Merge lp:~hikiko/compiz/compiz.glvector-fixes into lp:compiz/0.9.12

[Eleni Maria Stea]

Change in GLVector implementation

Bug:
The GLVectors of compiz are 4 dimensional (x, y, z, w): https://en.wikipedia.org/wiki/Homogeneous_coordinates The w coordinate should be initialized to 1 and be preserved when we perform vector operations (additions/multiplications etc) otherwise the transformations won't be correct. For example: if we add or subtract the w values during two vectors addition we might have unexpected projections when the new w value is > 1 or divisions by 0 (when the new w is 0) because opengl divides the x,y,z values by w.

Solution:
- Changed the constructors to initialize w to 1 and not to 0 by default.
- Fixed the vector operations to use the x, y, z coordinates only.
- Fixed the existing constructors in plugins to initialize w to 1 and not to 0.

Change in GLVector implementation

Bug:
The GLVectors of compiz are 4 dimensional (x, y, z, w): https://en.wikipedia.org/wiki/Homogeneous_coordinates The w coordinate should be initialized to 1 and be preserved when we perform vector operations (additions/multiplications etc) otherwise the transformations won't be correct. For example: if we add or subtract the w values during two vectors addition we might have unexpected projections when the new w value is > 1 or divisions by 0 (when the new w is 0) because opengl divides the x,y,z values by w.

Solution:
- Changed the constructors to initialize w to 1 and not to 0 by default.
- Fixed the vector operations to use the x, y, z coordinates only.
- Fixed the existing constructors in plugins to initialize w to 1 and not to 0.

[PS Jenkins bot (ps-jenkins)]

PASSED: Continuous integration, rev:3928
http://jenkins.qa.ubuntu.com/job/compiz-ci/30/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/compiz-vivid-amd64-ci/20
    SUCCESS: http://jenkins.qa.ubuntu.com/job/compiz-vivid-armhf-ci/20
    SUCCESS: http://jenkins.qa.ubuntu.com/job/compiz-vivid-i386-ci/20

Click here to trigger a rebuild:
http://s-jenkins.ubuntu-ci:8080/job/compiz-ci/30/rebuild

review: Approve (continuous-integration)

[Stephen M. Webb (bregma)]

review: Approve

=== modified file 'plugins/animation/src/glide.cpp'
--- plugins/animation/src/glide.cpp	2013-05-19 15:04:07 +0000
+++ plugins/animation/src/glide.cpp	2015-03-02 09:39:43 +0000
@@ -122,11 +122,11 @@
 		      mAWindow->savedOutRect () :
 		      mWindow->outputRect ());
 
-    GLVector rotAxis (1, 0, 0, 0);
+    GLVector rotAxis (1, 0, 0, 1);
     GLVector rotAxisOffset (outRect.x () + outRect.width () / 2.0f,
 			    outRect.y () + outRect.height () / 2.0f,
-			    0, 0);
-    GLVector translation (0, 0, finalz * forwardProgress, 0);
+			    0, 1);
+    GLVector translation (0, 0, finalz * forwardProgress, 1);
 
     float rotAngle   = finalRotAng * forwardProgress;
     glideModRotAngle = fmodf (rotAngle + 720, 360.0f);
@@ -142,9 +142,7 @@
     // animation rotation
     mTransform.rotate (rotAngle, rotAxis);
 
-    // intentional scaling of z by 0 to prevent weird opacity results and
-    // flashing that happen when z coords are between 0 and 1 (bug in compiz?)
-    mTransform.scale (1.0f, 1.0f, 0.0f);
+    mTransform.scale (1.0f, 1.0f, 1.0f);
 
     // place window rotation axis at origin
     mTransform.translate (-rotAxisOffset);

=== modified file 'plugins/expo/src/expo.cpp'
--- plugins/expo/src/expo.cpp	2014-06-24 18:40:39 +0000
+++ plugins/expo/src/expo.cpp	2015-03-02 09:39:43 +0000
@@ -778,10 +778,10 @@
 
     /* Zoom animation stuff */
     /* camera position for the selected viewport */
-    GLVector vpCamPos (0, 0, 0, 0);
+    GLVector vpCamPos (0, 0, 0, 1);
 
     /* camera position during expo mode */
-    GLVector expoCamPos (0, 0, 0, 0);
+    GLVector expoCamPos (0, 0, 0, 1);
 
     float sx = screen->width ()  / static_cast <float> (output->width ());
     float sy = screen->height () / static_cast <float> (output->height ());

