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testintersections.c
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/* Simple program: draw as many random objects on the screen as possible */
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include "common.h"
#define SWAP(typ,a,b) do{typ t=a;a=b;b=t;}while(0)
#define NUM_OBJECTS 100
static CommonState *state;
static int num_objects;
static SDL_bool cycle_color;
static SDL_bool cycle_alpha;
static int cycle_direction = 1;
static int current_alpha = 255;
static int current_color = 255;
static SDL_BlendMode blendMode = SDL_BLENDMODE_NONE;
void
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DrawPoints(SDL_Window * window)
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{
int i;
int x, y;
int window_w, window_h;
/* Query the sizes */
SDL_GetWindowSize(window, &window_w, &window_h);
SDL_SetRenderDrawBlendMode(blendMode);
for (i = 0; i < num_objects * 4; ++i) {
/* Cycle the color and alpha, if desired */
if (cycle_color) {
current_color += cycle_direction;
if (current_color < 0) {
current_color = 0;
cycle_direction = -cycle_direction;
}
if (current_color > 255) {
current_color = 255;
cycle_direction = -cycle_direction;
}
}
if (cycle_alpha) {
current_alpha += cycle_direction;
if (current_alpha < 0) {
current_alpha = 0;
cycle_direction = -cycle_direction;
}
if (current_alpha > 255) {
current_alpha = 255;
cycle_direction = -cycle_direction;
}
}
SDL_SetRenderDrawColor(255, (Uint8) current_color,
(Uint8) current_color, (Uint8) current_alpha);
x = rand() % window_w;
y = rand() % window_h;
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SDL_RenderDrawPoint(x, y);
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}
SDL_SetRenderDrawBlendMode(SDL_BLENDMODE_NONE);
}
#define MAX_LINES 16
int num_lines = 0;
SDL_Rect lines[MAX_LINES];
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static int
add_line(int x1, int y1, int x2, int y2)
{
if (num_lines >= MAX_LINES)
return 0;
if ((x1 == x2) && (y1 == y2))
return 0;
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printf("adding line (%d, %d), (%d, %d)\n", x1, y1, x2, y2);
lines[num_lines].x = x1;
lines[num_lines].y = y1;
lines[num_lines].w = x2;
lines[num_lines].h = y2;
return ++num_lines;
}
void
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DrawLines(SDL_Window * window)
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{
int i;
int x1, y1, x2, y2;
int window_w, window_h;
/* Query the sizes */
SDL_GetWindowSize(window, &window_w, &window_h);
SDL_SetRenderDrawBlendMode(blendMode);
for (i = 0; i < num_lines; ++i) {
SDL_SetRenderDrawColor(255, 255, 255, 255);
if (i == -1) {
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SDL_RenderDrawLine(0, 0, window_w - 1, window_h - 1);
SDL_RenderDrawLine(0, window_h - 1, window_w - 1, 0);
SDL_RenderDrawLine(0, window_h / 2, window_w - 1, window_h / 2);
SDL_RenderDrawLine(window_w / 2, 0, window_w / 2, window_h - 1);
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} else {
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SDL_RenderDrawLine(lines[i].x, lines[i].y, lines[i].w, lines[i].h);
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}
}
SDL_SetRenderDrawBlendMode(SDL_BLENDMODE_NONE);
}
#define MAX_RECTS 16
int num_rects = 0;
SDL_Rect rects[MAX_RECTS];
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static int
add_rect(int x1, int y1, int x2, int y2)
{
if (num_rects >= MAX_RECTS)
return 0;
if ((x1 == x2) || (y1 == y2))
return 0;
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if (x1 > x2)
SWAP(int, x1, x2);
if (y1 > y2)
SWAP(int, y1, y2);
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printf("adding rect (%d, %d), (%d, %d) [%dx%d]\n", x1, y1, x2, y2,
x2 - x1, y2 - y1);
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rects[num_rects].x = x1;
rects[num_rects].y = y1;
rects[num_rects].w = x2 - x1;
rects[num_rects].h = y2 - y1;
return ++num_rects;
}
static void
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DrawRects(SDL_Window * window)
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{
int i;
int window_w, window_h;
/* Query the sizes */
SDL_GetWindowSize(window, &window_w, &window_h);
SDL_SetRenderDrawBlendMode(SDL_BLENDMODE_NONE);
for (i = 0; i < num_rects; ++i) {
SDL_SetRenderDrawColor(255, 127, 0, 255);
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SDL_RenderFillRect(&rects[i]);
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}
SDL_SetRenderDrawBlendMode(SDL_BLENDMODE_NONE);
}
static void
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DrawRectLineIntersections(SDL_Window * window)
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{
int i, j, window_w, window_h;
/* Query the sizes */
SDL_GetWindowSize(window, &window_w, &window_h);
SDL_SetRenderDrawBlendMode(SDL_BLENDMODE_NONE);
for (i = 0; i < num_rects; i++)
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for (j = 0; j < num_lines; j++) {
int x1, y1, x2, y2;
SDL_Rect r;
r = rects[i];
x1 = lines[j].x;
y1 = lines[j].y;
x2 = lines[j].w;
y2 = lines[j].h;
if (SDL_IntersectRectAndLine(&r, &x1, &y1, &x2, &y2)) {
SDL_SetRenderDrawColor(0, 255, 55, 255);
