diff options
| author | Brian Paul <brianp@vmware.com> | 2011-10-20 15:13:17 -0600 |
|---|---|---|
| committer | Brian Paul <brianp@vmware.com> | 2011-10-20 15:13:17 -0600 |
| commit | c60eb632b7884fb00ba4d3ec460f070e0214d1b8 (patch) | |
| tree | c6ae70e14c404375807eb0bcdd88bdaac8720ba2 /docs/viewperf.html | |
| parent | 31874f074c2eaf2a9421c57f0798c79078d296c4 (diff) | |
docs: document known issues with Viewperf 11
Diffstat (limited to 'docs/viewperf.html')
| -rw-r--r-- | docs/viewperf.html | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/docs/viewperf.html b/docs/viewperf.html new file mode 100644 index 00000000000..cef584fd87f --- /dev/null +++ b/docs/viewperf.html @@ -0,0 +1,134 @@ +<HTML> + +<TITLE>Viewperf Issues</TITLE> + +<link rel="stylesheet" type="text/css" href="mesa.css"></head> + +<BODY> + +<h1>Viewperf Issues</h1> + +<p> +This page lists known issues with +<a href="http://www.spec.org/gwpg/gpc.static/vp11info.html" target="_main">SPEC Viewperf 11</a> +when running on Mesa-based drivers. +</p> + +<p> +The Viewperf data sets are basically GL API traces that are recorded from +CAD applications, then replayed in the Viewperf framework. +</p> + +<p> +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. +</p> + +<p> +These issues have been reported to the SPEC organization in the hope that +they'll be fixed in the future. +</p> + + + +<h2>Catia-03 tests 3, 4, 8</h2> + +<p> +These tests use features of the +<a href="http://www.opengl.org/registry/specs/NV/fragment_program2.txt" +target="_main"> +GL_NV_fragment_program2</a> and +<a href="http://www.opengl.org/registry/specs/NV/vertex_program3.txt" +target="_main"> +GL_NV_vertex_program3</a> extensions without checking if the driver supports +them. +</p> +<p> +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. +</p> + + + +<h2>sw-02 tests 1, 2, 4</h2> + +<p> +These tests depend on the +<a href="http://www.opengl.org/registry/specs/NV/primitive_restart.txt" +target="_main">GL_NV_primitive_restart</a> extension. +</p> + +<p> +If the Mesa driver doesn't support this extension the rendering will +be incorrect and the test will fail. +</p> + + +<h2>Lightwave-01 test 3</h2> + +<p> +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. +</p> + +<p> +A trace captured with +<a href="https://github.com/apitrace/apitrace" target="_main">API trace</a> +shows this sequences of calls like this: + +<pre> +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) +</pre> + +<p> +Note that one would expect call 2514 to be glTexImage(level=9, width=1, +height=1) but it's not there. +</p> + +<p> +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. +</p> + +<p> +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. +</p> + +<p> +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 <em>much</em> +brighter than NVIDIA's). +</p> + +<p> +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. + +</p> + + +</BODY> +</HTML> |