[PATCH weston] compositor: Fix xwayland surface alpha.

[Pekka Paalanen]

On Sat,  1 Sep 2012 21:58:45 -0600
Scott Moreau <oreaus at gmail.com> wrote:

> Re-add the opaque_rect hack back to shaders so xwayland surfaces are not broken. xwm
> is the only one that uses weston_surface::opaque_rect, specifically for this reason.
> It was removed by 0e5a2d02191 - "compositor: simplify shaders", which simplified them
> a bit too much.
> ---
>  src/compositor.c | 6 ++++++
>  src/compositor.h | 1 +
>  2 files changed, 7 insertions(+)
> 
> diff --git a/src/compositor.c b/src/compositor.c
> index 9ce44d4..b19cbaf 100644
> --- a/src/compositor.c
> +++ b/src/compositor.c
> @@ -1365,6 +1365,7 @@ weston_surface_draw(struct weston_surface *es, struct weston_output *output,
>  			   1, GL_FALSE, output->matrix.d);
>  	glUniform4fv(es->shader->color_uniform, 1, es->color);
>  	glUniform1f(es->shader->alpha_uniform, es->alpha);
> +	glUniform4fv(es->shader->opaque_uniform, 1, es->opaque_rect);
>  
>  	if (es->transform.enabled || output->zoom.active)
>  		filter = GL_LINEAR;
> @@ -3247,9 +3248,13 @@ static const char texture_fragment_shader_rgba[] =
>  	"varying vec2 v_texcoord;\n"
>  	"uniform sampler2D tex;\n"
>  	"uniform float alpha;\n"
> +	"uniform vec4 opaque;\n"
>  	"void main()\n"
>  	"{\n"
>  	"   gl_FragColor = alpha * texture2D(tex, v_texcoord)\n;"
> +	"   if (opaque.x <= v_texcoord.x && v_texcoord.x < opaque.y &&\n"
> +	"	opaque.z <= v_texcoord.y && v_texcoord.y < opaque.w)\n"
> +	"	gl_FragColor.a = alpha;\n"
>  	"}\n";
>  
>  static const char texture_fragment_shader_rgbx[] =
> @@ -3375,6 +3380,7 @@ weston_shader_init(struct weston_shader *shader,
>  	shader->tex_uniforms[2] = glGetUniformLocation(shader->program, "tex2");
>  	shader->alpha_uniform = glGetUniformLocation(shader->program, "alpha");
>  	shader->color_uniform = glGetUniformLocation(shader->program, "color");
> +	shader->opaque_uniform = glGetUniformLocation(shader->program, "opaque");
>  
>  	return 0;
>  }
> diff --git a/src/compositor.h b/src/compositor.h
> index 96a0477..13ee804 100644
> --- a/src/compositor.h
> +++ b/src/compositor.h
> @@ -248,6 +248,7 @@ struct weston_shader {
>  	GLint tex_uniforms[3];
>  	GLint alpha_uniform;
>  	GLint color_uniform;
> +	GLint opaque_uniform;
>  };
>  
>  enum {

NAK, I'm developing a proper fix, that removes
weston_surface::opaque_rect completely.

Now that we can paint opaque regions independently from non-opaques, we
can set the shader for opaque regions to the RGBX shader, which forces
the sampled alpha to 1.0. That way we can keep the shaders simple.


Thanks,
pq