[Mesa-dev] [PATCH 2/2] mesa: Ignor blits to/from missing buffers

[Brian Paul]

On 06/07/2011 02:01 PM, Ian Romanick wrote:
> From: Ian Romanick<ian.d.romanick at intel.com>
>
> The EXT_framebuffer_object spec (and later specs) say:
>
>       "If a buffer is specified in<mask>  and does not exist in both
>       the read and draw framebuffers, the corresponding bit is silently
>       ignored."
>
> Check for color, depth, and stencil that the source and destination
> FBOs have the specified buffers.  If the buffer is missing, remove the
> bit from the blit request mask and continue.
>
> Fixes the crash in piglit test 'fbo-missing-attachment-blit from', and
> fixes 'fbo-missing-attachment-blit es2 from'.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=37739
> ---
>   src/mesa/main/fbobject.c |   45 +++++++++++++++++++++++++++++++++++++--------
>   1 files changed, 37 insertions(+), 8 deletions(-)
>
> diff --git a/src/mesa/main/fbobject.c b/src/mesa/main/fbobject.c
> index d440070..2230b26 100644
> --- a/src/mesa/main/fbobject.c
> +++ b/src/mesa/main/fbobject.c
> @@ -2429,6 +2429,17 @@ _mesa_BlitFramebufferEXT(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
>      if (mask&  GL_COLOR_BUFFER_BIT) {
>         colorReadRb = readFb->_ColorReadBuffer;
>         colorDrawRb = drawFb->_ColorDrawBuffers[0];
> +
> +      /* From the EXT_framebuffer_object spec:
> +       *
> +       *     "If a buffer is specified in<mask>  and does not exist in both
> +       *     the read and draw framebuffers, the corresponding bit is silently
> +       *     ignored."
> +       */
> +      if ((colorReadRb == NULL) || (colorDrawRb == NULL)) {
> +	 colorReadRb = colorDrawRb = NULL;
> +	 mask&= ~GL_COLOR_BUFFER_BIT;
> +      }
>      }
>      else {
>         colorReadRb = colorDrawRb = NULL;
> @@ -2437,10 +2448,19 @@ _mesa_BlitFramebufferEXT(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
>      if (mask&  GL_STENCIL_BUFFER_BIT) {
>         struct gl_renderbuffer *readRb = readFb->_StencilBuffer;
>         struct gl_renderbuffer *drawRb = drawFb->_StencilBuffer;
> -      if (!readRb ||
> -          !drawRb ||
> -          _mesa_get_format_bits(readRb->Format, GL_STENCIL_BITS) !=
> -          _mesa_get_format_bits(drawRb->Format, GL_STENCIL_BITS)) {
> +
> +      /* From the EXT_framebuffer_object spec:
> +       *
> +       *     "If a buffer is specified in<mask>  and does not exist in both
> +       *     the read and draw framebuffers, the corresponding bit is silently
> +       *     ignored."
> +       */
> +      if ((readRb == NULL) || (drawRb == NULL)) {
> +	 readRb = drawRb = NULL;
> +	 mask&= ~GL_STENCIL_BUFFER_BIT;
> +      }
> +      else if (_mesa_get_format_bits(readRb->Format, GL_STENCIL_BITS) !=
> +	       _mesa_get_format_bits(drawRb->Format, GL_STENCIL_BITS)) {
>            _mesa_error(ctx, GL_INVALID_OPERATION,
>                        "glBlitFramebufferEXT(stencil buffer size mismatch)");
>            return;
> @@ -2450,10 +2470,19 @@ _mesa_BlitFramebufferEXT(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
>      if (mask&  GL_DEPTH_BUFFER_BIT) {
>         struct gl_renderbuffer *readRb = readFb->_DepthBuffer;
>         struct gl_renderbuffer *drawRb = drawFb->_DepthBuffer;
> -      if (!readRb ||
> -          !drawRb ||
> -          _mesa_get_format_bits(readRb->Format, GL_DEPTH_BITS) !=
> -          _mesa_get_format_bits(drawRb->Format, GL_DEPTH_BITS)) {
> +
> +      /* From the EXT_framebuffer_object spec:
> +       *
> +       *     "If a buffer is specified in<mask>  and does not exist in both
> +       *     the read and draw framebuffers, the corresponding bit is silently
> +       *     ignored."
> +       */
> +      if ((readRb == NULL) || (drawRb == NULL)) {
> +	 readRb = drawRb = NULL;
> +	 mask&= ~GL_DEPTH_BUFFER_BIT;
> +      }
> +      else if (_mesa_get_format_bits(readRb->Format, GL_DEPTH_BITS) !=
> +	       _mesa_get_format_bits(drawRb->Format, GL_DEPTH_BITS)) {
>            _mesa_error(ctx, GL_INVALID_OPERATION,
>                        "glBlitFramebufferEXT(depth buffer size mismatch)");
>            return;

Reviewed-by: Brian Paul <brianp at vmware.com>