testviewport.c

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Author : Sam Lantinga
Date : 2013-11-15 22:05:26
Hash : 44959a21
Message : Added viewport test, contributed by Andreas Schiffler and improved by me and Ryan Gordon. If it works correctly you should see a square moving from the upper left to the lower right, with a little yellow box at the top of the moving square. You can pass --target as a command line option to have it use a render target instead of rendering directly to the screen. The output should be identical in this case.
test/testviewport.c
/*
  Copyright (C) 1997-2013 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:  Check viewports */

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

#include "SDL_test.h"
#include "SDL_test_common.h"


static SDLTest_CommonState *state;

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void
quit(int rc)
{
    SDLTest_CommonQuit(state);
    exit(rc);
}

void
DrawOnViewport(SDL_Renderer * renderer, SDL_Rect viewport)
{    
    SDL_Rect rect;

    /* Set the viewport */
    SDL_RenderSetViewport(renderer, &viewport);
    
    /* Draw a gray background */
    SDL_SetRenderDrawColor(renderer, 0x80, 0x80, 0x80, 0xFF);
    SDL_RenderClear(renderer);

    /* Test inside points */
    SDL_SetRenderDrawColor(renderer, 0xFF, 0xFF, 0xF, 0xFF);
    SDL_RenderDrawPoint(renderer, viewport.h/2 + 10, viewport.w/2);
    SDL_RenderDrawPoint(renderer, viewport.h/2 - 10, viewport.w/2);
    SDL_RenderDrawPoint(renderer, viewport.h/2     , viewport.w/2 - 10);
    SDL_RenderDrawPoint(renderer, viewport.h/2     , viewport.w/2 + 10);

    /* Test horizontal and vertical lines */
    SDL_SetRenderDrawColor(renderer, 0x00, 0xFF, 0x00, 0xFF);
    SDL_RenderDrawLine(renderer, 1, 0, viewport.w-2, 0);
    SDL_RenderDrawLine(renderer, 1, viewport.h-1, viewport.w-2, viewport.h-1);
    SDL_RenderDrawLine(renderer, 0, 1, 0, viewport.h-2);
    SDL_RenderDrawLine(renderer, viewport.w-1, 1, viewport.w-1, viewport.h-2);

    /* Test diagonal lines */
    SDL_SetRenderDrawColor(renderer, 0x00, 0x00, 0xFF, 0xFF);
    SDL_RenderDrawLine(renderer, 0, 0,
                       viewport.w-1, viewport.h-1);
    SDL_RenderDrawLine(renderer, viewport.w-1, 0,
                       0, viewport.h-1);                      

    /* Test outside points */
    SDL_SetRenderDrawColor(renderer, 0xFF, 0xFF, 0xF, 0xFF);
    SDL_RenderDrawPoint(renderer, viewport.h/2 + viewport.h, viewport.w/2);
    SDL_RenderDrawPoint(renderer, viewport.h/2 - viewport.h, viewport.w/2);
    SDL_RenderDrawPoint(renderer, viewport.h/2     , viewport.w/2 - viewport.w);
    SDL_RenderDrawPoint(renderer, viewport.h/2     , viewport.w/2 + viewport.w);

    /* Add a box at the top */
    rect.w = 8;
    rect.h = 8;
    rect.x = (viewport.w - rect.w) / 2;
    rect.y = 0;
    SDL_RenderFillRect(renderer, &rect);
}

int
main(int argc, char *argv[])
{
    int i, j, done;
    SDL_Event event;
    Uint32 then, now, frames;
    SDL_Rect viewport;
    SDL_bool use_target = SDL_FALSE;

    /* 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], "--target") == 0) {
                use_target = SDL_TRUE;
                consumed = 1;
            }
        }
        if (consumed < 0) {
            SDL_Log("Usage: %s %s [--target]\n",
                    argv[0], SDLTest_CommonUsage(state));
            quit(1);
        }
        i += consumed;
    }
    if (!SDLTest_CommonInit(state)) {
        quit(2);
    }

    if (use_target) {
        int w, h;

        for (i = 0; i < state->num_windows; ++i) {
            SDL_GetWindowSize(state->windows[i], &w, &h);
            state->targets[i] = SDL_CreateTexture(state->renderers[i], SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, w, h);
            SDL_SetRenderTarget(state->renderers[i], state->targets[i]);
        }
    }

    for (i = 0; i < state->num_windows; ++i) {
        SDL_Renderer *renderer = state->renderers[i];
        SDL_SetRenderDrawColor(renderer, 0xA0, 0xA0, 0xA0, 0xFF);
        SDL_RenderClear(renderer);
    }

    /* Main render loop */
    frames = 0;
    then = SDL_GetTicks();
    done = 0;
    j = 0;
    while (!done) {
        /* Check for events */
        ++frames;
        while (SDL_PollEvent(&event)) {
            SDLTest_CommonEvent(state, &event, &done);
        }
        
        /* Move a viewport box in steps around the screen */                
        viewport.x = j * 100;
        viewport.y = viewport.x;
        viewport.w = 100 + j * 50;
        viewport.h = 100 + j * 50;
        j = (j + 1) % 4;            
        SDL_Log("Current Viewport x=%i y=%i w=%i h=%i", viewport.x, viewport.y, viewport.w, viewport.h);
        
        for (i = 0; i < state->num_windows; ++i) {
            if (state->windows[i] == NULL)
                continue;
                
            /* Draw using viewport */        
            DrawOnViewport(state->renderers[i], viewport);

            /* Update the screen! */
            if (use_target) {
                SDL_SetRenderTarget(state->renderers[i], NULL);
                SDL_RenderCopy(state->renderers[i], state->targets[i], NULL, NULL);
                SDL_RenderPresent(state->renderers[i]);
                SDL_SetRenderTarget(state->renderers[i], state->targets[i]);
            } else {
                SDL_RenderPresent(state->renderers[i]);
            }
        }
        
        SDL_Delay(1000);
    }

    /* Print out some timing information */
    now = SDL_GetTicks();
    if (now > then) {
        double fps = ((double) frames * 1000) / (now - then);
        SDL_Log("%2.2f frames per second\n", fps);
    }
    quit(0);
    return 0;
}

/* vi: set ts=4 sw=4 expandtab: */
kc3-lang/SDL/test/testviewport.c

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kc3-lang/SDL /test/testviewport.c
