vrend: Take swizzle + fallback combination into account

The code would previously look at the emulated alpha texture's
swizzle, or the application swizzle, but wouldn't combine them
together. This means that swizzling was incorrect when using an
emulated alpha texture in conjunction with application swizzle.

Also, remove swizzle_* from struct vrend_sampler_view since these
aren't used outside of this single function.

Fixes:
dEQP-GLES3.functional.texture.swizzle.multi_channel.alpha_*

Signed-off-by: Stéphane Marchesin <marcheu@chromium.org>

src/vrend_renderer.c

@@ -235,10 +235,6 @@ struct vrend_sampler_view {
    GLuint cur_base, cur_max;
    GLenum depth_texture_mode;
    GLuint srgb_decode;
-   GLuint swizzle_r:3;
-   GLuint swizzle_g:3;
-   GLuint swizzle_b:3;
-   GLuint swizzle_a:3;
    struct vrend_resource *texture;
 };
 
@@ -1332,6 +1328,8 @@ int vrend_create_sampler_view(struct vrend_context *ctx,
    struct vrend_sampler_view *view;
    struct vrend_resource *res;
    int ret_handle;
+   uint8_t swizzle[4];
+
    res = vrend_renderer_ctx_res_lookup(ctx, res_handle);
    if (!res) {
       report_context_error(ctx, VIRGL_ERROR_CTX_ILLEGAL_RESOURCE, res_handle);
@@ -1346,13 +1344,14 @@ int vrend_create_sampler_view(struct vrend_context *ctx,
    view->format = format;
    view->val0 = val0;
    view->val1 = val1;
-   view->swizzle_r = swizzle_packed & 0x7;
-   view->swizzle_g = (swizzle_packed >> 3) & 0x7;
-   view->swizzle_b = (swizzle_packed >> 6) & 0x7;
-   view->swizzle_a = (swizzle_packed >> 9) & 0x7;
    view->cur_base = -1;
    view->cur_max = 10000;
 
+   swizzle[0] = swizzle_packed & 0x7;
+   swizzle[1] = (swizzle_packed >> 3) & 0x7;
+   swizzle[2] = (swizzle_packed >> 6) & 0x7;
+   swizzle[3] = (swizzle_packed >> 9) & 0x7;
+
    vrend_resource_reference(&view->texture, res);
 
    view->srgb_decode = GL_DECODE_EXT;
@@ -1362,28 +1361,33 @@ int vrend_create_sampler_view(struct vrend_context *ctx,
          view->srgb_decode = GL_SKIP_DECODE_EXT;
    }
 
-   view->gl_swizzle_a = to_gl_swizzle(view->swizzle_a);
-   view->gl_swizzle_r = to_gl_swizzle(view->swizzle_r);
-   view->gl_swizzle_g = to_gl_swizzle(view->swizzle_g);
-   view->gl_swizzle_b = to_gl_swizzle(view->swizzle_b);
-
    if (!(util_format_has_alpha(format) || util_format_is_depth_or_stencil(format))) {
-       if (view->gl_swizzle_a == GL_ALPHA)
+      if (swizzle[0] == PIPE_SWIZZLE_ALPHA)
-           view->gl_swizzle_a = GL_ONE;
+          swizzle[0] = PIPE_SWIZZLE_ONE;
-       if (view->gl_swizzle_r == GL_ALPHA)
+      if (swizzle[1] == PIPE_SWIZZLE_ALPHA)
-           view->gl_swizzle_r = GL_ONE;
+          swizzle[1] = PIPE_SWIZZLE_ONE;
-       if (view->gl_swizzle_g == GL_ALPHA)
+      if (swizzle[2] == PIPE_SWIZZLE_ALPHA)
-           view->gl_swizzle_g = GL_ONE;
+          swizzle[2] = PIPE_SWIZZLE_ONE;
-       if (view->gl_swizzle_b == GL_ALPHA)
+      if (swizzle[3] == PIPE_SWIZZLE_ALPHA)
-           view->gl_swizzle_b = GL_ONE;
+          swizzle[3] = PIPE_SWIZZLE_ONE;
    }
 
    if (tex_conv_table[format].flags & VREND_BIND_NEED_SWIZZLE) {
-      view->gl_swizzle_r = to_gl_swizzle(tex_conv_table[format].swizzle[0]);
+      if (swizzle[0] <= PIPE_SWIZZLE_ALPHA)
-      view->gl_swizzle_g = to_gl_swizzle(tex_conv_table[format].swizzle[1]);
+         swizzle[0] = tex_conv_table[format].swizzle[swizzle[0]];
-      view->gl_swizzle_b = to_gl_swizzle(tex_conv_table[format].swizzle[2]);
+      if (swizzle[1] <= PIPE_SWIZZLE_ALPHA)
-      view->gl_swizzle_a = to_gl_swizzle(tex_conv_table[format].swizzle[3]);
+         swizzle[1] = tex_conv_table[format].swizzle[swizzle[1]];
+      if (swizzle[2] <= PIPE_SWIZZLE_ALPHA)
+         swizzle[2] = tex_conv_table[format].swizzle[swizzle[2]];
+      if (swizzle[3] <= PIPE_SWIZZLE_ALPHA)
+         swizzle[3] = tex_conv_table[format].swizzle[swizzle[3]];
    }
+
+   view->gl_swizzle_r = to_gl_swizzle(swizzle[0]);
+   view->gl_swizzle_g = to_gl_swizzle(swizzle[1]);
+   view->gl_swizzle_b = to_gl_swizzle(swizzle[2]);
+   view->gl_swizzle_a = to_gl_swizzle(swizzle[3]);
+
    ret_handle = vrend_renderer_object_insert(ctx, view, sizeof(*view), handle, VIRGL_OBJECT_SAMPLER_VIEW);
    if (ret_handle == 0) {
       FREE(view);