[MSX-C] Q&A official thread

Here goes the revised one, more clear and using #defines. It solves a bug too since SC5 images has a 7bytes header that we must skip:

#include<stdio.h>
#include<glib.h>

#define PAGE0 0x0000
#define PAGE1 0x8000
#define SCREEN5 (TINY)5
#define SCREEN0 (TINY)0
#define BUFSIZE 128
#define COUNT 1

loadimg() {
	FILE *fp;
	char buf[BUFSIZE];
	int i;
	int vrami=PAGE0;
	fp=fopen("arthur4.sc5","rb");
	if(fp==NULL) {
		printf("File read error!");
		return;
	}
	fread(buf,7,COUNT,fp);
	for(i=0; i<213; i++) {
		fread(buf,BUFSIZE,COUNT,fp);
		ldirvm(vrami,buf,BUFSIZE);
		vrami = vrami+BUFSIZE;
	}
	fclose(fp); 
}

main(){
	screen(SCREEN5);
	loadimg();
	getchar();
	screen(SCREEN0);
}

With this function, you can load an image in any VRAM page . Feel free to play with buffer size to test performance. One important question: it still needs palette read.

Let's wait your translation JaviLM

Nice! to make the function more reusable i would introduce some params (filename, page) but that's for the next version
About the palette, according to https://github.com/sharksym/CPMEMU_HI-TECH_C/blob/master/BLG...
It's almost the same routine as for the image, it loads the file (see bl_grp_load_ge5_pat()) and then places it into the VRAM. Maybe it helps, else you have to wait for other solutions :)

Sure, the idea is to make the function reusable: filename, page, even screen. BUFSIZE should calculate dinamically depending on SCREEN mode (128bytes for SC5, 256bytes for SC7/SC8) and the header size I'm not sure if equals in all screens (7 bytes).

For palette, lets wait for JaviLM translation. MSX-C libraries has several palette functions, so I suposse this time it's a good idea to use them instead to make it yourself ;) .

When the final version of both functions were finished, we'll share the source code.

Correct, but a little annotation: we can't access adresses above 0xFFFF, so the only way to load images in pages 2-3 is play with setpg and setting them as active pages.

I've corrected the code, it's not needed to modify bufsize of *fp since the read pointers increases automatically depending the read bytes. This is, if you read 7 bytes, the pointer increases 7. If you read 128 bytes, the pointer increases 128 bytes.

Ok, here's a quick translation of the MSX-C Library manual regarding the color handling functions. Looks pretty straighforward to me, and most likely the function you wanted is rstplt():

VOID color(fore, back, bord)
TINY fore, back, bord;

Changes the foreground, background and border colors of the screen. Doesn't return any value. If you use an invalid color (for example, color 250 under SCREEN 2) then the correct operation of this function is not guaranteed.

VOID iniplt()

Initializes the color palette (and the palette data stored in VRAM) to the default values.

VOID rstplt()

Restore the color palette stored in VRAM.

NAT getplt(pal)
TINY pal;

Returns the contents of the palette register especified by pal. See setplt() for the format of the value returned.

VOID setplt(pal, grbdat)
TINY pal;
NAT grbdat;

Set the palette register indicated by pal and saves it to the VRAM. grbdat is 2 bytes long, but only 12 bits are used, in groups of 4 bits. The meaning of these bits is as follows:

MSB |xxxx+0GGG|0RRR+0BBB| LSB

With GGG, RRR and BBB being the levels of green, red and blue, respectively.