From 658e90f9a8c0c68e0bee5007cf3f654cc95188b6 Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Mon, 23 May 2016 15:29:14 -0700 Subject: [PATCH] mesa: Document reasons for allowing XFB drawing modes in GLES 3.1 w/GL_OES_geometry_shader Originally this patch added the checks to allow the draw calls with XFB, but commit 2dabd497 beat me to it. Signed-off-by: Ian Romanick Reviewed-by: Ilia Mirkin Reviewed-by: Kenneth Graunke --- src/mesa/main/api_validate.c | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) diff --git a/src/mesa/main/api_validate.c b/src/mesa/main/api_validate.c index 384a8858e8b..b35751e4668 100644 --- a/src/mesa/main/api_validate.c +++ b/src/mesa/main/api_validate.c @@ -396,12 +396,30 @@ validate_DrawElements_common(struct gl_context *ctx, const GLvoid *indices, const char *caller) { - /* From the GLES3 specification, section 2.14.2 (Transform Feedback - * Primitive Capture): + /* Section 2.14.2 (Transform Feedback Primitive Capture) of the OpenGL ES + * 3.1 spec says: * * The error INVALID_OPERATION is also generated by DrawElements, * DrawElementsInstanced, and DrawRangeElements while transform feedback * is active and not paused, regardless of mode. + * + * The OES_geometry_shader_spec says: + * + * Issues: + * + * ... + * + * (13) Does this extension change how transform feedback operates + * compared to unextended OpenGL ES 3.0 or 3.1? + * + * RESOLVED: Yes... Since we no longer require being able to predict how + * much geometry will be generated, we also lift the restriction that + * only DrawArray* commands are supported and also support the + * DrawElements* commands for transform feedback. + * + * This should also be reflected in the body of the spec, but that appears + * to have been overlooked. The body of the spec only explicitly allows + * the indirect versions. */ if (_mesa_is_gles3(ctx) && !ctx->Extensions.OES_geometry_shader && _mesa_is_xfb_active_and_unpaused(ctx)) { @@ -730,6 +748,17 @@ valid_draw_indirect(struct gl_context *ctx, * * "An INVALID_OPERATION error is generated if * transform feedback is active and not paused." + * + * The OES_geometry_shader spec says: + * + * On p. 250 in the errors section for the DrawArraysIndirect command, + * and on p. 254 in the errors section for the DrawElementsIndirect + * command, delete the errors which state: + * + * "An INVALID_OPERATION error is generated if transform feedback is + * active and not paused." + * + * (thus allowing transform feedback to work with indirect draw commands). */ if (_mesa_is_gles31(ctx) && !ctx->Extensions.OES_geometry_shader && _mesa_is_xfb_active_and_unpaused(ctx)) { -- 2.30.2