st/mesa: simplify determination whether a draw needs min/max index

Reviewed-by: Mathias Fröhlich <mathias.froehlich@web.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3829>

src/mesa/main/arrayobj.c

@@ -611,9 +611,12 @@ _mesa_update_vao_derived_arrays(struct gl_context *ctx,
    const GLbitfield enabled = vao->Enabled;
    /* VBO array bits. */
    const GLbitfield vbos = vao->VertexAttribBufferMask;
+   const GLbitfield divisor_is_nonzero = vao->NonZeroDivisorMask;
 
    /* Compute and store effectively enabled and mapped vbo arrays */
    vao->_EffEnabledVBO = _mesa_vao_enable_to_vp_inputs(mode, enabled & vbos);
+   vao->_EffEnabledNonZeroDivisor =
+      _mesa_vao_enable_to_vp_inputs(mode, enabled & divisor_is_nonzero);
    /* Walk those enabled arrays that have a real vbo attached */
    GLbitfield mask = enabled;
    while (mask) {

src/mesa/main/arrayobj.h

@@ -211,6 +211,20 @@ _mesa_draw_user_array_bits(const struct gl_context *ctx)
 }
 
 
+/**
+ * Return which enabled vertex attributes have a non-zero instance divisor.
+ *
+ * Needs the a fully updated VAO ready for draw.
+ */
+static inline GLbitfield
+_mesa_draw_nonzero_divisor_bits(const struct gl_context *ctx)
+{
+   const struct gl_vertex_array_object *const vao = ctx->Array._DrawVAO;
+   assert(vao->NewArrays == 0);
+   return ~vao->_EffEnabledNonZeroDivisor & ctx->Array._DrawVAOEnabledAttribs;
+}
+
+
 /**
  * Return enabled current values attribute bits for draw.
  */

src/mesa/main/attrib.c

@@ -1580,8 +1580,10 @@ copy_array_object(struct gl_context *ctx,
    /* Enabled must be the same than on push */
    dest->Enabled = src->Enabled;
    dest->_EffEnabledVBO = src->_EffEnabledVBO;
+   dest->_EffEnabledNonZeroDivisor = src->_EffEnabledNonZeroDivisor;
    /* The bitmask of bound VBOs needs to match the VertexBinding array */
    dest->VertexAttribBufferMask = src->VertexAttribBufferMask;
+   dest->NonZeroDivisorMask = src->NonZeroDivisorMask;
    dest->_AttributeMapMode = src->_AttributeMapMode;
    dest->NewArrays = src->NewArrays;
 }

src/mesa/main/mtypes.h

@@ -1547,6 +1547,9 @@ struct gl_vertex_array_object
    /** Mask indicating which vertex arrays have vertex buffer associated. */
    GLbitfield VertexAttribBufferMask;
 
+   /** Mask indicating which vertex arrays have a non-zero instance divisor. */
+   GLbitfield NonZeroDivisorMask;
+
    /** Mask of VERT_BIT_* values indicating which arrays are enabled */
    GLbitfield Enabled;
 
@@ -1559,6 +1562,9 @@ struct gl_vertex_array_object
     */
    GLbitfield _EffEnabledVBO;
 
+   /** Same as _EffEnabledVBO, but for instance divisors. */
+   GLbitfield _EffEnabledNonZeroDivisor;
+
    /** Denotes the way the position/generic0 attribute is mapped */
    gl_attribute_map_mode _AttributeMapMode;
 

src/mesa/main/varray.c

@@ -174,6 +174,11 @@ _mesa_vertex_attrib_binding(struct gl_context *ctx,
       else
          vao->VertexAttribBufferMask &= ~array_bit;
 
+      if (vao->BufferBinding[bindingIndex].InstanceDivisor)
+         vao->NonZeroDivisorMask |= array_bit;
+      else
+         vao->NonZeroDivisorMask &= ~array_bit;
+
       vao->BufferBinding[array->BufferBindingIndex]._BoundArrays &= ~array_bit;
       vao->BufferBinding[bindingIndex]._BoundArrays |= array_bit;
 
@@ -250,6 +255,12 @@ vertex_binding_divisor(struct gl_context *ctx,
 
    if (binding->InstanceDivisor != divisor) {
       binding->InstanceDivisor = divisor;
+
+      if (divisor)
+         vao->NonZeroDivisorMask |= binding->_BoundArrays;
+      else
+         vao->NonZeroDivisorMask &= ~binding->_BoundArrays;
+
       vao->NewArrays |= vao->Enabled & binding->_BoundArrays;
    }
 }

src/mesa/state_tracker/st_atom_array.c

@@ -143,6 +143,8 @@ st_setup_arrays(struct st_context *st,
    GLbitfield userbuf_attribs = inputs_read & _mesa_draw_user_array_bits(ctx);
 
    *has_user_vertex_buffers = userbuf_attribs != 0;
+   st->draw_needs_minmax_index =
+      (userbuf_attribs & ~_mesa_draw_nonzero_divisor_bits(ctx)) != 0;
 
    while (mask) {
       /* The attribute index to start pulling a binding */
@@ -164,9 +166,6 @@ st_setup_arrays(struct st_context *st,
          vbuffer[bufidx].buffer.user = ptr;
          vbuffer[bufidx].is_user_buffer = true;
          vbuffer[bufidx].buffer_offset = 0;
-
-         if (!binding->InstanceDivisor)
-            st->draw_needs_minmax_index = true;
       }
       vbuffer[bufidx].stride = binding->Stride; /* in bytes */
 
@@ -296,8 +295,6 @@ st_update_array(struct st_context *st)
    unsigned num_velements;
    bool uses_user_vertex_buffers;
 
-   st->draw_needs_minmax_index = false;
-
    /* ST_NEW_VERTEX_ARRAYS alias ctx->DriverFlags.NewArray */
    /* Setup arrays */
    st_setup_arrays(st, vp, vp_variant, velements, vbuffer, &num_vbuffers,