CHROMIUM: dri: Define DRI_MutableRenderBuffer extensions

Define extensions DRI_MutableRenderBufferDriver and
DRI_MutableRenderBufferLoader. These are the two halves for
EGL_KHR_mutable_render_buffer.

Outside the DRI code there is one additional change.  Add
gl_config::mutableRenderBuffer to match
__DRI_ATTRIB_MUTABLE_RENDER_BUFFER. Neither are used yet.

BUG=b:77899911
TEST=No android-cts-7.1 regressions on Eve.

Change-Id: I4ca03d81e4557380b19c44d8d799a7cc9365d928

1 files changed, 124 insertions, 2 deletions

diff --git a/include/GL/internal/dri_interface.h b/include/GL/internal/dri_interface.h
index 98402eae057..7d9bf032d79 100644
--- a/include/GL/internal/dri_interface.h
+++ b/include/GL/internal/dri_interface.h
@@ -48,6 +48,7 @@ typedef unsigned int drm_drawable_t;
 typedef struct drm_clip_rect drm_clip_rect_t;
 #endif
 
+#include <stdbool.h>
 #include <stdint.h>
 
 /**
@@ -704,7 +705,8 @@ struct __DRIuseInvalidateExtensionRec {
 #define __DRI_ATTRIB_BIND_TO_TEXTURE_TARGETS	46
 #define __DRI_ATTRIB_YINVERTED			47
 #define __DRI_ATTRIB_FRAMEBUFFER_SRGB_CAPABLE	48
-#define __DRI_ATTRIB_MAX			(__DRI_ATTRIB_FRAMEBUFFER_SRGB_CAPABLE + 1)
+#define __DRI_ATTRIB_MUTABLE_RENDER_BUFFER	49 /* EGL_MUTABLE_RENDER_BUFFER_BIT_KHR */
+#define __DRI_ATTRIB_MAX			50
 
 /* __DRI_ATTRIB_RENDER_TYPE */
 #define __DRI_ATTRIB_RGBA_BIT			0x01	
@@ -1810,7 +1812,48 @@ struct __DRI2rendererQueryExtensionRec {
 
 enum __DRIimageBufferMask {
    __DRI_IMAGE_BUFFER_BACK = (1 << 0),
-   __DRI_IMAGE_BUFFER_FRONT = (1 << 1)
+   __DRI_IMAGE_BUFFER_FRONT = (1 << 1),
+
+   /**
+    * A buffer shared between application and compositor. The buffer may be
+    * simultaneously accessed by each.
+    *
+    * A shared buffer is equivalent to an EGLSurface whose EGLConfig contains
+    * EGL_MUTABLE_RENDER_BUFFER_BIT_KHR and whose active EGL_RENDER_BUFFER (as
+    * opposed to any pending, requested change to EGL_RENDER_BUFFER) is
+    * EGL_SINGLE_BUFFER.
+    *
+    * If the loader returns __DRI_IMAGE_BUFFER_SHARED, then it is returned
+    * alone without accompanying back nor front buffer.
+    *
+    * The loader returns __DRI_IMAGE_BUFFER_SHARED if and only if:
+    *     - The loader supports __DRI_MUTABLE_RENDER_BUFFER_LOADER.
+    *     - The driver supports __DRI_MUTABLE_RENDER_BUFFER_DRIVER.
+    *     - The EGLConfig of the drawable EGLSurface contains
+    *       EGL_MUTABLE_RENDER_BUFFER_BIT_KHR.
+    *     - The EGLContext's EGL_RENDER_BUFFER is EGL_SINGLE_BUFFER.
+    *       Equivalently, the EGLSurface's active EGL_RENDER_BUFFER (as
+    *       opposed to any pending,requested change to EGL_RENDER_BUFFER) is
+    *       EGL_SINGLE_BUFFER.
+    *
+    * A shared buffer is similar a front buffer in that all rendering to the
+    * buffer should appear promptly on the screen. It is different from
+    * a front buffer in that its behavior is independent from the
+    * GL_DRAW_BUFFER state. Specifically, if GL_DRAW_FRAMEBUFFER is 0 and the
+    * __DRIdrawable's current buffer mask is __DRI_IMAGE_BUFFER_SHARED, then
+    * all rendering should appear promptly on the screen if GL_DRAW_BUFFER is
+    * not GL_NONE.
+    *
+    * The difference between a shared buffer and a front buffer is motivated
+    * by the constraints of Android and OpenGL ES. OpenGL ES does not support
+    * front-buffer rendering. Android's SurfaceFlinger protocol provides the
+    * EGL driver only a back buffer and no front buffer. The shared buffer
+    * mode introduced by EGL_KHR_mutable_render_buffer is a backdoor though
+    * EGL that allows Android OpenGL ES applications to render to what is
+    * effectively the front buffer, a backdoor that required no change to the
+    * OpenGL ES API and little change to the SurfaceFlinger API.
+    */
+   __DRI_IMAGE_BUFFER_SHARED = (1 << 2),
 };
 
 struct __DRIimageList {
@@ -1949,4 +1992,83 @@ struct __DRIbackgroundCallableExtensionRec {
    GLboolean (*isThreadSafe)(void *loaderPrivate);
 };
 
