st/xorg: fix text with component alpha rendering

src/gallium/state_trackers/xorg/xorg_composite.c

@@ -109,6 +109,7 @@ blend_for_op(struct xorg_composite_blend *blend,
          blend->rgb_dst = PIPE_BLENDFACTOR_INV_SRC_COLOR;
       }
    }
+
    return supported;
 }
 
@@ -257,8 +258,15 @@ bind_shaders(struct exa_context *exa, int op,
    if (pMaskPicture) {
       vs_traits |= VS_MASK;
       fs_traits |= FS_MASK;
-      if (pMaskPicture->componentAlpha)
-         fs_traits |= FS_COMPONENT_ALPHA;
+      if (pMaskPicture->componentAlpha) {
+         struct xorg_composite_blend blend;
+         blend_for_op(&blend, op,
+                      pSrcPicture, pMaskPicture, NULL);
+         if (blend.alpha_src) {
+            fs_traits |= FS_CA_SRCALPHA;
+         } else
+            fs_traits |= FS_CA_FULL;
+      }
    }
 
    shader = xorg_shaders_get(exa->renderer->shaders, vs_traits, fs_traits);
@@ -289,21 +297,27 @@ bind_samplers(struct exa_context *exa, int op,
       exa->pipe->flush(exa->pipe, PIPE_FLUSH_RENDER_CACHE, NULL);
 
    if (pSrcPicture && pSrc) {
-      unsigned src_wrap = render_repeat_to_gallium(
-         pSrcPicture->repeatType);
-      int filter;
-
-      render_filter_to_gallium(pSrcPicture->filter, &filter);
-
-      src_sampler.wrap_s = src_wrap;
-      src_sampler.wrap_t = src_wrap;
-      src_sampler.min_img_filter = filter;
-      src_sampler.mag_img_filter = filter;
-      src_sampler.min_mip_filter = PIPE_TEX_MIPFILTER_NEAREST;
-      src_sampler.normalized_coords = 1;
-      samplers[0] = &src_sampler;
-      exa->bound_textures[0] = pSrc->tex;
-      ++exa->num_bound_samplers;
+      if (exa->has_solid_color) {
+         debug_assert(!"solid color with textures");
+         samplers[0] = NULL;
+         exa->bound_textures[0] = NULL;
+      } else {
+         unsigned src_wrap = render_repeat_to_gallium(
+            pSrcPicture->repeatType);
+         int filter;
+
+         render_filter_to_gallium(pSrcPicture->filter, &filter);
+
+         src_sampler.wrap_s = src_wrap;
+         src_sampler.wrap_t = src_wrap;
+         src_sampler.min_img_filter = filter;
+         src_sampler.mag_img_filter = filter;
+         src_sampler.min_mip_filter = PIPE_TEX_MIPFILTER_NEAREST;
+         src_sampler.normalized_coords = 1;
+         samplers[0] = &src_sampler;
+         exa->bound_textures[0] = pSrc->tex;
+         exa->num_bound_samplers = 1;
+      }
    }
 
    if (pMaskPicture && pMask) {
@@ -321,7 +335,7 @@ bind_samplers(struct exa_context *exa, int op,
       mask_sampler.normalized_coords = 1;
       samplers[1] = &mask_sampler;
       exa->bound_textures[1] = pMask->tex;
-      ++exa->num_bound_samplers;
+      exa->num_bound_samplers = 2;
    }
 
    cso_set_samplers(exa->renderer->cso, exa->num_bound_samplers,

src/gallium/state_trackers/xorg/xorg_exa_tgsi.c

@@ -55,10 +55,13 @@ src_in_mask(struct ureg_program *ureg,
             struct ureg_dst dst,
             struct ureg_src src,
             struct ureg_src mask,
-            boolean component_alpha)
+            int component_alpha)
 {
-   if (component_alpha) {
+   if (component_alpha == FS_CA_FULL) {
       ureg_MUL(ureg, dst, src, mask);
+   } else if (component_alpha == FS_CA_SRCALPHA) {
+      ureg_MUL(ureg, dst,
+               ureg_scalar(src, TGSI_SWIZZLE_W), mask);
    }
    else {
       ureg_MUL(ureg, dst, src,
@@ -289,7 +292,7 @@ create_fs(struct pipe_context *pipe,
    boolean is_solid   = fs_traits & FS_SOLID_FILL;
    boolean is_lingrad = fs_traits & FS_LINGRAD_FILL;
    boolean is_radgrad = fs_traits & FS_RADGRAD_FILL;
-   boolean is_comp_alpha = fs_traits & FS_COMPONENT_ALPHA;
+   unsigned comp_alpha = fs_traits & FS_COMPONENT_ALPHA;
 
    ureg = ureg_create(TGSI_PROCESSOR_FRAGMENT);
    if (ureg == NULL)
@@ -386,7 +389,7 @@ create_fs(struct pipe_context *pipe,
       ureg_TEX(ureg, mask,
                TGSI_TEXTURE_2D, mask_pos, mask_sampler);
       /* src IN mask */
-      src_in_mask(ureg, out, ureg_src(src), ureg_src(mask), is_comp_alpha);
+      src_in_mask(ureg, out, ureg_src(src), ureg_src(mask), comp_alpha);
       ureg_release_temporary(ureg, mask);
    }
 

src/gallium/state_trackers/xorg/xorg_exa_tgsi.h

@@ -24,7 +24,12 @@ enum xorg_fs_traits {
    FS_FILL             = (FS_SOLID_FILL |
                           FS_LINGRAD_FILL |
                           FS_RADGRAD_FILL),
-   FS_COMPONENT_ALPHA  = 1 << 5
+   /* src.rgba * mask.rgba */
+   FS_CA_FULL          = 1 << 5,
+   /* src.aaaa * mask.rgba */
+   FS_CA_SRCALPHA      = 1 << 6,
+   FS_COMPONENT_ALPHA  = (FS_CA_FULL |
+                          FS_CA_SRCALPHA)
 };
 
 struct xorg_shader {