From de6c39189f4b3fc615a6778984a60e895e9d18cb Mon Sep 17 00:00:00 2001
From: Matthew Waters <matthew@centricular.com>
Date: Fri, 13 Jan 2017 11:06:39 +1100
Subject: [PATCH] glutils: privatise matrix
 multiplication/videoaffinetransformation retrieval

---
 ext/gl/gstglutils.c                  | 60 ++++++++++++++++++++++++++++
 ext/gl/gstglutils.h                  |  3 ++
 gst-libs/gst/gl/gstglutils.c         |  2 +-
 gst-libs/gst/gl/gstglutils.h         |  6 ---
 gst-libs/gst/gl/gstglutils_private.h |  1 +
 gst-libs/gst/gl/gstglviewconvert.c   |  1 +
 6 files changed, 66 insertions(+), 7 deletions(-)

diff --git a/ext/gl/gstglutils.c b/ext/gl/gstglutils.c
index ca5e8ab06c..224923c15b 100644
--- a/ext/gl/gstglutils.c
+++ b/ext/gl/gstglutils.c
@@ -105,3 +105,63 @@ gst_gl_context_gen_shader (GstGLContext * context, const gchar * vert_src,
 
   return *shader != NULL;
 }
+
+static const gfloat identity_matrix[] = {
+  1.0f, 0.0f, 0.0, 0.0f,
+  0.0f, 1.0f, 0.0, 0.0f,
+  0.0f, 0.0f, 1.0, 0.0f,
+  0.0f, 0.0f, 0.0, 1.0f,
+};
+
+static const gfloat from_ndc_matrix[] = {
+  0.5f, 0.0f, 0.0, 0.5f,
+  0.0f, 0.5f, 0.0, 0.5f,
+  0.0f, 0.0f, 0.5, 0.5f,
+  0.0f, 0.0f, 0.0, 1.0f,
+};
+
+static const gfloat to_ndc_matrix[] = {
+  2.0f, 0.0f, 0.0, -1.0f,
+  0.0f, 2.0f, 0.0, -1.0f,
+  0.0f, 0.0f, 2.0, -1.0f,
+  0.0f, 0.0f, 0.0, 1.0f,
+};
+
+void
+gst_gl_multiply_matrix4 (const gfloat * a, const gfloat * b, gfloat * result)
+{
+  int i, j, k;
+  gfloat tmp[16] = { 0.0f };
+
+  if (!a || !b || !result)
+    return;
+
+  for (i = 0; i < 4; i++) {
+    for (j = 0; j < 4; j++) {
+      for (k = 0; k < 4; k++) {
+        tmp[i + (j * 4)] += a[i + (k * 4)] * b[k + (j * 4)];
+      }
+    }
+  }
+
+  for (i = 0; i < 16; i++)
+    result[i] = tmp[i];
+}
+
+void
+gst_gl_get_affine_transformation_meta_as_ndc (GstVideoAffineTransformationMeta *
+    meta, gfloat * matrix)
+{
+  if (!meta) {
+    int i;
+
+    for (i = 0; i < 16; i++) {
+      matrix[i] = identity_matrix[i];
+    }
+  } else {
+    gfloat tmp[16] = { 0.0f };
+
+    gst_gl_multiply_matrix4 (from_ndc_matrix, meta->matrix, tmp);
+    gst_gl_multiply_matrix4 (tmp, to_ndc_matrix, matrix);
+  }
+}
diff --git a/ext/gl/gstglutils.h b/ext/gl/gstglutils.h
index ee7d4c6982..5c9de83d64 100644
--- a/ext/gl/gstglutils.h
+++ b/ext/gl/gstglutils.h
@@ -28,6 +28,9 @@ G_BEGIN_DECLS
 gboolean gst_gl_context_gen_shader (GstGLContext * context,
     const gchar * shader_vertex_source,
     const gchar * shader_fragment_source, GstGLShader ** shader);
+void gst_gl_multiply_matrix4 (const gfloat * a, const gfloat * b, gfloat * result);
+void gst_gl_get_affine_transformation_meta_as_ndc (GstVideoAffineTransformationMeta *
+    meta, gfloat * matrix);
 
 G_END_DECLS
 
diff --git a/gst-libs/gst/gl/gstglutils.c b/gst-libs/gst/gl/gstglutils.c
index b41ed8f4fd..fb19156507 100644
--- a/gst-libs/gst/gl/gstglutils.c
+++ b/gst-libs/gst/gl/gstglutils.c
@@ -722,7 +722,7 @@ static const gfloat to_ndc_matrix[] = {
   0.0f, 0.0f, 0.0, 1.0f,
 };
 
-void
+static void
 gst_gl_multiply_matrix4 (const gfloat * a, const gfloat * b, gfloat * result)
 {
   int i, j, k;
diff --git a/gst-libs/gst/gl/gstglutils.h b/gst-libs/gst/gl/gstglutils.h
index e1207aafa7..4139302c2b 100644
--- a/gst-libs/gst/gl/gstglutils.h
+++ b/gst-libs/gst/gl/gstglutils.h
@@ -56,12 +56,6 @@ gboolean gst_gl_value_set_texture_target (GValue * value, GstGLTextureTarget tar
 GST_EXPORT
 GstGLTextureTarget gst_gl_value_get_texture_target_mask (const GValue * value);
 
-GST_EXPORT
-void gst_gl_multiply_matrix4 (const gfloat * a, const gfloat * b, gfloat * result);
-GST_EXPORT
-void gst_gl_get_affine_transformation_meta_as_ndc (GstVideoAffineTransformationMeta *
-    meta, gfloat * matrix);
-
 G_END_DECLS
 
 #endif /* __GST_GL_UTILS_H__ */
diff --git a/gst-libs/gst/gl/gstglutils_private.h b/gst-libs/gst/gl/gstglutils_private.h
index 9321d8d7af..008fcc6dcb 100644
--- a/gst-libs/gst/gl/gstglutils_private.h
+++ b/gst-libs/gst/gl/gstglutils_private.h
@@ -26,6 +26,7 @@
 G_BEGIN_DECLS
 
 gboolean gst_gl_run_query (GstElement * element, GstQuery * query, GstPadDirection direction);
+void gst_gl_get_affine_transformation_meta_as_ndc (GstVideoAffineTransformationMeta * meta, gfloat * matrix);
 
 G_END_DECLS
 
diff --git a/gst-libs/gst/gl/gstglviewconvert.c b/gst-libs/gst/gl/gstglviewconvert.c
index 11a98f2ae9..64c64f7ed9 100644
--- a/gst-libs/gst/gl/gstglviewconvert.c
+++ b/gst-libs/gst/gl/gstglviewconvert.c
@@ -34,6 +34,7 @@
 
 #include "gstglviewconvert.h"
 #include "gstglsl_private.h"
+#include "gstglutils_private.h"
 #include <gst/video/gstvideoaffinetransformationmeta.h>
 
 #define USING_OPENGL(context) (gst_gl_context_check_gl_version (context, GST_GL_API_OPENGL, 1, 0))