mesa: Allow GL_ALPHA FBOs with ARB_framebuffer_object.

Drivers still reject them today, but cairo would like to use these.

diff --git a/src/mesa/main/fbobject.c b/src/mesa/main/fbobject.c
index f33e027857424beec498d3e5949815e454008d55..1a2e9b1da6ff3a320fd897f7b608eaf3f5ed7aad 100644 (file)
--- a/src/mesa/main/fbobject.c
+++ b/src/mesa/main/fbobject.c
@@ -393,7 +393,9 @@ test_attachment_completeness(const GLcontext *ctx, GLenum format,
 
       if (format == GL_COLOR) {
          if (baseFormat != GL_RGB &&
-             baseFormat != GL_RGBA) {
+             baseFormat != GL_RGBA &&
+            (!ctx->Extensions.ARB_framebuffer_object ||
+             baseFormat != GL_ALPHA)) {
             att_incomplete("bad format");
             att->Complete = GL_FALSE;
             return;
@@ -572,7 +574,8 @@ _mesa_test_framebuffer_completeness(GLcontext *ctx, struct gl_framebuffer *fb)
          f = texImg->_BaseFormat;
          numImages++;
          if (f != GL_RGB && f != GL_RGBA && f != GL_DEPTH_COMPONENT
-             && f != GL_DEPTH_STENCIL_EXT) {
+             && f != GL_DEPTH_STENCIL_EXT
+            && (!ctx->Extensions.ARB_framebuffer_object || f != GL_ALPHA)) {
             fb->_Status = GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT;
             fbo_incomplete("texture attachment incomplete", -1);
             return;

diff --git a/src/mesa/main/framebuffer.c b/src/mesa/main/framebuffer.c
index 31689c8fe807defdcbcaad3194187f4b90642c26..01f84180af730a258fb5b3950a4c938176639494 100644 (file)
--- a/src/mesa/main/framebuffer.c
+++ b/src/mesa/main/framebuffer.c
@@ -544,7 +544,8 @@ _mesa_update_framebuffer_visual(struct gl_framebuffer *fb)
          const GLenum baseFormat = _mesa_get_format_base_format(rb->Format);
          const gl_format fmt = rb->Format;
          
-         if (baseFormat == GL_RGBA || baseFormat == GL_RGB) {
+         if (baseFormat == GL_RGBA || baseFormat == GL_RGB ||
+            baseFormat == GL_ALPHA) {
             fb->Visual.redBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
             fb->Visual.greenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
             fb->Visual.blueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);