[PATCH weston-ivi-shell v2 01/10] This vfunc lets us read out a rectangle of pixels from the currently attached surface buffer.

[Nobuhiko Tanibata]

Signed-off-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA at xddp.denso.co.jp>
---

Changes for v2:
   - gl_renderer_read_shmbuffer_pixels to support different types of format of
     shmbuffer.

 src/compositor.h  |   3 ++
 src/gl-renderer.c | 114 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 117 insertions(+)

diff --git a/src/compositor.h b/src/compositor.h
index 22a485f..ace75da 100644
--- a/src/compositor.h
+++ b/src/compositor.h
@@ -540,6 +540,9 @@ struct weston_renderer {
 			       pixman_format_code_t format, void *pixels,
 			       uint32_t x, uint32_t y,
 			       uint32_t width, uint32_t height);
+	int (*read_surface_pixels)(struct weston_surface *es,
+				   pixman_format_code_t format, void *pixels,
+				   int x, int y, int width, int height);
 	void (*repaint_output)(struct weston_output *output,
 			       pixman_region32_t *output_damage);
 	void (*flush_damage)(struct weston_surface *surface);
diff --git a/src/gl-renderer.c b/src/gl-renderer.c
index 0e5afbe..7881fd8 100644
--- a/src/gl-renderer.c
+++ b/src/gl-renderer.c
@@ -106,6 +106,8 @@ struct gl_renderer {
 	EGLContext egl_context;
 	EGLConfig egl_config;
 
+	GLuint fbo;
+
 	struct wl_array vertices;
 	struct wl_array vtxcnt;
 
@@ -585,6 +587,114 @@ out:
 	pixman_region32_fini(&repaint);
 }
 
+static int
+gl_renderer_read_shmbuffer_pixels(struct wl_shm_buffer *shm_buffer,
+				  void *pixels, int x, int y, int width, int height)
+{
+	int i;
+	int pixel_size = 0;
+	uint8_t *ptr = NULL;
+	int32_t src_width, src_height, src_stride;
+	int32_t dst_stride;
+	int32_t offset;
+
+	/* Get some parameters of wl_shm_buffer. */
+	src_width = wl_shm_buffer_get_width(shm_buffer);
+	src_height = wl_shm_buffer_get_height(shm_buffer);
+	src_stride = wl_shm_buffer_get_stride(shm_buffer);
+
+	assert((src_width > 0) && (src_height > 0));
+	if ((src_width <= 0) || (src_height <= 0))
+		return -1;
+
+	/* the start of reading position has to be changed. */
+	ptr = wl_shm_buffer_get_data(shm_buffer);
+	ptr += y * src_stride;
+	if ((x == 0) && (width == src_width) && (height <= (src_height - y))) {
+		/* If x is 0 and widths are the same,
+		 * whole pixel can be copied in only one time.
+		 */
+		memcpy(pixels, ptr, src_stride * height);
+	} else {
+		/* If x is not 0,
+		 * every line have to be copied one by one.
+		 */
+		pixel_size = src_stride / src_width;
+		assert(pixel_size < 5);
+		if (pixel_size > 4) return -1;
+
+		dst_stride = width * pixel_size;
+		offset = x * pixel_size;
+
+		for (i = 0; i < height; i++, ptr += src_stride) {
+			memcpy(pixels, ptr + offset, dst_stride);
+			pixels = (uint8_t*)pixels + dst_stride;
+		}
+	}
+
+	return 0;
+}
+
+static int
+gl_renderer_read_glsurface_pixels(struct weston_surface *es,
+				pixman_format_code_t format, void *pixels,
+				int x, int y, int width, int height)
+{
+	struct weston_compositor *ec = es->compositor;
+	struct gl_renderer *gr = get_renderer(ec);
+	struct gl_surface_state *gs = get_surface_state(es);
+	GLenum gl_format;
+
+	switch (format) {
+	case PIXMAN_a8r8g8b8:
+		gl_format = GL_BGRA_EXT;
+		break;
+	case PIXMAN_a8b8g8r8:
+		gl_format = GL_RGBA;
+		break;
+	default:
+		return -1;
+	}
+
+	if (gr->fbo == 0)
+		glGenFramebuffers(1, &gr->fbo);
+	glBindFramebuffer(GL_FRAMEBUFFER, gr->fbo);
+	glFramebufferTexture2D(GL_FRAMEBUFFER,
+			       GL_COLOR_ATTACHMENT0,
+			       GL_TEXTURE_2D,
+			       gs->textures[0], 0);
+
+	glReadPixels(x, y, width, height,
+		     gl_format, GL_UNSIGNED_BYTE, pixels);
+
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+
+	return 0;
+}
+
+static int
+gl_renderer_read_surface_pixels(struct weston_surface *es,
+				pixman_format_code_t format, void *pixels,
+				int x, int y, int width, int height)
+{
+	struct weston_buffer *buffer = es->buffer_ref.buffer;
+	struct wl_shm_buffer *shm_buffer = NULL;
+	int ret = 0;
+
+	if (buffer) {
+		shm_buffer = wl_shm_buffer_get(buffer->resource);
+	}
+	if (shm_buffer) {
+		ret = gl_renderer_read_shmbuffer_pixels(shm_buffer,
+				   pixels, x, y, width, height);
+	} else {
+		ret = gl_renderer_read_glsurface_pixels(es,
+				   format, pixels, x, y, width, height);
+	}
+
+	return ret;
+}
+
 static void
 repaint_views(struct weston_output *output, pixman_region32_t *damage)
 {
@@ -1602,6 +1712,9 @@ gl_renderer_destroy(struct weston_compositor *ec)
 
 	wl_signal_emit(&gr->destroy_signal, gr);
 
+	if (gr->fbo)
+		glDeleteFramebuffers(1, &gr->fbo);
+
 	if (gr->has_bind_display)
 		gr->unbind_display(gr->egl_display, ec->wl_display);
 
@@ -1699,6 +1812,7 @@ gl_renderer_create(struct weston_compositor *ec, EGLNativeDisplayType display,
 		return -1;
 
 	gr->base.read_pixels = gl_renderer_read_pixels;
+	gr->base.read_surface_pixels = gl_renderer_read_surface_pixels;
 	gr->base.repaint_output = gl_renderer_repaint_output;
 	gr->base.flush_damage = gl_renderer_flush_damage;
 	gr->base.attach = gl_renderer_attach;
-- 
1.8.3.1