From d16df5a5aab126d8114b932ba8abab05ff242026 Mon Sep 17 00:00:00 2001

From: "Owen W. Taylor" <otaylor@fishsoup.net>

Date: Mon, 28 Apr 2014 12:37:32 -0400

Subject: [PATCH] Add support for setting up stereo CoglOnscreens

If we want to show quad-buffer stereo with Cogl, we need to pick an

appropriate fbconfig for creating the CoglOnscreen objects. Add

cogl_onscreen_template_set_stereo_enabled() to indicate whether

stereo support is needed.

Add cogl_framebuffer_get_stereo_mode() to see if a framebuffer was

created with stereo support.

Add cogl_framebuffer_get_stereo_mode() to pick whether to draw to

the left, right, or both buffers.

Reviewed-by: Robert Bragg <robert.bragg@intel.com>

---

 cogl/cogl-context-private.h                     |  1 +

 cogl/cogl-framebuffer-private.h                 |  8 +++-

 cogl/cogl-framebuffer.c                         | 41 +++++++++++++++++++

 cogl/cogl-framebuffer.h                         | 52 +++++++++++++++++++++++++

 cogl/cogl-onscreen-template.c                   |  8 ++++

 cogl/cogl-onscreen-template.h                   | 18 +++++++++

 cogl/cogl-types.h                               | 15 +++++++

 cogl/driver/gl/cogl-framebuffer-gl.c            | 36 +++++++++++++++++

 cogl/winsys/cogl-winsys-glx-feature-functions.h |  1 +

 cogl/winsys/cogl-winsys-glx.c                   |  8 +++-

 10 files changed, 185 insertions(+), 3 deletions(-)

diff --git a/cogl/cogl-context-private.h b/cogl/cogl-context-private.h

index 1000ee5..9e66207 100644

--- a/cogl/cogl-context-private.h

+++ b/cogl/cogl-context-private.h

@@ -270,6 +270,7 @@ struct _CoglContext

   CoglBool current_gl_dither_enabled;

   CoglColorMask current_gl_color_mask;

+  GLenum current_gl_draw_buffer;

   /* Clipping */

   /* TRUE if we have a valid clipping stack flushed. In that case

diff --git a/cogl/cogl-framebuffer-private.h b/cogl/cogl-framebuffer-private.h

index 4891d53..99ac2fb 100644

--- a/cogl/cogl-framebuffer-private.h

+++ b/cogl/cogl-framebuffer-private.h

@@ -61,6 +61,7 @@ typedef struct

   int samples_per_pixel;

   CoglBool swap_throttled;

   CoglBool depth_texture_enabled;

+  CoglBool stereo_enabled;

 } CoglFramebufferConfig;

 /* Flags to pass to _cogl_offscreen_new_with_texture_full */

@@ -86,7 +87,8 @@ typedef enum _CoglFramebufferStateIndex

   COGL_FRAMEBUFFER_STATE_INDEX_COLOR_MASK         = 6,

   COGL_FRAMEBUFFER_STATE_INDEX_FRONT_FACE_WINDING = 7,

   COGL_FRAMEBUFFER_STATE_INDEX_DEPTH_WRITE        = 8,

-  COGL_FRAMEBUFFER_STATE_INDEX_MAX                = 9

+  COGL_FRAMEBUFFER_STATE_INDEX_STEREO_MODE        = 9,

+  COGL_FRAMEBUFFER_STATE_INDEX_MAX                = 10

 } CoglFramebufferStateIndex;

 typedef enum _CoglFramebufferState

@@ -99,7 +101,8 @@ typedef enum _CoglFramebufferState

   COGL_FRAMEBUFFER_STATE_PROJECTION         = 1<<5,

   COGL_FRAMEBUFFER_STATE_COLOR_MASK         = 1<<6,

   COGL_FRAMEBUFFER_STATE_FRONT_FACE_WINDING = 1<<7,

-  COGL_FRAMEBUFFER_STATE_DEPTH_WRITE        = 1<<8

+  COGL_FRAMEBUFFER_STATE_DEPTH_WRITE        = 1<<8,

+  COGL_FRAMEBUFFER_STATE_STEREO_MODE        = 1<<9

 } CoglFramebufferState;

 #define COGL_FRAMEBUFFER_STATE_ALL ((1<

@@ -154,6 +157,7 @@ struct _CoglFramebuffer

   CoglBool            dither_enabled;

   CoglBool            depth_writing_enabled;

   CoglColorMask       color_mask;

+  CoglStereoMode      stereo_mode;

