 (or null)
-     *
-     * @param m4Array array of 16-float matrices in column-major order
-     */
-
-    private static float[] multiplyMatrices4x4(float[][] m4Array) {
-        float[] result = new float[16];
-        android.opengl.Matrix.setIdentityM(result, 0);
-        float[] rhs = result;
-        for (int i = 0; i < m4Array.length; i++) {
-            float[] lhs = m4Array[i];
-            android.opengl.Matrix.multiplyMM(result, 0, lhs, 0, rhs, 0);
-            rhs = result;
-        }
-        return result;
-    }
 }