SDL/test/testrendertarget.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:  Move N sprites around on the screen as fast as possible */

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

#include "SDL_test_common.h"


static SDLTest_CommonState *state;

typedef struct {
    SDL_Window *window;
    SDL_Renderer *renderer;
    SDL_Texture *background;
    SDL_Texture *sprite;
    SDL_Rect sprite_rect;
    int scale_direction;
} DrawState;

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

SDL_Texture *
LoadTexture(SDL_Renderer *renderer, char *file, SDL_bool transparent)
{
    SDL_Surface *temp;
    SDL_Texture *texture;

    /* Load the sprite image */
    temp = SDL_LoadBMP(file);
    if (temp == NULL) {
        fprintf(stderr, "Couldn't load %s: %s", file, SDL_GetError());
        return NULL;
    }

    /* Set transparent pixel as the pixel at (0,0) */
    if (transparent) {
        if (temp->format->palette) {
            SDL_SetColorKey(temp, SDL_TRUE, *(Uint8 *) temp->pixels);
        } else {
            switch (temp->format->BitsPerPixel) {
            case 15:
                SDL_SetColorKey(temp, SDL_TRUE,
                                (*(Uint16 *) temp->pixels) & 0x00007FFF);
                break;
            case 16:
                SDL_SetColorKey(temp, SDL_TRUE, *(Uint16 *) temp->pixels);
                break;
            case 24:
                SDL_SetColorKey(temp, SDL_TRUE,
                                (*(Uint32 *) temp->pixels) & 0x00FFFFFF);
                break;
            case 32:
                SDL_SetColorKey(temp, SDL_TRUE, *(Uint32 *) temp->pixels);
                break;
            }
        }
    }

    /* Create textures from the image */
    texture = SDL_CreateTextureFromSurface(renderer, temp);
    if (!texture) {
        fprintf(stderr, "Couldn't create texture: %s\n", SDL_GetError());
        SDL_FreeSurface(temp);
        return NULL;
    }
    SDL_FreeSurface(temp);

    /* We're ready to roll. :) */
    return texture;
}

void
DrawComposite(DrawState *s)
{
    SDL_Rect viewport, R;
    SDL_Texture *target;

    static SDL_bool blend_tested = SDL_FALSE;
    if (!blend_tested) {
        SDL_Texture *A, *B;
        Uint32 P;

        A = SDL_CreateTexture(s->renderer, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_TARGET, 1, 1);
        SDL_SetTextureBlendMode(A, SDL_BLENDMODE_BLEND);

        B = SDL_CreateTexture(s->renderer, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_TARGET, 1, 1);
        SDL_SetTextureBlendMode(B, SDL_BLENDMODE_BLEND);

        SDL_SetRenderTarget(s->renderer, A);
        SDL_SetRenderDrawColor(s->renderer, 0x00, 0x00, 0x00, 0x80);
        SDL_RenderFillRect(s->renderer, NULL);

        SDL_SetRenderTarget(s->renderer, B);
        SDL_SetRenderDrawColor(s->renderer, 0x00, 0x00, 0x00, 0x00);
        SDL_RenderFillRect(s->renderer, NULL);
        SDL_RenderCopy(s->renderer, A, NULL, NULL);
        SDL_RenderReadPixels(s->renderer, NULL, SDL_PIXELFORMAT_ARGB8888, &P, sizeof(P));

        printf("Blended pixel: 0x%8.8X\n", P);

        SDL_DestroyTexture(A);
        SDL_DestroyTexture(B);
        blend_tested = SDL_TRUE;
    }

    SDL_RenderGetViewport(s->renderer, &viewport);

    target = SDL_CreateTexture(s->renderer, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_TARGET, viewport.w, viewport.h);
    SDL_SetTextureBlendMode(target, SDL_BLENDMODE_BLEND);
    SDL_SetRenderTarget(s->renderer, target);

    /* Draw the background.
       This is solid black so when the sprite is copied to it, any per-pixel alpha will be blended through.
     */
    SDL_SetRenderDrawColor(s->renderer, 0x00, 0x00, 0x00, 0x00);
    SDL_RenderFillRect(s->renderer, NULL);

    /* Scale and draw the sprite */
    s->sprite_rect.w += s->scale_direction;
    s->sprite_rect.h += s->scale_direction;
    if (s->scale_direction > 0) {
        if (s->sprite_rect.w >= viewport.w || s->sprite_rect.h >= viewport.h) {
            s->scale_direction = -1;
        }
    } else {
        if (s->sprite_rect.w <= 1 || s->sprite_rect.h <= 1) {
            s->scale_direction = 1;
        }
    }
    s->sprite_rect.x = (viewport.w - s->sprite_rect.w) / 2;
    s->sprite_rect.y = (viewport.h - s->sprite_rect.h) / 2;

