Abstract: A data processing apparatus and method are provided for tracing activities of a shader program executed on shader circuitry of a data processing apparatus. The data processing apparatus comprises shader circuitry which is responsive to input data for a pixel to execute a shader program to generate a color value for the pixel. The shader program has multiple execution paths via which the color value may be generated, and which execution path is taken is dependent on the input data. An image buffer having a plurality of storage locations is provided, with each storage location being used to store the color value generated by the shader circuitry for an associated pixel. In a trace mode of operation, execution of the shader program by the shader circuitry causes a trace vector to be generated containing a plurality of items of execution path information indicative of the execution path taken, the trace vector comprising a plurality of fields, each field being used to store one item of execution path information.

Abstract: A data processing apparatus and method are provided for tracing activities of a shader program executed on shader circuitry of a data processing apparatus. The data processing apparatus comprises shader circuitry which is responsive to input data for a pixel to execute a shader program to generate a colour value for the pixel. The shader program has multiple execution paths via which the colour value may be generated, and which execution path is taken is dependent on the input data. An image buffer having a plurality of storage locations is provided, with each storage location being used to store the colour value generated by the shader circuitry for an associated pixel.