[mutter/gbsneto/graphene2: 30/45] cogl/matrix: Frustum with graphene

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 10f1d3118cb70655b2e7212f72726f3f7e114694
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Wed Feb 27 19:00:02 2019 -0300

    cogl/matrix: Frustum with graphene

 cogl/cogl/cogl-matrix.c | 46 ++++++++++------------------------------------
 1 file changed, 10 insertions(+), 36 deletions(-)
---
diff --git a/cogl/cogl/cogl-matrix.c b/cogl/cogl/cogl-matrix.c
index 9953ab4ea..99e455201 100644
--- a/cogl/cogl/cogl-matrix.c
+++ b/cogl/cogl/cogl-matrix.c
@@ -392,41 +392,6 @@ cogl_matrix_rotate_euler (CoglMatrix *matrix,
   cogl_matrix_multiply (matrix, matrix, &rotation_transform);
 }
 
-/*
- * Apply a perspective projection matrix.
- *
- * Creates the projection matrix and multiplies it with matrix, marking the
- * MAT_FLAG_PERSPECTIVE flag.
- */
-static void
-_cogl_matrix_frustum (CoglMatrix *matrix,
-                      float left,
-                      float right,
-                      float bottom,
-                      float top,
-                      float nearval,
-                      float farval)
-{
-  float x, y, a, b, c, d;
-  float m[16];
-
-  x = (2.0f * nearval) / (right - left);
-  y = (2.0f * nearval) / (top - bottom);
-  a = (right + left) / (right - left);
-  b = (top + bottom) / (top - bottom);
-  c = -(farval + nearval) / ( farval - nearval);
-  d = -(2.0f * farval * nearval) / (farval - nearval);  /* error? */
-
-#define M(row,col)  m[col*4+row]
-  M (0,0) = x;     M (0,1) = 0.0f;  M (0,2) = a;      M (0,3) = 0.0f;
-  M (1,0) = 0.0f;  M (1,1) = y;     M (1,2) = b;      M (1,3) = 0.0f;
-  M (2,0) = 0.0f;  M (2,1) = 0.0f;  M (2,2) = c;      M (2,3) = d;
-  M (3,0) = 0.0f;  M (3,1) = 0.0f;  M (3,2) = -1.0f;  M (3,3) = 0.0f;
-#undef M
-
-  matrix_multiply_array_with_flags (matrix, m);
-}
-
 void
 cogl_matrix_frustum (CoglMatrix *matrix,
                      float       left,
@@ -436,7 +401,16 @@ cogl_matrix_frustum (CoglMatrix *matrix,
                      float       z_near,
                      float       z_far)
 {
-  _cogl_matrix_frustum (matrix, left, right, bottom, top, z_near, z_far);
+  graphene_matrix_t frustum, m;
+
+  graphene_matrix_init_frustum (&frustum, left, right, bottom, top, z_near, z_far);
+
+  cogl_matrix_to_graphene_matrix (matrix, &m);
+  graphene_matrix_transpose (&m, &m);
+
+  graphene_matrix_multiply (&m, &frustum, &m);
+  graphene_matrix_to_cogl_matrix (&m, matrix);
+
   _COGL_MATRIX_DEBUG_PRINT (matrix);
 }