demo_bitblit.c

/*****************************************************************************
 * MIDRES Library - an isomorphic gamelib for retrocomputers                 *
 *****************************************************************************
 * Copyright 2020-2021 Marco Spedaletti (asimov@mclink.it)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *----------------------------------------------------------------------------
 * Concesso in licenza secondo i termini della Licenza Apache, versione 2.0
 * (la "Licenza"); è proibito usare questo file se non in conformità alla
 * Licenza. Una copia della Licenza è disponibile all'indirizzo:
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Se non richiesto dalla legislazione vigente o concordato per iscritto,
 * il software distribuito nei termini della Licenza è distribuito
 * "COSÌ COM'È", SENZA GARANZIE O CONDIZIONI DI ALCUN TIPO, esplicite o
 * implicite. Consultare la Licenza per il testo specifico che regola le
 * autorizzazioni e le limitazioni previste dalla medesima.
 ****************************************************************************/

#ifdef __DEMO_BITBLIT__

 /****************************************************************************
  ** INCLUDE SECTION
  ****************************************************************************/

#include <stdio.h>

#include "main.h"
#include "midres.h"

/****************************************************************************
 ** RESIDENT VARIABLES SECTION
 ****************************************************************************/

// All variables defined as global within the resident body of the code are 
// accessible from all modules, both resident and changing ones.

// Width and height of the sprite, in mixels.
#define		SPRITE_WIDTH		10
#define		SPRITE_HEIGHT		10

// Speed of the sprite, in mixels/frame
#define		SPRITE_SPEED		2

// Or with "mr_blitop_color" if you want to have a colored sprite:
// in this case, however, you will have color clashes.
#define		SPRITE_COLOR		mr_blitop_set

// Position of the sprite on the screen.
int x = 0, y = 0;

// Speed along abscissa and ordinate, in mixels/frame
int dx = SPRITE_SPEED, dy = SPRITE_SPEED;

// This flag is used to know if the background has been saved.
unsigned char p = 0;

// Position of last saved background.
int px = 0, py = 0;

/****************************************************************************
 ** RESIDENT FUNCTIONS SECTION
 ****************************************************************************/

// All the functions defined within the resident body of the code are 
// accessible from all modules, both resident and changing ones.

// Generate a color sprite and save it on the auxiliary screen 
// at (0,0)-(SPRITE_WIDTH, SPRITE_HEIGHT)
void create_sprite() {
	mr_recte(0, 0, SPRITE_WIDTH-1, SPRITE_HEIGHT-1, MR_COLOR_YELLOW);
	mr_linee(0, 0, SPRITE_WIDTH - 1, SPRITE_HEIGHT - 1, MR_COLOR_RED);
	mr_linee(SPRITE_WIDTH - 1, 0, 0, SPRITE_HEIGHT - 1, MR_COLOR_RED);
	mr_blit_from_screene(0, 0, SPRITE_WIDTH, SPRITE_HEIGHT, MR_AUX_DEFAULT, 0, 0, SPRITE_COLOR);
	mr_clear_bitmape();
}

// Draw the color sprite on the screen.
void draw_sprite() {

	// If needed, restore the screen. The saved background is
	// at position (SPRITE_WIDTH+1,0).
	if (p > 0) {
		mr_blit_to_screene(MR_AUX_DEFAULT,
				SPRITE_WIDTH+1, 0, SPRITE_WIDTH, SPRITE_HEIGHT, 
				px, py, mr_blitop_set | mr_blitop_color);
	}

	// Save the background.
	mr_blit_from_screene( x, y, SPRITE_WIDTH, SPRITE_HEIGHT, 
		MR_AUX_DEFAULT, SPRITE_WIDTH+1, 0,
				mr_blitop_set | mr_blitop_color);
	
	// Draw the sprite.
	mr_blit_to_screene(MR_AUX_DEFAULT, 0, 0, SPRITE_WIDTH, SPRITE_HEIGHT,
			x, y, 
			SPRITE_COLOR);

	// Save the fact we draw the sprite at position given.
	p = 1;
	px = x;
	py = y; 

}

void demo_bitblit() {

	// Initialize the graphical subsystem.
	mr_init();

	// Enable the double buffering.
	mr_doublebuffer_init();

	// Clear all involved screens.
	mr_clear_bitmap(MR_AUX_DEFAULT);
	mr_clear_bitmapv();
	mr_clear_bitmape();

	// Update the frame.
	mr_doublebuffer_switch();

	// Create a sprite to move.
	create_sprite();

	// Endless loop.
	while (1) {
		
		// Draw the sprite on the screen
		draw_sprite();
		
		// Update the screen
		mr_doublebuffer_switch();

		// Move the sprite along the direction.
		x = x + dx;
		y = y + dy;

		// Change direction if we are going to hit the borders.
		if ((x + SPRITE_WIDTH+1) >= MR_SCREEN_WIDTH * 2) {
			dx = -dx;
		}
		if ((y + SPRITE_HEIGHT+1) >= (MR_SCREEN_HEIGHT) * 2) {
			dy = -dy;
		}
		if (x == 0) {
			dx = -dx;
		}
		if (y == 0) {
			dy = -dy;
		}


	}

}

#endif