=== modified file 'plugins/opengl/include/opengl/vector.h'
--- plugins/opengl/include/opengl/vector.h	2012-05-17 10:41:21 +0000
+++ plugins/opengl/include/opengl/vector.h	2015-03-02 09:39:43 +0000
@@ -40,7 +40,7 @@
 	} VectorCoordsEnum;
 
 	GLVector ();
-	GLVector (float x, float y, float z, float w = 0.0f);
+	GLVector (float x, float y, float z, float w = 1.0f);
 
 	/**
 	 * Returns a reference to the x, y, z or w value by using

=== modified file 'plugins/opengl/src/vector.cpp'
--- plugins/opengl/src/vector.cpp	2012-12-04 15:28:01 +0000
+++ plugins/opengl/src/vector.cpp	2015-03-02 09:39:43 +0000
@@ -52,7 +52,8 @@
 
 GLVector::GLVector ()
 {
-    memset (v, 0, sizeof (v));
+    v[0] = v[1] = v[2] = 0.0;
+    v[3] = 1.0;
 }
 
 GLVector::GLVector (float x,
@@ -63,7 +64,7 @@
     v[0] = x;
     v[1] = y;
     v[2] = z;
-    v[3] = w;
+    v[3] = 1.0;
 }
 
 float&
@@ -95,7 +96,7 @@
 GLVector&
 GLVector::operator+= (const GLVector& rhs)
 {
-    for (int i = 0; i < 4; i++)
+    for (int i = 0; i < 3; i++)
 	v[i] += rhs[i];
 
     return *this;
@@ -107,7 +108,7 @@
 {
     GLVector result;
 
-    for (int i = 0; i < 4; i++)
+    for (int i = 0; i < 3; i++)
 	result[i] = lhs[i] + rhs[i];
 
     return result;
@@ -116,7 +117,7 @@
 GLVector&
 GLVector::operator-= (const GLVector& rhs)
 {
-    for (int i = 0; i < 4; i++)
+    for (int i = 0; i < 3; i++)
 	v[i] -= rhs[i];
 
     return *this;
@@ -128,7 +129,7 @@
 {
     GLVector result;
 
-    for (int i = 0; i < 4; i++)
+    for (int i = 0; i < 3; i++)
 	result[i] = lhs[i] - rhs[i];
 
     return result;
@@ -139,7 +140,7 @@
 {
     GLVector result;
 
-    for (int i = 0; i < 4; i++)
+    for (int i = 0; i < 3; i++)
 	result[i] = -vector[i];
 
     return result;
@@ -148,7 +149,7 @@
 GLVector&
 GLVector::operator*= (const float k)
 {
-    for (int i = 0; i < 4; i++)
+    for (int i = 0; i < 3; i++)
 	v[i] *= k;
 
     return *this;
@@ -160,7 +161,7 @@
 {
     float result = 0;
 
-    for (int i = 0; i < 4; i++)
+    for (int i = 0; i < 3; i++)
 	result += lhs[i] * rhs[i];
 
     return result;
@@ -172,7 +173,7 @@
 {
     GLVector result;
 
-    for (int i = 0; i < 4; i++)
+    for (int i = 0; i < 3; i++)
 	result[i] = k * vector[i];
 
     return result;
@@ -188,7 +189,7 @@
 GLVector&
 GLVector::operator/= (const float k)
 {
-    for (int i = 0; i < 4; i++)
+    for (int i = 0; i < 3; i++)
 	v[i] /= k;
 
     return *this;
@@ -200,7 +201,7 @@
 {
     GLVector result;
 
-    for (int i = 0; i < 4; i++)
+    for (int i = 0; i < 3; i++)
 	result[i] = vector[i] / k;
 
     return result;
@@ -222,7 +223,7 @@
     result[0] = lhs[1] * rhs[2] - lhs[2] * rhs[1];
     result[1] = lhs[2] * rhs[0] - lhs[0] * rhs[2];
     result[2] = lhs[0] * rhs[1] - lhs[1] * rhs[0];
-    result[3] = 0.0f;
+    result[3] = 1.0f;
 
     return result;
 }
@@ -230,22 +231,20 @@
 float
 GLVector::norm ()
 {
-    if (v[3] != 0.0)
-	return 1.0;
     return sqrt ((v[0] * v[0]) + (v[1] * v[1]) + (v[2] * v[2]));
 }
 
 GLVector &
 GLVector::normalize ()
 {
-    float normal = norm ();
+    float mag = norm ();
 
-    /* Vector is not homogenous */
-    if (normal == 1.0)
+    /* avoid division by 0 */
+    if (mag == 0.0)
 	return *this;
 
     for (unsigned int i = 0; i < 3; i++)
-	v[i] /= normal;
+	v[i] /= mag;
     return *this;
 }