ir_constant_expression: Add support for matrix multiplication.

Also handles matrix/vector and vector/matrix multiplication.

Fixes piglit tests const-matrix-multiply-01.frag,
const-matrix-multiply-02.frag, and const-vec-mat.frag.

diff --git a/src/glsl/ir_constant_expression.cpp b/src/glsl/ir_constant_expression.cpp
index e039504d4e42d431c94d9e0f4229c73035efb25a..d05aa104f8dab8dd438bbe344567534705759466 100644 (file)
--- a/src/glsl/ir_constant_expression.cpp
+++ b/src/glsl/ir_constant_expression.cpp
@@ -362,6 +362,7 @@ ir_constant_visitor::visit(ir_expression *ir)
 
       break;
    case ir_binop_mul:
+      /* Check for equal types, or unequal types involving scalars */
       if ((op[0]->type == op[1]->type && !op[0]->type->is_matrix())
          || op0_scalar || op1_scalar) {
         for (unsigned c = 0, c0 = 0, c1 = 0;
@@ -382,9 +383,30 @@ ir_constant_visitor::visit(ir_expression *ir)
               assert(0);
            }
         }
-      } else
-        /* FINISHME: Support vector/matrix and matrix multiplication. */
-        return;
+      } else {
+        assert(op[0]->type->is_matrix() || op[1]->type->is_matrix());
+
+        /* Multiply an N-by-M matrix with an M-by-P matrix.  Since either
+         * matrix can be a GLSL vector, either N or P can be 1.
+         *
+         * For vec*mat, the vector is treated as a row vector.  This
+         * means the vector is a 1-row x M-column matrix.
+         *
+         * For mat*vec, the vector is treated as a column vector.  Since
+         * matrix_columns is 1 for vectors, this just works.
+         */
+        const unsigned n = op[0]->type->is_vector()
+           ? 1 : op[0]->type->vector_elements;
+        const unsigned m = op[1]->type->vector_elements;
+        const unsigned p = op[1]->type->matrix_columns;
+        for (unsigned j = 0; j < p; j++) {
+           for (unsigned i = 0; i < n; i++) {
+              for (unsigned k = 0; k < m; k++) {
+                 data.f[i+n*j] += op[0]->value.f[i+n*k]*op[1]->value.f[k+m*j];
+              }
+           }
+        }
+      }
 
       break;
    case ir_binop_div: