The Sinclair QL Forum

stevepoole wrote:<>
Per's RPIX% seems to get that problem right, but the returned (16 bit ?) colours cannot be reused as INK values for shading...

So, is there a way of getting the original 256 INK colours from the 16 bit returned values when using QPC2?
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Any suggestions ? Steve.
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The Knoware RPIX% always returns the "native" colour code, so in mode 16 the value is the 1 byte colour code, and in mode 32/33 the corresponding two byte code. To use those codes to set ink, paper, block colour etc you need to first set the per job colour definition, ie in this case COLOUR_NATIVE. (For the RPIX24 function, set the colour definition to COLOUR_24.)

The colour definition setting is only valid until it is changed, so if you need to switch back to COLOUR_QL you can.

HTH

Derek_Stewart wrote:

XorA wrote:

Derek_Stewart wrote:Hi,

You could also try RPIXL in the QPTR toolkit, does the same thing, and probably written before all the above.

considering this is sQLux could also add an extension to it to do this in emulator space much faster.

HI,

Sounds interesting, can you outline how the emulator space cab be extended?

Look in QL_baseext.c file for examples of basic extensions. I recently added scr_base extension.

stevepoole wrote:Hi Folks,

Following the various suggestions about getting Pixel colours, I have cobbled together a prototype shader for 3d perspective windowing.

It works fine using the DIY Tk PIXEL% under SGC, but on QPC2 it does not seem to fathom out where in memory to look, and returns garbage values. (Screen set to 512x256).

Per's RPIX% seems to get that problem right, but the returned (16 bit ?) colours cannot be reused as INK values for shading...

So, is there a way of getting the original 256 INK colours from the 16 bit returned values when using QPC2?

The prototype is slow under QDOS, faster with SMSQ/E, but nips along under QPC2. But I need to find the solutions to these colour problems...

Any suggestions ? Steve.
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Steve, I presume that when you mention a shader, you are referring to either SBasic or M68k code that runs within the emulator, rather than the OpenGL shaders that have been added to sQLux, which run on the host gpu? The OpenGL shaders have access to colour information at each pixel position.

Are you able to share your prototype code please?

Hi Folks,

Thanks to Dilwyn's site, and advice from Per, I now have a working shader prototype, which is mainly SuperBasic code, and now runs OK under QDOS or QPC2.

I need to tweak it still further to make it fully adaptable. (Pity I haven't seen how the SQLUX shaders operate. Do they ray-trace for example ?).

At present it lifts images off the #2 screen, and wraps them onto any 3d perspective surface orientation, (but only flat ones for the moment).

The code is short and well-tested, and I will put it on the forum as soon as I am sure that it will be fully user-friendly.

But only being one day old, I need a little time before releasing it, as it covers some new ground to me.

Steve.
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stevepoole wrote: Pity I haven't seen how the SQLUX shaders operate. Do they ray-trace for example ?
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Steve, I think what you are doing is different, but complimentary, to the sQLux shaders.

The sQLux shaders perform an in place transformation on the whole QL screen. The output is then displayed instead of the original image, in the screen space that the original image would have occupied. They run at real time, 50 times per second if the screen is being regularly updated. As they are modifying the output in the x-y plane, there is no need for ray tracing. When generating the full set of effects (Scan lines, Shadow mask, Bloom and Screen curvature) the shaders pretty much max out the GPU performance of a Pi0, but I expect that the average PC GPU is barely ticking over

So, you could run your shader program in sQLux, and then run the sQLux shaders as well, to make your output look like it was being displayed on an 80s, CRT, rather than a modern LCD.

Hi Exile,

Thanks for the SQLUX info. I suppose my SuperBasic program should not be called a shader, to avoid confusion. A Texture_Wrapper, perhaps ?

Work is progressing though, and I have included the possibility to wrap photos, using photon's FPIC_LOAD function.

The photo used is a screen shot of an '80s program on my SGC QL to display text at any angle ! (But not in perspective ...).

Next I hope to wrap any textures onto multiple surfaces. Many thanks again to Per for his excellent RPIX.bin !

Steve.

Hi Folks,

Here is a first version of the shader program, now renamed as WRAPPER3D_bas for you to tinker with. First UNZIP to your selected device. (say dos4_)

Then LRESPR RPIX.bin and PHGTK.bin. Type er%=FJPEG(dos4_YourPhoto.jpg,dos4_pic_pic) , with YourPhoto.jpg being smaller than 20ko so as to fit.

RUN, or change the variables sc (.5 1 2 4) , direction (-360 to 360) , angle ( 10 to 90 ) , slope ( +/- 10 to 85 ), xs (+/- .75 ) , ys ( +/- 1 ) ;

SC is scale factor : DIRECTION to look at the image : ANGLE step clockwise around image : SLOPE to look up or down : XS and YS invert the images...

Row and column details can also be changed, but for the moment I have not implemented them. (future versions will). <<< Tested on QPC2 >>>

Experiment by modifying the Channel#2 screen background in INIT... Regards, Steve.

Hi Folks,
Here is a QL image you have all seen, converted ready for the Wrapper 3D program, (to save you reducing jpegs using PAINT).

Steve. PS: All acknowledgements to Per and Photon for their excellent toolkits.....

stevepoole wrote:Hi Folks,

Here is a first version of the shader program, now renamed as WRAPPER3D_bas for you to tinker with.<>

Nice one, Steve
But I cant help thinking that it would be easier to "tinker" if youd tidy your code a bit so those of us who didnt write it can see whats going on
Im sure theres room to speed things up a little, like by keeping repeated calculations outside of loops (PI*2 leaps out at one but I suspect theres more..) It may not amount to much in the end, but every little helps.
And whats the issue with ATAN? If there are bugs we should know - and try to fix them.
Perhaps time to move this thread elsewhere?
Keep QLing!

Hi,

I can not get this to run on sQLux, czn you give me some hints how to get more colours on sQLux?