glsl: use bitmask of active xfb buffer indices

This allows us to print the correct binding point when not all
buffers declared in the shader are bound.

For example if we use a single buffer:

layout(xfb_buffer=2, offset=0) out vec4 v;

We now print '2' when the buffer is not bound rather than '0'.

Reviewed-by: Dave Airlie <airlied@redhat.com>

diff --git a/src/compiler/glsl/link_varyings.cpp b/src/compiler/glsl/link_varyings.cpp
index 8aefb7e201d590b66abbda04a96b048c31b7f3e7..cb0c8baf8aa353e637fe60d8e705b0f6c7e79f74 100644 (file)
--- a/src/compiler/glsl/link_varyings.cpp
+++ b/src/compiler/glsl/link_varyings.cpp
@@ -872,6 +872,11 @@ store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
                      unsigned num_tfeedback_decls,
                      tfeedback_decl *tfeedback_decls, bool has_xfb_qualifiers)
 {
+   /* Make sure MaxTransformFeedbackBuffers is less than 32 so the bitmask for
+    * tracking the number of buffers doesn't overflow.
+    */
+   assert(ctx->Const.MaxTransformFeedbackBuffers < 32);
+
    bool separate_attribs_mode =
       prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS;
 
@@ -904,6 +909,7 @@ store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
                     num_outputs);
 
    unsigned num_buffers = 0;
+   unsigned buffers = 0;
 
    if (!has_xfb_qualifiers && separate_attribs_mode) {
       /* GL_SEPARATE_ATTRIBS */
@@ -913,6 +919,7 @@ store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
                                        has_xfb_qualifiers))
             return false;
 
+         buffers |= 1 << num_buffers;
          num_buffers++;
       }
    }
@@ -949,6 +956,7 @@ store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
          } else {
             buffer = num_buffers;
          }
+         buffers |= 1 << num_buffers;
 
          if (!tfeedback_decls[i].store(ctx, prog,
                                        &prog->LinkedTransformFeedback,
@@ -956,12 +964,11 @@ store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
                                        has_xfb_qualifiers))
             return false;
       }
-      num_buffers++;
    }
 
    assert(prog->LinkedTransformFeedback.NumOutputs == num_outputs);
 
-   prog->LinkedTransformFeedback.NumBuffers = num_buffers;
+   prog->LinkedTransformFeedback.ActiveBuffers = buffers;
    return true;
 }
 

diff --git a/src/mesa/drivers/dri/i965/gen6_sol.c b/src/mesa/drivers/dri/i965/gen6_sol.c
index 2f6eadffd2e0b4bfa6249a07a8cee6f6c9fb62d7..08d4e1b52ca32140fb566e95fb8d82b5be78ca51 100644 (file)
--- a/src/mesa/drivers/dri/i965/gen6_sol.c
+++ b/src/mesa/drivers/dri/i965/gen6_sol.c
@@ -256,7 +256,7 @@ brw_begin_transform_feedback(struct gl_context *ctx, GLenum mode,
     * overflowing any of the buffers currently being used for feedback.
     */
    unsigned max_index
-      = _mesa_compute_max_transform_feedback_vertices(xfb_obj,
+      = _mesa_compute_max_transform_feedback_vertices(ctx, xfb_obj,
                                                       linked_xfb_info);
 
    /* Initialize the SVBI 0 register to zero and set the maximum index. */

diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index ae0c8a84dda35ed9e4f349b40d96ebf1a402e0ff..02e60626b4a8c6e4a0259ebe68d61a7620e530b9 100644 (file)
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1649,10 +1649,8 @@ struct gl_transform_feedback_info
 {
    unsigned NumOutputs;
 
