77 lines
1.6 KiB
C
77 lines
1.6 KiB
C
/*
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Demonstrates the 64x48 multicolor mode.
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This mode is a little tricky to implement,
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but each pixel can have its own color with no
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clashing effects.
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*/
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#include <stdlib.h>
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#include <cv.h>
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#include <cvu.h>
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#include "common.h"
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void multicolor_fullscreen_image_table(word ofs) {
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byte x,y;
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for (y=0; y<48; y++) {
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for (x=0; x<32; x++) {
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cvu_voutb(x + (y>>2)*32, ofs++);
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}
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}
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}
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void setup_multicolor() {
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cvu_vmemset(0, 0, 0x4000);
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cv_set_image_table(IMAGE);
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cv_set_character_pattern_t(PATTERN);
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cv_set_screen_mode(CV_SCREENMODE_MULTICOLOR); // mode 3
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multicolor_fullscreen_image_table(IMAGE);
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}
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typedef void SetPixelFunc(byte x, byte y, byte color);
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void set_pixel(byte x, byte y, byte color) {
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word pg = (x>>1)*8 + (y & 7) + (y & ~7)*32 + PATTERN;
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byte b = cvu_vinb(pg);
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if (x&1)
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b = color | (b & 0xf0);
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else
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b = (color<<4) | (b & 0xf);
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cvu_voutb(b, pg);
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}
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void set_two_pixels(byte x, byte y, byte leftcolor, byte rightcolor) {
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word pg = (x>>1)*8 + (y & 7) + (y & ~7)*32 + PATTERN;
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byte b = rightcolor | (leftcolor << 4);
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cvu_voutb(b, pg);
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}
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void draw_line(int x0, int y0, int x1, int y1, byte color) {
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int dx = abs(x1-x0);
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int sx = x0<x1 ? 1 : -1;
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int dy = abs(y1-y0);
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int sy = y0<y1 ? 1 : -1;
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int err = (dx>dy ? dx : -dy)>>1;
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int e2;
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for(;;) {
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set_pixel(x0, y0, color);
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if (x0==x1 && y0==y1) break;
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e2 = err;
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if (e2 > -dx) { err -= dy; x0 += sx; }
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if (e2 < dy) { err += dx; y0 += sy; }
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}
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}
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#ifdef __MAIN__
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void main() {
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setup_multicolor();
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cv_set_screen_active(true);
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while(1) {
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draw_line(rand()%64, rand()%48, rand()%64, rand()%48, rand()&15);
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}
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while (1);
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}
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#endif
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