From 10ccd3450d484de96060d85ec5cbf34d1fd19e4a Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Wed, 29 May 2013 08:07:01 -0700 Subject: [PATCH] mesa: Add a helper function for determining the restart index. The derived state approach currently used (_RestartIndex) doesn't work: in the GL_PRIMITIVE_RESTART_FIXED_INDEX case, the restart index depends on the index buffer's data type, and that isn't known until draw time. The existing code also fails to obey the GL 4.3 rules which say that FIXED_INDEX takes precedence over normal primitive restart. This helper function correctly determines the restart index, and will replace the derived state. NOTE: This is a candidate for the 9.1 branch. Signed-off-by: Kenneth Graunke Reviewed-by: Eric Anholt Reviewed-by: Ian Romanick (cherry picked from commit 959d076b30fce8aa9f09c68e5fe885e98c55aaa5) --- src/mesa/main/varray.c | 24 ++++++++++++++++++++++++ src/mesa/main/varray.h | 2 ++ 2 files changed, 26 insertions(+) diff --git a/src/mesa/main/varray.c b/src/mesa/main/varray.c index 213b845c9ca..059bd0b7114 100644 --- a/src/mesa/main/varray.c +++ b/src/mesa/main/varray.c @@ -1153,6 +1153,30 @@ _mesa_VertexAttribDivisor(GLuint index, GLuint divisor) } +unsigned +_mesa_primitive_restart_index(const struct gl_context *ctx, GLenum ib_type) +{ + /* From the OpenGL 4.3 core specification, page 302: + * "If both PRIMITIVE_RESTART and PRIMITIVE_RESTART_FIXED_INDEX are + * enabled, the index value determined by PRIMITIVE_RESTART_FIXED_INDEX + * is used." + */ + if (ctx->Array.PrimitiveRestartFixedIndex) { + switch (ib_type) { + case GL_UNSIGNED_BYTE: + return 0xff; + case GL_UNSIGNED_SHORT: + return 0xffff; + case GL_UNSIGNED_INT: + return 0xffffffff; + default: + assert(!"_mesa_primitive_restart_index: Invalid index buffer type."); + } + } + + return ctx->Array.RestartIndex; +} + /** * Copy one client vertex array to another. diff --git a/src/mesa/main/varray.h b/src/mesa/main/varray.h index 904fa1bea8f..46e9dc49568 100644 --- a/src/mesa/main/varray.h +++ b/src/mesa/main/varray.h @@ -248,6 +248,8 @@ _mesa_PrimitiveRestartIndex(GLuint index); extern void GLAPIENTRY _mesa_VertexAttribDivisor(GLuint index, GLuint divisor); +extern unsigned +_mesa_primitive_restart_index(const struct gl_context *ctx, GLenum ib_type); extern void _mesa_copy_client_array(struct gl_context *ctx,