src/: Refactor to not use gbm bo explicitly.

There are two ways to do rendering, with:

 * gbm_bo_create + eglCreateImageKHR -> gl rendererbuffer (doable, but not what most users do), or
 * gbm_surface_create + EGLSurface -> egl surface rendering + gbm_surface_lock_front_buffer + eglCreateImageKHR

We were confused before doing both opposing mechanisms and so,
we pick the latter here of 'gbm_surface+EGLSurface+eglSwapBuffers'.

Signed-off-by: Edward O'Callaghan <funfunctor@folklore1984.net>

5 files changed, 23 insertions, 47 deletions

diff --git a/src/common.h b/src/common.h
index 7f3ecf2..6c168f1 100644
--- a/src/common.h
+++ b/src/common.h
@@ -27,7 +27,6 @@ struct drm_fb {
 	uint32_t handle; /** a DRM handle to the buffer object that we can draw into */
 
 	/* Used by gbm fbs */
-	struct gbm_bo *bo;
 	struct gbm_device *gbm_dev;
 	struct gbm_surface *gbm_surface;
 	/* Used by dumb fbs */
diff --git a/src/framebuffer.c b/src/framebuffer.c
index 870a67f..15bf685 100644
--- a/src/framebuffer.c
+++ b/src/framebuffer.c
@@ -113,7 +113,6 @@ static int modeset_create_gbm_fb(struct drm_fb *dev, int fd)
 	int format = GBM_FORMAT_XRGB8888;
 	uint32_t bpp = 32, depth = 24;
 
-	struct gbm_bo * bo;
 	int ret;
        
 	struct gbm_device * gbm_dev = gbm_create_device(fd);
@@ -124,25 +123,6 @@ static int modeset_create_gbm_fb(struct drm_fb *dev, int fd)
 	}
 	dev->gbm_dev = gbm_dev;
 
-	bo = gbm_bo_create(gbm_dev, dev->width, dev->height, format, flags);
-	assert(bo);
-
-	/* create framebuffer object for the dumb-buffer */
-	ret = drmModeAddFB(fd,
-			gbm_bo_get_width(bo),
-			gbm_bo_get_height(bo),
-			depth, bpp,
-			gbm_bo_get_stride(bo),
-			gbm_bo_get_handle(bo).u32,
-			&dev->fb);
-	if (ret) {
-		fprintf(stderr, "cannot create framebuffer (%d): %m\n", errno);
-		gbm_bo_destroy(bo);
-		return -errno;
-	}
-
-	dev->bo = bo;
-
 	dev->gbm_surface = gbm_surface_create(gbm_dev, dev->width, dev->height, format, flags);
 	if (!dev->gbm_surface) {
 		fprintf(stderr, "failed to create gbm surface\n");
@@ -155,7 +135,6 @@ static int modeset_create_gbm_fb(struct drm_fb *dev, int fd)
 
 static int modeset_cleanup_gbm_fb(struct drm_fb *dev, int fd)
 {
-	gbm_bo_destroy(dev->bo);
 	gbm_surface_destroy(dev->gbm_surface);
 	gbm_device_destroy(dev->gbm_dev);
 	drmModeRmFB(fd, dev->fb);
diff --git a/src/gl_minimal.c b/src/gl_minimal.c
index 9afc01f..b5d29df 100644
--- a/src/gl_minimal.c
+++ b/src/gl_minimal.c
@@ -10,26 +10,7 @@
 
 void run_gl_example(struct display * d)
 {
-	EGLImageKHR image;
-	GLuint fb, color_rb, depth_rb;
-
-	glGenFramebuffers(1, &fb);
-	glBindFramebuffer(GL_FRAMEBUFFER_EXT, fb);
-
-	image = eglCreateImageKHR(d->egl.display, NULL, EGL_NATIVE_PIXMAP_KHR, d->dev->bo, NULL);
-
-	/* Set up render buffer... */
-	glGenRenderbuffers(1, &color_rb);
-	glBindRenderbuffer(GL_RENDERBUFFER_EXT, color_rb);
-	glEGLImageTargetRenderbufferStorageOES(GL_RENDERBUFFER, image);
-	glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_RENDERBUFFER_EXT, color_rb);
-
-	/* and depth buffer */
-	glGenRenderbuffers(1, &depth_rb);
-	glBindRenderbuffer(GL_RENDERBUFFER_EXT, depth_rb);
-	glRenderbufferStorage(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, d->dev->width, d->dev->height);
-	glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, depth_rb);
-
+#if 0
 	// wipe the drawing surface clear
 	for (unsigned i = 0; i < 3; i++) {
 		GLfloat r =0.0,g = 0.0,b = 0.0;
@@ -42,6 +23,7 @@ void run_gl_example(struct display * d)
 		glFlush();
 		sleep(3);
 	}
+#endif
 
 	const GLfloat vertices[] = {
 	   0.0f,  0.5f,  0.0f,
@@ -117,10 +99,26 @@ void run_gl_example(struct display * d)
 	glDrawArrays(GL_TRIANGLES, 0, 3);
 	glBindVertexArray(0);
 
-	glFlush();
-	sleep(3);
-
 	glDeleteVertexArrays(1, &vao);
 	glDeleteBuffers(1, &vbo);
 
+	eglSwapBuffers(d->egl.display, d->egl.surface);
+
+	/* this must be _after_ calling eglSwapBuffers */
+	struct gbm_bo * bo;
+	bo = gbm_surface_lock_front_buffer(d->dev->gbm_surface);
+	assert(bo);
+
+	uint32_t bpp = 32, depth = 24;
+	/* create framebuffer object for the gbm bo extracted from the gbm surf */
+	int ret = drmModeAddFB(d->rnode.fd,
+			gbm_bo_get_width(bo),
+			gbm_bo_get_height(bo),
+			depth, bpp,
+			gbm_bo_get_stride(bo),
+			gbm_bo_get_handle(bo).u32,
+			&d->dev->fb);
+	if (ret) {
+		fprintf(stderr, "cannot create framebuffer\n");
+	}
 }
diff --git a/src/main.c b/src/main.c
index 289381c..a6b36f1 100644
--- a/src/main.c
+++ b/src/main.c
@@ -85,6 +85,8 @@ int main()
 	/* draw here?? */
 	run_gl_example(&d);
 	/* ...... */
+	modeset_crtc(d.rnode.fd);
+	sleep(3); // XXX keep rendered scene on screen for a bit
 
 
 	/* cleanups */
diff --git a/src/modesetting.c b/src/modesetting.c
index c454083..7860a25 100644
--- a/src/modesetting.c
+++ b/src/modesetting.c
@@ -205,8 +205,6 @@ int modeset(struct display * d)
 
 	drmModeFreeResources(res);
 
-	modeset_crtc(fd);
-
 	return 0;
 }