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Small test program showing the behaviors found.

test.cpp (text/plain), 3.89 KB, created by Luiggi Reffatti on 2014-08-25 04:02:21 UTC

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Creator: Luiggi Reffatti

Created: 2014-08-25 04:02:21 UTC

Size: 3.89 KB

patch

obsolete

>/*
> * Testcase for a bug report for SDL2,
> * The bug basically involves SDL_SetRenderTarget and SDL_RenderReadPixels
> *
> *  Created on: 24/08/2014
> *      Author: Luiggi Reffatti
> */
>
>#include <SDL2/SDL.h>
>#include <stdlib.h>
>
>/// In my system setup I need to undef the main macro so that everything works.
>#undef main
>
>int main(int argc, char **argv)
>{
>	/// Pointers to stuff we need
>	SDL_Window* window;
>	SDL_Renderer* renderer;
>
>	/// Initialize everything
>	SDL_Init(SDL_INIT_VIDEO);
>
>	window = SDL_CreateWindow("test", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1024, 768, 0);
>
>	/// With direct3d, its impossible to read pixel data from the texture that is the current
>	///		render target. SDL_RenderReadPixels always returns the pixels that are on screen.
>	SDL_SetHintWithPriority(SDL_HINT_RENDER_DRIVER, "opengl", SDL_HINT_OVERRIDE);
>	/// With opengl SDL_RenderReadPixels returns the pixels from the target correclty, but flipped
>	//		upside down. I don't know if this is expected behavior, but it doen't look for me.
>	//SDL_SetHintWithPriority(SDL_HINT_RENDER_DRIVER, "direct3d", SDL_HINT_OVERRIDE);
>
>	renderer = SDL_CreateRenderer(window, -1, 0);
>
>	SDL_SetRenderDrawColor(renderer, 0xFF, 0x00, 0x00, 0xFF);
>
>	/// Create an image and render to check that it is ok
>	SDL_Surface* surfaceImage;
>	SDL_Texture* textureImage;
>	SDL_Rect rectImage;
>	rectImage.x = 0;	rectImage.y = 0;
>	rectImage.w = 600;	rectImage.h = 768;
>	surfaceImage = SDL_LoadBMP("TestImage.bmp");
>	textureImage = SDL_CreateTextureFromSurface(renderer, surfaceImage);
>
>	SDL_FreeSurface(surfaceImage);
>
>	SDL_RenderClear(renderer);
>	SDL_RenderCopy(renderer, textureImage, NULL, &rectImage);
>	SDL_RenderPresent(renderer);
>	SDL_Delay(2000);
>
>	/// Cleaning the screen. Without this the bug didnt happen
>	SDL_SetRenderDrawColor(renderer, 0x80, 0x80, 0x80, 0xFF);
>	SDL_RenderClear(renderer);
>	SDL_RenderPresent(renderer);
>
>	/// Creating a render target and rendering the image to it:
>	SDL_Texture* textureTarget;
>	SDL_Rect rectTarget;
>	rectTarget.x = 0;	rectTarget.y = 0;
>	rectTarget.w = 768;	rectTarget.h = 768;
>	SDL_DisplayMode mode;
>	SDL_GetCurrentDisplayMode(0, &mode);
>	textureTarget = SDL_CreateTexture(renderer, mode.format,
>			SDL_TEXTUREACCESS_TARGET, rectTarget.w, rectTarget.h);
>
>	SDL_SetRenderTarget(renderer, textureTarget);
>	SDL_SetRenderDrawColor(renderer, 0xFF, 0x00, 0xFF, 0xFF);
>	SDL_RenderClear(renderer);
>	SDL_RenderCopy(renderer, textureImage, NULL, &rectImage);
>
>	SDL_DestroyTexture(textureImage);
>
>	/// testing to see if its ok
>	rectTarget.x += 100;
>	SDL_SetRenderTarget(renderer, NULL);
>	SDL_SetRenderDrawColor(renderer, 0x00, 0xFF, 0x00, 0xFF);
>	SDL_RenderClear(renderer);
>	SDL_RenderCopy(renderer, textureTarget, NULL, &rectTarget);
>	SDL_RenderPresent(renderer);
>	SDL_Delay(2000);
>
>	/// Cleaning the screen. Without this the bug didnt happen
>	SDL_SetRenderDrawColor(renderer, 0x80, 0x80, 0x80, 0xFF);
>	SDL_RenderClear(renderer);
>	SDL_RenderPresent(renderer);
>
>	/// Now for the problematic part
>	SDL_Texture* textureFromPixels;
>	rectTarget.x = 0;
>	int w = rectTarget.w;
>	int h = rectTarget.h;
>	int depth = 32;    /// the depth of the surface in bits
>	int pitch = w * 4; /// the length of a row of pixels in bytes
>	void* pixels = malloc(pitch * h);
>
>	SDL_SetRenderTarget(renderer, textureTarget);
>
>	SDL_RenderReadPixels(renderer, &rectTarget, 0, pixels, pitch);
>
>	SDL_Surface *surfaceFromPixels = SDL_CreateRGBSurfaceFrom(pixels, w, h, depth, pitch, 0,0,0,0);
>
>	textureFromPixels = SDL_CreateTextureFromSurface(renderer, surfaceFromPixels);
>
>	SDL_SetRenderTarget(renderer, NULL);
>	SDL_FreeSurface(surfaceFromPixels);
>	free(pixels);
>	SDL_DestroyTexture(textureTarget);
>
>	/// testing to see if its ok
>	rectTarget.x += 100;
>	SDL_SetRenderDrawColor(renderer, 0x00, 0x00, 0xFF, 0xFF);
>	SDL_RenderClear(renderer);
>	SDL_RenderCopy(renderer, textureFromPixels, NULL, &rectTarget);
>	SDL_RenderPresent(renderer);
>	SDL_Delay(2000);
>
>/// Ignoring cleanup and deallocation, for simplicity
>
>	return 0;
>}

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We are currently migrating Bugzilla to GitHub issues.Any changes made to the bug tracker now will be lost, so please do not post new bugs or make changes to them.When we're done, all bug URLs will redirect to their equivalent location on the new bug tracker.

We are currently migrating Bugzilla to GitHub issues.
Any changes made to the bug tracker now will be lost, so please do not post new bugs or make changes to them.
When we're done, all bug URLs will redirect to their equivalent location on the new bug tracker.