[Mesa-dev] [PATCH 5/5] mesa: Fix GL_TRANSFORM_FEEDBACK_BUFFER_SIZE query when glBindBufferBase used.

[Paul Berry]

>From the GL 4.3 spec, section 6.7.1 (Indexed Buffer Object Limits and
Binding Queries):

    To query the starting offset or size of the range of a buffer
    object binding in an indexed array, call GetInteger64i v with
    target set to respectively the starting offset or binding size
    name from table 6.5 for that array. index must be in the range
    zero to the number of bind points supported minus one. If the
    starting offset or size was not specified when the buffer object
    was bound (e.g. if it was bound with BindBufferBase), or if no
    buffer object is bound to the target array at index, zero is
    returned.

Similar language exists in the EXT_transform_feedback spec and in the
GLES3 spec.

Previously, if a buffer object was bound by glBindBufferBase(), the
GL_TRANSFORM_FEEDBACK_BUFFER_SIZE query returned the size of the
buffer.

Fixes GLES3 conformance tests
transform_feedback_{builtin_type,state_variables}.test.
---
 src/mesa/main/get.c               |  2 +-
 src/mesa/main/mtypes.h            |  7 +++++++
 src/mesa/main/transformfeedback.c | 10 ++++++----
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/src/mesa/main/get.c b/src/mesa/main/get.c
index f3dbda2..2348486 100644
--- a/src/mesa/main/get.c
+++ b/src/mesa/main/get.c
@@ -1574,7 +1574,7 @@ find_value_indexed(const char *func, GLenum pname, GLuint 
index, union value *v)
         goto invalid_value;
       if (!ctx->Extensions.EXT_transform_feedback)
         goto invalid_enum;
-      v->value_int64 = ctx->TransformFeedback.CurrentObject->Size[index];
+      v->value_int64 = ctx->TransformFeedback.CurrentObject->QuerySize[index];
       return TYPE_INT64;
 
    case GL_TRANSFORM_FEEDBACK_BUFFER_BINDING:
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 18ab2db..333b2c9 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1827,6 +1827,13 @@ struct gl_transform_feedback_object
    GLintptr Offset[MAX_FEEDBACK_BUFFERS];
    /** Max data to put into dest buffer (in bytes) */
    GLsizeiptr Size[MAX_FEEDBACK_BUFFERS];
+   /**
+    * Size that should be returned from GL_TRANSFORM_FEEDBACK_BUFFER_SIZE
+    * queries.  If the transform feedback buffer was set up with
+    * glBindBufferBase() or glBindBufferOffsetEXT().  If it was set up with
+    * glBindBufferRange() it is equal to ActualSize.
+    */
+   GLsizeiptr QuerySize[MAX_FEEDBACK_BUFFERS];
 };
 
 
diff --git a/src/mesa/main/transformfeedback.c 
b/src/mesa/main/transformfeedback.c
index 7d500bc..092c343 100644
--- a/src/mesa/main/transformfeedback.c
+++ b/src/mesa/main/transformfeedback.c
@@ -383,7 +383,8 @@ _mesa_EndTransformFeedback(void)
 static void
 bind_buffer_range(struct gl_context *ctx, GLuint index,
                   struct gl_buffer_object *bufObj,
-                  GLintptr offset, GLsizeiptr size)
+                  GLintptr offset, GLsizeiptr size,
+                  GLsizeiptr query_size)
 {
    struct gl_transform_feedback_object *obj =
       ctx->TransformFeedback.CurrentObject;
@@ -407,6 +408,7 @@ bind_buffer_range(struct gl_context *ctx, GLuint index,
 
    obj->Offset[index] = offset;
    obj->Size[index] = size;
+   obj->QuerySize[index] = query_size;
 }
 
 
@@ -450,7 +452,7 @@ _mesa_bind_buffer_range_transform_feedback(struct 
gl_context *ctx,
       return;
    }  
 
-   bind_buffer_range(ctx, index, bufObj, offset, size);
+   bind_buffer_range(ctx, index, bufObj, offset, size, size);
 }
 
 
@@ -485,7 +487,7 @@ _mesa_bind_buffer_base_transform_feedback(struct gl_context 
*ctx,
     */
    size = bufObj->Size & ~0x3;
 
-   bind_buffer_range(ctx, index, bufObj, 0, size);
+   bind_buffer_range(ctx, index, bufObj, 0, size, 0);
 }
 
 
@@ -546,7 +548,7 @@ _mesa_BindBufferOffsetEXT(GLenum target, GLuint index, 
GLuint buffer,
     */
    size = (bufObj->Size - offset) & ~0x3;
 
-   bind_buffer_range(ctx, index, bufObj, offset, size);
+   bind_buffer_range(ctx, index, bufObj, offset, size, 0);
 }
 
 
-- 
1.8.0.2

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