+/**
+ * The driver portion of EGL_KHR_mutable_render_buffer.
+ *
+ * If the driver creates a __DRIconfig with
+ * __DRI_ATTRIB_MUTABLE_RENDER_BUFFER, then it must support this extension.
+ *
+ * To support this extension:
+ *
+ *    - The driver should create at least one __DRIconfig with
+ *      __DRI_ATTRIB_MUTABLE_RENDER_BUFFER. This is strongly recommended but
+ *      not required.
+ *
+ *    - The driver must be able to handle __DRI_IMAGE_BUFFER_SHARED if
+ *      returned by __DRIimageLoaderExtension:getBuffers().
+ *
+ *    - When rendering to __DRI_IMAGE_BUFFER_SHARED, it must call
+ *      __DRImutableRenderBufferLoaderExtension::displaySharedBuffer() on each
+ *      application-initiated flush. This includes glFlush, glFinish,
+ *      GL_SYNC_FLUSH_COMMANDS_BIT, EGL_SYNC_FLUSH_COMMANDS_BIT, and possibly
+ *      more. (Android applications expect that glFlush will immediately
+ *      display the buffer when in shared buffer mode because that is common
+ *      behavior among Android drivers). It :may: call displaySharedBuffer()
+ *      more often than required.
+ *
+ *    - When rendering to __DRI_IMAGE_BUFFER_SHARED, it must ensure that the
+ *      buffer is always in a format compatible for display because the
+ *      display engine (usually SurfaceFlinger or hwcomposer) may display the
+ *      image at any time, even concurrently with 3D rendering. For example,
+ *      display hardware and the GL hardware may be able to access the buffer
+ *      simultaneously. In particular, if the buffer is compressed than take
+ *      care that SurfaceFlinger and hwcomposer can consume the compression
+ *      format.
+ *
+ * \see __DRI_IMAGE_BUFFER_SHARED
+ * \see __DRI_ATTRIB_MUTABLE_RENDER_BUFFER
+ * \see __DRI_MUTABLE_RENDER_BUFFER_LOADER
+ */
+#define __DRI_MUTABLE_RENDER_BUFFER_DRIVER "DRI_MutableRenderBufferDriver"
+#define __DRI_MUTABLE_RENDER_BUFFER_DRIVER_VERSION 1
+
+typedef struct __DRImutableRenderBufferDriverExtensionRec __DRImutableRenderBufferDriverExtension;
+struct __DRImutableRenderBufferDriverExtensionRec {
+   __DRIextension base;
+};
+
+/**
+ * The loader portion of EGL_KHR_mutable_render_buffer.
+ *
+ * Requires loader extension DRI_IMAGE_LOADER, through which the loader sends
+ * __DRI_IMAGE_BUFFER_SHARED to the driver.
+ *
+ * \see __DRI_MUTABLE_RENDER_BUFFER_DRIVER
+ */
+#define __DRI_MUTABLE_RENDER_BUFFER_LOADER "DRI_MutableRenderBufferLoader"
+#define __DRI_MUTABLE_RENDER_BUFFER_LOADER_VERSION 1
+
+typedef struct __DRImutableRenderBufferLoaderExtensionRec __DRImutableRenderBufferLoaderExtension;
+struct __DRImutableRenderBufferLoaderExtensionRec {
+   __DRIextension base;
+
+   /**
+    * Inform the display engine (usually SurfaceFlinger or hwcomposer)
+    * that the __DRIdrawable has new content. The display engine may ignore
+    * this, for example, if it continually refreshes and displays the buffer
+    * on every frame, as in EGL_ANDROID_front_buffer_auto_refresh. On the
+    * other extreme, the display engine may refresh and display the buffer
+    * only in frames in which the driver calls this.
+    *
+    * If the fence_fd is not -1, then the display engine will display the
+    * buffer only after the fence signals.
+    *
+    * The drawable's current __DRIimageBufferMask, as returned by
+    * __DRIimageLoaderExtension::getBuffers(), must contain
+    * __DRI_IMAGE_BUFFER_SHARED.
+    */
+   void (*displaySharedBuffer)(__DRIdrawable *drawable, int fence_fd,
+                               void *loaderPrivate);
+};
+
 #endif