mirror of https://github.com/OpenRCT2/OpenRCT2.git
150 lines
3.8 KiB
C
150 lines
3.8 KiB
C
/*****************************************************************************
|
|
* Copyright (c) 2014 Ted John, Peter Hill, Duncan Frost
|
|
* OpenRCT2, an open source clone of Roller Coaster Tycoon 2.
|
|
*
|
|
* This file is part of OpenRCT2.
|
|
*
|
|
* OpenRCT2 is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*****************************************************************************/
|
|
|
|
#include "drawing.h"
|
|
|
|
/*
|
|
* Draws a horizontal line of specified colour to a buffer.
|
|
* rct2: 0x0068474C
|
|
*/
|
|
void gfx_draw_line_on_buffer(rct_drawpixelinfo *dpi, char colour, int y, int x, int no_pixels)
|
|
{
|
|
y -= dpi->y;
|
|
|
|
//Check to make sure point is in the y range
|
|
if (y < 0)return;
|
|
if (y >= dpi->height)return;
|
|
//Check to make sure we are drawing at least a pixel
|
|
if (!no_pixels) no_pixels++;
|
|
|
|
x -= dpi->x;
|
|
|
|
//If x coord outside range leave
|
|
if (x < 0){
|
|
//Unless the number of pixels is enough to be in range
|
|
no_pixels += x;
|
|
if (no_pixels <= 0)return;
|
|
//Resets starting point to 0 as we don't draw outside the range
|
|
x = 0;
|
|
}
|
|
|
|
//Ensure that the end point of the line is within range
|
|
if (x + no_pixels - dpi->width > 0){
|
|
//If the end point has any pixels outside range
|
|
//cut them off. If there are now no pixels return.
|
|
no_pixels -= x + no_pixels - dpi->width;
|
|
if (no_pixels <= 0)return;
|
|
}
|
|
|
|
char* bits_pointer;
|
|
//Get the buffer we are drawing to and move to the first coordinate.
|
|
bits_pointer = dpi->bits + y*(dpi->pitch + dpi->width) + x;
|
|
|
|
//Draw the line to the specified colour
|
|
for (; no_pixels > 0; --no_pixels, ++bits_pointer){
|
|
*((uint8*)bits_pointer) = colour;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Draws a line on dpi if within dpi boundaries
|
|
* rct2: 0x00684466
|
|
* dpi (edi)
|
|
* x1 (ax)
|
|
* y1 (bx)
|
|
* x2 (cx)
|
|
* y2 (dx)
|
|
* colour (ebp)
|
|
*/
|
|
void gfx_draw_line(rct_drawpixelinfo *dpi, int x1, int y1, int x2, int y2, int colour)
|
|
{
|
|
// Check to make sure the line is within the drawing area
|
|
if ((x1 < dpi->x) && (x2 < dpi->x)){
|
|
return;
|
|
}
|
|
|
|
if ((y1 < dpi->y) && (y2 < dpi->y)){
|
|
return;
|
|
}
|
|
|
|
if ((x1 >(dpi->x + dpi->width)) && (x2 >(dpi->x + dpi->width))){
|
|
return;
|
|
}
|
|
|
|
if ((y1 > (dpi->y + dpi->height)) && (y2 > (dpi->y + dpi->height))){
|
|
return;
|
|
}
|
|
|
|
//Bresenhams algorithm
|
|
|
|
//If vertical plot points upwards
|
|
int steep = abs(y2 - y1) > abs(x2 - x1);
|
|
if (steep){
|
|
int temp_y2 = y2;
|
|
int temp_x2 = x2;
|
|
y2 = x1;
|
|
x2 = y1;
|
|
y1 = temp_x2;
|
|
x1 = temp_y2;
|
|
}
|
|
|
|
//If line is right to left swap direction
|
|
if (x1 > x2){
|
|
int temp_y2 = y2;
|
|
int temp_x2 = x2;
|
|
y2 = y1;
|
|
x2 = x1;
|
|
y1 = temp_y2;
|
|
x1 = temp_x2;
|
|
}
|
|
|
|
int delta_x = x2 - x1;
|
|
int delta_y = abs(y2 - y1);
|
|
int error = delta_x / 2;
|
|
int y_step;
|
|
int y = y1;
|
|
|
|
//Direction of step
|
|
if (y1 < y2)y_step = 1;
|
|
else y_step = -1;
|
|
|
|
for (int x = x1, x_start = x1, no_pixels = 1; x < x2; ++x,++no_pixels){
|
|
//Vertical lines are drawn 1 pixel at a time
|
|
if (steep)gfx_draw_line_on_buffer(dpi, colour, x, y, 1);
|
|
|
|
error -= delta_y;
|
|
if (error < 0){
|
|
//Non vertical lines are drawn with as many pixels in a horizontal line as possible
|
|
if (!steep)gfx_draw_line_on_buffer(dpi, colour, y, x_start, no_pixels);
|
|
|
|
//Reset non vertical line vars
|
|
x_start = x + 1;
|
|
no_pixels = 1;
|
|
y += y_step;
|
|
error += delta_x;
|
|
}
|
|
|
|
//Catch the case of the last line
|
|
if (x + 1 == x2 && !steep){
|
|
gfx_draw_line_on_buffer(dpi, colour, y, x_start, no_pixels);
|
|
}
|
|
}
|
|
return;
|
|
} |