Implementation of render targets, by Mason Wheeler and Gabriel Jacobo

Thanks guys!

test/testrendertarget.c

@@ -0,0 +1,204 @@
+/*
+  Copyright (C) 1997-2011 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.h"
+#include "common.h"
+
+#define WINDOW_WIDTH    640
+#define WINDOW_HEIGHT   480
+
+static 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)
+{
+    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
+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_SetTargetTexture(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_SetTargetTexture(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;
+
+    /* 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) {
+            fprintf(stderr, "Usage: %s %s\n", argv[0], CommonUsage(state));
+            return 1;
+        }
+        i += consumed;
+    }
+    if (!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];
+        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)) {
+            CommonEvent(state, &event, &done);
+        }
+        for (i = 0; i < state->num_windows; ++i) {
+            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;
+}
+
+/* vi: set ts=4 sw=4 expandtab: */