compositor: specialised fragment shader for RGBX
Remove the weston_surface::blend attribute, which really meant that the
texture produced valid alpha values. This was used to override the opaque
region for RGBX surfaces, which produce undefined values for alpha.
Instead, compile a new shader especially for RGBX surfaces, that
hardcodes the sampled alpha as 1.0.
Before "compositor: optimize/simplify shaders" there was a 'vec4 opaque'
in the shaders, that would cause part of the texture to be forced to
alpha=1.0. Now that is gone, and we need this replacement.
To test: launch simple-shm, and use the super+alt+mousewheel combination
to make it transparent. It should not show a light cross over the window.
Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
diff --git a/src/compositor.c b/src/compositor.c
index 684fcd7..e48a44f 100644
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -240,7 +240,6 @@
surface->compositor = compositor;
surface->alpha = 1.0;
- surface->blend = 1;
surface->opaque_rect[0] = 0.0;
surface->opaque_rect[1] = 0.0;
surface->opaque_rect[2] = 0.0;
@@ -790,7 +789,6 @@
if (wl_buffer_is_shm(buffer)) {
es->pitch = wl_shm_buffer_get_stride(buffer) / 4;
- es->shader = &ec->texture_shader_rgba;
es->target = GL_TEXTURE_2D;
ensure_textures(es, 1);
@@ -799,9 +797,9 @@
es->pitch, es->buffer->height, 0,
GL_BGRA_EXT, GL_UNSIGNED_BYTE, NULL);
if (wl_shm_buffer_get_format(buffer) == WL_SHM_FORMAT_XRGB8888)
- es->blend = 0;
+ es->shader = &ec->texture_shader_rgbx;
else
- es->blend = 1;
+ es->shader = &ec->texture_shader_rgba;
} else if (ec->query_buffer(ec->egl_display, buffer,
EGL_TEXTURE_FORMAT, &format)) {
for (i = 0; i < es->num_images; i++)
@@ -1307,7 +1305,7 @@
&ec->primary_plane.damage, &repaint);
glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
- if (es->blend || es->alpha < 1.0) {
+ if (1 || es->alpha < 1.0) {
/* blended region is whole surface minus opaque region: */
pixman_region32_init_rect(&surface_blend, 0, 0,
es->geometry.width, es->geometry.height);
@@ -3205,6 +3203,17 @@
" gl_FragColor = alpha * texture2D(tex, v_texcoord)\n;"
"}\n";
+static const char texture_fragment_shader_rgbx[] =
+ "precision mediump float;\n"
+ "varying vec2 v_texcoord;\n"
+ "uniform sampler2D tex;\n"
+ "uniform float alpha;\n"
+ "void main()\n"
+ "{\n"
+ " gl_FragColor.rgb = alpha * texture2D(tex, v_texcoord).rgb\n;"
+ " gl_FragColor.a = alpha;\n"
+ "}\n";
+
static const char texture_fragment_shader_egl_external[] =
"#extension GL_OES_EGL_image_external : require\n"
"precision mediump float;\n"
@@ -3709,6 +3718,9 @@
if (weston_shader_init(&ec->texture_shader_rgba,
vertex_shader, texture_fragment_shader_rgba) < 0)
return -1;
+ if (weston_shader_init(&ec->texture_shader_rgbx,
+ vertex_shader, texture_fragment_shader_rgbx) < 0)
+ return -1;
if (has_egl_image_external &&
weston_shader_init(&ec->texture_shader_egl_external,
vertex_shader, texture_fragment_shader_egl_external) < 0)