[virglrenderer-devel] [PATCH 4/4] blit: fix blitting to red-alpha texture

[marcandre.lureau at redhat.com]

From: Marc-André Lureau <marcandre.lureau at redhat.com>

glBlitFramebuffer() doesn't take swizzling into account, so use
blit_gl() fallback in this case with a alpha->red swizzle.

This fixes text rendering with Qt
QGLTextureGlyphCache::resizeTextureData(), as can be reproduced with
stellarium or qt5/examples/widgets/graphicsview/chip/chip.

Signed-off-by: Marc-André Lureau <marcandre.lureau at redhat.com>
---
 src/vrend_blitter.c  | 2 ++
 src/vrend_renderer.c | 8 ++++++++
 src/vrend_renderer.h | 1 +
 3 files changed, 11 insertions(+)

diff --git a/src/vrend_blitter.c b/src/vrend_blitter.c
index 8783a4f..cacf28b 100644
--- a/src/vrend_blitter.c
+++ b/src/vrend_blitter.c
@@ -525,6 +525,8 @@ void vrend_renderer_blit_gl(struct vrend_context *ctx,
    glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);
 
    glBindTexture(src_res->target, src_res->id);
+   if (vrend_is_red_alpha_format(dst_res->base.format))
+      glTexParameteri(src_res->target, GL_TEXTURE_SWIZZLE_R, GL_ALPHA);
 
    glTexParameteri(src_res->target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(src_res->target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
diff --git a/src/vrend_renderer.c b/src/vrend_renderer.c
index c3605b3..5b9d5f6 100644
--- a/src/vrend_renderer.c
+++ b/src/vrend_renderer.c
@@ -434,6 +434,11 @@ static inline bool vrend_format_is_ds(enum virgl_formats format)
    return tex_conv_table[format].bindings & VREND_BIND_DEPTHSTENCIL;
 }
 
+bool vrend_is_red_alpha_format(enum virgl_formats format)
+{
+   return tex_conv_table[format].bindings & VREND_BIND_RED_ALPHA;
+}
+
 bool vrend_is_ds_format(enum virgl_formats format)
 {
    return vrend_format_is_ds(format);
@@ -5491,6 +5496,9 @@ static void vrend_renderer_blit_int(struct vrend_context *ctx,
    if (info->src.box.depth != info->dst.box.depth)
       use_gl = true;
 
+   if (vrend_is_red_alpha_format(dst_res->base.format))
+      use_gl = true;
+
    if (use_gl) {
       vrend_renderer_blit_gl(ctx, src_res, dst_res, info);
       vrend_clicbs->make_current(0, ctx->sub->gl_context);
diff --git a/src/vrend_renderer.h b/src/vrend_renderer.h
index bc96497..0d4e3be 100644
--- a/src/vrend_renderer.h
+++ b/src/vrend_renderer.h
@@ -364,6 +364,7 @@ void vrend_fb_bind_texture(struct vrend_resource *res,
                            int idx,
                            uint32_t level, uint32_t layer);
 bool vrend_is_ds_format(enum virgl_formats format);
+bool vrend_is_red_alpha_format(enum virgl_formats format);
 
 /* blitter interface */
 void vrend_renderer_blit_gl(struct vrend_context *ctx,
-- 
2.7.4