testdraw2.c

/*
  Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely.
*/

/* Simple program:  draw as many random objects on the screen as possible */

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

#ifdef __EMSCRIPTEN__
#include <emscripten/emscripten.h>
#endif

#include "SDL_test_common.h"

#define NUM_OBJECTS 100

static SDLTest_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;
static Uint32 next_fps_check, frames;
static const Uint32 fps_check_delay = 5000;

int done;

void
DrawPoints(SDL_Renderer * renderer)
{
    int i;
    int x, y;
    SDL_Rect viewport;

    /* Query the sizes */
    SDL_RenderGetViewport(renderer, &viewport);

    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(renderer, 255, (Uint8) current_color,
                               (Uint8) current_color, (Uint8) current_alpha);

        x = rand() % viewport.w;
        y = rand() % viewport.h;
        SDL_RenderDrawPoint(renderer, x, y);
    }
}

void
DrawLines(SDL_Renderer * renderer)
{
    int i;
    int x1, y1, x2, y2;
    SDL_Rect viewport;

    /* Query the sizes */
    SDL_RenderGetViewport(renderer, &viewport);

    for (i = 0; i < num_objects; ++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(renderer, 255, (Uint8) current_color,
                               (Uint8) current_color, (Uint8) current_alpha);

        if (i == 0) {
            SDL_RenderDrawLine(renderer, 0, 0, viewport.w - 1, viewport.h - 1);
            SDL_RenderDrawLine(renderer, 0, viewport.h - 1, viewport.w - 1, 0);
            SDL_RenderDrawLine(renderer, 0, viewport.h / 2, viewport.w - 1, viewport.h / 2);
            SDL_RenderDrawLine(renderer, viewport.w / 2, 0, viewport.w / 2, viewport.h - 1);
        } else {
            x1 = (rand() % (viewport.w*2)) - viewport.w;
            x2 = (rand() % (viewport.w*2)) - viewport.w;
            y1 = (rand() % (viewport.h*2)) - viewport.h;
            y2 = (rand() % (viewport.h*2)) - viewport.h;
            SDL_RenderDrawLine(renderer, x1, y1, x2, y2);
        }
    }
}

void
DrawRects(SDL_Renderer * renderer)
{
    int i;
    SDL_Rect rect;
    SDL_Rect viewport;

    /* Query the sizes */
    SDL_RenderGetViewport(renderer, &viewport);

    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(renderer, 255, (Uint8) current_color,
                               (Uint8) current_color, (Uint8) current_alpha);

        rect.w = rand() % (viewport.h / 2);
        rect.h = rand() % (viewport.h / 2);
        rect.x = (rand() % (viewport.w*2) - viewport.w) - (rect.w / 2);
        rect.y = (rand() % (viewport.h*2) - viewport.h) - (rect.h / 2);
        SDL_RenderFillRect(renderer, &rect);
    }
}

void
loop()
{
    Uint32 now;
    int i;
    SDL_Event event;

    /* Check for events */
    while (SDL_PollEvent(&event)) {
        SDLTest_CommonEvent(state, &event, &done);
    }
    for (i = 0; i < state->num_windows; ++i) {
        SDL_Renderer *renderer = state->renderers[i];
        if (state->windows[i] == NULL)
            continue;
        SDL_SetRenderDrawColor(renderer, 0xA0, 0xA0, 0xA0, 0xFF);
        SDL_RenderClear(renderer);

        DrawRects(renderer);
        DrawLines(renderer);
        DrawPoints(renderer);

        SDL_RenderPresent(renderer);
    }
#ifdef __EMSCRIPTEN__
    if (done) {
        emscripten_cancel_main_loop();
    }
#endif
    frames++;
    now = SDL_GetTicks();
    if (SDL_TICKS_PASSED(now, next_fps_check)) {
        /* Print out some timing information */
        const Uint32 then = next_fps_check - fps_check_delay;
        const double fps = ((double) frames * 1000) / (now - then);
        SDL_Log("%2.2f frames per second\n", fps);
        next_fps_check = now + fps_check_delay;
        frames = 0;
    }

}

int
main(int argc, char *argv[])
{
    int i;

    /* Enable standard application logging */
    SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);

    /* Initialize parameters */
    num_objects = NUM_OBJECTS;

    /* Initialize test framework */
    state = SDLTest_CommonCreateState(argv, SDL_INIT_VIDEO);
    if (!state) {
        return 1;
    }
    for (i = 1; i < argc;) {
        int consumed;

        consumed = SDLTest_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 + 1], "mod") == 0) {
                        blendMode = SDL_BLENDMODE_MOD;
                        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) {
            static const char *options[] = { 
                "[--blend none|blend|add|mod]", 
                "[--cyclecolor]",
                "[--cyclealpha]",
                "[num_objects]",
                NULL };
            SDLTest_CommonLogUsage(state, argv[0], options);
            return 1;
        }
        i += consumed;
    }
    if (!SDLTest_CommonInit(state)) {
        return 2;
    }

    /* Create the windows and initialize the renderers */
    for (i = 0; i < state->num_windows; ++i) {
        SDL_Renderer *renderer = state->renderers[i];
        SDL_SetRenderDrawBlendMode(renderer, blendMode);
        SDL_SetRenderDrawColor(renderer, 0xA0, 0xA0, 0xA0, 0xFF);
        SDL_RenderClear(renderer);
    }

    srand((unsigned int)time(NULL));

    /* Main render loop */
    frames = 0;
    next_fps_check = SDL_GetTicks() + fps_check_delay;
    done = 0;

#ifdef __EMSCRIPTEN__
    emscripten_set_main_loop(loop, 0, 1);
#else
    while (!done) {
        loop();
    }
#endif


    SDLTest_CommonQuit(state);

    return 0;
}

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