Call SDL_GL_GetDrawableSize() directly because we may be in the initialization path and SDL_GetRendererOutputSize() will fail because the renderer magic isn't set up yet.
ny00
Using the OpenGL ES 1.1 renderer, after updating a texture with SDL_UpdateTexture (or SDL_UnlockTexture), a following call to SDL_RenderFillRect draws a rectangle with the wrong color (which appears to be the same as the texture's top-left pixel).
Comparing SDL_render_gles.c:GLES_UpdateTexture to SDL_render_gl.c:GL_UpdateTexture, a missing call to glDisable appears to be the cause. After adding it back, the bug is resolved.
Simon Hug
The description of the SDL_RenderClear function in the SDL_render.h header says the following:
"This function clears the entire rendering target, ignoring the viewport."
The word "entire" implies that the clipping rectangle set with SDL_RenderSetClipRect also gets ignored. This is left somewhat ambiguous if only the viewport is mentioned. Minor thing, but let's see what the implementations actually do.
The software renderer ignores the clipping rectangle when clearing. It even has a comment on this: /* By definition the clear ignores the clip rect */
Most other render drivers (opengl, opengles, opengles2, direct3d, and psp [I assume. Can't test it.]) use the scissor test for the ClipRect and don't disable it when clearing. Clearing will only happen within the clipping rectangle for these drivers.
An exception is direct3d11 which uses a clear function that ignores the scissor test.
Simon Hug
When updating the viewport in GLES_UpdateViewport, the OpenGL ES renderer doesn't flip the projection matrix for target textures. The lines, rectangles and textures (if drawn with glDrawArrays) are upside down when drawing to target textures.
Simon Hug
The OpenGL ES 2 renderer does not check the target texture format when using SDL_RenderReadPixels and just always uses ABGR8888. This can result in swapped or wrong colors.
The attached patch adds a check and selects the target texture format, if a texture is set as the target.
Simon Hug
All OpenGL renderers always flip the rows of the pixels that come from glReadPixels. This is unnecessary for target textures since these are already top down.
Also, the rect->y value can be used directly for target textures for the same reason. I don't see any code that would handle the logical render size for target textures. Or am I missing something?
The attached patch makes the renderers only the flip rows if the data comes from the default framebuffer.
Simon Hug
The GL_SetBlendMode and GLES_SetBlendMode functions of the opengl and opengles renderers call the glTexEnvf to set the texture env mode to either GL_MODULATE (the default) or GL_REPLACE for the NONE blend mode. Using GL_REPLACE disables color and alpha modulation for textures.
These glTexEnv calls were put in the SetBlendMode function back in 2006 [1], but there the NONE code still used the GL_DECAL mode. The GL_REPLACE mode came in 2008 [2]. I'm a bit confused why that wasn't always GL_MODULATE and a bit surprised nobody reported that yet (unless I missed it). I guess only a few use the gles renderer and the newish shaders mask the issue.
Simon Hug
It seems not everyone implemented glDrawTexfOES the same. Intel and Mesa ignore the viewport entirely, whereas the Raspberry Pi implementation offsets the coordinates and does viewport clipping.
The glDrawTexfOES extension text [1] for the function says "Xs and Ys are given directly in window (viewport) coordinates." I guess this wasn't clear enough.
Alex Szpakowski
Honestly I'd probably remove that codepath from SDL_Render entirely. It's an OpenGL ES 1-specific extension that isn't likely to give huge performance gains and adds additional maintenance overhead to SDL_Render while also having bugs in some drivers (as seen here).
chasesan
When using SDL_RenderCopyEx, I get a problem on some platforms where the output is offset by +/-1 on other platforms and not on others. I tried it with a center of both 0,0 (and offsetting by width/height) and NULL (for centered).
The rotation involved is 90, and/or -90 rotation. The rotation was a constant, no arithmetic was involved when inputting it into SDL_RenderCopyEx.
This occurred with 32x32, 24x24, and 16x16 texture sizes. I apologize that I don't have more precise information, as I received the information as a bug report myself. But I have tracked the problem down to here.
My program requires pixel perfect alignment on several different platforms, so this is something of a showstopper for me.
--
Sylvain
It appears the RenderCopyEx is done as expected,
this is the red rectangle which is not correctly positionned !
So, here's patch with a 0.5 float increment, like for opengles2, for DrawLines, and also Draw Points.
This fixes an issue where an empty cliprect is treated the same as a NULL
cliprect, causing the render backends to disable clipping.
Also adds a new API, SDL_RenderIsClipEnabled(render) that allows you to
differentiate between:
- SDL_RenderSetClipRect(render, NULL)
- SDL_Rect r = {0,0,0,0}; SDL_RenderSetClipRect(render, &r);
Fixes https://bugzilla.libsdl.org/show_bug.cgi?id=2504
--HG--
extra : amend_source : 9e5ac76e3f009d9ae49bc61c350df3ba891267b5
extra : histedit_source : b92b8be4d05b19a89fa0dee57f7ed6b1e924cb99%2Cce419f6ade87bafc78ff42702c1f263d2469e7e7
If the window has been created with values for SDL_GL_CONTEXT_PROFILE_MASK,
SDL_GL_CONTEXT_MAJOR_VERSION and SDL_GL_CONTEXT_MINOR_VERSION not matching those
required by the renderer, attempt to recreate the window.
This is needed on platforms where both GL and GLES 1/2 surfaces are supported
by the video backend, requiring that the window be recreated when switching
between context types.
Andreas Ertelt
The problem in question is caused by changeset 7771 (http://hg.libsdl.org/SDL/rev/4434498bf4b9 / https://bugzilla.libsdl.org/show_bug.cgi?id=2121)
The redefinition of __inline__ (introduced by the addition of begin_code.h:128's "|| __STRICT_ANSI__") results in mingw's gcc throwing multiple
warning: always_inline function might not be inlinable [-Wattributes]
as well as a whole bunch of redefinitions of mingw internals which break linking of projects including the SDL2 headers.
PoopiSan
GLES2_RenderReadPixels, GLES_RenderReadPixels, GL_RenderReadPixels and possibly other backends is incorrectly implemented.
If the current target viewport is different than window size the function is reading garbage and according to the function documentation should work with any rendering target "Read pixels from the current rendering target.".
this seems to be caused by this line:
...
SDL_GetWindowSize(window, &w, &h);
Martin Gerhardy
the coordinate system from sdl is not correctly transformed to the coordinate system of opengl. glScissor expects them to be a little bit different. Attached is a patch that fixes this
This lets us change things like this...
if (Failed) {
SDL_SetError("We failed");
return -1;
}
...into this...
if (Failed) {
return SDL_SetError("We failed");
}
Fixes Bugzilla #1778.
