Please keep your replies on the list so that others can potentially help/reply.
On 07/10/2013 12:05 PM, Andy Li wrote: > Hi Brain, > > Thank you for your reply. > You were right, my plan is to use OSMesa and draw into malloc'd frame > buffer in my device, so I can display the image on the screen. > > For base functions, what i meant are the drawline() or drawpix() functions. > In other words, I am wondering which are the functions OSMesa used to > draw a line/pixel into the memory (changing the color/rgba value in > frame buffer)? In the swrast code, look at s_lines.c, s_triangle.c, etc. to see how lines and triangles are drawn. In some (simple) cases we can write directly into the framebuffer but other times we call functions like _swrast_write_rgba_span() to do fragment processing/writing. To access the framebuffer's memory we use the ctx->Driver.Map/UnmapRenderbuffer() functions. > Why am I trying to find these functions? The other part of my project is > to rewrite these functions with an accelerator, so that I can speed up > the rendering process with the embedded system I am using. > > Would you be able to give me some info/ suggestions on what I am doing? See above. Otherwise, just study the code for a while. It's not all that complicated. -Brian > > Thanks, > > Andy > > > Date: Wed, 10 Jul 2013 07:49:09 -0600 > > From: bri...@vmware.com > > To: lilap...@hotmail.com > > CC: mesa-dev@lists.freedesktop.org > > Subject: Re: [Mesa-dev] OSMesa Help > > > > On 07/09/2013 11:20 PM, Andy Li wrote: > > > Hello everyone, > > > > > > > > > I have some questions regarding to OSMesa. > > > > > > I am currently working on a project which I have to use Mesa on an > > > embedded system. > > > > > > My current goal is to port the base functions over to the embedded > > > system, so that I can draw a line on a provided VGA screen. > > > > > > Since the embedded system I am using does not contain a GPU, > therefore I > > > have decided to use OSMesa for rendering process. > > > > > > I am wondering if there are any documentations/ specifications for > OSMesa? > > > > End users of OSMesa generally get by on the comments in osmesa.h and the > > example programs. But you're working on the driver implementation side. > > > > > > > Anyone know which are the base functions that OSMesa used for the > > > rendering process? > > > > I don't know what you mean by base functions. In Mesa/master git, the > > OSMesa can either be used with the legacy swrast driver or with the > > gallium softpipe/llvmpipe drivers. > > > > > > > I have looked into src/mesa/swrast/s_lines.c and s_drawpix.c and trying > > > to figure out how the code works, am I in the right direction? > > > > That code is used by the legacy OSMesa driver, but it's also used by the > > old Xlib driver too. > > > > > > > Moreover, for example, if I found a drawpix() function, how do I > know if > > > OSMesa actually used this function during rendering process? Is there > > > any tool/debugger I can use to confirm my findings? > > > > One would normally set a breakpoint on the function in gdb or another > > debugger. > > > > Let's take a few steps back here first. You said you want to display > > graphics on your VGA screen. OSMesa will not do that for you. > > OS=Off-Screen. The whole point of OSMesa is to draw into malloc'd > > framebuffer memory, rather than drawing to a real/displayed framebuffer. > > > > You could use OSMesa and then do some sort of memcpy of the image into > > your devices's actual frame buffer. Is that what you want to do? > > > > -Brian > > _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
