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Implemented RenderReadPixels for the OpenGL ES 2.0 renderer.

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slouken committed Oct 31, 2011
1 parent 074180c commit ff4302b26e2cda6031201aae0498416bbc4206f9
Showing with 54 additions and 0 deletions.
  1. +54 −0 src/render/opengles2/SDL_render_gles2.c
@@ -786,6 +786,8 @@ static int GLES2_RenderDrawLines(SDL_Renderer *renderer, const SDL_Point *points
static int GLES2_RenderFillRects(SDL_Renderer *renderer, const SDL_Rect *rects, int count);
static int GLES2_RenderCopy(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_Rect *srcrect,
const SDL_Rect *dstrect);
static int GLES2_RenderReadPixels(SDL_Renderer * renderer, const SDL_Rect * rect,
Uint32 pixel_format, void * pixels, int pitch);
static void GLES2_RenderPresent(SDL_Renderer *renderer);


@@ -1047,6 +1049,57 @@ GLES2_RenderCopy(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_Rect *s
return 0;
}

static int
GLES2_RenderReadPixels(SDL_Renderer * renderer, const SDL_Rect * rect,
Uint32 pixel_format, void * pixels, int pitch)
{
SDL_Window *window = renderer->window;
Uint32 temp_format = SDL_PIXELFORMAT_ABGR8888;
void *temp_pixels;
int temp_pitch;
Uint8 *src, *dst, *tmp;
int w, h, length, rows;
int status;

GLES2_ActivateRenderer(renderer);

temp_pitch = rect->w * SDL_BYTESPERPIXEL(temp_format);
temp_pixels = SDL_malloc(rect->h * temp_pitch);
if (!temp_pixels) {
SDL_OutOfMemory();
return -1;
}

SDL_GetWindowSize(window, &w, &h);

glPixelStorei(GL_PACK_ALIGNMENT, 1);

glReadPixels(rect->x, (h-rect->y)-rect->h, rect->w, rect->h,
GL_RGBA, GL_UNSIGNED_BYTE, temp_pixels);

/* Flip the rows to be top-down */
length = rect->w * SDL_BYTESPERPIXEL(temp_format);
src = (Uint8*)temp_pixels + (rect->h-1)*temp_pitch;
dst = (Uint8*)temp_pixels;
tmp = SDL_stack_alloc(Uint8, length);
rows = rect->h / 2;
while (rows--) {
SDL_memcpy(tmp, dst, length);
SDL_memcpy(dst, src, length);
SDL_memcpy(src, tmp, length);
dst += temp_pitch;
src -= temp_pitch;
}
SDL_stack_free(tmp);

status = SDL_ConvertPixels(rect->w, rect->h,
temp_format, temp_pixels, temp_pitch,
pixel_format, pixels, pitch);
SDL_free(temp_pixels);

return status;
}

static void
GLES2_RenderPresent(SDL_Renderer *renderer)
{
@@ -1176,6 +1229,7 @@ GLES2_CreateRenderer(SDL_Window *window, Uint32 flags)
renderer->RenderDrawLines = &GLES2_RenderDrawLines;
renderer->RenderFillRects = &GLES2_RenderFillRects;
renderer->RenderCopy = &GLES2_RenderCopy;
renderer->RenderReadPixels = &GLES2_RenderReadPixels;
renderer->RenderPresent = &GLES2_RenderPresent;
renderer->DestroyTexture = &GLES2_DestroyTexture;
renderer->DestroyRenderer = &GLES2_DestroyRenderer;

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