How does the patent application US 2011/0037768 “System for Emulating Graphics Operations” filed by Apple (filing date Oct 15, 2010) differ from Microsoft's DirectX/DirectDraw HEL (Hardware Emulation Layer) which has been around for a couple of decades? Issued patent US8040353.
Here are the first few claims:
1. A method of creating an image, the method comprising:
- receiving a request to render a polygon having a plurality of pixels, the polygon represented by a programmable graphics processing unit (GPU) fragment program, the programmable GPU program comprising a plurality of programmable GPU fragment programs;
- converting the programmable GPU program to a central processing unit (CPU) program;
- unrolling a loop in the CPU program such that the unrolled loop will process N of the plurality of pixels;
- executing, by a CPU, the unrolled loop a variable number of times; and
- rendering the N pixels in groups of L pixels, by executing, by the CPU, the unrolled loop L/N times.
2. The method of claim 1 wherein the act of rendering comprises performing texture lookups for each group of L pixels before rendering any of the L pixels.
3. The method of claim 1 further comprising:
- dividing the polygon into sections;
- selecting a first section for rendering; and
- selecting a first scan line in the first section for rendering.