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Just to throw this in: my iOS project Ejecta[1] also does all the Vector drawing on the GPU using OpenGL ES2. It's not as advanced as NVidia's implementation (e

Just to throw this in: my iOS project Ejecta[1] also does all the Vector drawing on the GPU using OpenGL ES2. It's not as advanced as NVidia's implementation (e.g. Ejecta computes all bezier points on the CPU and just draws on the GPU), but it's still much faster than what Apple is doing in CoreGraphics. [1] http://impactjs.com/ejecta http://impactjs.com/ejecta

vanderZwan 13y ago
That is a really cool project, thanks for sharing! > (e.g. Ejecta computes all bezier points on the CPU and just draws on the GPU) I guess that's where the biggest gain comes from with NVIDIA: it's the only pure-GPU option right now, which probably eliminates quite a few bottlenecks. Freeing up the CPU is also never a bad thing.
pbsurf 13y ago
Have you looked into using Loop-Blinn[1] for drawing Beziers? I'd love to be able to use the GPU for vector graphics and Loop-Blinn seems to solve the problem of drawing curves, but I'm still looking for a way to get coverage-based antialiasing when drawing straight lines with the GPU. [1] http://http.developer.nvidia.com/GPUGems3/gpugems3_ch25.html http://http.developer.nvidia.com/GPUGems3/gpugems3_ch25.html - https://github.com/hansent/lbfont https://github.com/hansent/lbfont is a good example
- seanmcdirmid 13y ago
  Anti-aliasing seem to be why we still prefer pixel art over vector art. I thought high-res would eliminate this problem (more pixels, less worry about artifacts), but apparently not yet. The Loop/Blinn work is really cool, and of course we now have hull shaders to really exploit it. It is a problem many people are actively working on...e.g. with Direct2D, but doing everything on the GPU is currently infeasible given round trip times between the CPU and GPU. Great if you can render everything in one pass, not so great if you can't.
simscitizen 13y ago
If you set the drawsAsynchronously or acceleratesDrawing property on a CALayer (the former is public and the latter is private), then the CGContext passed to you in -[CALayer drawsInContext:] or -[UIView drawRect:] will be GPU-accelerated in the same way. WebKit on iOS uses this to accelerate 2D rendering. Having said this, don't go turning this on everywhere, like on every tiny little UILabel. That GPU-accelerated CGContext is rendered in an offscreen pass using render-to-texture so it is often faster to use the CPU. This property was more designed for, say, a full-screen drawing app on a retina iPad that uses a a single screen-sized CGContext for its drawing canvas, or for the Safari case where there are a number of same-sized CGContext tiles to draw into.

vanderZwan 13y ago

That is a really cool project, thanks for sharing! > (e.g. Ejecta computes all bezier points on the CPU and just draws on the GPU) I guess that's where the biggest gain comes from with NVIDIA: it's the only pure-GPU option right now, which probably eliminates quite a few bottlenecks. Freeing up the CPU is also never a bad thing.

pbsurf 13y ago

Have you looked into using Loop-Blinn[1] for drawing Beziers? I'd love to be able to use the GPU for vector graphics and Loop-Blinn seems to solve the problem of drawing curves, but I'm still looking for a way to get coverage-based antialiasing when drawing straight lines with the GPU. [1] http://http.developer.nvidia.com/GPUGems3/gpugems3_ch25.html http://http.developer.nvidia.com/GPUGems3/gpugems3_ch25.html - https://github.com/hansent/lbfont https://github.com/hansent/lbfont is a good example

seanmcdirmid 13y ago
Anti-aliasing seem to be why we still prefer pixel art over vector art. I thought high-res would eliminate this problem (more pixels, less worry about artifacts), but apparently not yet. The Loop/Blinn work is really cool, and of course we now have hull shaders to really exploit it. It is a problem many people are actively working on...e.g. with Direct2D, but doing everything on the GPU is currently infeasible given round trip times between the CPU and GPU. Great if you can render everything in one pass, not so great if you can't.

simscitizen 13y ago

If you set the drawsAsynchronously or acceleratesDrawing property on a CALayer (the former is public and the latter is private), then the CGContext passed to you in -[CALayer drawsInContext:] or -[UIView drawRect:] will be GPU-accelerated in the same way. WebKit on iOS uses this to accelerate 2D rendering. Having said this, don't go turning this on everywhere, like on every tiny little UILabel. That GPU-accelerated CGContext is rendered in an offscreen pass using render-to-texture so it is often faster to use the CPU. This property was more designed for, say, a full-screen drawing app on a retina iPad that uses a a single screen-sized CGContext for its drawing canvas, or for the Safari case where there are a number of same-sized CGContext tiles to draw into.