mesa: Fix glGetTransformFeedbackVarying().

The current implementation was totally broken -- it was looking in an
unpopulated structure for varyings, and trying to do so using the
current list of varying names, not the list used at link time.

v2: Fix leaking of memory into the program per re-link.

Reviewed-by: Paul Berry <[email protected]>

2 files changed, 31 insertions, 27 deletions

diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 35458e396ad..50d7e341f56 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1817,6 +1817,12 @@ struct prog_instruction;
 struct gl_program_parameter_list;
 struct gl_uniform_list;
 
+struct gl_transform_feedback_varying_info {
+   char *Name;
+   GLenum Type;
+   GLint Size;
+};
+
 /** Post-link transform feedback info. */
 struct gl_transform_feedback_info {
    unsigned NumOutputs;
@@ -1835,6 +1841,13 @@ struct gl_transform_feedback_info {
       unsigned DstOffset;
    } Outputs[MAX_PROGRAM_OUTPUTS];
 
+   /** Transform feedback varyings used for the linking of this shader program.
+    *
+    * Use for glGetTransformFeedbackVarying().
+    */
+   struct gl_transform_feedback_varying_info *Varyings;
+   GLint NumVarying;
+
    /**
     * Total number of components stored in each buffer.  This may be used by
     * hardware back-ends to determine the correct stride when interleaving
@@ -2227,7 +2240,13 @@ struct gl_shader_program
     */
    struct string_to_uint_map *FragDataBindings;
 
-   /** Transform feedback varyings */
+   /**
+    * Transform feedback varyings last specified by
+    * glTransformFeedbackVaryings().
+    *
+    * For the current set of transform feeedback varyings used for transform
+    * feedback output, see LinkedTransformFeedback.
+    */
    struct {
       GLenum BufferMode;
       GLuint NumVarying;
diff --git a/src/mesa/main/transformfeedback.c b/src/mesa/main/transformfeedback.c
index 02681c61583..c2114c22766 100644
--- a/src/mesa/main/transformfeedback.c
+++ b/src/mesa/main/transformfeedback.c
@@ -694,8 +694,7 @@ _mesa_GetTransformFeedbackVarying(GLuint program, GLuint index,
                                   GLsizei *size, GLenum *type, GLchar *name)
 {
    const struct gl_shader_program *shProg;
-   const GLchar *varyingName;
-   GLint v;
+   const struct gl_transform_feedback_info *linked_xfb_info;
    GET_CURRENT_CONTEXT(ctx);
 
    shProg = _mesa_lookup_shader_program(ctx, program);
@@ -705,36 +704,22 @@ _mesa_GetTransformFeedbackVarying(GLuint program, GLuint index,
       return;
    }
 
-   if (index >= shProg->TransformFeedback.NumVarying) {
+   linked_xfb_info = &shProg->LinkedTransformFeedback;
+   if (index >= linked_xfb_info->NumVarying) {
       _mesa_error(ctx, GL_INVALID_VALUE,
                   "glGetTransformFeedbackVaryings(index=%u)", index);
       return;
    }
 
-   varyingName = shProg->TransformFeedback.VaryingNames[index];
+   /* return the varying's name and length */
+   _mesa_copy_string(name, bufSize, length,
+		     linked_xfb_info->Varyings[index].Name);
 
-   v = _mesa_lookup_parameter_index(shProg->Varying, -1, varyingName);
-   if (v >= 0) {
-      struct gl_program_parameter *param = &shProg->Varying->Parameters[v];
-
-      /* return the varying's name and length */
-      _mesa_copy_string(name, bufSize, length, varyingName);
-
-      /* return the datatype and value's size (in datatype units) */
-      if (type)
-         *type = param->DataType;
-      if (size)
-         *size = param->Size;
-   }
-   else {
-      name[0] = 0;
-      if (length)
-         *length = 0;
-      if (type)
-         *type = 0;
-      if (size)
-         *size = 0;
-   }
+   /* return the datatype and value's size (in datatype units) */
+   if (type)
+      *type = linked_xfb_info->Varyings[index].Type;
+   if (size)
+      *size = linked_xfb_info->Varyings[index].Size;
 }