[Mesa-dev] [PATCH 1/8] mesa: Record transform feedback stride in linker output.

[Paul Berry]

This patch adds the field gl_transform_feedback_info::BufferStride,
which records the total number of components (per vertex) that
transform feedback is being instructed to store in each buffer.  The
i965 gen6 back-end needs this information in order to set up binding
tables, and it seems better to have the linker provide this
information rather than force the back-end to recompute it.
---
 src/glsl/linker.cpp    |    4 +++-
 src/mesa/main/mtypes.h |    5 +++++
 2 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index b8a7126..5eb2a20 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -1599,6 +1599,7 @@ tfeedback_decl::store(struct gl_shader_program *prog,
       info->Outputs[info->NumOutputs].NumComponents = this->vector_elements;
       info->Outputs[info->NumOutputs].OutputBuffer = buffer;
       ++info->NumOutputs;
+      info->BufferStride[buffer] += this->vector_elements;
    }
    return true;
 }
@@ -1863,7 +1864,8 @@ store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
                      tfeedback_decl *tfeedback_decls)
 {
    unsigned total_tfeedback_components = 0;
-   prog->LinkedTransformFeedback.NumOutputs = 0;
+   memset(&prog->LinkedTransformFeedback, 0,
+          sizeof(prog->LinkedTransformFeedback));
    for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
       unsigned buffer =
          prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS ? i : 0;
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 1934349..d4c600a 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1822,6 +1822,11 @@ struct gl_transform_feedback_info {
       unsigned OutputBuffer;
       unsigned NumComponents;
    } Outputs[MAX_PROGRAM_OUTPUTS];
+
+   /**
+    * Number of components stored in each buffer.
+    */
+   unsigned BufferStride[MAX_FEEDBACK_ATTRIBS];
 };
 
 /**
-- 
1.7.6.4