Enhanced early coverage discard using opportunistic bypassing and dynamic queue resizing

A method to reduce overdraw of primitives in a graphics processing unit (GPU), the method comprising:

• determining, in a pipeline stage of the GPU, an occlusion index (OI) for a first tile of one or more tiles of a batch of graphical data, each tile comprising one or more blocks of graphical data;
• entering masks into an early coverage discard (ECD) first-in, first out (FIFO) memory in a depth unit of the GPU based on the OI for the first tile being greater than a first threshold value, each mask corresponding to a primitive of the first tile and each primitive being represented in a corresponding mask by element values of the mask, a primitive represented in a first mask being evaluated with respect to a primitive represented in a second mask that is entered into the ECD FIFO memory after the first mask, and element values of the first mask being changed based on the primitive in the second mask occluding the first primitive;
• and
• changing a queue length of the ECD FIFO memory for the first tile based on the OI for the first tile being greater than the first threshold value and less than a second threshold value, the second threshold value being greater than the first threshold value.

A depth unit for a graphics processing unit (GPU), the depth unit comprising:

• an early coverage discard (ECD) first-in, first-out (FIFO) memory;
• and
• a comparator that compares an occlusion index (OI) for a first tile against a first threshold value, the first tile comprising one of one or more tiles of a batch of graphical data,
• the depth unit being configured to bypass blocks of the first tile from the ECD FIFO memory based on the OI for the first tile being less than the first threshold value and enter masks into the ECD FIFO memory based on the OI for the first tile being greater than the first threshold value, each mask corresponding to a primitive of the first tile and each primitive being represented in a corresponding mask by element values of the mask, a primitive represented in a first mask being evaluated with respect to a primitive represented in a second mask that is entered into the ECD FIFO memory after the first mask, and element values of the first mask being changed based on the primitive in the second mask occluding the first primitive.