mesa: Pure software accum buffer.

The existing implementation was already implemented on software, but relied
on the pipe driver to always support the R16G16B16A16_SNORM format. This
patch eliminates that, without prejudice against a future hardware-only
implementation.

It also avoids some of the short <-> float conversions, and only does a read
transfer of the color buffer on GL_RETURN if absolutely necessary.

1 files changed, 9 insertions, 8 deletions

diff --git a/src/mesa/state_tracker/st_framebuffer.c b/src/mesa/state_tracker/st_framebuffer.c
index daaad65ccaf..331575660d3 100644
--- a/src/mesa/state_tracker/st_framebuffer.c
+++ b/src/mesa/state_tracker/st_framebuffer.c
@@ -63,20 +63,20 @@ st_create_framebuffer( const __GLcontextModes *visual,
          /* XXX allocation should only happen in the unusual case
             it's actually needed */
          struct gl_renderbuffer *rb
-            = st_new_renderbuffer_fb(colorFormat, samples);
+            = st_new_renderbuffer_fb(colorFormat, samples, FALSE);
          _mesa_add_renderbuffer(&stfb->Base, BUFFER_FRONT_LEFT, rb);
       }
 
       if (visual->doubleBufferMode) {
          struct gl_renderbuffer *rb
-            = st_new_renderbuffer_fb(colorFormat, samples);
+            = st_new_renderbuffer_fb(colorFormat, samples, FALSE);
          _mesa_add_renderbuffer(&stfb->Base, BUFFER_BACK_LEFT, rb);
       }
 
       if (depthFormat == stencilFormat && depthFormat != PIPE_FORMAT_NONE) {
          /* combined depth/stencil buffer */
          struct gl_renderbuffer *depthStencilRb
-            = st_new_renderbuffer_fb(depthFormat, samples);
+            = st_new_renderbuffer_fb(depthFormat, samples, FALSE);
          /* note: bind RB to two attachment points */
          _mesa_add_renderbuffer(&stfb->Base, BUFFER_DEPTH, depthStencilRb);
          _mesa_add_renderbuffer(&stfb->Base, BUFFER_STENCIL, depthStencilRb);
@@ -87,34 +87,35 @@ st_create_framebuffer( const __GLcontextModes *visual,
          if (visual->depthBits == 32) {
             /* 32-bit depth buffer */
             struct gl_renderbuffer *depthRb
-               = st_new_renderbuffer_fb(depthFormat, samples);
+               = st_new_renderbuffer_fb(depthFormat, samples, FALSE);
             _mesa_add_renderbuffer(&stfb->Base, BUFFER_DEPTH, depthRb);
          }
          else if (visual->depthBits == 24) {
             /* 24-bit depth buffer, ignore stencil bits */
             struct gl_renderbuffer *depthRb
-               = st_new_renderbuffer_fb(depthFormat, samples);
+               = st_new_renderbuffer_fb(depthFormat, samples, FALSE);
             _mesa_add_renderbuffer(&stfb->Base, BUFFER_DEPTH, depthRb);
          }
          else if (visual->depthBits > 0) {
             /* 16-bit depth buffer */
             struct gl_renderbuffer *depthRb
-               = st_new_renderbuffer_fb(depthFormat, samples);
+               = st_new_renderbuffer_fb(depthFormat, samples, FALSE);
             _mesa_add_renderbuffer(&stfb->Base, BUFFER_DEPTH, depthRb);
          }
 
          if (visual->stencilBits > 0) {
             /* 8-bit stencil */
             struct gl_renderbuffer *stencilRb
-               = st_new_renderbuffer_fb(stencilFormat, samples);
+               = st_new_renderbuffer_fb(stencilFormat, samples, FALSE);
             _mesa_add_renderbuffer(&stfb->Base, BUFFER_STENCIL, stencilRb);
          }
       }
 
       if (visual->accumRedBits > 0) {
          /* 16-bit/channel accum */
+         /* TODO: query the pipe screen for accumulation buffer format support */
          struct gl_renderbuffer *accumRb
-            = st_new_renderbuffer_fb(DEFAULT_ACCUM_PIPE_FORMAT, 0); /* XXX accum isn't multisampled right? */
+            = st_new_renderbuffer_fb(PIPE_FORMAT_R16G16B16A16_SNORM, 0, TRUE);
          _mesa_add_renderbuffer(&stfb->Base, BUFFER_ACCUM, accumRb);
       }