cogl: removes unused _cogl_setup_viewport

Clutter has now taken responsibility for managing its viewport,
projection matrix and view transform as part of ClutterStage so
_cogl_setup_viewport is no longer used by anything, and since it's quite
an obscure API anyway it's we've taken the opportunity to remove the
function.

cogl/cogl.c

@@ -411,80 +411,6 @@ cogl_viewport (unsigned int width,
   cogl_set_viewport (0, 0, width, height);
 }
 
-void
-_cogl_setup_viewport (unsigned int width,
-                      unsigned int height,
-                      float fovy,
-                      float aspect,
-                      float z_near,
-                      float z_far)
-{
-  float z_camera;
-  CoglMatrix projection_matrix;
-  CoglMatrixStack *modelview_stack;
-
-  _COGL_GET_CONTEXT (ctx, NO_RETVAL);
-
-  cogl_set_viewport (0, 0, width, height);
-
-  /* For Ortho projection.
-   * _cogl_matrix_stack_ortho (projection_stack, 0, width, 0,  height, -1, 1);
-   */
-
-  cogl_perspective (fovy, aspect, z_near, z_far);
-
-  /*
-   * In theory, we can compute the camera distance from screen as:
-   *
-   *   0.5 * tan (FOV)
-   *
-   * However, it's better to compute the z_camera from our projection
-   * matrix so that we get a 1:1 mapping at the screen distance. Consider
-   * the upper-left corner of the screen. It has object coordinates
-   * (0,0,0), so by the transform below, ends up with eye coordinate
-   *
-   *   x_eye = x_object / width - 0.5 = - 0.5
-   *   y_eye = (height - y_object) / width - 0.5 = 0.5
-   *   z_eye = z_object / width - z_camera = - z_camera
-   *
-   * From cogl_perspective(), we know that the projection matrix has
-   * the form:
-   *
-   *  (x, 0,  0, 0)
-   *  (0, y,  0, 0)
-   *  (0, 0,  c, d)
-   *  (0, 0, -1, 0)
-   *
-   * Applied to the above, we get clip coordinates of
-   *
-   *  x_clip = x * (- 0.5)
-   *  y_clip = y * 0.5
-   *  w_clip = - 1 * (- z_camera) = z_camera
-   *
-   * Dividing through by w to get normalized device coordinates, we
-   * have, x_nd = x * 0.5 / z_camera, y_nd = - y * 0.5 / z_camera.
-   * The upper left corner of the screen has normalized device coordinates,
-   * (-1, 1), so to have the correct 1:1 mapping, we have to have:
-   *
-   *   z_camera = 0.5 * x = 0.5 * y
-   *
-   * If x != y, then we have a non-uniform aspect ration, and a 1:1 mapping
-   * doesn't make sense.
-   */
-
-  cogl_get_projection_matrix (&projection_matrix);
-  z_camera = 0.5 * projection_matrix.xx;
-
-  modelview_stack =
-    _cogl_framebuffer_get_modelview_stack (_cogl_get_framebuffer ());
-  _cogl_matrix_stack_load_identity (modelview_stack);
-  _cogl_matrix_stack_translate (modelview_stack, -0.5f, -0.5f, -z_camera);
-  _cogl_matrix_stack_scale (modelview_stack,
-                            1.0f / width, -1.0f / height, 1.0f / width);
-  _cogl_matrix_stack_translate (modelview_stack,
-                                0.0f, -1.0 * height, 0.0f);
-}
-
 CoglFeatureFlags
 cogl_get_features (void)
 {

cogl/cogl.h

@@ -290,32 +290,6 @@ cogl_ortho (float left,
             float near,
             float far);
 
-/*
- * _cogl_setup_viewport:
- * @width: Width of the viewport
- * @height: Height of the viewport
- * @fovy: Field of view angle in degrees
- * @aspect: Aspect ratio to determine the field of view along the x-axis
- * @z_near: Nearest visible point along the z-axis
- * @z_far: Furthest visible point along the z-axis
- *
- * Replaces the current viewport and projection matrix with the given
- * values. The viewport is placed at the top left corner of the window
- * with the given width and height. The projection matrix is replaced
- * with one that has a viewing angle of @fovy along the y-axis and a
- * view scaled according to @aspect along the x-axis. The view is
- * clipped according to @z_near and @z_far on the z-axis.
- *
- * This function is used only by Clutter.
- */
-void
-_cogl_setup_viewport (unsigned int width,
-                      unsigned int height,
-                      float fovy,
-                      float aspect,
-                      float z_near,
-                      float z_far);
-
 #ifndef COGL_DISABLE_DEPRECATED
 
 /**