From 7700ac3d80ae70d00e3cca52b6ea3d00122c7893 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Marek=20Ol=C5=A1=C3=A1k?= Date: Tue, 3 Mar 2020 15:08:09 -0500 Subject: [PATCH] mesa: optimize get_index_size Reviewed-by: Ian Romanick Part-of: --- src/mesa/main/draw.c | 25 +++++++++---------------- 1 file changed, 9 insertions(+), 16 deletions(-) diff --git a/src/mesa/main/draw.c b/src/mesa/main/draw.c index b39d200c098..99a5afebd27 100644 --- a/src/mesa/main/draw.c +++ b/src/mesa/main/draw.c @@ -107,22 +107,15 @@ check_array_data(struct gl_context *ctx, struct gl_vertex_array_object *vao, static inline void get_index_size(GLenum type, struct _mesa_index_buffer *ib) { - switch (type) { - case GL_UNSIGNED_INT: - ib->index_size_shift = 2; - break; - case GL_UNSIGNED_SHORT: - ib->index_size_shift = 1; - break; - case GL_UNSIGNED_BYTE: - ib->index_size_shift = 0; - break; - default: - assert(!"unsupported index data type"); - /* In case assert is turned off */ - ib->index_size_shift = 0; - break; - } + /* The type is already validated, so use a fast conversion. + * + * GL_UNSIGNED_BYTE - GL_UNSIGNED_BYTE = 0 + * GL_UNSIGNED_SHORT - GL_UNSIGNED_BYTE = 2 + * GL_UNSIGNED_INT - GL_UNSIGNED_BYTE = 4 + * + * Divide by 2 to get 0,1,2. + */ + ib->index_size_shift = (type - GL_UNSIGNED_BYTE) >> 1; } /** -- 2.30.2