   /* We journal the textured rectangles we want to submit to OpenGL so

    * we have an oppertunity to batch them together into less draw

diff --git a/cogl/cogl-framebuffer.c b/cogl/cogl-framebuffer.c

index 135b873..1f70d3d 100644

--- a/cogl/cogl-framebuffer.c

+++ b/cogl/cogl-framebuffer.c

@@ -907,6 +907,14 @@ _cogl_framebuffer_compare_depth_write_state (CoglFramebuffer *a,

     COGL_FRAMEBUFFER_STATE_DEPTH_WRITE : 0;

 }

+static unsigned long

+_cogl_framebuffer_compare_stereo_mode (CoglFramebuffer *a,

+				       CoglFramebuffer *b)

+{

+  return a->stereo_mode != b->stereo_mode ?

+    COGL_FRAMEBUFFER_STATE_STEREO_MODE : 0;

+}

+

 unsigned long

 _cogl_framebuffer_compare (CoglFramebuffer *a,

                            CoglFramebuffer *b,

@@ -959,6 +967,10 @@ _cogl_framebuffer_compare (CoglFramebuffer *a,

           differences |=

             _cogl_framebuffer_compare_depth_write_state (a, b);

           break;

+        case COGL_FRAMEBUFFER_STATE_INDEX_STEREO_MODE:

+          differences |=

+            _cogl_framebuffer_compare_stereo_mode (a, b);

+          break;

         default:

           g_warn_if_reached ();

         }

@@ -1046,6 +1058,12 @@ _cogl_framebuffer_get_stencil_bits (CoglFramebuffer *framebuffer)

   return bits.stencil;

 }

+gboolean

+cogl_framebuffer_get_is_stereo (CoglFramebuffer *framebuffer)

+{

+  return framebuffer->config.stereo_enabled;

+}

+

 CoglColorMask

 cogl_framebuffer_get_color_mask (CoglFramebuffer *framebuffer)

 {

@@ -1069,6 +1087,29 @@ cogl_framebuffer_set_color_mask (CoglFramebuffer *framebuffer,

       COGL_FRAMEBUFFER_STATE_COLOR_MASK;

 }

+CoglStereoMode

+cogl_framebuffer_get_stereo_mode (CoglFramebuffer *framebuffer)

+{

+  return framebuffer->stereo_mode;

+}

+

+void

+cogl_framebuffer_set_stereo_mode (CoglFramebuffer *framebuffer,

+				  CoglStereoMode   stereo_mode)

+{

+  if (framebuffer->stereo_mode == stereo_mode)

+    return;

+

+  /* Stereo mode changes don't go through the journal */

+  _cogl_framebuffer_flush_journal (framebuffer);

+

+  framebuffer->stereo_mode = stereo_mode;

+

+  if (framebuffer->context->current_draw_buffer == framebuffer)

+    framebuffer->context->current_draw_buffer_changes |=

+      COGL_FRAMEBUFFER_STATE_STEREO_MODE;

+}

+

 CoglBool

 cogl_framebuffer_get_depth_write_enabled (CoglFramebuffer *framebuffer)

 {

diff --git a/cogl/cogl-framebuffer.h b/cogl/cogl-framebuffer.h

index 347284f..58d65a8 100644

--- a/cogl/cogl-framebuffer.h

+++ b/cogl/cogl-framebuffer.h

@@ -737,6 +737,23 @@ cogl_framebuffer_get_alpha_bits (CoglFramebuffer *framebuffer);

 int

 cogl_framebuffer_get_depth_bits (CoglFramebuffer *framebuffer);

+/*

+ * cogl_framebuffer_get_is_stereo:

+ * @framebuffer: a pointer to a #CoglFramebuffer

+ *

+ * Retrieves whether @framebuffer has separate left and right

+ * buffers for use with stereo drawing. See

+ * cogl_framebuffer_set_stereo_mode().

+ *

+ * Return value: %TRUE if @framebuffer has separate left and

+ * right buffers.

+ *

+ * Since: 1.20

+ * Stability: unstable

+ */

+CoglBool

+cogl_framebuffer_get_is_stereo (CoglFramebuffer *framebuffer);

+

 /**

  * cogl_framebuffer_get_dither_enabled:

  * @framebuffer: a pointer to a #CoglFramebuffer

@@ -847,6 +864,41 @@ cogl_framebuffer_set_color_mask (CoglFramebuffer *framebuffer,

                                  CoglColorMask color_mask);

 /**

+ * cogl_framebuffer_get_stereo_mode:

+ * @framebuffer: a pointer to a #CoglFramebuffer

+ *

+ * Gets the current #CoglStereoMode, which defines which stereo buffers

+ * should be drawn to. See cogl_framebuffer_set_stereo_mode().

