[Mesa-dev] [PATCH 2/2] glsl/cs: Initialize gl_LocalInvocationIndex in main()

[Ian Romanick]

On 08/23/2015 01:50 AM, Jordan Justen wrote:
> We initialize gl_LocalInvocationIndex based on the extension spec
> formula:
> 
>     gl_LocalInvocationIndex =
>         gl_LocalInvocationID.z * gl_WorkGroupSize.x * gl_WorkGroupSize.y +
>         gl_LocalInvocationID.y * gl_WorkGroupSize.x +
>         gl_LocalInvocationID.x;
> 
> https://www.opengl.org/registry/specs/ARB/compute_shader.txt
> 
> Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
> ---
>  src/glsl/builtin_variables.cpp | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/src/glsl/builtin_variables.cpp b/src/glsl/builtin_variables.cpp
> index 8f8be90..082c73a 100644
> --- a/src/glsl/builtin_variables.cpp
> +++ b/src/glsl/builtin_variables.cpp
> @@ -1059,6 +1059,7 @@ builtin_variable_generator::generate_cs_special_vars()
>     add_system_value(SYSTEM_VALUE_WORK_GROUP_ID, glsl_type::uvec3_type,
>                      "gl_WorkGroupID");
>     add_variable("gl_GlobalInvocationID", glsl_type::uvec3_type, ir_var_auto, 0);
> +   add_variable("gl_LocalInvocationIndex", glsl_type::uint_type, ir_var_auto, 0);
>     /* TODO: finish this. */
>  }
>  
> @@ -1217,6 +1218,11 @@ _mesa_glsl_initialize_variables(exec_list *instructions,
>  }
>  
>  
> +using ir_builder::swizzle_x;
> +using ir_builder::swizzle_y;
> +using ir_builder::swizzle_z;
> +
> +

Too man blank lines.

Also... I though that other places did 'using namespace ir_builder;' to
avoid all the ir_builder:: stuff.  It would certainly improve the
readability of the hunk below.

>  /**
>   * Initialize compute shader variables with values that are derived from other
>   * compute shader variable.
> @@ -1249,6 +1255,28 @@ initialize_cs_derived_variables(gl_shader *shader,
>                                                           gl_WorkGroupSize),
>                                           gl_LocalInvocationID));
>     main_sig->body.push_head(inst);
> +
> +   /* gl_LocalInvocationIndex =
> +    *    gl_LocalInvocationID.z * gl_WorkGroupSize.x * gl_WorkGroupSize.y +
> +    *    gl_LocalInvocationID.y * gl_WorkGroupSize.x +
> +    *    gl_LocalInvocationID.x;
> +    */
> +   ir_expression *index_z =
> +      ir_builder::mul(ir_builder::mul(swizzle_z(gl_LocalInvocationID),
> +                                      swizzle_x(gl_WorkGroupSize)),
> +                      swizzle_y(gl_WorkGroupSize));
> +   ir_expression *index_y =
> +      ir_builder::mul(swizzle_y(gl_LocalInvocationID),
> +                      swizzle_x(gl_WorkGroupSize));
> +   ir_expression *index_y_plus_z = ir_builder::add(index_y, index_z);
> +   ir_builder::operand index_x(swizzle_x(gl_LocalInvocationID));
> +   ir_expression *index_x_plus_y_plus_z =
> +      ir_builder::add(index_y_plus_z, index_x);
> +   ir_variable *gl_LocalInvocationIndex =
> +      shader->symbols->get_variable("gl_LocalInvocationIndex");
> +   assert(gl_LocalInvocationIndex);
> +   inst = ir_builder::assign(gl_LocalInvocationIndex, index_x_plus_y_plus_z);
> +   main_sig->body.push_head(inst);
>  }
>  
>