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SDL_RenderDrawLine(x1, y1, x2, y2);
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}
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}
SDL_SetRenderDrawBlendMode(SDL_BLENDMODE_NONE);
}
static void
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DrawRectRectIntersections(SDL_Window * window)
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{
int i, j;
SDL_SetRenderDrawBlendMode(SDL_BLENDMODE_NONE);
for (i = 0; i < num_rects; i++)
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for (j = i + 1; j < num_rects; j++) {
SDL_Rect r;
if (SDL_IntersectRect(&rects[i], &rects[j], &r)) {
SDL_SetRenderDrawColor(255, 200, 0, 255);
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SDL_RenderFillRect(&r);
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}
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}
SDL_SetRenderDrawBlendMode(SDL_BLENDMODE_NONE);
}
int
main(int argc, char *argv[])
{
int mouse_begin_x = -1, mouse_begin_y = -1;
int i, done;
SDL_Event event;
Uint32 then, now, frames;
/* Initialize parameters */
num_objects = NUM_OBJECTS;
/* Initialize test framework */
state = CommonCreateState(argv, SDL_INIT_VIDEO);
if (!state) {
return 1;
}
for (i = 1; i < argc;) {
int consumed;
consumed = CommonArg(state, i);
if (consumed == 0) {
consumed = -1;
if (SDL_strcasecmp(argv[i], "--blend") == 0) {
if (argv[i + 1]) {
if (SDL_strcasecmp(argv[i + 1], "none") == 0) {
blendMode = SDL_BLENDMODE_NONE;
consumed = 2;
} else if (SDL_strcasecmp(argv[i + 1], "blend") == 0) {
blendMode = SDL_BLENDMODE_BLEND;
consumed = 2;
} else if (SDL_strcasecmp(argv[i + 1], "add") == 0) {
blendMode = SDL_BLENDMODE_ADD;
consumed = 2;
}
}
} else if (SDL_strcasecmp(argv[i], "--cyclecolor") == 0) {
cycle_color = SDL_TRUE;
consumed = 1;
} else if (SDL_strcasecmp(argv[i], "--cyclealpha") == 0) {
cycle_alpha = SDL_TRUE;
consumed = 1;
} else if (SDL_isdigit(*argv[i])) {
num_objects = SDL_atoi(argv[i]);
consumed = 1;
}
}
if (consumed < 0) {
fprintf(stderr,
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"Usage: %s %s [--blend none|blend|add] [--cyclecolor] [--cyclealpha]\n",
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argv[0], CommonUsage(state));
return 1;
}
i += consumed;
}
if (!CommonInit(state)) {
return 2;
}
/* Create the windows and initialize the renderers */
for (i = 0; i < state->num_windows; ++i) {
SDL_SelectRenderer(state->windows[i]);
SDL_SetRenderDrawColor(0xA0, 0xA0, 0xA0, 0xFF);
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SDL_RenderClear();
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}
srand(time(NULL));
/* Main render loop */
frames = 0;
then = SDL_GetTicks();
done = 0;
while (!done) {
/* Check for events */
++frames;
while (SDL_PollEvent(&event)) {
CommonEvent(state, &event, &done);
switch (event.type) {
case SDL_MOUSEBUTTONDOWN:
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mouse_begin_x = event.button.x;
mouse_begin_y = event.button.y;
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break;
case SDL_MOUSEBUTTONUP:
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if (event.button.button == 3)
add_line(mouse_begin_x, mouse_begin_y, event.button.x,
event.button.y);
if (event.button.button == 1)
add_rect(mouse_begin_x, mouse_begin_y, event.button.x,
event.button.y);
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break;
case SDL_KEYDOWN:
switch (event.key.keysym.sym) {
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case 'l':
if (event.key.keysym.mod & KMOD_SHIFT)
num_lines = 0;
else
add_line(rand() % 640, rand() % 480, rand() % 640,
rand() % 480);
break;
case 'r':
if (event.key.keysym.mod & KMOD_SHIFT)
num_rects = 0;
else
add_rect(rand() % 640, rand() % 480, rand() % 640,
rand() % 480);
break;
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}
break;
case SDL_WINDOWEVENT:
switch (event.window.event) {
case SDL_WINDOWEVENT_EXPOSED:
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SDL_SelectRenderer(SDL_GetWindowFromID(event.window.windowID));
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SDL_SetRenderDrawColor(0xA0, 0xA0, 0xA0, 0xFF);
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SDL_RenderClear();
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break;
}
break;
default:
break;
}
}
for (i = 0; i < state->num_windows; ++i) {
SDL_SelectRenderer(state->windows[i]);
SDL_SetRenderDrawColor(0xA0, 0xA0, 0xA0, 0xFF);
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SDL_RenderClear();
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DrawRects(state->windows[i]);
DrawPoints(state->windows[i]);
DrawRectRectIntersections(state->windows[i]);
DrawLines(state->windows[i]);
DrawRectLineIntersections(state->windows[i]);
SDL_RenderPresent();
}
}
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CommonQuit(state);
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/* Print out some timing information */
now = SDL_GetTicks();
if (now > then) {
double fps = ((double) frames * 1000) / (now - then);
printf("%2.2f frames per second\n", fps);
}
return 0;
}
/* vi: set ts=4 sw=4 expandtab: */