From 5b61cb12366f65a5d7e21b47fa3501a03fd884ee Mon Sep 17 00:00:00 2001 From: Martin Peres Date: Tue, 26 May 2015 15:32:21 +0300 Subject: [PATCH] glsl: fix constructing a vector from a matrix MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Without this patch, the following constructs (not an extensive list) would crash mesa: - mat2 foo = mat2(1); vec4 bar = vec4(foo); - mat3 foo = mat3(1); vec4 bar = vec4(foo); - mat3 foo = mat3(1); ivec4 bar = ivec4(foo); The first case is explicitely allowed by the GLSL spec, as seen on page 101 of the GLSL 4.40 spec: "vec4(mat2) // the vec4 is column 0 followed by column 1" The other cases are implicitely allowed also. The actual changes are quite minimal. We first split each column of the matrix to a list of vectors and then use them to initialize the vector. An additional check to make sure that we are not trying to copy 0 elements of a vector fix the (i)vec4(mat3) case as the last vector (3rd column) is not needed at all. Reviewed-by: Tapani Pälli Signed-off-by: Martin Peres --- src/glsl/ast_function.cpp | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/src/glsl/ast_function.cpp b/src/glsl/ast_function.cpp index 1e77124bd15..92e26bf2416 100644 --- a/src/glsl/ast_function.cpp +++ b/src/glsl/ast_function.cpp @@ -993,11 +993,15 @@ emit_inline_vector_constructor(const glsl_type *type, ir_variable *var = new(ctx) ir_variable(type, "vec_ctor", ir_var_temporary); instructions->push_tail(var); - /* There are two kinds of vector constructors. + /* There are three kinds of vector constructors. * * - Construct a vector from a single scalar by replicating that scalar to * all components of the vector. * + * - Construct a vector from at least a matrix. This case should already + * have been taken care of in ast_function_expression::hir by breaking + * down the matrix into a series of column vectors. + * * - Construct a vector from an arbirary combination of vectors and * scalars. The components of the constructor parameters are assigned * to the vector in order until the vector is full. @@ -1091,6 +1095,14 @@ emit_inline_vector_constructor(const glsl_type *type, rhs_components = lhs_components - base_component; } + /* If we do not have any components left to copy, break out of the + * loop. This can happen when initializing a vec4 with a mat3 as the + * mat3 would have been broken into a series of column vectors. + */ + if (rhs_components == 0) { + break; + } + const ir_constant *const c = param->as_constant(); if (c == NULL) { /* Mask of fields to be written in the assignment. @@ -1681,11 +1693,11 @@ ast_function_expression::hir(exec_list *instructions, return ir_rvalue::error_value(ctx); } - /* Later, we cast each parameter to the same base type as the - * constructor. Since there are no non-floating point matrices, we - * need to break them up into a series of column vectors. + /* Matrices can never be consumed as is by any constructor but matrix + * constructors. If the constructor type is not matrix, always break the + * matrix up into a series of column vectors. */ - if (constructor_type->base_type != GLSL_TYPE_FLOAT) { + if (!constructor_type->is_matrix()) { foreach_in_list_safe(ir_rvalue, matrix, &actual_parameters) { if (!matrix->type->is_matrix()) continue; -- 2.30.2