    SDL_RenderCopy(s->renderer, s->sprite, NULL, &s->sprite_rect);

    SDL_SetRenderTarget(s->renderer, NULL);
    SDL_RenderCopy(s->renderer, s->background, NULL, NULL);

    SDL_SetRenderDrawBlendMode(s->renderer, SDL_BLENDMODE_BLEND);
    SDL_SetRenderDrawColor(s->renderer, 0xff, 0x00, 0x00, 0x80);
    R.x = 0;
    R.y = 0;
    R.w = 100;
    R.h = 100;
    SDL_RenderFillRect(s->renderer, &R);
    SDL_SetRenderDrawBlendMode(s->renderer, SDL_BLENDMODE_NONE);

    SDL_RenderCopy(s->renderer, target, NULL, NULL);
    SDL_DestroyTexture(target);

    /* Update the screen! */
    SDL_RenderPresent(s->renderer);
}

void
Draw(DrawState *s)
{
    SDL_Rect viewport;
    SDL_Texture *target;

    SDL_RenderGetViewport(s->renderer, &viewport);

    target = SDL_CreateTexture(s->renderer, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_TARGET, viewport.w, viewport.h);
    SDL_SetRenderTarget(s->renderer, target);

    /* Draw the background */
    SDL_RenderCopy(s->renderer, s->background, NULL, NULL);

    /* Scale and draw the sprite */
    s->sprite_rect.w += s->scale_direction;
    s->sprite_rect.h += s->scale_direction;
    if (s->scale_direction > 0) {
        if (s->sprite_rect.w >= viewport.w || s->sprite_rect.h >= viewport.h) {
            s->scale_direction = -1;
        }
    } else {
        if (s->sprite_rect.w <= 1 || s->sprite_rect.h <= 1) {
            s->scale_direction = 1;
        }
    }
    s->sprite_rect.x = (viewport.w - s->sprite_rect.w) / 2;
    s->sprite_rect.y = (viewport.h - s->sprite_rect.h) / 2;

    SDL_RenderCopy(s->renderer, s->sprite, NULL, &s->sprite_rect);

    SDL_SetRenderTarget(s->renderer, NULL);
    SDL_RenderCopy(s->renderer, target, NULL, NULL);
    SDL_DestroyTexture(target);

    /* Update the screen! */
    SDL_RenderPresent(s->renderer);
}

int
main(int argc, char *argv[])
{
    DrawState *drawstates;
    int i, done;
    SDL_Event event;
    int frames;
    Uint32 then, now;
    SDL_bool test_composite = 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], "--composite") == 0) {
                test_composite = SDL_TRUE;
                consumed = 1;
            }
        }
        if (consumed < 0) {
            fprintf(stderr,
                    "Usage: %s %s [--composite]\n",
                    argv[0], SDLTest_CommonUsage(state));
            quit(1);
        }
        i += consumed;
    }
    if (!SDLTest_CommonInit(state)) {
        quit(2);
    }

    drawstates = SDL_stack_alloc(DrawState, state->num_windows);
    for (i = 0; i < state->num_windows; ++i) {
        DrawState *drawstate = &drawstates[i];

        drawstate->window = state->windows[i];
        drawstate->renderer = state->renderers[i];
        if (test_composite) {
            drawstate->sprite = LoadTexture(drawstate->renderer, "icon-alpha.bmp", SDL_TRUE);
        } else {
            drawstate->sprite = LoadTexture(drawstate->renderer, "icon.bmp", SDL_TRUE);
        }
        drawstate->background = LoadTexture(drawstate->renderer, "sample.bmp", SDL_FALSE);
        if (!drawstate->sprite || !drawstate->background) {
            quit(2);
        }
        SDL_QueryTexture(drawstate->sprite, NULL, NULL,
                         &drawstate->sprite_rect.w, &drawstate->sprite_rect.h);
        drawstate->scale_direction = 1;
    }

    /* Main render loop */
    frames = 0;
    then = SDL_GetTicks();
    done = 0;
    while (!done) {
        /* Check for events */
        ++frames;
        while (SDL_PollEvent(&event)) {
            SDLTest_CommonEvent(state, &event, &done);
        }
        for (i = 0; i < state->num_windows; ++i) {
            if (test_composite) {
                DrawComposite(&drawstates[i]);
            } else {
                Draw(&drawstates[i]);
            }
        }
    }

    /* 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);
    }

    SDL_stack_free(drawstates);

    quit(0);
    return 0;
}

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