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Submitted by pop..@..isk.fr

Assigned to mes..@..op.org

Link to original bug (#108853)

Description

When installing OSMesa using

./configure --prefix=$install_dir
--enable-opengl --disable-gles1 --disable-gles2
--disable-va --disable-xvmc --disable-vdpau
--enable-shared-glapi
--disable-texture-float
--with-gallium-drivers=swrast
--disable-dri --with-dri-drivers=
--disable-egl --with-platforms= --disable-gbm
--enable-glx --with-platforms=x11
--disable-osmesa --enable-gallium-osmesa

i.e. using the gallium osmesa implementation, the depth buffer returned by OSMesaGetDepthBuffer is flipped vertically relative to the OSMesa framebuffer.

Using the non-gallium osmesa implementation returns a depth buffer correctly aligned with the framebuffer.

The gallium-returned depth buffer can be fixed using something like:

fbdepth_t * framebuffer_depth (framebuffer * p) { unsigned int * depth; GLint width, height, bytesPerValue; OSMesaGetDepthBuffer (p->ctx, &width, &height, &bytesPerValue, (void **)&depth); assert (p->width == width && p->height == height && bytesPerValue == 4); assert (sizeof(fbdepth_t) == bytesPerValue); #if GALLIUM // fix for bug in gallium/libosmesa // the depth buffer is flipped vertically for (GLint j = 0; j < height/2; j++) for (GLint i = 0; i < width; i++) { unsigned int tmp = depth[jwidth + i]; depth[jwidth + i] = depth[(height - 1 - j)*width + i]; depth[(height - 1 - j)*width + i] = tmp; } #endif // GALLIUM return depth; }

Version: 18.2