+ *

+ * Returns: A #CoglStereoMode

+ * Since: 1.20

+ * Stability: unstable

+ */

+CoglStereoMode

+cogl_framebuffer_get_stereo_mode (CoglFramebuffer *framebuffer);

+

+/**

+ * cogl_framebuffer_set_stereo_mode:

+ * @framebuffer: a pointer to a #CoglFramebuffer

+ * @stereo_mode: A #CoglStereoMode specifying which stereo buffers

+ *               should be drawn tow.

+ *

+ * Sets which stereo buffers should be drawn to. The default

+ * is %COGL_STEREO_BOTH, which means that both the left and

+ * right buffers will be affected by drawing. For this to have

+ * an effect, the display system must support stereo drawables,

+ * and the framebuffer must have been created with stereo

+ * enabled. (See cogl_onscreen_template_set_stereo_enabled(),

+ * cogl_framebuffer_get_is_stereo().)

+ *

+ * Since: 1.20

+ * Stability: unstable

+ */

+void

+cogl_framebuffer_set_stereo_mode (CoglFramebuffer *framebuffer,

+				  CoglStereoMode stereo_mode);

+

+/**

  * cogl_framebuffer_set_depth_texture_enabled:

  * @framebuffer: A #CoglFramebuffer

  * @enabled: TRUE or FALSE

diff --git a/cogl/cogl-onscreen-template.c b/cogl/cogl-onscreen-template.c

index 5a5e54c..3940627 100644

--- a/cogl/cogl-onscreen-template.c

+++ b/cogl/cogl-onscreen-template.c

@@ -95,3 +95,11 @@ cogl_onscreen_template_set_swap_throttled (

 {

   onscreen_template->config.swap_throttled = throttled;

 }

+

+void

+cogl_onscreen_template_set_stereo_enabled (

+					   CoglOnscreenTemplate *onscreen_template,

+					   CoglBool enabled)

+{

+  onscreen_template->config.stereo_enabled = enabled;

+}

diff --git a/cogl/cogl-onscreen-template.h b/cogl/cogl-onscreen-template.h

index cd1d853..d8714fa 100644

--- a/cogl/cogl-onscreen-template.h

+++ b/cogl/cogl-onscreen-template.h

@@ -107,6 +107,24 @@ cogl_onscreen_template_set_swap_throttled (

                                           CoglBool throttled);

 /**

+ * cogl_onscreen_template_set_stereo_enabled:

+ * @onscreen_template: A #CoglOnscreenTemplate template framebuffer

+ * @enabled: Whether framebuffers are created with stereo buffers

+ *

+ * Sets whether future #CoglOnscreen framebuffers derived from this

+ * template are attempted to be created with both left and right

+ * buffers, for use with stereo display. If the display system

+ * does not support stereo, then creation of the framebuffer will

+ * fail.

+ *

+ * Since: 1.20

+ * Stability: unstable

+ */

+void

+cogl_onscreen_template_set_stereo_enabled (

+					   CoglOnscreenTemplate *onscreen_template,

+					   CoglBool enabled);

+/**

  * cogl_is_onscreen_template:

  * @object: A #CoglObject pointer

  *

diff --git a/cogl/cogl-types.h b/cogl/cogl-types.h

index b4d79c7..6accf8d 100644

--- a/cogl/cogl-types.h

+++ b/cogl/cogl-types.h

@@ -920,6 +920,21 @@ typedef enum { /*< prefix=COGL_READ_PIXELS >*/

   COGL_READ_PIXELS_COLOR_BUFFER = 1L << 0

 } CoglReadPixelsFlags;

+/**

+ * CoglStereoMode:

+ * @COGL_STEREO_BOTH: draw to both stereo buffers

+ * @COGL_STEREO_LEFT: draw only to the left stereo buffer

+ * @COGL_STEREO_RIGHT: draw only to the left stereo buffer

+ *

+ * Represents how draw should affect the two buffers

+ * of a stereo framebuffer. See cogl_framebuffer_set_stereo_mode().

