VIGS: clear color before compositing dpy image

Needs to be done to avoid artifacts with underlays (e.g. when
bottom plane does not fit the whole screen and the root surface
has alpha enabled).

Change-Id: I58b1f3c98a9a6dac5042118441a553de23283491
Signed-off-by: Vasiliy Ulyanov <v.ulyanov@samsung.com>

diff --git a/hw/vigs/vigs_gl_backend.c b/hw/vigs/vigs_gl_backend.c
index efe89c2..d7b431b 100644 (file)
--- a/hw/vigs/vigs_gl_backend.c
+++ b/hw/vigs/vigs_gl_backend.c
@@ -2184,6 +2184,8 @@ static bool vigs_gl_backend_composite(struct vigs_surface *surface,
     gl_backend->FramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                      GL_TEXTURE_2D, gl_backend->dpy_tex, 0);
 
+    gl_backend->Clear(GL_COLOR_BUFFER_BIT);
+
     bottom = vigs_gl_backend_composite_planes(gl_backend,
                                               sorted_planes,
                                               false,
@@ -2771,6 +2773,7 @@ bool vigs_gl_backend_init(struct vigs_gl_backend *gl_backend)
     gl_backend->dpy_scale_prog_texSize_loc = gl_backend->GetUniformLocation(gl_backend->dpy_scale_prog_id, "texSize");
     gl_backend->dpy_scale_prog_brightness_loc = gl_backend->GetUniformLocation(gl_backend->dpy_scale_prog_id, "brightness");
 
+    gl_backend->ClearColor(0.0f, 0.0f, 0.0f, 0.0f);
     gl_backend->Disable(GL_DEPTH_TEST);
     gl_backend->Disable(GL_BLEND);