-   /**
-    * Number of transform feedback buffers in use by this program.
-    */
-   unsigned NumBuffers;
+   /* Bitmask of active buffer indices. */
+   unsigned ActiveBuffers;
 
    struct gl_transform_feedback_output *Outputs;
 

diff --git a/src/mesa/main/transformfeedback.c b/src/mesa/main/transformfeedback.c
index f73a89f6c0f4bd79afc5b93b7f16ece2e38dca4f..39ba3dcd7c0b9d641fff641ae836f6fa814d4304 100644 (file)
--- a/src/mesa/main/transformfeedback.c
+++ b/src/mesa/main/transformfeedback.c
@@ -347,23 +347,25 @@ compute_transform_feedback_buffer_sizes(
  * enabled transform feedback buffers without overflowing any of them.
  */
 unsigned
-_mesa_compute_max_transform_feedback_vertices(
+_mesa_compute_max_transform_feedback_vertices(struct gl_context *ctx,
       const struct gl_transform_feedback_object *obj,
       const struct gl_transform_feedback_info *info)
 {
    unsigned max_index = 0xffffffff;
    unsigned i;
 
-   for (i = 0; i < info->NumBuffers; ++i) {
-      unsigned stride = info->BufferStride[i];
-      unsigned max_for_this_buffer;
+   for (i = 0; i < ctx->Const.MaxTransformFeedbackBuffers; i++) {
+      if ((info->ActiveBuffers >> i) & 1) {
+         unsigned stride = info->BufferStride[i];
+         unsigned max_for_this_buffer;
 
-      /* Skip any inactive buffers, which have a stride of 0. */
-      if (stride == 0)
-        continue;
+         /* Skip any inactive buffers, which have a stride of 0. */
+         if (stride == 0)
+           continue;
 
-      max_for_this_buffer = obj->Size[i] / (4 * stride);
-      max_index = MIN2(max_index, max_for_this_buffer);
+         max_for_this_buffer = obj->Size[i] / (4 * stride);
+         max_index = MIN2(max_index, max_for_this_buffer);
+      }
    }
 
    return max_index;
@@ -445,12 +447,14 @@ _mesa_BeginTransformFeedback(GLenum mode)
       return;
    }
 
-   for (i = 0; i < info->NumBuffers; ++i) {
-      if (obj->BufferNames[i] == 0) {
-         _mesa_error(ctx, GL_INVALID_OPERATION,
-                     "glBeginTransformFeedback(binding point %d does not have "
-                     "a buffer object bound)", i);
-         return;
+   for (i = 0; i < ctx->Const.MaxTransformFeedbackBuffers; i++) {
+      if ((info->ActiveBuffers >> i) & 1) {
+         if (obj->BufferNames[i] == 0) {
+            _mesa_error(ctx, GL_INVALID_OPERATION,
+                        "glBeginTransformFeedback(binding point %d does not "
+                        "have a buffer object bound)", i);
+            return;
+         }
       }
    }
 
@@ -470,7 +474,7 @@ _mesa_BeginTransformFeedback(GLenum mode)
        * feedback.
        */
       unsigned max_vertices
-         = _mesa_compute_max_transform_feedback_vertices(obj, info);
+         = _mesa_compute_max_transform_feedback_vertices(ctx, obj, info);
       obj->GlesRemainingPrims = max_vertices / vertices_per_prim;
    }
 

diff --git a/src/mesa/main/transformfeedback.h b/src/mesa/main/transformfeedback.h
index eb274ad65407b4acc9db66ed98e39c9569c7b511..c83f917a532c792ba8f98bf251e6d6f73ec495a5 100644 (file)
--- a/src/mesa/main/transformfeedback.h
+++ b/src/mesa/main/transformfeedback.h
@@ -50,7 +50,7 @@ extern void
 _mesa_init_transform_feedback_functions(struct dd_function_table *driver);
 
 extern unsigned
-_mesa_compute_max_transform_feedback_vertices(
+_mesa_compute_max_transform_feedback_vertices( struct gl_context *ctx,
       const struct gl_transform_feedback_object *obj,
       const struct gl_transform_feedback_info *info);