+This page lists known issues with +SPEC Viewperf 11 +when running on Mesa-based drivers. +
+ ++The Viewperf data sets are basically GL API traces that are recorded from +CAD applications, then replayed in the Viewperf framework. +
+ ++The primary problem with these traces is they blindly use features and +OpenGL extensions that were supported by the OpenGL driver when the trace +was recorded, +but there's no checks to see if those features are supported by the driver +when playing back the traces with Viewperf. +
+ ++These issues have been reported to the SPEC organization in the hope that +they'll be fixed in the future. +
+ + + ++These tests use features of the + +GL_NV_fragment_program2 and + +GL_NV_vertex_program3 extensions without checking if the driver supports +them. +
++When Mesa tries to compile the vertex/fragment programs it generates errors +(which Viewperf ignores). +Subsequent drawing calls become no-ops and the rendering is incorrect. +
+ + + ++These tests depend on the +GL_NV_primitive_restart extension. +
+ ++If the Mesa driver doesn't support this extension the rendering will +be incorrect and the test will fail. +
+ + ++This test uses a number of mipmapped textures, but the textures are +incomplete because the last/smallest mipmap level (1 x 1 pixel) is +never specified. +
+ ++A trace captured with +API trace +shows this sequences of calls like this: + +
+2504 glBindTexture(target = GL_TEXTURE_2D, texture = 55) +2505 glTexImage2D(target = GL_TEXTURE_2D, level = 0, internalformat = GL_RGBA, width = 512, height = 512, border = 0, format = GL_RGB, type = GL_UNSIGNED_SHORT, pixels = blob(1572864)) +2506 glTexImage2D(target = GL_TEXTURE_2D, level = 1, internalformat = GL_RGBA, width = 256, height = 256, border = 0, format = GL_RGB, type = GL_UNSIGNED_SHORT, pixels = blob(393216)) +2507 glTexImage2D(target = GL_TEXTURE_2D, level = 2, internalformat = GL_RGBA, width = 128, height = 128, border = 0, format = GL_RGB, type = GL_UNSIGNED_SHORT, pixels = blob(98304)) +[...] +2512 glTexImage2D(target = GL_TEXTURE_2D, level = 7, internalformat = GL_RGBA, width = 4, height = 4, border = 0, format = GL_RGB, type = GL_UNSIGNED_SHORT, pixels = blob(96)) +2513 glTexImage2D(target = GL_TEXTURE_2D, level = 8, internalformat = GL_RGBA, width = 2, height = 2, border = 0, format = GL_RGB, type = GL_UNSIGNED_SHORT, pixels = blob(24)) +2514 glTexParameteri(target = GL_TEXTURE_2D, pname = GL_TEXTURE_MIN_FILTER, param = GL_LINEAR_MIPMAP_LINEAR) +2515 glTexParameteri(target = GL_TEXTURE_2D, pname = GL_TEXTURE_WRAP_S, param = GL_REPEAT) +2516 glTexParameteri(target = GL_TEXTURE_2D, pname = GL_TEXTURE_WRAP_T, param = GL_REPEAT) +2517 glTexParameteri(target = GL_TEXTURE_2D, pname = GL_TEXTURE_MAG_FILTER, param = GL_NEAREST) ++ +
+Note that one would expect call 2514 to be glTexImage(level=9, width=1, +height=1) but it's not there. +
+ ++The minification filter is GL_LINEAR_MIPMAP_LINEAR and the texture's +GL_TEXTURE_MAX_LEVEL is 1000 (the default) so a full mipmap is expected. +
+ ++Later, these incomplete textures are bound before drawing calls. +According to the GL specification, if a fragment program or fragment shader +is being used, the sampler should return (0,0,0,1) ("black") when sampling +from an incomplete texture. +This is what Mesa does and the resulting rendering is darker than it should +be. +
+ ++It appears that NVIDIA's driver (and possibly AMD's driver) detects this case +and returns (1,1,1,1) (white) which causes the rendering to appear brighter +and match the reference image (however, AMD's rendering is much +brighter than NVIDIA's). +
+ ++If the fallback texture created in _mesa_get_fallback_texture() is +initialized to be full white instead of full black the rendering appears +correct. +However, we have no plans to implement this work-around in Mesa. + +
+ + + +