+ */

+typedef enum {

+  COGL_STEREO_BOTH,

+  COGL_STEREO_LEFT,

+  COGL_STEREO_RIGHT

+} CoglStereoMode;

+

 COGL_END_DECLS

 #endif /* __COGL_TYPES_H__ */

diff --git a/cogl/driver/gl/cogl-framebuffer-gl.c b/cogl/driver/gl/cogl-framebuffer-gl.c

index c0f094d..793b10b 100644

--- a/cogl/driver/gl/cogl-framebuffer-gl.c

+++ b/cogl/driver/gl/cogl-framebuffer-gl.c

@@ -236,6 +236,39 @@ _cogl_framebuffer_gl_flush_front_face_winding_state (CoglFramebuffer *framebuffe

   context->current_pipeline_age--;

 }

+static void

+_cogl_framebuffer_gl_flush_stereo_mode_state (CoglFramebuffer *framebuffer)

+{

+  CoglContext *ctx = framebuffer->context;

+  GLenum draw_buffer = GL_BACK;

+

+  if (framebuffer->type == COGL_FRAMEBUFFER_TYPE_OFFSCREEN)

+    return;

+

+  /* The one-shot default draw buffer setting in _cogl_framebuffer_gl_bind

+   * must have already happened. If not it would override what we set here. */

+  g_assert (ctx->was_bound_to_onscreen);

+

+  switch (framebuffer->stereo_mode)

+    {

+    case COGL_STEREO_BOTH:

+      draw_buffer = GL_BACK;

+      break;

+    case COGL_STEREO_LEFT:

+      draw_buffer = GL_BACK_LEFT;

+      break;

+    case COGL_STEREO_RIGHT:

+      draw_buffer = GL_BACK_RIGHT;

+      break;

+    }

+

+  if (ctx->current_gl_draw_buffer != draw_buffer)

+    {

+      GE (ctx, glDrawBuffer (draw_buffer));

+      ctx->current_gl_draw_buffer = draw_buffer;

+    }

+}

+

 void

 _cogl_framebuffer_gl_bind (CoglFramebuffer *framebuffer, GLenum target)

 {

@@ -406,6 +439,9 @@ _cogl_framebuffer_gl_flush_state (CoglFramebuffer *draw_buffer,

           /* Nothing to do for depth write state change; the state will always

            * be taken into account when flushing the pipeline's depth state. */

           break;

+        case COGL_FRAMEBUFFER_STATE_INDEX_STEREO_MODE:

+          _cogl_framebuffer_gl_flush_stereo_mode_state (draw_buffer);

+          break;

         default:

           g_warn_if_reached ();

         }

diff --git a/cogl/winsys/cogl-winsys-glx-feature-functions.h b/cogl/winsys/cogl-winsys-glx-feature-functions.h

index 1e2cec1..ed9df70 100644

--- a/cogl/winsys/cogl-winsys-glx-feature-functions.h

+++ b/cogl/winsys/cogl-winsys-glx-feature-functions.h

@@ -184,6 +184,7 @@ COGL_WINSYS_FEATURE_BEGIN (255, 255,

                            "swap_event\0",

                            0,

                            COGL_WINSYS_FEATURE_SYNC_AND_COMPLETE_EVENT)

+

 COGL_WINSYS_FEATURE_END ()

 COGL_WINSYS_FEATURE_BEGIN (255, 255,

diff --git a/cogl/winsys/cogl-winsys-glx.c b/cogl/winsys/cogl-winsys-glx.c

index 3095acf..bf2b5be 100644

--- a/cogl/winsys/cogl-winsys-glx.c

+++ b/cogl/winsys/cogl-winsys-glx.c

@@ -909,6 +909,11 @@ glx_attributes_from_framebuffer_config (CoglDisplay *display,

   attributes[i++] = 1;

   attributes[i++] = GLX_STENCIL_SIZE;

   attributes[i++] = config->need_stencil ? 1: GLX_DONT_CARE;

+  if (config->stereo_enabled)

+    {

+      attributes[i++] = GLX_STEREO;

+      attributes[i++] = TRUE;

+    }

   if (glx_renderer->glx_major == 1 && glx_renderer->glx_minor >= 4 &&

       config->samples_per_pixel)

@@ -948,6 +953,7 @@ find_fbconfig (CoglDisplay *display,

                                              xscreen_num,

                                              attributes,

                                              &n_configs);

+

   if (!configs || n_configs == 0)

     {

       _cogl_set_error (error, COGL_WINSYS_ERROR,

@@ -1856,7 +1862,7 @@ _cogl_winsys_onscreen_swap_region (CoglOnscreen *onscreen,

                                       rect[0], rect[1], x2, y2,

                                       GL_COLOR_BUFFER_BIT, GL_NEAREST);

         }

-      context->glDrawBuffer (GL_BACK);

+      context->glDrawBuffer (context->current_gl_draw_buffer);

     }

   /* NB: unlike glXSwapBuffers, glXCopySubBuffer and

-- 

2.1.0